Geotechnical 101 Webinar Series
1. It's Not Dirt, It's Soil!
Get your notepad ready because Pivvot is taking you back to school. Joining Terracon means we have new coworkers to not only brag about, but learn from, and because our parents taught us sharing is caring, we’re inviting you to join the fun!
Our Geotechnical 101 Series begins with industry leaders, Ryan Feist and Levi Denton. Ryan is our National Director of Geotechnical Services, overseeing the quality, growth, and development of over 550 Geotechnical Engineers and Levi leads the quality, safety, and operations of the largest drilling fleet in the country.
Ryan and Levi will walk you through their roles during the geotechnical phase of the project lifecycle. Learn how these subject matter experts evaluate subsurface conditions, characterize a site, and provide engineering recommendations and consultation services in order to align design elements and site mitigation techniques to the owner’s needs and risk tolerances. Also, learn how Pivvot’s solution can be utilized to save time and budget during the site selection process, determine the slope of the terrain, depth of bedrock, and other geological factors that are useful for geotechnical experts to be aware of.
Webinar Main Topics:
- Geotechnical Engineering and the Project Lifecycle
- Site Characterization
- Typical field and laboratory testing
- How subsurface conditions impact your projects
This first webinar will set the foundation (pun intended;) for part two, “Solar Site Characterization and Engineering” where we’ll have Tamara Hashimoto, P.E., walk you through what every geotechnical engineer wishes you knew during solar site selection. How does the depth of bedrock, soft clays, and other factors impact project site configurations, schedules, and budgets.
Jessica Turner - Speaker 2 (00:00:57):
Welcome everyone. Thanks for, we will go ahead and get started are in the right place. Both also sit back and enjoy the music. Get started here. All right. Welcome the webinar we are hop on and make sure they're all set up.
All right. So we are going to go ahead and get started. I am Jessica Turner and I am just here to kick us off and hand it over to some of our awesome guest speakers that we have today. Just a quick couple of things that we need to go over before we jump in all attendees have been muted. However, there is a Q and a feature that you can use, and you can use that throughout. However, just note we'll, we'll try to keep track of it. And, and there may some responses that are happening in there, but we will have about five to 10 minutes at the end, as we're wrapping up to go through those Q and as in more detail, there is a recording that we will send out to all registered attendees and it will be available on our website as well. And then if you are here and you are hoping to receive AIA credits for this presentation, we will be kind of tracking who's coming in and out. And then at the end of the AIA portion, we will actually give you a link so that you can just give us your name and your AIA number and let us know if you actually want a certificate or not. And we'll provide that at the end.
So, with Terracon, we always like to start every meeting with a safety moment. And today is that it would be good timing to talk about mosquitoes. And as the temperatures are kind of hitting their peak here in north America, and we're working outside more and playing outside, and it just enjoying where we, we are living and working insect safety is a topic that is often forgotten. So besides the annoyance of basic insects by insect bites, it's also important to think about the diseases that are transmitted, transmitted by mosquitoes in particular. So obviously they've got a wide range of viruses, including Zika, dengue fever, and west Nile virus. So just make sure that you're kind of keeping that front of mind as you're outside hanging out and enjoying the weather.
All right, this is our first of our series that we're, we're starting here. So we've got the geotechnical 1 0 1 series that is this AIA credits, and that is the basics of what a geotechnical engineer does. And we really like to highlight that it's not dirt it's soil. The next one in our series is actually the solar site, characterization and engineering. So we've got Jimmy Jackson, one of our solar SMEs that will be leading us through that. And then we've got the geotechnical perspective for electric transmission routing as well. When we wrap up that Geotech 1 0 1, we'll head over to environmental 1 0 1 and kick that off a little later in the fall.
All right. So the project life cycle, we wanted to just give you a high level overview of this before we, we took a dive into the geotechnical pieces of that. So this is a client centered approach to how we work at Terracon and, and now pivot. So you can see here, we've got flex site design and mitigation, then construction, and then managing your assets. So in today's presentation, we have some awesome speakers that will be going through the design and mitigate side, and that's the geotechnical services, but they'll also hit on how you can get information a lot earlier in that project life cycle process, to make sure that you're, you're making the most out of that project process.
So this is, is the portion that we're heading into the, the a I a credits. We are registered provider, and here's all the, the information we need to provide on this. This is the SGC 0 0 1 presentation. And you are really lucky because we have some awesome, awesome speakers that have joined us. And we're very, very thankful that they are here today. We maybe had to put a couple of our, our pivot employees. Next paycheck rep is collateral to try and get these folks in here. They are just awesome. So we did manage to convince them to come on. They are famous and not to boast, but we've even got one. I'm not going to tell you which one that has a street named after him and his family in Ohio. So we've got Ryan Feist, who is our national director of geotechnical services. So he oversees the quality, the growth and the development of over 700 geotechnical engineers throughout the country, an organization. And then we have Levi who is our national director of the geotechnical site characterization. So he oversees the quality safety and the operations of one of the countries, or actually the country's largest drilling fleet. So now I'm going to hand it over to Ryan and he's going to go through our learning objectives,
Ryan Fiest - Speaker 3 (00:10:13):
Jessica you're too kind. Thank you for the introduction. Yes. The, the purpose of, of this presentation, some of those learning objectives behind it is just a, a general overview of what is geotechnical engineering. We will spend some time going through different collection methods on site characterization. How do we collect those soil and bedrock samples out in the field? And then how do we analyze those for different soil, characteristics and properties? And then we'll get a little bit into what some of that engineering analysis and consulting looks like in a traditional geotechnical engineering report.
So what, what is geotechnical engineering? And I must say when, when I'm out and about, and people ask me, oh, what do you do for a living? I, they usually start with civil engineering. Why? Because when you say geotechnical engineering, a lot of people don't know what that is. And if they start probing a little bit, then, then perhaps I'll, I'll tell them, I'm a geotechnical engineer, but the fundamental of it, the foundation pun intended is that geotechnical engineers interface between the earth, the soil and the bedrock and structures, and that the structures can be pavements, retaining walls, buildings, solar, arrays, whatever we're putting on top of it. How does, how do those structures interact with the soil they're, they're resting on?
Right? So this is all relative. Tell you a little bit of a story. As we get started, my parents have a greenhouse and I say, I grew up in a greenhouse that's. That was my first job as oh, mid teenager. And I recall when I was working at the greenhouse, I was filling pots with what I thought was dirt. And at the end of end of the shift, I went up to the grower and I was like, Hey, I I've got some extra dirt. What, what would you like me to do with it? And this person just shook their head and said, Ryan, it's not dirt. This is soil. Dirt is the stuff that you see outside you plant in soil. It's like, got it. So next five years, I was working with soil in the greenhouse fast forward. I'm now in college and I'm in my soil's lab.
And we're, we're doing a Proctor, which is one of the lab tests to see what the density moisture relationship is and get done with the test, working in my group. And I go up to my professor who eventually ended up being my graduate advisor. I said, Dr. Bowers, we're finished with the test. What should we do at the extra dirt? He just shook his head. Didn't say anything until the end of the class. And he says, some of you may call this dirt, but I will tell you, dirt is what you plant in. This is soil where we have engineering properties of it. So, the point of the story is it's all relative and its soil to different people. It's important to different organizations.
So, for this presentation, we're going to talk more about those soil properties. How do we think of it? Like steel that I beam, we know what the properties are. We have specific manufacturing, qualities and procedures to get the, the right tensile strength of that steel. Well, soil's got a lot of different components to it and it acts differently depending on what the ratios of those different soil types are within it. So it's our job to figure out what the properties are of that particular soil and how that will impact whatever structure we're putting on top of it. So, with that, I think we're going to switch over to Levi and he's going to walk us through the site characterization. What are some of the, the equipment that we use to collect the, the soil and bedrock samples? And then what type of tests do we do to identify what those engineering of the soil are? Levi.
Levi Denton - Speaker 4 (00:14:55):
Thanks, Ryan. Can you give me an audio check?
Ryan Fiest - Speaker 3 (00:15:01):
You got it.
Levi Denton - Speaker 4 (00:15:03):
Okay. Thanks. You're seeing the drill R here.
Ryan Fiest - Speaker 3 (00:15:05):
Levi Denton - Speaker 4 (00:15:06):
All right. Great. Thanks. Thanks Ryan. Like Ryan was saying, we're going to get into now, you know, how do we go out and, and, and grab those soul samples and evaluate it. And, you know, as, as Ryan indicated, you know, we don't have a, we don't have a manual for that. So we can't grab a book and figure out what the, you know, what the compressive strength or the you don't stress, or that is. So, we have to actually go out and get these, collect these samples and, and bring them back and test them and look at them, touch them stress them to their limits so we can, so we can learn about them. And so, the first thing is geotechnical engineers, we have to do is actually go out and, and, and meet it and meet it where it's at. And that's in the field where you're going to be doing the, doing the projects.
And so when we talk about doing geo site characterization, a lot of the first thing people think about is, is a drill rig or soul sampling, some type of soul sampling apparatus. And so that's kind of what you're seeing here. And that's, that's primarily what we might, might engage you out there and do something like that. But there's also, there's lots of other ways you can do it too. And I just thought, you know, and, and we'll probably focus on drill rigs and those more typical ways, but I just wanted to point out that there's, there's lots of things you can do to go characterize a site. You know, first off you can go, just visit a site. You can look around, you can look at, you can look at natural rock cuts, you can see what's going on out there, how things are behaving, natural, you know, just natural features of the land.
So there's a lot to gain just by going out and taking a look when you're exploring. So from a site visit, there's also you standard penetration test boards, which you'll talk in more detail about kinda like from like this machine you're looking at here, drill rig. We can go out and do test pits with like excavators or backhoes. We can do geophysics types of explorations. We can look at groundwater monitoring, well, data, install, Wells, and then we can also do more, more advanced testing, what we call tests or like comp penetration, testing, some other, some other methods like that. That we'll talk more about in terms of going out with exploratory equipment. There's lots of different kinds of, of equipment. So the, the first, the first one you saw on that previous screen was a, was a track manager rig, but there's also numerous types of exploratory rigs.
And one of the things you got to think about when you're going out are the conditions you're going to be encountering, and that'll dictate to a large extent what type of drilling rig, for instance, you might take out there. And, and then also it depends on what kind of test you're going to be trying to do, whether you're going to be doing some AER drilling or with some rotary work or pouring, or whether you're going to be trying to push a cone or, or some other type of device. And so there's, there's lots of different options. There's these track mounted pieces of equipment, truck mounted. So if you're a, you know, smooth, flat pavement type services, a truck might work well, but if you're in a, a more rugged landscape, something like an ATV or a track might work might work better. So depending on what you're, what you're going to encounter, you know, we'd select the different type of piece of equipment.
And then with those different pieces of equipment, we can do different, different kinds of tests. And so, and, and this by far isn't is an exhaustive list, but you can do standard penetration test. That's a pretty basic test com penetration test Delto modules, testing pressure, meter testing, ban testing. And we're going to talk about, we're going to mainly focus on S PT and CCPT today. Cause that's probably the most common and these tests have been some have been around for quite a long time and, and others were developed later, but you can see you, the S PT is by far been around the longest. Probably the only thing that's been around longer than that is a test bit.
The next thing up would've been the vein shear. And then, and then C P T and then pressure meter tested and diner came along. The, the S P T is what I would call kind of the standard. And then everything to the right would be what I would call a little more, a little more special, what we call specialized in situ capabilities in the, in the vein shear and the pump and trimer and the pressure meter and different things. And we'll, we'll get into that here in just a little bit, but first thing we'll get into today is the, is the standard penetration test. This is probably by far sort of the industry standard it's, it's tried and true. It's proven it's been around for a long time, as I indicated. And you saw there on the screen, when you, when you do the standard penetration test, when you talk, when you hear, you know, kind of the jargon, it would be like, what, what are the blow counts of the soul?
The end values that that's what you're getting with the standard penetration test. It's, you're basically pounding a pounding, a piece of pipe into the ground with 140 pound hammer in a split sleeve. And when you get that sample out, you have a disturbed sample. Cause obviously you counted a piece of pipe through it and, and you get something that you can look at, you pull it out of the ground and you can see it. You can, you can get a sample out of that. And you've got that amount of resistance that it took to pound that, to pound that sampler into the, into the earth. So when you look at that, at that first drill rig, that, that we put in there, that this has taken a, an SBT test. So you would advance a, an auger hole that makes this open cavity. Then you send that sampler down in the ground. And then this, this hammered device on the machine has a, a apparatus. And it's just continue pounding that spoon. And you're getting the blow counts.
And basic from that, we're going to get, we're get those blow counts. And then we're going to start creating the field log and, and start, start defining the, what we're seeing as we, as we explore the soul and we're going to make that field log. And then we're going to start, start creating this log. So really it paints a picture of what's below the ground so that we can understand what's going on. When you get a geotechnical report from, from an engineer, from someone like us, you're, it's going to contain a lot of information and we'll go through a little bit of that today. This is pretty, pretty standard, boring log it's been scrub. So it's, you know, it's pretty sanitized if you will. But if you look in here, there's lots of information on this log. And if we zoom in zoom in a little bit closer here about what's, what's in a boring log on that standard penetration test, those blow counts, you know, that we're driving that sampler in.
That's what you're going to see in this result. So we've counted and it took us two blow two, two hammer strikes to drive that sampler first six inches. And then the next six inches, it took us three blows. And the third six inches, it took us another three blows. And then when you add the last two that's, that gives you six and that's our end value. That's the, that's the standard penetration test. And, you know, it might show up in a different place on the log. Ours look like this, but you know, that's what you're looking for is the end value.
The next thing we'll talk about is the, the cone penetration test. It's a little more advanced, a little more sophisticated. The, the result of a, a CPT log is a, is a log that looks something like this. And it's going to give you a, a continuous profile of the tip resistance and the sleeve friction of that cone, the ratio, the friction ratio between those and then a poor pressures are going down. And you'll also get an indication of the soil, be behave of what the soil is based on ratios of those, of the tip and the sleeve friction. And we'll get into that here in a second. This is what a CT app rig looks like. It's can be a truck like this with a big box on the back and on the inside, you have a, a hydraulic press that is essentially pressing these rods down into the ground pretty much continuously.
So you'll, you'll push down one, one section of rod. You add another rod and you keep pressing that down and so on and so forth till you get to the depth where you're going, kind of works like this. So here's your column. It's a 10 square centimeter tip. That's not the only size. There's also another common size is a 15, 15 square centimeter tip. And it's pushed at a constant rate into the, into the ground at about two centimeters per second for the TM. There's a load cell. There's a load cell on that cone on the tip, and we're going to be measuring the, the penetration resistance, and we're going to be gathering up that tip resistance in sleeve, sleeve friction, as we indicated on the log there, there's another transducer behind the cone tip and it's measuring core pressure. So that's important. Cause as you're pushing through fine grain SOS, you're building the core pressures up.
And so to get that, to get that kind of normal stress out of there, you get a back those poor pressures out. And as these poor pressures, give us an idea also about, you know, the permeability of that soil as you build the pressures up, the soil is less permeable than say in a sand where it can dissipate more quickly. Another key thing to note about the, the penetration test is that it collects data pretty much continuously as you're pushing it down. So you, you know, with an S PT sample, you're general generally getting a sample or an indicator of what's going on every two and a half to five feet. And that's test is actually taking over an interval of a foot and a half. Whereas, you know, this, this C PT test, you're getting information at about, you know, every three quarters of an inch. And so for all intents and purposes, it's pretty much continuous directly. And then that information comes up through either a wire or through, through acoustic, up to your computer. And you're getting that data pretty much instantaneously.
The, the information on the, on the tip and the sleeve stress is going to give us an indication of a lot of different soil parameters. You can get correlations between the, the unre shear strength, the friction angle of the soil, the over consolidation ratio, the, the hydro collectivity, that's also permeability. And there's some empirical correlations of, of those parameters to actually what the soil is. So while you're not collecting a sample out of ground, we get something called the, the normalized soil behavior type. And that's what you're going to see in the log over here, where it's telling you, you know, this is a soil, this is a S silk or clay or sand or whatnot. And that's how we can, we can get an I idea of actually what's there without, without getting a physical sample of the, of, of the soil. And so here, you can see how that plots out.
This is the, I believe this is Roberts' chart, but you can have a, a, a friction ratio in, in the corn resistance and where that plots on the chart. That's what we're indicating there is the, is the sole behavior type on this area over here. And that's, that's how we indicate what the soil is without necessarily looking at it. So a lot of times, what, what you'll do on, on some sites is you would do this pump penetration test. And then with you need to collect physical soil samples, we would do the drilling and we'd get some confirmation actually by seeing the soil to correlate that with the C PT data. So a lot of times these tests are used in conjunction with one another, another test I'll just point out pretty quickly and then move on just so we can get through all this today.
But as the pressure meter test, this's another in situ method. So in this, you'd actually pre bore the soil boring, and then you lower this lower this device down into the, into the hole. And you're basically inflating that inflating that device against the bore hole wall. And you're getting an actual moist, a direct moist measurement down the bore hole. So you're getting a stress, you're getting a displacement and therefore you get this, you get this pressure and volume, and then that gives you a modular value directly. So it's a pretty neat test for if you're doing a something that's got a lateral load against, you know, like a pile for instance, or a, or foundation or something pressing laterally against the side, you can get that direct measurement down the hole. It's also pretty, pretty neat test.
So from there, we're out in the field. The next thing that we would do is we collected samples. We go back into the lab and then what we need to do is further characterize the soils that we collect in the laboratory. So we do some laboratory soil testing, and there's, there's lots of tests, way more than we're going to cover here today, but we are going to go through some common ones and I'm going to go back to the, go back to the boring log. And generally a lot of this information we'll put on the log. So I want, you know, put this in the context of how you, how you can see all this information if you're looking in report. So when you come back and we do some of those lab testing, a lot of this data that you see on the log has been developed where we've, we've logged the boring while we're out in the field, but we've also collected field data.
That's here. And then there's other lab data that shows up, and this is all in the boring log. And it's presented in, in the order in which, you know, in the Strato. So that's important if you look here in this log, we'll zoom, we'll zoom back in on this one particular part. And then over here on the right hand side of this log, you'll see, we've got some other data, some water content, something we call the, the plasticity or the Aaberg limits, these strength test a to a Tova test, that's she strength measure of shear strength. And so these are all things that we determine in the lab and then report back. Also, if here on the, on the, on the soil board, another thing just at a more basic level would just be, you know, verifying the soil types. We log this as we're out in the field, but when we get back to the lab, we actually run test these soils to determine what is the classification of that soil.
Exactly. So, you know, is it a clay, a silt sand? And you know, is it a, is it a plastic clay or a low plasticity clay? So we determine all that in the lab. And then we that on this log. So when you look at this boring log in its final form, it's been looked at by an engineer and then have laboratory tests that, that verify that, that what we logged in the field is in fact also what we, what we have in the lab. So that's important to note as well, as I mentioned, when you, when you bring that soil in, there's several different types of soil that, that you can encounter. And I'm going to talk about what those basic soil types are. And then we'll turn it back over in a second, about what that means in the context of what's going to happen on a project site.
So in general soil, when it's encountered the most elemental way, the soil ranges from large particle size down, the very small particle sizes and at the largest size is, is obviously like rock like bedrock. And then from there, it weathers down into other materials and as it gets smaller, it, the, the properties of that soil chain. So you have rock. And then as you, you know, screened out to finer to the finer souls, that rock then becomes like cobbles and then boulders and smaller, smaller rocks. And then it goes to sands and gravels, and then even finer than that, you have clays and clays. And silts when we get back into the lab and we run these tests, we, we perform these gradation tests, and this tells us a lot about the particle sizes of that material, but then also how that behaves. And so this is a typical grain size distribution curve.
You would see a Geotech report and it has, you can see the range here from cobbles, you know, just like we described before cobbles gravels sands down to place. And when you get down to, to, to even finer down to the silts and clays, there's, there's other parameters that we talk about, and that's the plasticity and that that has to do with how workable the soil is, will it shrink or swell, things like that. So, typical test that will perform to determine that plasticity of the fine grain soil is what we call an Atterberg limits test. And that's going to consist of a liquid limit test, a plastic limit test. And then as you take the difference of those that tells you what we will call the plasticity index, and that lets us know is at a low plasticity or a high plasticity. So I'm going to, to pull the curtains back on what that test looks like.
And it's pretty basic. Actually, you, you get this sample in and you to do this liquid limit test, you actually take the soil, you run it through a Sid, you mash it up, you add some water to it and turn it almost into like a put and you put it into this cup and you, you run a little trip hammer here, and this cup bangs down until, until this groove closes it, you cut in the soil. And if the water content and which that groove closes in a certain amount of blows is what we call that liquid limit.
Similarly, the plastic limit is going to be how, what the water content at which we can roll these threads down into this eight inch diameter thread before they start breaking into one eight inch pieces. So if that water content's too high, you're going to roll that down into a really thin thread. And it'll be on this, you know, thread like, and you'll have to lower that water content. So as imprecise as that sounds, that's the plasticity he, that we use. And we have been using it for a long time. And that gives us an indication of the, of the plasticity index. And all that is, is basically just the water content, the liquid minus the water content. That's what you reported the thing in of the classifying the soul. So if you, if, when we're talking about that liquid limit plastic limit, we run that through the TMS and through this, through this chart and based on how that soil behaves and the amount of silt soils, clay silts proportion of S silk clay with sand will give us that classification. And so if you take that, if you take that amount of soil passing the 200 and you get the liquid limit on that, and it's a, let's say it's a 60 liquid limit, and it's a, and it's a 20 P you plot that. And we determine that's a, that's a high plastic seal. So nothing magic about that, but that's how we do the classifications.
Another, another test that a typical test that we run in labs are strength tests. And I, and there's lots of strength tests. There's Trix strength tests, there's run confined compression test there's Toine shear test that we do pocket pins. There's lots of tests that we do. This is a pretty, a pretty typical UN confined compression tests set up. So basically that just means you're taking this, this sample, you're putting it into this, you're putting it into this device. You're noting it in any way. And you're just switching it on the top and bottom, and you're recording the stress that, that it can take before it fails. And then you plot that out. And this gives you like an UN confined compressive test. And you look over here and this gives you bone during the end, during cheer strength. So pretty basic, but there are lots of different tests that we do to, to determine sheer and soil strengths.
When we, when we go through that process of, of identifying all the stratigraphy and all the different types of soil and their, and their characteristics and properties, we can, we can then begin to get a, a visual picture of how that site's going to behave. And, you know, as we look at what, what types of soil we have, the, what you can expect from, from a granular soil is, you know, how, how they feel. They grainy, they transmit water pretty well. You know, water can flow from their well-drained. They have no plasticity. And when they're, when they're dry, there's, there's not really cohesion there. If you got to pile of sand, it kind of, it kinda SLS down at its if you think to like dry sand, what that's like clay on the other hand behaves quite a bit differently. The grains are really small, they're tight. They tend to attract water in between the particles. And as you get the water in there between the particles, it, it lubes 'them up. They become soft, not as strong, the more, the more wet they are. And as the plasticity increases, they have different challenges when you're using them.
Bedrock is, is the other extreme end of you know, soils, you know, intact rock. And there's all different kinds of rock here. And we won't go into all those different rock types today, but there's sandstones clay stones, stones, and those are more of like a depositional type of rock. And then you have the, the other harder rocks, like nicest granites, things like that, or Igni or metamorphic rocks. And they're more intact, have much higher compressor strength and support higher loads. Ryan's going to get into a little bit more about sole characteristics here in the next part and how they, how they impact projects. But in generally in general, here, these, these generally in, in terms of support and, and performance, the gravels are good. And as you go down, these, these kind of decrease in terms of desirability for, in all things considered, and Ron's going to go into that and, and quite a bit of detail and how these can impact your project in terms of, and foundations and support and, and things, project life that I'm, you
Ryan Fiest - Speaker 3 (00:37:29):
Just gimme a thumbs up, if you can see that. Thank you. Yeah. Just to dovetail into what Levi was saying, where we've identified, we've collected the samples, we've tested 'em in the lab. We've now got this engineering properties of it to go over a little bit more on this table. I mean, essentially the Coser grain materials, the gravels in the sands, they support structures better. I like to think of it like a sponge, your kitchen sink sponge. It's got all those little pores in it. It's the same structure that soils have in it. It's just usually filled with air or water, but as you get smaller and smaller, that water can't get out of those poor spaces nearly as fast. So where a, a sand may stay firm with that water in it, that clay, it, it just can't get out of it fast enough.
It's like a hydraulic press where you you're putting pressure on it and the water's squeezing out slowly, but it just can't outta that soil fast enough. Well, what does that mean? That means that when we apply pressure on the top of it, say a foundation for a building or other structures, it takes a while for that to normalize. And it may take months for that clay to allow that water, to get out, to support that new load. So generally more granular soils have better engineering properties, characteristics for support of structures. As you get smaller and smaller, it just takes a little bit longer. They have less strength to them, but they also have less stability.
One of those might be if you're on a really clay site and, and you've seen the construction equipment running over it, you almost get a water bed effect where you have too high, a water con in it content in there because the, the soil just can't get that water out of it fast enough, which results in that instability. So as we, so what do we do with all this information? We've collected all this stuff out in the field, how do we summarize it all? And that's where a typical geotechnical report would come in. So what, what the, the geotechnical engineering report, as I always say to all of our practitioners, this should only be a summary of what we've talked to the, the team and the clients about no surprises, but there's a couple of things that build the story. A geotechnical engineering report is a story.
First part of that story, what are we building? What's the project description. This is where that team aspect and the collaboration really comes into play. What type of building is it? How heavy are the loads? What do you anticipate the finished floor of that building being, or if there's proposed grades that helps us determine what the cuts and the fills are. What's your settlement tolerance for those buildings typically for, for buildings, it might be around an inch. Other aspects, as I had mentioned is really based around what's that grading plan look like, are we going to have retaining walls? Do we have below grade structures, fuel facilities with their, with their tanks that can be affected by groundwater and then pavements, it all comes down to what load are we applying to the soil over what type of area? And that load can be pavements. That load can be building foundations can be transmission tower foundations. It's just, how are we transferring those loads? And what do those loads look like?
Here's an example, just from a transmission line standpoint, what, what type of structures are we building in this particular example? It's around H structures and then direct embed poles. Typically on transmission lines, we don't have a lot of grading activities associated with it, but the loads, particularly the overturning loads on those towers can be quite large. Levi had talked about that pressure meter testing on, on really dialing in those lateral pressures down in the ground. This is where they come into play. Those, those towers. They may not have a lot of down pressure axial compression, but they have a lot of overturning, particularly in those, those wind storms. And that's where we can help design the most efficient foundation types by giving as much data as we can from the field collection. And then the, the lab testing site conditions. Another part of the equation, right? Yes.
Jessica Turner - Speaker 2 (00:42:27):
This seems like a good question to answer live here and not wait until the end. They are asking, do the soil characteristics evaluations apply for solar PV piles or is that a ranking specific to buildings?
Ryan Fiest - Speaker 3 (00:42:42):
Nope, that's a great question. So Jimmy Jackson is going to be presenting the next series in this really with respect to solar, haven't ignored it, but absolutely they may be lighter loads, but there's a, there's a huge cost savings for those H piles that hold up to solar arrays. Thousands, if not tens of thousands, hundreds of thousands of those piles that go in the ground, again, not heavy loads, but if we can dial in the, the properties of that soil and we can do some load testing out in the field and we can save even a foot of steel on each one of those piles, over a hundred thousand, 200,000 piles, it's an extreme cost savings to the project. So yes, it very much applies to solar arrays.
Great question. A lot more detail in, in the second part of the series, when we really dial into solar arrays and how we utilize the, the field collection, as well as the engineering side of it, the analysis. So other parts of this, this equation, so we've got, what are we, what load are we applying to the soil now, what do we have out there? Just from a ground surface perspective on this particular example, we've got it's undeveloped bar of vegetation, but then it says there's an apparent dry Creek bisecting, the site that keys you into, well, there's probably sediment down in that Creek. How is that going to impact things? What do we need to remove in order to, to give the performance to whatever structure might be going on top of that? So all of these things, and then down in the bottom there, even though it's under the geology, there was a highway built next to this particular site and there was BEMs. They had extra soil from a highway project 30 years ago. Well, now we've got old fill sitting on that site, and that's something else that we may need to address depending on where the building sits in relation to that fill. And I say, building, I'm just going to broaden that to structures, whether that's pavement, solar array, transmission lines.
So that site characterization Levi really spent a lot of time on this. We, we now take what we call a geo model and we, we dial in, what are the engineering properties associated with different layers on this particular example, we've got fill soils, we've got some native sands and clays. And then below that we get into some weathered sandstone and then some weekly cemented sandstone as it progressively gets harder as we go down into the, into the ground. So we use this as kind of that key, that legend as we go through the report. So we can talk about those native sands. And then we, we dial in the engineering properties for that kind of broader group. As you saw in those boring logs, we can, we can dissect it into a lot of different layers. This helps us generalize it, particularly for the structural engineers. So we can assign friction angles and cohesion and strength values to those particular layers.
We're going to spend a little bit of time on, on that site characterization. This is a, a building site, got some out parcels around it, lots of borings that we did around here. We want to make sure we've got a good understanding of what that profile looks like. We're going to focus in on this building down here. Each one of these crosshatched boring symbols is where we've, we've AED into the ground and collected those soil samples. And the squares are test pits. So we have this cross section through the building. We'll circle back to that in just a second. Those geo models, this specific layers that we had called out in that chart. We look at that kind, this is just all the borings for the building. It's kind of congested there, but it gives a good indication of where the finished floor of the building's going to be in relation to say that old fill that we encountered in those BES or where we're going to have to put new fill in there. Our borings, you see dip down the ground surfaces down here, but then we can start to see where the clays are and the sands, and then eventually getting down into that bedrock. And you can see here where the bedrock actually comes up into the finished floor elevation. This gives us a good indication where we may have some difficult excavations within portions of the building. Going back to that cross sectional view.
This gives us an indication of when we're in construction, where are we going to encounter those things specifically within that building footprint? And you can see that a lot of the fills are going to get removed as we cut down through it, but we will have to deal with some old material below the finished floor elevation in some particular areas. So again, we're building the story. What structures are we putting on it? What are those grades look like? What do those site conditions old, fill creeks, drainages, things of that. And then how are we going to address it with our recommendations?
One more, just from a, from a transmission line standpoint, I thought this was a, a good tie in, of not just using what we're collecting out in the field. We also want to tie it to available a publicly available information, geologic maps. So this was a several hundred mile long transmission line. This is the overview of that, that blue line is where that transmission line's going to go. And you can see that it crosses over a lot of different geology as it goes along that alignment dialed it in a little bit. So this guy is right up in here. The other screenshot is from over here. Well, we've taken select borings, although they may look closely space on this. They're probably about a mile apart. So that might represent five to 10 structures between borings. By combining these two things, we can better interpret what those conditions may be between the borings, another product that we have.
We, we have a product called stage one, which Jessica hit on a little bit later, but we that's a desktop review where we looking at those geologic maps and we can start to put together some predictive foundation parameters from, for some cost estimating. But for this purpose, this is really what can we do to get as much information from not only our borings, but the, the geology maps that we have available. Levi also hit on those, those other types of exploration over on the right here, perhaps there was a, a mountain, a hillside that we just could not get a rig in there practically. Perhaps our, our track rig couldn't get there would have to be helicoptered in well, instead of doing that, we can use geophysics to sound the ground and see how deep that bedrock is. And then we can also correlate that with that underlying geology. So we use a lot of tools in our tool belt to come up with what those recommendations are based on site constraints and even geologic constraints.
So now that we've gathered all that information, we need to apply it to our design recommendations. There's a lot more that we could get into. I wanted to just give a brief overview of several aspects of a project where we can provide those geotechnical design recommendations. We'll touch on a couple of these in a little bit more detail, but earthwork is always a big one, depending on what part of the country you're in that seismic or liquefaction. If you're on the coastal areas could play in foundations are a huge one. And that's where the structural engineers usually gravitate towards. And again, there's a ton of other ones in there just depending on the needs of that particular site, a couple of those different aspects, earthwork difficult excavations, this particular site. They had some huge chunks of, of bedrock that were in the soil profile.
I mean, those are big trucks and we've got some big boulders that, that were on this particular site. They ended up using this as fill they'd crush 'em essentially, but that shallow bedrock and we had talked about the solar. I'm sure Jimmy will get into this as well on the next one, shallow bedrock and pile driving for those solar arrays is a big deal. And if we get pile refusal early, it can cause a great cost increase where you may have to pre-drill those things, a ground water is another aspect. How do we dewater a site? How do we deal with that, that groundwater that might be on those particular sites.
We talk about that steel in the beginning, and it has specific properties because it's a manufactured element that we can incorporate into building construction. We're trying to do the same thing with soils. That's why we call it engineered soil. So after we dissect the properties of that, then we say, all right, how do we place fill? So it can support the structures that we need it to, to support. What does that density of that material need to be in order to get, say a 3000 pounds per square foot bearing capacity out of it. Other aspects that we provide guidance on would be the grading and the drainage.
Another aspect is settlement monitoring. This particular one was for a, a surcharge, the soils underneath. I had talked about those clays, not allowing the water to get out fast enough. We ended up placing gosh, 10 to 20 feet of fill extra fill on this building pad, because if we put the building straight on this, it would actually settle over time. Think of the leaning tower of Pisa, but not, not to that extent of time. So we we've accelerated. We want to compress those soils underneath. This allowed us to, to take that, that settlement. Instead of taking a couple of years, that would the building. We were able to accomplish that settlement within about three months. Then we take off this fill and then we can put the building on it. Now that it's been surcharged other aspects, you can see some water on that. Fill there. If that were on your subgrade, say over in the, the, the brown colored reddish brown colored area over here, we can chemically stabilize that soil to improve the, the characteristics of it.
Foundation design and recommendations, just a snapshot of shallow spread footings. In this particular case, I reference that 3000 pounds for square foot. These are the structural engineers. Usually come to find the information that they design their foundations, the concrete and the reinforcing steel around it. We, and we also give guidance on frost depth in this particular area at 60 inches. That is where the bottom of those foundations need to be in order to get outside of the frost zone must be up in Wisconsin or Minnesota, somewhere other aspects. And this is, this is an example from a transmission line where there's, again, information available for the structural engineers to design those drilled piers for those mega towers and that dials into what's that effective weight of the soil, those friction angles. How, how rough is that material? The adhesion, the cohesion values for the clays, lots of different values that the structural engineer can apply to the, the foundation design.
Other aspects would be wind turbines. We have a proprietary system that we use for wind turbines. It saves a lot on concrete costs and then other ground improvements. We talked about the surcharge there's other improvement methods that we can provide that might be cheaper than over excavating soil. And then bringing that back in is compacted fill. The last one that I wanted to touch on are pavements. Those are, are big for commercial developments, and it can make a huge difference for those solar arrays and, and wind projects. Particularly with the aggregate surface roads, I worked on a wind project where they really wanted to thin it up, said, wow, we don't really care. It's just a dirt road, dirt soil road. We just needed to, to work for us while we're putting the turbines in there. It's just going to be a support truck that goes out there and it's like, that's fine.
But I know schedule wise, these are very scheduled driven projects. And if you don't build the road well enough and you get a rainy season in there, you could have problems. This particular one, it and I, I live in Colorado. This was done down in Southern Colorado, dry 11 months out of the year, as they were bringing in the turbines, we got a freak snowstorm in April shut down the site for a month, though, all those turbines were sitting on the side of the road. They couldn't get in cuz it was a clay site and the road only had six inches of gravel on it and it just blew up on them. So they, they lost about three months’ worth of time, took a risk there on a, a lower grade road. But unfortunately it bit him on that one. So that's where we can help develop those recommendations to support the schedule and also keep cost in mind.
Last, last slide here got a little bit of an overrun there. Apologize geotechnical consulting. Please get us involved early in the project process. We'd love to collaborate with all the stakeholders and other team members, the design team members, just as I had talked about, what, what is that structure? What are the loads? What are the settlement tolerances? Our ultimate goal as a quality project that meets the clients and the clients and the owners, financial and risk expectations. We want that to be a long term project with the performance that's expected from that client. And I cannot emphasize enough communication, communication, communication. That's what, that's what we love. A consultant is an engineer that can communicate effectively so we can have that high quality project. I will turn it back over to Jessica to wrap things up.
Jessica Turner - Speaker 2 (00:58:05):
All right, well thank you, Ryan and Levi, this does wrap up our AI a portion. So if you do have additional questions about the AIA pieces of this, you can talk to Ryan or Levi. I will leave their information up here and then we will also provide it in a follow up email as well. If you wish to reach out to either of them, Frank, we do have it. We do need to get the link out to everyone. So please check your chat. If you do want to sign up for those AIA credits, just simply fill out this form. It's really quick. It's just first name, last name, your AIA member number. And then if you want that certificate or not, so we will move over here and right before we open it up for questions, I do just want to circle back to the topic of pivot and stage one.
So we pivot is the reason why we all signed up today. So we are really excited. Pivot joined the Terracon family a little over a year ago, and they are a software and technology firm really excited that as we're kind of merging these conversations and figuring out where pivot fits into the project life cycle. So if you are looking for software to aid you in cost, estimating, finding sites, making those go, no go decisions and getting some preliminary high level information before ever stepping foot on a site. Pivot is the tool for you. So after this, you'll have an opportunity to reach out to us to get more information on that. And then we have stage one. So stage one is where we take experts like Ryan and Levi that are situated all across the country. And we combine that with our over 55 years of historical project data. And we're able to provide you what we expect to find on that site. So pivot will help you narrow down the site. Stage one will get you some additional preliminary information with that expert enhanced opinion. And then we can move it over into that, the field exploration site, characterization and engineering and consulting. All right, so now we're going to open it up for questions and we do have a few minutes here. We'll head to the top. We've got Dylan and Levi having, having a quick discussion. Does any, do you want to add anything to that, Levi?
Levi Denton - Speaker 4 (01:00:49):
I don’t know if Dylan can chime in, if I kinda answer some of the questions in the chat, but he did have some questions related to the different types of exploration methods and when you would use certain methods over other methods and you know, we could the day course on that, but in general, the, when you're pushing C PT, you're, you're pushing that calm down and kind of forcing its way through the soil. So you're not removing soil out of the way as you're going. So you're limited on the C PT in some ways, once it reaches a certain density, it's hard to push that column. So we use that in soft deposits up. The kinda, you know, I'd say even up to pretty stiff deposits, but once you start hitting rocks and, and very stiff soil or bedrock or anything, that's going to refuse out your CPT.
And then you could supplement in with conventional drilling to where you're actually removing the soil as you go and take physically extracting the sample out along the way you would use those methods. And a lot of times we, we, we go in, we go in and a lot of times with a notion of what's already going to be there. So when we go out and explore a site, it's not like we're going out into an unknown land where we're, we're just randomly doing a grid of borings. And then like we're finding new things. We're not expecting a lot of those maps and things like Ryan show. We have a pretty good idea of what we're encountering when we get out there. And we like to really go in, in more of a confirmation mode and fighting a cold here, going into a mode of confirmation where we're, we're confirming what we think we already know versus, you know, we just don't know anything at all. What's going out there now that said, you always run the risk of, of encountering something that you're, you're not expecting in that case. You got to be nimble and change the course while you're out there. But in general, that's the way we approach that.
Jessica Turner - Speaker 2 (01:02:44):
Thanks Levi. We have. Would any of Terracon's databases be available on pivot for, for site analysis? So either Levi or Ryan, do you want to go into the, the SBC and the soil, parent material layers and things like that?
Ryan Fiest - Speaker 3 (01:03:01):
Yeah. As, as Jessica had mentioned, we've got 50 years plus of historical data and we are, there are publicly available GIS layers. We are developing our own internal GIS layers such as from all of our projects. What does pile embedment look like? Thermal resistivity values corrosion. So we're building some internal things based on all of the data that we have. Those will be rolled out in our pivot platform, particularly over the next year as we dial those in. So there are some available now, but more to come.
Jessica Turner - Speaker 2 (01:03:46):
Thanks, Ryan. All right, we have another one. Could you summarize the cost and benefits between ground screws for solar foundations and pre-drilling for piles? If bedrock is present?
Ryan Fiest - Speaker 3 (01:03:57):
No stay tuned for, for number two with Jimmy Jackson on our solar. I say that tongue in cheek there, the ground screws have a hard time penetrating that bedrock. And that's where that pre-drilling really comes into play. And this is where that site selection comes in. If we can identify areas where there's shallow bedrock, and that can be avoided before you even get too far on that site and you can shift it perhaps down the road to where that bedrock isn't as shallow, you may be better off, but I, I believe Jamie's going to be able to talk a little bit more about those ground screws versus pre-drilling
Jessica Turner - Speaker 2 (01:04:40):
All right, which is perfect. We do have another question on signing up for future sessions. So we will go ahead and get that scheduled. It'll probably be between three and four weeks out. So everybody that has registered today, you can, you will see that email to register for the second in the series. And it will also be posted on our social media channel. So go find us on LinkedIn and you will get that link to, to register. So Jimmy is, is getting all set up. I saw a sneak peek of his presentation and it'll be awesome. All right. Well, we are a couple minutes over. So I think we can wrap it up. Like I said, Ryan and Levi's contact information will be provided in the follow up email. So you can reach out to them if you have additional questions and then make sure that if you're looking for those AIA credits that you fill out that link for us. Other than that, we appreciate your time today and we will see you on the second series towards the end of August.
Ryan Fiest - Speaker 3 (01:05:53):
You thank you everybody.
Levi Denton - Speaker 4 (01:05:56):
And thanks a lot. Enjoyed the time. Everyone feel free to reach out to you have any
Ryan Fiest - Speaker 3 (01:06:00):
Questions? Absolutely. All right. I'm bail out.
Jessica Turner - Speaker 2 (01:06:48):
All right. Thank you.
Client Development Manager
Levi Denton, P.E.
National Director of Site Characterization
Ryan Feist, P.E.
National Director of Geotechnical Services
2. Solar Site Characterization and Engineering
Are you still taking notes? Because Pivvot is continuing the lesson! For our second webinar in the Geotechnical 101 series, we’ll be joined by Tamara Hashimoto, P.E. Department Manager & Senior Associate at Terracon, who works day to day with Geotechnical engineers and evaluating solar field sites and we’re inviting you to join the fun!
Tamara will cover:
- Some of the commonly asked questions Solar Engineers receive from Geotechnical Engineers while working together during the site selection process
- Common misconceptions and constraints when it comes to site selection
- What every geotechnical engineer wishes they knew during solar site selection
- How depth of bedrock, soft clays, and other factors impact project site configurations, schedules, and budgets
- Pile Load, thermal and geophysical testing for subsurface exploration and condition reporting, so you can stop saying “what are they doing out there anyway?”
Second, Rich will demonstrate Pivvot's understanding of data, technology and digital solutions which can be utilized during your site selection process.
To wrap things up, Tamara will walk you through the project development lifecycle, including where you can use Pivvot’s technology and Terracon’s Stage1 with the support of Scott Neely, P.E., P.G., senior consultant, solar subject matter expert who will answer your questions at the end of the webinar.
Register now to save your spot!
Speaker 2: Jessica Turner (00:04:01):
All right. Well, thanks everyone for joining us on this Wednesday morning. Thank and for part two of our geotechnical 101 webinar series. So if you did miss part one, that's okay. We have a recording of it for you that you can go back and watch, and we'll be hitting on some of the highlights of that here in this presentation. So I am Jessica Turner. I am the client development and marketing manager for Terracon digital services, Stage1 and Pivvot, and I will be facilitating today, and I get the joy of introducing and setting up our awesome speakers for the rest of the webinar. So before we get started here, wanted you to know that we have muted everyone. However, we do have a Q and A function available, and you can see kind of where that is highlighted there. And you can feel free to ask questions throughout the webinar. However, we will be taking those questions and we may be able to answer them throughout the webinar, but we will save some of those that we need are experts to answer for the end. There will also be a recording that is sent out ahead of time, or sorry, sent out after the webinar is complete.
All right. So here at Terracon, one of our number one priorities is safety and August happens to be I safety month. So we like to start every meeting out with what we call an IIF moment, our incident and injury free moment. So it's often easier to remember your PPE and safety when you are clocked in and out on a job site. However, taking that back home with you, oftentimes those same reminders aren't in place. And so I just wanted to highlight the importance of making sure that you're wearing eye protection when you're doing some of those daily tasks like cleaning when you've got some harsh chemicals involved. And then when you're doing home improvement projects and then yard work is a really big one. I know I was mowing my lawn recently and there was just a little pebble that flew out and hit the windshield of my car and ended up damaging my windshield. So I can't imagine had that gone in my eye, how awful that would be. So just kind of keep that front of mind and where eye protection while you're out there doing household stuff too.
So this is part two, like I said, in the beginning, the first part was just the really basic foundation of what a geotechnical engineer does. We're taking that. And we're going on a deeper dive here today. And we're focusing specifically on what a geotechnical engineer does during solar site characterization and the engineering that is associated with that. The third part of the geotechnical service series will be the electric transmission routing. And that will be from the eyes of the geotechnical engineer as well. That will be next month and you will be able to register on our website. And then we'll also be sending out some email notifications and social media that will direct you to register as well. After we wrap up our geo series, we will have an environmental series as well, and that will start towards the end of the year and go into the beginning of the year.
All right. So when we're talking about Terracon, it is really hard to beat the footprint that we have across the nation when it comes to solar work, where we definitely have the experience here, and that's why these experts we're so looking forward to hearing from them today. So in the last four years, Terracon has completed over 4,000 solar projects across the nation with projects in all 50 states. And recently our E R rankings came out and we're really excited about a lot of these and we're number 12 for design firms. And then we're three with solar power.
So for our last webinar, here's some of the topics they ranged from all the way from going back to that very early. What is the definition of soil and bedrock into what is the type of equipment are field staff uses and they're out there doing field explorations and there's that site characterization with the laboratory data as well, and then all the way through how they take that information from their explorations. And they develop that engineering report that usually gets into your hands. So today we're going to hit on the importance of good siding and how we get information over to that geotechnical engineering team, so that they're set up for success. And then we've got Tamara, that's going to go through geologic hazards, current solar geotechnical practices, and then even get into a little bit of pile, load testing and analysis.
So I am so excited to introduce our speakers today. We have rich Henry who is my boss and the director of customer success for Pivvot. He brings over 15 years of consulting to product management and system implementation experience and experience in the energy sector. He's known to roll out the red carpet for his customers, and he is the go-to guide just to know what the customer experience is like and how to translate that back to make sure that the Pivvot product is enhanced to meet your needs. And then we have Tamara, Tamara began her career in our Terracon orange county office, and she now leads a team of about seven in our Las Vegas office with her nearly 10 years of experience in the industry. Her passion for solar energy projects has led her to the role of one of our solar subject matter experts. So she reviews and consults on subsurface conditions that impact solar projects throughout the United States.
All right. So at Terracon, we do have what we call the project life cycle, and it is a client centered approach to representing Terracon service in a more holistic way, the life cycle categorizes asset development into four different phases. As you see here on the screen. So we've got site selection, design and mitigation construction, and then managing those assets after they're developed in the next 40 ish minutes, or so we're going to walk through those top two. So the top left and the top. So the project life cycle, site selection phase, and then the design and mitigation phase. So we at Terracon want you to be able to learn as much as you possibly can about your site even earlier than you have before. So that includes talking about two of Terra, con's newest digital services. So we have Pivvot and Stage1 here, and we have an environmental expert on our team that has coined kind of the term pre diligence.
So Pivvot and Stage1 kind of fall under that category. And we have rich who will go through about a 10-minute demo of Pivvot, and we'll talk about Stage1 as well. And then we want to make sure that the design team is set up for success. So that's when Tamara will come in and show how we're going to use that Pivvot in Stage1 information to get you through the geotechnical services, the structural engineering services and the environmental services as well. So with that, I am going to hand it over to rich, and he's going to do a quick demo of pivvot.
Speaker 4: Tamara Hashimoto (00:13:10):
You are on mute rich.
Speaker 5: Rich Henry (00:13:17):
Thanks, Tamara, of course. All right. And thanks Jessica for the introduction and thanks everyone for being on the call. We're glad you're here. So as Jessica mentioned, this is kind of a demonstration. It's really what we want to start to presence with you all is how Terracon is starting to really push towards data and digital solutions to help inform you all, even ourselves as we move through the site selection conversation, and move through the life cycle of a particular site. So as we think about and talk about Pivvot, it's very much in the early stages. So this includes prospecting for opportunities and understanding the viability of the site and all the while we're leveraging the data to do that right, to inform us. So when we talk about Pivvot, we typically start with data. We think of ourselves as the data company. And when we think about our data, we think about that in three ways.
One we've gone out and curated a bajillion pieces of data that's publicly available, whether that's federal state, and sometimes county level data, we're getting that information, putting it inside our database, optimizing it. So it's performing and all the fun stuff to make it usable inside these applications. And we're also keeping that information up to date. So you can kind of check that off the list. You don't have to think about that part. The second way we think about data is sometimes we actually have to go out and license this information. So for example, we license the parcel data so that we can have nationwide coverage. And we can have that information in our system, which allows us to do cool things like aggregate properties that are adjacent to each other that are owned by the same property owner and get those really large opportunities. Another piece of data that we license is actually the energy infrastructure data.
So now we're talking about power lines and substations and existing pipelines, oil and gas pipelines that are out there. Why are we paying for that data? Well, given the activity and the focus on renewables right now, the publicly available data out there that represents particularly line information and substation information is just not sufficient. So based on our assessment and our experience and the experiences of our customers, we license information so that we can make it a much more robust data set. And I mean, in magnitudes of eight or nine times larger than some of the publicly available data. And then the last way we think about it is for us, this is super exciting. So I worked with a person that often would talk about beautiful collisions. And when I think about the Terracon purchasing, Pivvot, that relationship, that partnership is a beautiful collision. So you have Pivvot that walks in with deep bench strength and technology, understanding data.
How do we visualize that data? How do we analyze it? How do we produce reports, et cetera? We've got that right. It's our pocket. And then you've got Terracon. Who's been doing this for 50 years and has a bajillion boring locations out there to paint the picture of what's happening below the surface. So how do we bring those two stories together and walks that be beautiful collision. As we sit here today, there are several data sets that we already have available inside our platform, specifically cars and also soil behavior class, which I'll touch on a little bit, but we've got folks right now that are heads down between the Terracon side and the Pivvot side, those two teams coming together right now and talking about how we can take those 2 million boring locations and start thinking about new and innovative ways to flip the script a little bit on how we start to understand what's happening below the surface.
So more to come there. So that's the kind of three ways we often talk about data. What I'd like to do now is just use the siding application. This is one of two siding applications that we have inside our platform. This one's obviously going to go look for parcels out there typically for solar and wind opportunities. We also have a corridor siding application, which Jessica mentioned earlier that we'll talk about in the next part of the series. All right. So to kind of kick things off. So what we're looking at right now is our siding application. And on the screen, you'll notice that we've got all this huge magenta blob on there that represents areas that are around this feature here in the middle, where this paddle is, right. That's a substation. So I've said, look, I want to understand where within three miles of that substation could I potentially build.
So we're using our usable area calculator and has taken into account some of these constraints that you see over here on the left hand side. And I should mention to the folks that are on the call that are responsible for prospecting. This is just one way that you can approach it, understand the usable area front, then go start hand picking sites. We probably have 10 other ways that you can go in there and start finding opportunities. So we're just not spending time on that. Of course, we would love to take 30 minutes, 45 minutes with you to cover that and get into the details. But for the sake of this conversation, now at this point, we can start picking locations. And I have a couple of those right here. I'll go ahead and zoom to one of 'em. So when we talk about leveraging that data, we just did it.
We just used that to go understand the usable area around a three mile buffer around a substation. So we're doing some of those kind of special back flips to kind of figure out where we can and cannot build. All right. So to take that conversation a little bit further, another way that you all or we can utilize that data to help better inform you is just from that desktop analysis perspective. So everybody on this call, I am nearly a hundred percent certain that you all are using Google earth, at least once a week to go in and just kind of look at what's happening in particular area, totally buy into it. We're mapping folks, love maps, love satellite imagery, except that just having satellite imagery clearly is not sufficient enough. So what we've done is we've made all of the data sets that we've gathered.
We've made those layers that you can actually turn on the screen. So for example, here, we can turn on things like hydrologic group. I like to pick this one because I don't know it's pretty right. And it makes sense. So we can view these layers on the map, start to give this area a little bit more context. We can come down here for those that are doing some of that early site origination, we can start to identify, is there any prime farmland on this site? And of course, as we scroll down, you're going to see things like flow lines and water bodies and wetlands, all the typical constraints that's really valuable. Of course. And then we take it a step further when I was talking to you earlier about some of the data sets that Terracon is starting to provide or make available inside the platform.
So for example, we have this soil behavior class, and then this is something that Tamara could definitely nerd out on for quite some time. But you know, can see over here, the layer and the legend that starts to represent it's an approximation of soil and rock conditions that folks like Tamara or others can start to use to better understand kind of design conditions on that site. So there's that zero to two feet. We also have a layer that goes two to six feet. Is this engineering data? No, it's not right, but it gets us back to that pre diligence idea, which is get as much relevant information in front of us as quickly as possible. And by quickly as possible, although I've been yapping for a few minutes, a person could come in here, spin up a siding project, identify this site and understand the suitability of that site from a usable area perspective.
And also from an early preliminary design and engineering perspective, literally in minutes. So again, for the solar developers on this call, the name of the game is speed. Find those sites as quick as you can. Okay. So we've talked about having that data available to help find sites, understand usable area. In fact, why don't I come down here and we'll just look at the usable area for this particular site. So now we can see where we can build on this site and also where we can't build. So we've used the data to help us support that activity. We have those layers on the map that we can use for that kind of desktop review. And then here again, we want to be able to not only communicate where we can build, but what's happening in the areas where we can't. So, what I'm going to do is I'm going to come over here and turn off some of the noise.
I'm going to come over here and turn on the constraints. This is kind of like when you were in math class and the math teacher was like, don't bother giving me the answer. If you don't have the work, we don't want to be a black box. We want to show as much work as possible because understanding where those constraints are been to visualize those is important from a mitigative perspective. Are there opportunities here that we could take some mitigative actions to increase the buildable area on there, thus increasing the megawatts available on that particular site? So we can visualize that another way, of course, that we are leveraging the information here inside citing this from a reporting perspective, we have a federal level permitting punch list that kind of racks out some of the common federal level permits and lets based on the data, whether that particular permit has been triggered or not as much information as possible, green light, yellow light, red light a site, some of that's, some of that permitting, discussion's going to come into play as well.
And then we also have what we refer to as either the citing report or a constraint report. This is a pretty report. This means that now you can hand off this PDF to somebody and they can take a look at as opposed to jumping into the application and doing that particular work. So here's an example of that hydrologic group. Again, again, pretty colors, but you also get a summary down here of what the hydrologic groups are. And also the impacts on that site here again is that soil behavior class. And I got to tell you, I love this next one. That's what we're looking at now is zero to two feet. This next one is two to six feet and it's like red light doesn't even do it. Justice. There's a spot right there in the middle of our site that is going to cause us some sort of pain.
And that's the sort of information that we want to bring to light leverage our experiences with Terracon and their expertise to bring this information to light as soon as possible, right? No one's saying we need to necessarily can this particular site, but at least we have some visibility on what the type of activity on that particular site is. And to take that a step further, that was a pretty report. And now we're going to get into the nerdy Excel type reports, no offense, Tamara, but this is probably the type of data that you'd probably really dig into. So now we're looking at basically all of the data sets that we have in our inventory and basically taking all of that information and just kind of shoving it right through the site and of doing a cookie cutter to find out what are the impacts, particularly inside the usable area that you may encounter.
And also give you in terms of metrics, the impact, the acres impact on that site. So here, as we look at these two data sets around corrosivity right corrosivity as it relates to concrete and steel, you'll have that information available to you very early on in the process. And also as these sites mature, getting back to some of our solar developers, if you're able to mature these sites more and more, that that increases kind of the return on the investment. Also, when you start to hand these sites off to the designers and engineers, they're going to have this information available to 'em immediately, as opposed to getting to a situation where you put boots on the ground. And somebody's like, look, we have to change a configuration on this because of body blows on the particular site. So you'll have this level of information and to kind of take that a step further.
And I'm going to transition now over to Jessica, who's going to talk about the Stage1, a lot of this information is publicly available. You're not necessarily going to drive your engineering activities on this information. So, when we think about that life cycle, we have that preliminary sighting, what we're looking at right now, and then we're going to shift over to look. We want some more expertise on this. We want to get our SMEs involved and understand what's happening on this site. Make some recommendations, raise their hand to say there's some red flags here, which is how we transition into Stage1. And so from here, I'll pass the mic over to you, Jessica.
Speaker 2: Jessica Turner (00:26:22):
All right. Thanks. Rich. Just spend a couple minutes here with Pivvot. Rich showed you how you can not only identify a site, but actually come up with that usable area and those constraints associated with it. When you are ready to take that a step further and really drill down and refine those preliminary budgets and designs and schedules, then you can tap into Stage1. So with Stage1, we think of it in three parts. The first is all of Terra, con's historical data. So we have over 55 years and in some places like Cincinnati, we have over a hundred years of data that we are, have uploaded into our system and we have geo-referenced it. So within a matter of seconds, our practitioners can identify sites close by and pull up that historical, the boring logs as well as any lab, lab data associated with it.
So then we've taken that and we've paired it with a whole bunch of publicly available information, as well as some of the proprietary data sets that rich was talking about that are now included in Pivvot as well. And then the third piece, which is the most exciting piece for me is that we have experts across the nation who in some cases have 40, 45 years of experience. And they just know that area like the back of their hand. So we're combining all three of those into a report of anticipated site conditions for both geotechnical and environmental information. So we wrapped that all up and we have a team of dedicated client service managers and they turned these reports around fast. So what a preliminary desktop study was in the past, maybe taking three, four plus weeks to get into your hands. We are now turning around in a matter of days because we have a centralized team helping us get these out the door and work with those local experts to get their opinion.
So with S one, we have the geotechnical section, which is truly, if you were to take a drill rig out on site and drill a site, this is what we would expect to find. And we let you know if we have any concern about variation across the site and we let you know how confident we are in that information as well. And then with environmental, it is actually two different sections. We've got the subsurface environmental, which is really a high level phase one. And it's actually going to let you know if there's any sort of red flags or triggers or additional permitting processes that are going to take place when you do go through with an actual phase one, and then we have the natural and cultural resources. So with the cultural resources, we'll let you know if there's any sort of issues out on site where you may need an archeologist or your schedule's going to be delayed because of historical or public lands. We'll also go into the federally protected species. We'll go through what they are that are triggered on that site, as well as if any of them will actually cause any sort of issues for development. And then the last pieces, we'll start talking about any sort of wetlands or waters considerations that you need to keep in mind as you're doing those preliminary designs. So with that, all of these have been identified by an expert at this point. And that's when we get someone like Tamara involved. So, I'm going to hand it over to you.
Speaker 4: Tamara Hashimoto (00:30:17):
Thank you, Jessica. Okay. So this is the part where I get to nerd out about what a geotechnical engineer can do for you on a solar facility project. Thank you for that rich. So most, if not all the following hazards I'll go over can be identified with Pivvot or Stage1 and identification of these hazards early on. Not only help with site selection, but they also help SGO technical engineers to create a field exploration program and pile load testing program that is specifically tailored to your site. So if you remember that map that rich showed where it had the hard rock located at the very center of the site. So we would want to put some exploration points in that area, maybe utilizing different drilling methods to make sure we can break through the bedrock, maybe rock coring, as well as having alternative pile installation methods in order to make sure we can drive piles in that area.
So maybe pre-drilling before we install piles in that area or using alternative foundation types for that area of a solar site. So, starting out with frost and adfreeze, that's probably not a concern for me since I live in Las Vegas, but maybe for some others on the call, this is an issue. So these conditions will impact design of different foundations and the roadways, and it can also impact your pile embedment depth. So during our pile load testing program, we're going to want to either pre-drill or excavate oversized, pilot holes to that ad-free depth for two reasons mainly. So if you're doing a pile load testing program during the winter, you'll notice those upper soils will be frozen. So we want to remove those frozen soils that are providing higher capacities, then what those soils would have if they were not frozen. And then the other reason is that we would want to optimize the skin friction of the pile below that frost step.
So shallow bedrock. So again, like what rich showed us. If we have shallow bedrock on the site, that's a concern, right? So these conditions can impact the foundation type or installation procedures you might need to do pre-drilling before you install your piles. So, we then us geotechnical engineers can propose performing geophysics borings test pits to assist with determining those shallow bedrock ups on your site. Well, as I previously mentioned, we'll also want to make sure we're testing piles, utilizing those different alternative installation methods, such as pre-drilling prior to installing the piles in order to model those test and test those methods that you want to use during production previous mining. So, when you have this hazard on your site, we would want to do an in-depth settlement, evaluation of the deep fills. And we have two major questions that we want to figure out when we're doing our evaluation and that's how long ago was it backfilled and what was it backfilled with?
Liquefaction so shout out to my west coast people on this call. I'm sure you know what this phenomenon is, but this occurs where loose sand or non-plastic silt soils exist below groundwater, but it can also occur with sensitive plastic silt or clays below groundwater. So also known as cyclic softening. This is caused by an increase in poor pressure during seismic events, leading to a loss in sheer strength in soils. And it typically occurs in the upper 50 feet. So, when we do our geotechnical exploration, we want to make sure that we're performing a boring to the 50-foot depth, and then we're running some additional lab tests and performing our liquefaction analysis. So, when you have a site that has liquefaction hazard potential, especially on larger solar sites, there's not much we can do to mitigate these conditions. So it might be a risk to the owner, or you might decide to just to walk away from the site.
So if you have a small site, though, fiber columns can be a mitigation me measure, but I understand this can be pretty costly and sinkhole. So this occurs when limestone gradually erodes away with water over time informs these sinkhole features at the surface. So the way we evaluate these is we would perform a desktop review and also review LIDAR data and then perform a site reconnaissance. So, we typically recommend men that you want to stay at least 50 or a hundred feet away from these features, but if you wanted to get closer to them, when you're constructing the way we can evaluate the invest, the extent of these features is through geophysics and we do something called multiple electrode resistivity.
So another issue would be expansive soils. So what expansive soils do is they cause upward forces on your piles and that can require piles to be embedded deeper erosion. So this can impact pile embedment depths as well. We can collect some samples and run radiation tests on those near surface soils and surface soils. However, typically it's the civil engineer that handles erosion issues or figures out scour deaths and then corrosive soils. So this, the soils can deteriorate steel and concrete over time, which is something we identify in Pivvot reports that like rich went over earlier. So we can perform laboratory testing. We call it the corrosion suite of tests, which I'll go over later in the laboratory test slide, but corrosion engineers can utilize our lab test results and they can figure out how to mitigate this issue or see how much galvanization the piles will need.
Okay. Exploring subsurface conditions. So, on our previous geo 101 webinar, we went more in depth on some of these exploration methods. So if you would like to review that we go more in depth in that discussion, but some things we do for a typical solar facility project are site visits, borings cone, penetrometer test, test pits, geophysics, groundwater, monitoring, Wells field permeability, pile, load testing, electrical, resistivity testing, and thermal resistivity testing. So, Terracon has our own internal frequency like the exploration and testing frequency to prepare a design level report for you. So we use borings CPTs and test bits to do our field exploration. So as previously mentioned on our last geo 1 0 1 webinar, we go more in depth about what each of those types of exploration methods are. But CBTS typically are good for soil types that are lower I density and free of cobbles boulders, cemented deposits and bedrock.
But if you do have those type of soil conditions on your site, we can explore the site with borings and test pits. So borings, we just need to make sure we're using the correct drilling types so we can break through those harder soil conditions, or we might do rock pouring as well. And then test pits are really good for those soil conditions. So with cobbles boulders cemented deposits and bedrock, because then you can open up an entire excavation and see what it is you might be refusing on with your C P T or borings to determine if it was one of those soil types. So for solar arrays, we typically recommend one exploration for every 25 acres. And your borings will be between 15 and 20 feet test pits up to 10 feet or refusal for substations. We typically recommend two explorations sometimes more. And then for your battery energy storage system, that really depends on the size of the best and also the foundation types that will be utilized to support the structures in the best.
So this is what our typical boring logs look like that we present in the report. So on the far left boring log, if you look under the field test results, you can see that the blow counts are relatively low in the upper materials. So, whenever we see boring logs like this, we generally feel that it's going to be easy pile driving or pilot installation conditions. However, when you look at the middle and the boring log to the right, so for the middle boring log, you can see under the field test results column, there's a lot of 50 plus refusal blow counts. And you can also see that apparent cobles were logged out of depth of five feet below the ground surface. So when we see these conditions, we would recommend pre-drilling pile prior to installing piles on a site. Cause we think that's going to impede pile drivability. And again, on the right boring log, you can see that there's bedrock log. So that's another reason why we might recommend pre-drilling or some other alternative method for your, a pile load testing program and for production. So this is a typical C P T log. And so not going to in depth on this, because again, you can review the go 1 0 1 webinar previously, but you can see that we have tip resistance and sleeve friction values on this chart, which we utilize. We then utilize to correlate different soil parameters for our design. And you can also see based on this graph, there's you can see where the tip resistance or sleeve friction increases. So when you see those high jumps and values, that indicates stronger soil layers, which also may impede pile driving
Field electrical resistivity testing. So the electrical engineer will utilize our test results to help design their grounding systems. And what we do is we typically run it in general accordance with a S TM G 57, which is the winner for electrode method. And that consists of two mutually perpendicular arrays per test. And so for solar array areas, we typically test ACE spacings up to 200 feet. And then for the substation and best areas, we typically test ACE spacings up to 300 or 400 feet other unless otherwise specified by the electrical design team. So these are the typical geotechnical laboratory tests we perform for solar projects. However, it does depend on the soil conditions and project requirements as well. But as I mentioned before, we do a corrosive suite of corrosivity suite of tests to test the soils corrosivity. So we have pH minimum resistivity, sulfates chlorides redox, potential and sulfides that are included as that suite of testing
Thermal resistivity testing. So this can be used for design of cable or conductor sizes. You can measure the soil's ability to dissipate heat. So you can see from this graph, it does the thermal resistivity does vary significantly with moisture content. And then it forms what we call is this thermal dry out curve, which is included in your report. So if we are not provided specific testing requirements by the client, what we do is we typically run these tests, the samples at 85% of the maximum dry density determined by the standard Proctor. So a S TM D 6 98, and that's because this, it gives us a conservative value and models, trench backfill with little to no compaction effort. We also like to have generally at least three to four moisture points in order to create that dry out curve. And it usually ranges from dry condition to insitu or optimum moisture content depending which is higher. Okay. So now I'll go over pile, load testing and analysis, which includes pile installations, the three types of load testing that we perform when we're out in the field. So axial tension, axial compression and lateral, and then as well as the pile load, test results and analysis.
So when we install piles, we like to install the piles to the target embedment depths or refusal. And we like to install two piles at each, at least two piles at each test location with two different embedment depths. And we'll talk about why that's important later on in another side. So we install them to target embedment depth or refusal. And so our typical refusal criteria is less than one foot of embedment after 120 seconds, unless there's a different refusal, quite criteria that's specified by the client. And then we usually allow the piles to set for at least 72 hours before load testing. So to allow for soil setup so that our load test results are more accurate. And then the two test piles at each location are tested for axial tension and lateral load testing with the two different embedment depths. And then for compression load test locations, we'll install a third test pile at that shallower embedment depth of the two previous piles. So if you had a location with five foot embedment and eight foot embedment, we would install the compression pile at five foot embedment. So what we do on our pile drive time plots as we present the drive times per foot in a graphical format, such as this. And so this just presents what we typically include in our report.
So this is what it looks like in the field when we perform axial tension pile, load testing. So we're pulling the pile out of the ground and Terracon has their own proprietary low test system, this tripod. And because we strive to be innovative and due to our commitment to safety, we identified that our previous tripod system was really heavy and cumbersome to work with for our field crews when we're doing pile load testing. So what we did is we recently designed this tripod for safety reasons, and it's now called the Terra PODD 2100, and now it is much shorter and lighter for our field crews to maneuver. So our typical load test schedule when we're doing axial load testing is loading up an increments of 500 pounds up to 10,000 pounds or to the deflection criteria. Then unloading debt back down to zero pounds. And the deflection criteria is three quarter inches, which is average between the two deflection gauges on the pile. And of course we can adjust our load schedule and deflection criteria based on the design loads, if we're provided them or the client's request,
When we are analyzing axial tension load, test results, we are plotting them on graphs like this. And then we're checking what the ultimate load is at a quarter inch deflection. So on the left side, you have the five foot embedment test pile, which has a load of about 4,500 pounds at that quarter inch deflection. However, because we installed that second pile to a deeper embedment depth at the same test location, you'll see that the load did it didn't even reach the quarter inch deflection. So then what we utilize is the maximum test load, which was 10,000 pounds for that eight foot embedment test pile
For axial compression load testing. You can see, we use heavy equipment as a reaction force. So that way we can push down on the pile when we're doing our compression load testing. And our typical load test schedule is loading an increments of 500 pounds up to 13,000 pounds or the deflection criteria again, then back down to zero pounds. So again for compression, it's three quarter inch deflection average between the two deflection gauges on the test pile. So we can adjust that load schedule and deflection criteria, depending on the design loads and or the client's request as well, analyzing the data for the compression load test data. We, we look at a quarter inch deflection. So for this scenario for example, it was, they didn't achieve the quarter inch deflection. So we utilize the maximum test load, which was 13,000 pounds,
Lateral load testing. So here you can see, we have the two different test piles at a location. So those are the two piles with different embedment depths, and we test them concurrently such that they're reaction force to one another. So the typical Terra on load test schedule is loading up in increments of 500 pounds up to about 7,500 pounds and at least five cycles of loading. So what that means is we'll gradually load up and then go back down to zero and load up again in five cycles. So for example, 500 pounds, 1000 pounds, 1500 pounds back down to zero 1500 pounds, 2000 pounds, 2,500 pounds back down to zero and five cycles of loading. And then we go up to that, the max load or deflection criteria then unload down to zero at the very end. And the deflection criteria for lateral load testing is one inch deflection average between two gauges. So each test pile has two gauges attached to it and we're testing them at the same time. But if one fails, we can continue testing the other test pile. So the deflection gauges are situated approximately six inches above the ground surface. And that matters because as you go higher up on the pile, the pile is going to move more. The higher up you are. And then the lateral load is applied anywhere between 24 inches to 48 inches above the ground surface.
When we are analyzing lateral load test results, we are taking a look at half inch deflection. So for this example, we're at about 4,400 pounds at that half inch of deflection.
Okay. So why is having two different embedment depths important? So for instance, if we only installed that one five foot embedment pile at a test location, after all our skin friction calculations and analysis, we would come up with a required embedment depth of 10.2 feet. However, because Terracon has that additional data from that eight foot embedment pile, we're able to calculate skin frictions from that five to eight feet, and that helps us optimize the design. And then the required abandonment depth then becomes 7.6 feet. So by installing that deeper pile, that second pile at the test location, we save 2.6 feet of steel. So assuming we have a hundred thousand test piles that can equate to approximately 1.9 million in savings end bearing. So the way we calculate end bearing again. So we're taking our compressive load at a quarter inch deflection minus our tension load at a quarter inch deflection. And that will give us the end bearing value. And for the examples that I showed previously, that would be 8,500 pounds
Lateral analysis. So based on the results of our geotechnical exploration and our pile load testing program, we can then delineate your project site into different zones based on those different soil conditions at each exploration or test point. So this helps us to optimize the design for you. And then what we do is we prepare a pile soil input parameters based on those different soil zones, which are determined based on the field and load test data. And then we can provide you with a, we perform our LPI pile analysis and which we give P and Y multipliers in the report.
Now taking the results of skin friction analysis and bearing analysis that a pile analysis, and also giving consideration to adfreeze and expansive soil conditions. We can then determine the minimum required embedment depth for your project based on this pile in depth pile, embedment depth analysis that we perform. Another service that we offer is structural design for all the piles on your project as well, which we previously mentioned in that project life cycle slide. So we understand that our competitors also have a lot of solar experience, but what sets Terracon apart is our desire to lead an innovation by improving our processes like what we did with the safer and more efficient proprietary tripod system or the Terra PODD 2100. And also, with our visionary digital service solutions, those 4,000 plus solar projects that Jessica referenced in the beginning have expanded our data to include over 2.5 million subsurface data points across the nation.
So we're able to get this valuable information to you earlier to help you make go no-go decisions on your site and refine preliminary designs, budgets, and schedules. We also have an internal GIS database of all of our historical project data, which can be mine for soil's information and to help provide preliminary recommendations without ever having step foot on your site. By having this readily available data, we can also fine tune our services and tailor a specific scope of work that's unique to your project. So, we're here to help you from selecting a site and refining usable area with Pivvot to the start of early planning with Stage1. And then as you enter the design phase, we can provide geotechnical, environmental and structural engineering services that will lead you through to construction, where we can also provide you with construction material testing services. So with that, I just wanted to thank you all for your time today, but I would also like to end this presentation with a dad joke because I love dad jokes. So obviously you don't have to answer because you're on mute, but why doesn't the sun like clouds? Cause they're always throwing shade. And I know that wasn't funny, but I hope I at least brightened your day. Okay. Now I'll hand it over to Jessica to open it up for questions.
Speaker 2: Jessica Turner (00:52:50):
All right. Thanks camera. We have quite a few questions in queue. Alright. So the first one is from Kelsey. Is there much of a push to acquire geophysical geochemical data and near surface reports from oil and gas operations to better enhance the data sets
Speaker 4: Tamara Hashimoto (00:53:12):
Oil and gas operations? Maybe does that kind of sounds maybe like a Pivvot thing. If that's something we can
Speaker 5: Rich Henry (00:53:24):
Talking for my, maybe we could follow up. I don't have the person in front of you. I mean we could follow up and get a little more detail for me to understand that a little bit better.
Speaker 2: Jessica Turner (00:53:33):
Okay. Kelsey, we may reach out to you after to understand that a little more. We have Garrett who's asking in borings, what frequency of blow counts per foot would you typically recommend for pre-drilling assuming no full refusal.
Speaker 4: Tamara Hashimoto (00:54:57):
So what we typically do for our sample intervals, which gives you those field test results, the blow counts, SBT blow counts. We'll do every two and a half feet and the upper 10 feet and then every five feet after that. And then with when you have pre-drilling conditions, we don't really do different sampling methods. We just identify those areas of the site that we would likely want to pre-drill if not the entire site. And that's helped that what helps us is riches Pivvot report. So we are where we are able to identify those harder soil areas in advance of our exploration. So, we'll propose to do pre-drilling in those areas unless the client would like for us to do the entire site, because it depends on what's more cost effective and we want to do what they want to perform during production or construction.
Speaker 2: Jessica Turner (00:54:47):
Okay. We've got Neil, why is an ACE SPAC? Why is an ACE spacing of 200 feet required for winter?
Speaker 4: Tamara Hashimoto (00:54:57):
That's not what's required of us. That's just some the ACE typical ACE spacings we've seen requested by the electrical design team for solar arrays. We used to do 'em up to 50 feet, but we're now noticing that clients and electrical design teams are requesting larger ACE pacing’s in the solar arrays. So it depends on what they want for the project.
Speaker 2: Jessica Turner (00:55:21):
All right. Are the target embedment depths based on preliminary estimates using geotechnical parameters from exploration and the design modes?
Speaker 4: Tamara Hashimoto (00:55:31):
Yes. However, in certain areas we already have an idea of what our proposed embedment depths would be for a pile load testing program. We typically want to go shallower than what we think the recommended minimum recommended embedment would be for design.
Speaker 2: Jessica Turner (00:55:52):
All right. And then we have Kirsten, who's asking if we have a video that we can share of pile, load testing in action. And I do believe we have that and we might be able to add that into our follow up email with the recording of the webinar.
Speaker 4: Tamara Hashimoto (00:56:09):
Yeah, I think that would be really interesting because you guys probably don't know what it looks like when we go out and do our field exploration and pile load testing programs. And it would be cool to also see our new Terra PODD 2100 in action.
Speaker 2: Jessica Turner (00:56:24):
Definitely. All right. This one is from Kevin and it says one of the most common problems I run into is sites like in mid Texas, where there are variable soils, typically clay and limestone, some of the site has refusals. Some of the site has very low blow counts with bedrock. Is it typically hard to determine the exact areas where to pre-drill would be required? And then there's a second part, but I'll let you answer that first.
Speaker 4: Tamara Hashimoto (00:56:56):
Okay. Maybe I might get Scott, Neely's help with this one, what we're doing in order to delineate those different soil zones. But I feel like we could use a combination of methods, exploratory methods like borings as well as test bits and then with geophysics as well, possibly. But Scott Neely, do you want to chime in on that?
Speaker 6: Scott Neely (00:57:20):
Hey, thank thanks, Tamara. And good morning, everybody. I would say that it is difficult. We've done many projects in west and middle Texas. And though we have delineated, the sites with zones understood from our contractors that for the most part, it was helpful, but they still had piles that they had to remediate because they would hit shallow refusal. So without spending a great deal of money in geophysical approaches, I just don't know that there's any better way to estimate where you're going to encounter the refusal.
Speaker 4: Tamara Hashimoto (00:58:08):
Thanks, Scott. Sorry. I forgot to introduce Scott Neely, but he is like the ultimate solar subject matter expert for our company.
Speaker 2: Jessica Turner (00:58:19):
All right. So the second part of that question is have you considered adding multichannel analysis, surface wave analysis to your scope of work, to create better maps of the soil density?
Speaker 4: Tamara Hashimoto (00:58:30):
I feel like we've performed that in some areas of the site. Scott, has that been helpful in helping to delineate these types of projects, but differing soil conditions?
Speaker 6: Scott Neely (00:58:42):
Yes we have, but actually we tend to stay with the size of refraction only because it's a cheaper and quicker test and it's actually even better and more accurate, but either of those methods requires a great deal of time. And so it's a great deal of expense. So we have done it on a few projects, but I won't say that we do this routine.
Speaker 2: Jessica Turner (00:59:13):
All right, we've got from Dylan, how many piles are installed at each test location? I heard two, but is that for each type of test?
Speaker 4: Tamara Hashimoto (00:59:23):
I just realized I didn't go over the frequency that we perform pile load testing. So on your solar project, within the solar arrays, we perform, we have one pile load test location per 50 acres. And then at each test location, we'll have at least those two test piles for axial tension and lateral testing. And then depending on the soil conditions, test a certain number of those load test locations for compression load testing in which we'll install a third compression load test pile. So what was the second part of that question? I don't know if I covered everything.
Speaker 2: Jessica Turner (01:00:04):
Speaker 4: Tamara Hashimoto (01:00:05):
See, or did that cover it?
Speaker 2: Jessica Turner (01:00:08):
I think it covered it. Okay.
Speaker 4: Tamara Hashimoto (01:00:09):
Yeah, if it didn't let me know.
Speaker 2: Jessica Turner (01:00:13):
Okay. Next, has there been standardization applied in the pile drive time calculations to account for the different hammer, blow strength of the various pile driver brands and sizes?
Speaker 4: Tamara Hashimoto (01:00:29):
I don't know if we've done anything. How about you, Scott? Typically we're just presenting our we'll present on those plots, like our results, and then we'll give the pile driving or pile the pile rig type. And then some clients will request like the specs of that pile driving rig. But for us on our end geotechnical engineering end, we are not doing anything with that data. Do you know of anything, Scott?
Speaker 6: Scott Neely (01:00:57):
That's correct. Tamara. We know that different hammers deliver different energy, but in general, all the pod drivers that were aware, they're putting this at near 100% of the capacity and then they turn it on. And so that's generally what we understand contractors are actually doing as well in the field. So we're trying to emulate what the contractor is doing with that power driver.
Speaker 2: Jessica Turner (01:01:32):
Speaker 6: Scott Neely (01:01:33):
We just don’t know the difference between the hammers.
Speaker 2: Jessica Turner (01:01:38):
All right. Thanks Scott. We do have a lot more questions in the queue and we are kind of running out of time. So we'll get one more in there. And then if we did not answer your question, we will follow up with you in an email. So this next one is, can you discuss and compare ground screws versus piles from a geotechnical standpoint,
Speaker 4: Tamara Hashimoto (01:02:07):
I don't worked on a project with ground screws. I know that's a good alternative for harder soil conditions. What I have heard is it's pretty costly to install ground screws, but I know they get installed to a certain torque instead of a certain embedment depth sometimes. And that whoever the specialty contractor is that has those ground screws, they're the ones who are going to be installing and performing the load testing of those gr ground screws. And then Terracon will be present to document and record the results. But Scott, do you have any other feedback on ground screws?
Speaker 6: Scott Neely (01:02:48):
No. I think ground screws though, is we need to be careful of the term only in that ground screws. A lot of people might think of helical piers. And yet I do know that there are several proprietary screws out there. One is by TerraSmart. Another one is by Ojo. And so I don't think we know exactly what those costs are pile and how it compares with just a regular steel pile. So I think that would need to be farmed out by each of those suppliers and the actual costs.
Speaker 2: Jessica Turner (01:03:29):
All right. Very good. Well, we are at time and we do want to be respectful of the time that we set aside today. So like I said, if we did not answer your question, we will have one of our solar subject matter experts just respond to you in an email directly and we appreciate everyone for hopping on. And we definitely thank Tamara and rich and Scott for helping us with this as well. And we will be sending out that email with the recording of this. And we'll also go ahead and put the link for the first webinar in our follow up email as well. So with that hope you enjoy the rest of your Wednesday and take care everyone.
Speaker 4: Tamara Hashimoto (01:04:12):
Thank you. Take care.
Speaker 5: Rich Henry (01:04:14):
Speaker 6: Scott Neely (01:04:16):
Client Development Manager
Tamara Hashimoto, P.E.
Department Manager & Solar SME
Director, Customer Success
Scott Neely, P.E., P.G.
Senior Consultant, Solar SME
3. Electric Transmission Routing from the Eyes of a Geotechnical Engineer
Welcome to the third webinar in our Geotechnical 101 series! We are excited to have you back to learn more about electric transmission routing (ETR) through the eyes of a geotechnical engineer. In this webinar, we will be joined by Travis Kassebaum, P.E., ETR Subject Matter Expert. He is excited to share his knowledge and experience to provide you with tools to make the most of your routing journey.
Travis will cover:
- How practitioners utilize Terracon historical data to receive preliminary design parameters and identify highly critical areas of risk prior to performing field exploration.
- What a typical geotechnical ETR field exploration and subsurface site characterization includes.
- When site and subsurface compatibility and engineering consultation is warranted.
To tie everything together, Rich Henry will give a live demonstration of Pivvot’s Route application, which can be utilized to generate preferred electric transmission corridors with associated crossing reports in hours, rather than weeks.
Rich will discuss:
- How to determine preferred, low avoidance, avoidance, and exclusion constraints to meet business objectives.
- Where to identify route alternatives, permitting issues, and collocation opportunities earlier in the process.
- How to save associated overhead costs with reduced research, resource time costs, and time on site and in the field.
- How to compare routes against a cost surface to select the optimal alignment.
Speaker 1: Jessica Turner (00:00:00):
All right. Hello everyone. We will give it another 30 seconds or so before we officially get started. I will go ahead and welcome you here to the call today. You're excited. We've got some great guest speakers and it is the third and final of our Geotech 101 series. So, my name is Jessica Turner and I am the client development and marketing manager for Pivvot. And I have been actually with Terracon for a little over 10 years now and I was super excited to hop over and join the Pivvot team when they became part of Terracon because I love innovation and I love just getting in there and being visionary and trying to disrupt the industry a little bit. So as we are starting here, just a couple things to keep in mind. All attendees have been muted. However, we do have a q and a that is open, so you can utilize that q and a throughout the presentation. However, we probably will not stop and answer questions in the presentation. We'll go ahead and kind of gather those up and answer those at the end. And then when we are done here, everybody that has registered will receive a recording of the webinar and it will be available for you on pivvot.com.
So here at Terracon, we do start every meeting with what we call an IIF moment. So incident and injury free. We like to keep safety at the forefront of everything that we do. And October is pedestrian safety month. So, there's just a few sobering facts over here. I'm not going to read through them all, but unfortunately the trend is not great. Since 2018, we have risen from 5.8% to almost 12% of the pedestrian deaths across the United States being children 15 or younger. So just something to keep in mind is to make sure that especially when you're in school zones or you're in neighborhoods where there are kiddos running around, that you are just being extra diligent, giving yourself time to stop and look ahead and be aware of the situation and of pedestrians.
So, as I mentioned earlier, this is the third installment of our Geotech 101 series. And thank you everyone who's enjoyed the first two. We've received some great feedback there. We will have the Environmental 101 series starting in the beginning of the year. So you've got November and December to have that time off with your families and when we'll, we'll start back up with the environmental series and bring some Terracon subject matters in on those as well. Subject matter experts, sorry. So today we have some two very awesome guests that I have known for quite a while. We've got Travis first and our, actually, I'm sorry, it's Rich first. And he is our director of Customer Success with Pivvot. And he's brought over, he brings over 15 years of experience of in the consulting product management and system implementation role specifically within the energy sector. And then we have Travis Kassebaum. He is the geotechnical department manager in our St. Louis office. And his role today is really highlighting his subject matter expertise specifically with electric transmission routes throughout the country. So he gets involved, involved and helped out quite a bit.
All right, so Terracon has quite a large number and extensive amount of experience throughout the country. I was really impressed when I was pulling these numbers last week. We have, in the last four years, we have more than 4,200 electric transmission projects that have been completed throughout the United States. And we have projects in all of the contiguous 48 states. On top of that, the ENR rankings just kind of came out and you can see we are continuing to increase on the Terra side. We made it up to 12 with the hundred pure designer firms and 21 for the 500 top 500 design firms.
So, in today's webinar we will touch on electric, electric transmission routing and how Pivvot can be utilized to help with identifying those alignments and routes. And then Travis is going to talk about how Terracon takes some of that historical data that they have and they get it in your hands earlier for preliminary foundation parameters. And then Travis is going to talk about really what a geotechnical engineer is doing and looking at during that site characterization and the engineering consulting that goes along with that. And then how to keep your geotechnical engineer involved during the construction process. And then we'll leave some time for q and a at the end.
All right, so at Terracon we have a newer concept that came about last year, and that is how we can be of assistance to you and serve you throughout the entire project cycle. So, we think of this in four different phases, and the first is when you're out there and you're selecting a site, and we want to help you make really smart defendable decisions in that time. So we've got two services that can help with that. And obviously Pivvot is one of them. And then we have stage one and stage one is where we are wrapping up those preliminary design parameters as well. And then the second phase is the design and mitigate phase. And here is really where the geotechnical and environmental services come to light. And then we've got the construct phase. So that's where we're going to get our materials testing team involved, as well as keeping Geotech in the loop so that they can be part of that process. And then the fourth phase is managing those assets after they've been developed.
All right, so we're going to switch over and we're going to talk about Pivvot. And when we think about Pivvot, we're more than just a GIS platform. So Pivvot streamline, streamlines sighting, suitability analysis and permitting for energy projects by highlighting where those possibilities exist. And then eliminating sites with fatal flaws even earlier in that project process. So, we do have a few applications, and the first is citing, and that's where you're just going to be citing by acreage for energy projects. And the second is take if you have a site already established, pulling together that information and understanding the context and the location intelligence around what's already on that site. And then the third is route, and that is really where I'm going to hand it off to Rich and he's going to be walking us through that as well as giving a demo today.
Speaker 2: Rich Henry (00:08:14):
All right, thanks Jessica. You want to keep that slide up? Yeah, let's go to the next one. Okay, so by way of introduction, this will be a very brief introduction to Pivvot. Of course, we're looking, we would love an opportunity to sit with you all and dig into the details, but what Jessica was saying is pivvot. Pivvot is it is a platform made up of applications. It's a platform made up of applications sitting on data, and that's really important. I also think it's just important to understand that it is a platform. Our solution is being used by two and three person shops on up to some of the nationally known utilities and EPCs. And I think that's an important distinguishing piece of our offering, which means that which means that we can support large and small scale operations. And we're also, from a security perspective, we're SOC two compliant.
And that has been really important, particularly in today's environment with security. So Pivvot, as I talked about, and we'll talk a little bit more, we build our applications on our data. We'll get into those details in just a minute. But the intent is to be able to allow folks to be able to get into this conversation of siting, exploring the data, exploring their project areas very early with a comprehensive amount of data to help you understand and mitigate risk. And that again, covers some of those siting from a wind and solar perspective and also from a routing, routing or corridor perspective, be that electrical transmission or oil and gas. As that conversation evolves, of course it's nice to be able to find those sites. It's nice to understand where those corridors are, but you're also going to have to have some of those analytics behind it.
So how many acres of high depth to bedrock are occurs in my particular area? So that's where we get into some of those analytics and reporting, whether that's impact reports, constraint reports, crossing reports, et cetera. And also you'll notice there on that third bullet point in the middle, we've recently released cost estimation within our electrical transmission routing. And when I say recently, I mean last night. So we'll dip our toe into that conversation. We're super excited about that because it just expands what our solution is providing to give you all a much greater perspective of what's happening on a particular project. So as we continue through this sort of life cycle here, we move into supporting collaboration, so produce all the results, produce the deliverables, et cetera. We can see the routes, but we need to also be able to pull in outside all the stakeholders, whether they're internally or externally into the conversation so they can start having some visibility and be able to start commenting on what's happening on those particular projects.
So we'll go ahead and start talking about the data a little bit. Like I said, we have built our applications and our platform on top of a lot of data. I no longer remember how many data sets or terabytes we have. This is kind of a summarized version of our data inventory. We cover lots of different topics, whether that's talking about environmental justice or whether it's talking about surface and subsurface data. And a couple things to note here is that the information that you're seeing on the screen is updated anywhere between 30 and 90 days. There are a couple exceptions there, but we keep this information up to date, we're tracking the metadata on it so you'll understand when the last published date was and where the agency is coming from. I should also mention that when we think about our data, we think about our data in a few way or several ways.
The first one of course is the publicly available data. Many of you are probably very familiar with those data sets. We probably have some that we've been pulling in based on customer feedback that you might not have typically included in your conversations to we have brought those in to make those available. And then another way we think about our data is some of the licensed information that we have that's going to include things like the energy infrastructure data. We pay a fee for that and we are happy to do it because that information is significantly better than some of the publicly available data. We, given the climate around energy, having a more robust inventory of where these existing assets exist is very important to the conversation. And we just felt like the publicly available data was just grossly insufficient. So we have that included in our platform.
And then of course we also have parcel data for the entire United States that you can not only visualize, but you can also download if you need to leverage that into your own systems. Third way we think about data is not actually ours, but actually yours. So you do have the ability to upload your information into your account. It's secure, it's only available to you, but you can pull your data into the account from a visibility perspective or from an analytics meaning that you can use that information to help create your routes or help with some of your other siting activities. And then the last way we think about data, and this is we're at probably 18 months now since we've been acquired by Terracon. And it is presenting a incredible opportunities, not for just Pivvot, but also Terracon, right? Terracon is dead set on building out a much more robust digital offering.
They've been in operation now for roughly 55 years and they've got over 2 million boring locations that help describe the actual mythology at these locations. And now it's time to find ways that we can leverage that information. Jessica mentioned the stage one, we use that information to support our stage one efforts and now we're finding ways, innovative ways to bring that information and make that available inside our application. And it goes without saying, the possibilities are super exciting for us and also really exciting for our customers. So, we're going to talk about route at a high-level route was designed to connect dots, not only connect dots just from one point to the other, but any opportunities in between. So you'll have a start point in endpoint, you might have some way points in between. And then we drive that routing based on preferences and we're using that data.
It goes without saying that any routing project is going to be controversial. So the ability to have objective routes, routes that are built based on your preferences, but also built around data so that you can defend those if necessary is very important. And then also being able to have that data in hand will be critical. So whether that's reports or the actual spatial data or the actual spatial data and then the ability to share that information and collaborate on that is also equally important. And so, what I'd like to do for the next 10 minutes, I'm going to walk through the routing application. This is not meant to be a deep demo of the application is just meant to kind of introduce it and then also tee up the conversation for Travis. So the routing application, I'll go ahead and start trying to share my screen as I talk.
The routing application is meant to produce, of course, produce the routes, almost there produce the routes, but also all the data to support it. And that data will be used to help feed some of the activities following that preliminary routing exercise. And so we're talking about things like pulling in survey crews or geotechnical crews, for example, what travels will be talking about. So what we're looking at right now is actually one of the deliverables of our routing application. My agree, we refer to this as a site view. The intent here is to export out the results into a mapping environment where you can pull in your internal stakeholders or external stakeholders so they can start to visualize those routes on a map and start having those communications or conversations about what they're seeing. So, what we've got right now is we've got to start point over here in Monticello in the bottom left, and then over here we're heading towards Birmingham and we've got two routes.
And these routes were generated using two different methods. One was just kind of greenfield routing, understand what the preferences are in terms of what data types of features or data do we want to avoid, are we okay passing through or nearby? And then the blue one represents a route that was based on co-location, right? And so you can see for the most part with either existing power lines or existing road infrastructure. The other reason I wanted to start out here is because we create a layer, it's called our suitability map, which is a graphical representation of your preferences. So, when you go into the routing application, you're going to go configure this algorithm that says, Look, we want to avoid this, and we prefer that. But this suitability map allows you to kind of dissect what's happening and this entire aoi, and even if we took the routes off the map right now, you would start to get a sense of what are the obstacles that we're potentially facing in this project area.
So this has been a huge asset for us, particularly as we try to communicate to our customers why the route's doing what it's doing. So you can start investigating it so you can start iterating through those opportunities. I'm going to zoom in here just a little bit and you'll notice anything that is kind of dark orange to red is something that we want to exclude. And you can see examples of that on the map. So for example, right here, I know that this is a cemetery with a thousand foot buffer, and so you can see how that route is kind of skirting that. And then up here we've got a highly populated area. You can see how even though it's along this road, you can see how it's kind of avoiding that area as well. And then if we come over here, you can see the same sort of activity happening.
So it's taken it very literally in terms of the data, in terms of the data as it goes through its kind of routing process. A couple other things that I think is worth mentioning is that this suitability map represents again, your preferences, but you also have the ability to come in here and turn on things like the wetland information to start visualizing that data. We can also come down here and turn on the power line information. And then if we come down a little bit further, we can turn on some of the sergo data, whether as it relates to steel or concrete. So you can start to visualize those layers on the map and start to interpret what's going on in that particular project area. So, with that said, what I'd like to do now is we're going to actually jump into the routing application itself.
And again, in the vein of starting from the deliverables and working towards how we create those routing projects, we're going to jump into some of the reports. All right, so what we're looking at right now are crossing and impact reports, and I've got two of my routes enabled right now, so I can do that side by side comparison. At a high level we can see the difference in length. And as we start to scroll down, we've talked about co-location. One of my projects, this one over here on the right, you can see that it's heavily co-locating with power lines and roads, whereas this first option here is primarily going greenfield. And then as we continue to scroll down, these dark bars here represent our different data sets. I've gone ahead and expanded things like depth to bedrock so you can have an appreciation for some of the reporting that we're doing, some of the things that could pose some potential risk for you as you develop this project.
And so, we're going to report to you the mileage and also acreage impact on those different depth to bedrocks subtypes. And then we're going to also have crossings here. So how many pipelines or power lines are we crossing with these particular routes, flood plain information. And then we get down to some of that surface and subsurface data. So we do have the NRCS sergo data, which is a very complicated data set and we used to just report on it in its raw format, but we found from conversations with our customers that just wasn't granular enough. So what we've done is we've carved out some of that data to speak to some of those key data sets, those key attributes that could pose risk. So we have things like corrosivity as it relates to concrete, as it relates to steel, what is the depth to water? Do we have hydro conditions?
What are the hydrologic soil groups in that particular area? Those layers have been particularly helpful as a project moves from that kind of site origination or development stage to that preliminary design and engineering. And then of course, as that makes its way to conversations that Travis will start to have, of course we're going to also report on some of the hydrology information and environmental information as well. I'm going to go ahead and jump to this next report here. So that first one was our summary report. We also have access to what we refer to as detail reports. And so these are the individual data sets that we're reporting on. I'm just going to comment on a couple of them that I think you might find interesting, one of which is the control point table. So, what we're going to do here is just identify all of those points of inflection along that route, so you can start to have an understanding of what that really looks like.
And then as we start to scroll down here, let's see here, we'll get down to that as it relates to concrete. So as you start to think about those foundations, you can start to have an understanding of where potentially we have areas of high corrosivity. So we can come in here and filter this information down to some of that data. We can also come in here and actually visualize where those particular features exist, so you have a sense of where you might want to avoid as you start to consider where you're going to be putting those foundations. As we continue to scroll down, I think it's important to also mention we have that property data, I mentioned the parcel data. We have that subscription that has nationwide coverage, and so you'll be able to understand what landowners you're impacting, but not only by name but also in terms of acreage impact.
And what I'm hoping you're starting to kind of see here is that these reports are not only to identify where the risks are, but they're also going to be very helpful as you start to generate estimates along your project. And just one other data set that I thought or table that I thought might be interesting to you is this slope and elevation table. And so what we're trying to do here is actually describe the workspace. So we have elevation along that particular route, but we're also reporting what's happening on either side of that route, anywhere between 30 feet and 60 feet. And so, we're going to start relaying back to you the elevation characteristics and also slope characteristics. So as you start to consider that workspace and some of the obstacles you may face from that perspective. All right, let this bar is in my way. You come over here and turn on this next report.
This is that cost estimation report that we talked about earlier. Like I said, this just got rolled out last night and this cost estimation report is built on the miso cost estimation template. And the intent here is really for planning purposes. And so we provide our kind of crossing and impact reports so you understand some of the features that you might be facing where you might have particular hazards or obstacles that might present challenges from a construction or engineering perspective. We want to start extending that conversation into an actual kind of monetary cost. And so again, we're leveraging that miso cost estimation template. You'll be able to come in and modify those parameters. Right now we're just seeing the reports, but it's as part of the routing application, you can come in and start assigning cost per structure, cost per acre of crop land or pasture land or whatever the case may be.
And we'll generate this cost estimate for each of your routes. And so what we're looking at right now, again, are those two routes that I had selected previously. And now we can do a comparison side by side comparison. In between the two, you can see there's roughly a 10 million difference. And then we have some other summary information up top and then we get into some of the actual parameters that are part of that cost estimation template. So we are super excited about this, we're looking forward to getting feedback from our customers. It's really exciting for us to be able to extend the conversation from some of those risks that are actually on the ground, some of those obstacles to actually some of the actual monetary costs associated with generating or producing these routes. So we started out with that map, we saw those routes on that map, the ability to visualize those, share that information with your stakeholders.
We talked about that suitability map that really gives you that visual insight on what's happening on the ground in your particular project area. We've covered how we go beyond that subjective view of seeing the map, the routes on the map to the actual analytics behind that. I'm going to just take two minutes here to just talk about how these projects are created and how these routes are generated. So this is really talking to the button pushers in the room. So out of the gate we need to identify our objectives. Again, I said that you could have at minimum two objectives, your start point and endpoint. We also support having multiple objectives. And so maybe you have a start point over here and you have several endpoints that you want to consider along an existing power line. We can support that as well. And once we create those objectives, that's going to help us define this area of interest.
The reason I'm bringing this up is because getting back to that conversation at the introduction where we talked about how these projects and be very controversial, at some point you may need to defend these routes, whether that's generating those preliminary routes or maybe months down the line. So we create this aoi, this sandbox represented in black so that we can create an archive of the data that's being used to generate the routes that we're seeing on that screen. And so you'll also have access to those reports that again are based on that particular data. So if you find yourself having to defend these routes, you'll have the information necessary to do that. So once we have those objectives in place, this is where you get to come in and you'll start to configure this, what we refer to as our play. And play stands for, let me get over here, prefer low avoidance, avoid and exclude.
This is that algorithm. So you come in, slide the sliders based on your preferences, based on the project demands, et cetera. We'll generate that suitability map and then we'll again, we'll use that suitability map to basically connect those dots. So this is where you'll come in and start assigning those preferences. And I should mention that this is a very iterative process. So out of the gate for my particular project, I created two routes. Again, we talked about how one of them was primarily greenfield and one of them was basically based on co-location. And then I also went in because these routes out of the gate are going to have nuances about it that may not just make sense. And so you'll need the ability to come in and make kind of tweaks to those routes. So you can see right here in this particular example where my red one was the original, you can see lots of points of inflection.
I came in using the pivvot route application to come in and smooth out that line based on the data that we have. So we acknowledge the fact that at some point these routes are going to leave the application, but we want to try to keep that conversation that preliminary routing inside the platform as long as possible until you start putting boots on the ground when inevitably conversations with landowners and that sort of thing are going to end up modifying the route that certainly can occur here or oftentimes it's pulled out and pulled into some external system. Getting back to this page right here, this is just where you generate your various route scenarios. For any given project, you may have dozens of route scenarios. We have customers that are routing 300 mile pipe, excuse me, 300 mile electrical transmission lines, but they have thousands of miles in there based on the different alternatives that they've created.
So the application well support very large long electrical transmission lines to things like in this example are like 25 miles. And in terms of speed, which is important for folks, particularly in today's environment, we're basically routing and generating these reports at about a hundred miles per hour just to give you a sense of how quick we're producing those results. And then just really quickly on deliverables, we've talked about the reports, all that information can be exported out to a spreadsheet and then we want to give you that raw data. So, if you need to pull that into your GIS, AutoCAD environment or whatever, you'll be able to export out that data and pull it into your systems as well. This conversation is really important because we, as one of our slides said, we're not trying to act like we are GIS, right? I mean we're based on GIS, our applications are based on GIS, but we're not trying to replace any sort of GIS systems.
The intent is sit alongside and also provide opportunities for some more of your technical resources to do some of the more complicated analysis and let us do some of the heavy lifting and some of that monotonous work and also be in an environment where you can aggregate that data but also have it available to you, whether it's via our platform or API, to leverage that information and not have to worry about keeping it up to date. And of course the intent is to be able to provide you this information so you can make better and more informed decisions. And so as this conversation on your particular routing project evolves and as you start to hand that information off to folks like Travis, they'll come in with that level of certainty around that project as opposed to finding risks later in the process. So, with that said, Travis, I'm going to go ahead and hand it off to you. I'm going to go ahead and stop sharing if you want to take the screen.
Speaker 3: Travis Kassebaum (00:31:46):
Yes, thank you Rich. Appreciate it. Very cool information and exciting and as Rich mentioned, it's been a great journey so far seeing how their data and what they offer can help supplement what Terra's been working on past several years. So, I'm going to talk a little bit about geotechnical services and how that pertains to a transmission line project. So the first thing is really looking at that preliminary existing data that's out there using the information that Pivvot pulls together, but also using data that Terracon has acquired over the years from our services of drilling borings all across the country, then going into field testing, doing lab tests, doing the engineering analysis, and then working with the design engineer throughout the process for these transmission line projects. Really the data utilization has been a big focus for us. As Rich mentioned, we almost have 3 million data points across the company and as you can see, we have a very enormous footprint of offices all over the country.
This map here gives you an idea as to where the number and the quantity of our borings are located. It's a heat map kind of showing those purples and blues. That's where we have the largest density of current data. And as you go to the west, you can see there's maybe a little few more locations with a little bit sparser information out there. There's over 1100 different public data layers that's using some of the data layers that Pivvot has brought with them and at our fingertips. So by using the combination of this existing data, the public data and terra's historical data, we're able to come up and develop these preliminary reports called the stage one report. And what we're doing for the transmission line projects is this stage one report is supplemented with what we call our preliminary foundation design parameter. Our PFP and the information with the PFP is really used for figuring out what type of transmission structures are going to be needed across your site.
So, we're looking at the soil classifications across this alignment that has already been prepared by pivvot and their routing tools, seeing which ones are optimized, using that information, breaking it down by the soil types, breaking it down by what type of rock we're going to encounter. And then looking at our existing historical data that we have to basically be able to develop design parameters, very preliminary design parameters of what we think would be acceptable parameters to use for this preliminary design. Oftentimes when we get pulled into a transmission project, it is very early on and we may not have site access to go out there and drill boings at the transmission structures. There may be permitting issues, there may be site access issues, it may be the wrong time of the year to be able to drive across the farm field. And by being able to access our existing data that's out there and use it, we're able to really help design engineers kind of get a jump on the design process with confidence. So I'm going to share a short little video. So many of you probably know Scott Neely. He's one of our transmission experts across the company. He's really integral in helping develop and coming up with the idea of this preliminary design parameter concept. And so he's prepared a little video. I'm going to share, it's about four minutes and then we'll jump right back to this PowerPoint,
Speaker 4: PFP Video (00:35:43):
Understanding how we have obtained estimated blow counts for various soil component horizons.
Speaker 1: Jessica Turner (00:35:52):
Hey Travis, various
Speaker 7 (00:35:53):
Speaker 1: Jessica Turner (00:35:54):
The, it is not showing the other screen.
Speaker 3: Travis Kassebaum (00:35:57):
Oh my goodness, why not? Okay, let me stop share and go back to it. Are you seeing it now?
Speaker 1 (00:36:13):
Yep, you're good.
Speaker 4: PFP Video (00:36:15):
Understanding how we have obtained estimated blow counts for various soil component horizons at various locations along the transmission line alignment. We will take that information now and have put it into our predictive foundations parameters spreadsheet. That spreadsheet is what you see here in front of you. There are two tabs, there's one tab with structure locations and then there is another tab with soil properties by series. We will get to that tab in just a second. Basically what one should understand is that on this first tab as provided by the transmission line engineer, we have the location of all the different structures. Here are the structure, numbers, segments, their location, and then due to their specific locations, we have specific NRCS, soil component names and series this far. I column 'em is a percentage of each of these components made up by this specific soil series.
Okay, so let's just take for an example and go to canola. Let's say we wanted to know this tower here, number six, which is canola. We'll click on it and we immediately jump to the second tab. And here is canola. Here's the canola series. The canola series is comprised of some fact clay over weathered rock over rock. Here are our estimated depths for these various layers based off of our estimated values. And in this case, based off of this one particular project, we have drilled a boring on the project in canola. If we had not would see like in the dentist series, we have the estimated values which come from the virtual soil borings themselves. So, after we have this estimated blow count for noma series and in this case a measured blow count, we can obtain the dry density, the soil parameters C and fee, or if we happen to be in rock lock, we are with canola, the estimated C and fee of the rock itself.
We do assign water contents based off of our experience or any existing information such as from these borings. We also assign the LPI parameters. This is a parameter for which the rest of the spreadsheet is tied to. So we assign these values. So after we have assigned these values and we have our estimated end value, the spreadsheet calculates the end bearing the skin friction, the mods of Deion for the rock and from those parameters then a transmission line foundation engineer can go in and actually design the foundation for the project just so that each, so that the transmission line design understands his exposure or risk or the owner understands their risk. We have assigned a confidence factor algorithm here to the right. Now this algorithm can be modified, but basically this algorithm is based off of the number of borings that were identified for this particular soil series, the number of towers that are in this series, and the percent of soil component for which the series makes it up.
And in this case we blend these three together in an algorithm and in this case we came up with a 97% overall confidence factor. Thus it is highly confident there are various confidence factors such as here's 67%, it's fair to even chance down a little lower, we can get pretty low like 0.3 less than fair to even chance. Those are all outlined here in this summary table. So this soil series table will cover the entire project unless there is just no information such as here is a soil series hits soil for which there is no data. In that case, we can come up with estimated parameters, but we would want to talk with the transmission line engineer and owner to assess how they would like for us to go ahead and assign these parameters, understanding what level of risk would they be wanting to assume. So that is our foundation parameters spreadsheet.
Speaker 3: Travis Kassebaum (00:41:10):
So, as you can see that combined with the pivvot information, now we have a good route and we can also look at it from a engineering geotechnical engineering perspective as to really understanding what the subsurface conditions are going to likely be like at those individual structure locations. Sometimes we have the individual structure locations and can assign the parameters for each structure. Sometimes it's earlier in the phase, we don't have actual structure locations and we'll assign take a measurement or a snapshot every quarter mile or maybe every mile and provide what the information at that location to give good ideas as that whole alignment.
In addition to coming up with those design parameters during the PFP process and our stage one process, we're able to identify a lot of potential hazards across this alignment that may be encountered and help identify those and maybe during the routing process help deter some of those. And especially when we're at that pivvot data, as I know they have a lot of the tools that will identify such as Rich mentioned the slopes and there's cars and shallow bedrock and some of those features that we can try to avoid with the overall route. And then going into some of the more traditional geotechnical engineering. Prior to having all this data at our fingertips, it wasn't until the route had been determined and we're ready. We have site access agreements in place and we have structure locations determined, we'd actually then go out and do the borings.
The beautiful thing with the PFP is we can use our historical data to come up with some estimated values, estimated parameters, and then when we actually go out there for drilling or CPT for the physical locations, we can go back and supplement that spreadsheet so that the design engineers already using the spreadsheet and now they have a increased confidence with those physical borings drilled for their project. The geotechnical process will kind of then go transition into the site visits, the borings, maybe geophysics, C P T, load testing, electrical resistivity, thermal resistivity, just dependent on the needs for the particular site and what's what we're looking at. Soil lab testing for transmission projects. You kind of see a list of different tests out there that we'll perform in house and it's really dependent on the location, the type of soils or rock that we're going to encounter and what some of the concerns are for those individual sites.
We'll kind of direct what tests we determine are suitable and needed for your transmission project. Thermal resistivity, so if there's any buried conduits going out there, understanding how the thermal properties or the soil for dry out may perform and make sure we don't have any kind of overheating going from a substation to various projects within that transmission line route fuel, electrical resistivity for grounding, going out there and collecting that resistivity data to supplement the boring data and the soil data that we already have collected. Sometimes we'll get into projects where there's known pipelines but unknown where those pipelines exist. And going out there with some geophysical tools, we're able to map large areas very quickly. As you can see here, we have a picture of our EM tool that you mount behind a pickup truck and drive down the highway, drive down multiple fields and find those potential pipelines that are in the area as well as looking for archeological sites, unmarked graves, historical sites, items that we know are in the area, we just don't know their actual location.
Once we've collected all the data from the field and all the preliminary information that we've pulled together, then for each structure we'll be able to go through and really define and assign detailed information for both axial and lateral design parameters that then the transmission engineer will be able to use and finalize their design for the overall structure. In addition, our reports will include options and recommendations depending on what's needed, but definitely foundations for your transmission structures depending on the soils encountered and the loads of the structures. Maybe for the lighter loads it'll be embedded poles, you get heavier loads, you're looking at drilled shafts. And then of course, depending on the site conditions and the loads, maybe something like micro piles or tension list peers, foundations might be needed.
Little bit, and I'm not going to go too deep into it cuz I know we've already had a Geotech 101 webinar, but drilled shafts, it's a very popular and widely used type of deep foundation for transmission structures. It's very versatile, it can be drilled in almost any condition out there through cobbles rock, frozen ground, soft soils, hard rock. It just kind of depends on what you're looking at in the load. Whether or not the drilled shaft may or may not be a great tool for that particular structure. Micro piles a little bit more of a specialty, especially useful when you're in an environmentally sensitive area. There's not the big drill cuttings that are coming up with the drilled shaft method and so there's very small footprint access in small areas, much smaller rigs. So if you're going through an urban area, it might be the rig of choice and the foundation of choice if you get into needing to really support some of your heavier loads considerations for an anchor deep foundation where you can really withstand some of the heaviest dead loads as well as the tenuous peer deep foundation. Kind of similar, just different type of style, same method of going in there, drooling out the soils and filling it. The 10 tension list may be a little more cost effective in some applications cuz you have less reinforcement and it's lots of concrete within a steel tube essentially.
So we go through, do the preliminary work, we do the field testing, we do the lab testing, we write the geotechnical report, we have communications with the transmission line engineer, the owner, they have a good game plan, they're moving forward with construction. Sometimes unfortunately the last day Geotech engineer will be involved with the project. Hopefully it's not and there's a lot of value and other aspects that the Geotech engineer can assist with and help improve the final deliverable of the overall project during construction, not just having our construction material testing team out there, testing the concrete testing back fill compactions, but also during the construction of these deep foundation elements. Drilled piers for example. There's multiple methods that they could be installed with depending on the type of soils that you're encountering, where ground water may or may not be will help dictate what method is going to be best.
Whether you do a dry, wet or even use casing for the drill drilled shaft. Having a good clean shaft excavation prior to pouring concrete into that drilled shaft is critical for the strength and known parameters of that drilled shaft. And with the loads that it will be able to withstand a good drilled shaft. Nice clean sides, kind of like what you see on the picture on the right one that may be a little questionable and a little harder to really understand how well it's going to perform is that picture on the left. If you actually look towards the middle of that picture, you can see exposed rebar on the left hand side of that drilled shaft, which is really going to compromise the strength in capacity of that drilled shaft. Some other anomalies that a experienced geotechnical engineer when they're out there on the site can help recognize and determine course of action on repairing or remediating.
The issue are listed here. There's also various tests that we're able to do on drilled shaft and other deep foundations to really understand how well uniform the structure was prepared and some of the other parameters that goes along with those deep foundation elements. Crosshole sonic logging known csl probably one of the most common for a drilled shaft. It's great at really determining do we have uniform, concrete all the way throughout the shaft? Is there any areas where maybe there's lesser concrete, a hole, a void within that drilled shaft? There's also limitations with cross. So logging sometimes we see bonding of the access tubes that would then make it challenging to really know if whether the anomaly that we see in the data is avoid or if it's simply bonding from that access tube. And that's where using a combination of some of the tools out there may be able to help provide good reliable information of that drilled shaft or other foundation element load testing of the drilled shafts or other foundations. Can it help prove that that element can withstand the loads that you're looking at and given the soils that were rock encountered and the actual installation, following the installation of that deep foundation element, the osl great tool to gather good data installed and kind of sacrificial at the bottom of the shaft and then be able to provide good valuable information of that drilled shaft to make sure and ensure that we're getting the capacity that was developed and was based on the design overall.
So, kind of summarizing a little bit, involving the Geotech engineer early, we have lots of data at our fingertips. Data that we didn't really have readily available five years ago is now at our fingertips and we can quickly compile that information to give good valuable preliminary information for your project during the post the Geotech report and issuing it, reviewing the plans and specs, making sure that what we stated in the report was understood, it was clear and it's been carried over to the actual design of the overall project. Were great at finding those little things that maybe was missed and help remediate that before it actually goes out to construction bid. And then during the actual construction monitoring, making sure that these critical aspects of the transmission structure are of what they should be, their quality foundation elements, they're going to withstand the transmission structures as they designed to summarizing the overall project life cycle like Rich talked about with the routing application that pivvot brings is really early on in the overall process and supplementing that with our historical data before the project actually gets kicked off before it. We have site access, we can give and provide lots of valuable data that may help determine where or where we shouldn't be going with a transmission line during the Geotech and design phase and including environmental services, we're able to help develop those engineering and finalize those engineering parameters that we provided previously in the PFP and then during construction onto managing the assets, our information's going to be available to the project for the entire life of the project.
And that kind of summarizes our overall presentation. We do have a few minutes here for questions. There should be a chat function. You should be able to type in any questions you have in the chat and then we can respond to those accordingly.
Speaker 1: Jessica Turner (00:55:34):
All right, and Travis, we do have one in there already. So, what are the usual thermal conductivity values you usually encounter and what are the standards reference that guide the decisions whether the soil is suitable or not from a thermal conductivity point of view?
Speaker 3: Travis Kassebaum (00:55:54):
So I will say I am not a thermal expert, but they are going to range really dependent on the soil conditions. A sand is going to be very, very different from a clay and highly dependent on the amount of moisture that's retained and within that soil.
Speaker 1: Jessica Turner (00:56:22):
Okay, thanks. We've got another one. As the project transitions to field work drilling, are you capturing any of the utility information and pivvot to use later as part of the continued planning process?
Speaker 3: Travis Kassebaum (00:56:42):
Rich, do you want to take that one?
Speaker 3: Travis Kassebaum (00:56:53):
I guess from the,
Speaker 2: Rich Henry (00:56:54):
Yeah, sorry. I'm sorry. Sorry, I was reading it. I was trying to come off mute. I mean we are taking that into account during the routing process. I know Travis was talking about that cool truck, the cool thing on the back, identifying some of the existing utilities out there. Like I mentioned earlier, we do have some of that utility information, those existing easements in the database so we're able to kind of flag those earlier in the workflow. Although I can't speak specifically as it relates to kind of that transition towards drilling.
Speaker 3: Travis Kassebaum (00:57:30):
And I guess that to that function, like you said, the GPR EM is a great tool. A lot of times these, if they're not marked in the field and you're in a very, very large field, it may be very difficult to know exactly where that pipeline is. And that's where some of the geophysical tools, we'll use that information from pivvot of where approximately those lines may be. And then we can go out there and fine tune it market in the field to ensure that when we're out there drilling or the contractors out there digging the foundations, we're not going to encounter and hit those utilities.
Speaker 1: Jessica Turner (00:58:14):
All right, thank you both. It doesn't look like we have any more questions teed up. So with that, if any more questions do happen to come in, we will answer that in our email with the recording. We'll also include Travis and probably a couple other Terracon subject matter expert for ETR in that email as well as Rich's contact information. So again, we just thank you all for joining us today and keep an eye out for the environmental series that's starting at the beginning of the year.
Speaker 2: Rich Henry (00:58:55):
Speaker 3: Travis Kassebaum (00:58:57):