How To Build an Engineered Retaining wall & Avoid Contractors that cut corners

[Music] This is the perfect cross-section of a retaining wall. You can see where all the drainage aggregate is and then you can see where the structural fill soil starts. Everybody go. [Music] All right, guys. We're going to be building an engineered retaining wall today, but we're going to be talking about the difference between an engineered retaining wall that holds up a load, which is this one, and then on this exact same site, we're going to be building the identical retaining wall, identical height over here, that does not hold up a load. And so, we're going to actually walk you step by step through the process on how to build an engineered retaining wall. The first thing I want to talk about real quick before we get too deep into this is when do you need an engineered retaining wall or when do you need to engineer a retaining wall and that is any wall that's over 4T in height or any wall that has a load on it and a load can be considered two things a hill another retaining wall or actually a structure like a house. So if so those are three things but technically any any wall that's going to be under those circumstances you need to engineer even if the walls under 4 ft in height at 3 ft in height. Another thing that some guys are going to be looking at this video and going screaming is well my county my city my blah blah blah doesn't require it. Who gives a crap? You're building a wall that you need to last for the customer. A hill another wall. Those things don't care if the county requires you to engineer it or not because they will eventually push your wall over and make it fall down if you don't build it the right way. That's the difference that we're talking about. So whether your county requires it or not isn't the point. The point is you need to engineer. Now let me show you something. Let's go. Let's actually look at an engineered plan. [Music] All right. Now would also be a good time for me to jump in here and explain the difference between a reinforced retaining wall and an engineered retaining wall, which aren't necessarily the same thing. A reinforced retaining wall means that it has geog grid in the retaining wall, but that doesn't mean that the retaining wall was designed by an engineer. You see, there's very few people that actually know how to design retaining walls. A lot of guys will go out and actually have a civil engineer design a retaining wall for them. And I'm going to tell you straight up, that's a big no no. Now, I know I'm going to have a bunch of civil engineers jump on here and tell me I don't know what I'm talking about, but I've tried to build retaining walls after a civil engineer has designed them, and they usually have way too many things wrong with them. They're either built overkill or underkill, and they're not designed specifically for the application that they are needed. Now, there are retaining wall engineers, and those are the guys that you want to design your retaining wall. And a retaining wall engineer is a civil engineer that has specialized in retaining wall design. They can they account for the types of soils that you have, the type of load you have, but then they also get into the mind of the installer and understand what it takes to actually accomplish this job. That's the third most critical element into building an engineered retaining wall. Now remember, a reinforced retaining wall doesn't mean it was actually designed by an engineer. An engineered retaining wall will typically be a reinforced retaining wall that is actually put together and designed and drafted by a licensed certified engineer that has experience in retaining walls. Sorry for taking so long to explain that, but I think it's pretty important that you guys know the difference. Southwest Wall 250 PSF. So, this wall right here is designed, this one behind us, to hold up a parking pad right here. And you can see that this is an 8ft tall wall. So, these horizontal indicators are actually the geog grid length. Now, this wall is 9 foot or this these grids are 9 f' 6 in in length. We're going to flip the page and we're going to show you an engineered retaining wall. Same height, different circumstances. The grid lengths shorten up by 2 ft. This is only a 7'6 in geog grid length here. But the layers of geogrid don't. 1 2 3 4 5 six layers of grid in this wall. And on the wall with the load, one, two, three, four, five, six layers of grid. So, you can see that there's a few different elements that go into engineering a retaining wall. And we're going to show you step by step what they are while we actually build a wall. Now, I think this would be a good time to jump in here and tell you one of the things you don't want to do with a retaining wall, and that's plant a tree on top of it. Now, bushes and shrubs are okay, but a tree actually represents a dynamic load. As that tree grows upward, the roots grow downward and push out. The retaining wall is not designed to resist that kind of movement. And then on top of it, when the tree experiences high wind and the tree starts to move and shake from the wind, that adds dynamic force into the wall below it that can lead to premature failure. So, bushes and shrubs are okay, but trees Stay away from holding the camera and as he's filling the bucket, I can't help but you see the camera jerk like this every now and then. It's be just my instinct to all I'm doing is technically I'm catching myself bucket flipping the material up and into the bucket even though I'm I'm technically not in the machine and I'm literally holding the camera. Still can't help it. I feel like I need to bucket flip sometimes. All right guys, so when we build an engineered retaining wall, it's not excavating back for the depth of the block and the depth of the drainage aggregate which we can see over there. Can you pan over there real quick? You can see all of that material we imported. How many tons did we import, Todd? Oh, like 64 ton just for this portion of the retaining wall. All right, guys. So, when you're trying to figure out how many tons of rock you need for your retaining wall project, measure out how many square feet of wall you have, multiply that by 200, and that will tell you how many pounds of rock you need because the formula is 200 lb per square foot of retaining wall. Then you take that number and divide by 2,000 to convert the pounds that you need for your wall into tons because that's how it will be delivered out to your job site. So let's recap this. Take the square footage of your retaining wall, multiply it by 200. That gives you how many pounds of rock you need, divide by 2,000, and that converts the pounds into tons. Pretty straightforward, right? But what I want to show you is how far back we excavate for the geog grid. The wall guys is up here. The excavation area is all the way back here because we got to lay geog grid in here. We got to actually for this 8ft tall wall. We have six layers here. That's because we got a search charge. So we're designing this wall to be able to hold up a car eventually up on the top. It's a completely different design than a standard gravity wall. and a completely different design than just a normal engineered retaining wall that has no search charge or no load on the top. So, you've got to realize that you think you need to think ahead when you're building a retaining wall. What's going to happen during the life of this wall? Will it actually be holding something up so that you can build it the right way? [Applause] So you can see we do not let the geog grid come all the way through the face of the retaining wall because that looks like a hack job. That's as simple as that. But we get it as close to the front as possible. So when Blaine's cutting grid, he actually picks a line and he stays in between the line. I'll get try to get as close as I can to show you guys. Not rocket science, but I see guys cutting the backside of their grid higgled piggledy. And what happens is your next grid, next time you use that grid, you're not going to have a straight line to go through the face or it's not going to have a straight edge to go up tight to the face of the wall without it coming through. [Applause] [Music] All right, while we're talking about grid, we also need to explain the orientation of the grid, cuz there's a right way and a wrong way to this as well. You see, if you have a 200 foot long retaining wall, you can't just roll the grid out behind the whole wall, parallel to it, and say that it's good. That's not the right orientation. The geog grid needs to run perpendicular to the face of the wall. So, if your wall is right here, your grid has to run this way behind it. It can't run the long way behind it. It's just not meant to do it. Don't do it. Johnny Ne says, "Don't do it. Don't do that." All right. So, let's take a cross look at what we've got going on here. We're in the middle of a demo of an existing retaining wall. And this wall isn't that old. I can tell by the block they're using, but do you notice there's no drainage aggregate in it. And when you look closely at the soil behind this retaining wall, you can see that there's zero geogrid in it. And you'll also notice that this wall was initially installed as a double terrace retaining wall, which is a typical tactic that a lot of landscape companies will use when they're trying to circumvent the need for engineering. Well, what happens is when you put a double terrace retaining wall in is you literally need to take the height of the bottom wall, double that, and that's where you can then start the height of the second wall so that this second wall doesn't place a sir charge or a load onto the bottom wall. You'll see in this job site that none of that was done. And across the United States of America, unfortunately, it happens way too often. And there's no material locking it together. We do have some mixed in, but the rock that you see mixed in. Let's go in tight. Seems like that would be good base, but that's river rock. It has a little bit of angular stone in it, but it's technically a a 1/2 in river rock. Not doesn't make a good base. And how do you know? Well, take a look at the corner. Do you see where we go boop sagging down? We do not want river rock as back fill or as drainage zone because it doesn't lock in place. The block they used is the sole reason why this wall even is lasting as long as it is. That's an excellent block because there's so much mass to it. It's just such a monstrous block that it accomplishes the job even when you don't do everything behind the wall the right way. Let's take a look at good drainage aggregate right here. This is angular stone locks together. [Music] When there's rain in the forecast and we know we're not going to be on site, we dome all our piles, compact any open excavation areas and spots that we can't compact. We tarp. That way, when the weather cooperates, we're ready to get right back into work. Looks good, guys. You'd be done by tomorrow, right? Oh, at least quite a while. When you get into a big project like this, sometimes your plans change on the fly. Now, in an ideal world, the corner that butts up to the house would have been a radius. But here's what happened. It was too tight of a radius to make it work without compromising the integrity of the blocks. At least by going with a 90° corner in this situation, we're able to overlap each block and so that we can build upon it. An inside 90° isn't quite as good as an inside radius, but if you don't you don't have the room to make an inside radius, then an inside 90° is your next best bet because it's your only next best bet, right? So, let's go look at the backside and the magic that makes a 90° inside corner work. Now, I haven't seen this So, we're going to be testing Blaine and seeing how well he does. Here's Blaine. [Laughter] All right. So, um Blaine, can you actually hold camera for me? Cuz this is a really well done 90° inside corner. This is actually an overbuilt 90° inside corner. One of the things that I want to point out to you guys is a n the 90° corner is actually here. And Blaine's actually got it overbuilt all the way over here because now instead of cutting half C's or half blocks, he's utilizing a full block. It does eat up a little bit more material, but the longevity, the strength of this 90° corner in comparison to something where you literally snip blocks in half, there's no comparison. This is the way you want your 90° corner. So, let me let me come in here and show these guys exactly a closeup of it. You can see that the 90° actually stops there and he's built it out that way. He's built all the block all the way up on top of each other and brought it all the way back. You see? See? I mean, look at this. This entire block right here isn't even needed technically, but in our book, that adds strength to the entire inside corner. So, add it if you can add it. It's the right way to do it. If this was my house, this is how I'd want my 90° corners built. Damn. At least you do one thing right, Blaine. You notice it is still straight. It's standing still. Actually, I will go on record of saying Blaine and Todd are craftsmen. Nice 90° corner. Nice. Nice. Nice. All right. Another thing I want to look at are these lifts. So, take a look at this lift, guys. Literally, when was the last time you guys seen me out on this job? Two weeks ago. Oh, at least week ago. Week and a half. Two weeks ago, right? And I didn't I don't ever tell you when I'm going to stop in. So, it's not like you did this. The reason I ask is it's not like you did this for the camera. This is the way we operate. So, you've got a lift. It's compacted. The grid is folded up. It'll be folded out when it's ready to go. The dirt isn't left unfinished. Even where we step down. Now, this gets to be a little bit of a tougher area to do, but even on the transitions down, this is what I call rain ready. Todd, will you grab this camera? Really, what I want them these guys to see is this transition can't be left loose right here. So, you've got your elevation established here, and if you just let this soil go without compacting it, and you leave it rough, it's not going to be compacted when you go ahead and put your transitions or your lifts down below. You're going to always have these little tiny areas which can have settlement. What these guys have done is they've compacted all the way down, even in the areas where it's more difficult to compact, especially when you're using a,000lb plate packer like this. Can you see that in here, Todd? This is a beefy piece of equipment. It's not easy to run it up and down. But this is where they've got it parked right now because they've been packing the transition zones as well as the lifts. And we just walked up and we seen them putting a lift in. We've got Let's actually look at the lift right here. So, we can see. You can see right here. It's all compacted solid. And then I think you guys just literally put a four or 5 in lift in. Yeah. I mean, and realistically, you could put a 6 to 8 in lift in, but with this way, we know we're not going to have any settlement down the road. This is the perfect cross-section of a retaining wall. You can see where all the drainage aggregate is. And then you can see where the structural fill soil starts. And then this gets compacted. The grid gets laid out. And then, bada bing, bada boom, onward and upward. Heat. Heat. Okay, guys. Now, this one is good to go. The top of the wall. Here's a little fun fact for you. You can never compact within 3 ft of the backside of a retaining wall. That's just the g the technical G engineering term. That's what they tell you. We get a little closer than that. All right, guys. We went a little deep today. I hope I didn't lose you guys. You guys got to tell me down below. Did I include enough detail and enough information? And if so, is this the kind of videos that you guys like? Because if they are, then I'll try to make more of these guys to help you out. So when you're going out and tackling your own project, you you know the difference between a reinforced retaining wall, an engineered retaining wall, or if you're looking at hiring a contractor, making sure that they're doing the proper building techniques so that when your job is done, you don't have to call anybody for a very long time because it's done the right way. I hope this video's helped you guys out. You