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Utilizing Trenchless Technology in New Projects & Rehab Methods

Trenchless technology is a method of underground construction that involves minimal excavation or, in some cases, no excavation at all. It’s a rapidly growing sector in the construction and civil engineering industry. This family of methods, materials, and equipment is suitable for installing new or rehabilitating underground infrastructure with minimal disruption to surface traffic, businesses, and other activities.

Traditionally, installing new wastewater or water supply pipes in established residential areas is a high-impact process that requires removing sidewalks, roadways, and driveways and disrupting existing landscaping. However, trenchless construction technology is an innovative underground construction method that often eliminates the need for excavation.

Our experts, Wes Farrand, P.E., and Patrick Williams, EI, discuss all aspects of trenchless construction and how to incorporate this environmentally and financially sound alternative to traditional excavation techniques.

Podcast Agenda

  • Why Trenchless Technology Demand Has Increased (1:29)
  • Intangible Community Benefits (2:38)
  • Understanding Possible Downfalls of Trenchless Construction (3:56)
  • New Trenchless Insertion Technologies (7:36)
  • Pipe Material & Application Considerations (15:22)
  • Trenchless Construction Methods for Rehabilitation Projects (17:07)
  • Manhole Recovering as a Secondary Rehabilitation Option (25:09)
  • Utilizing Trenchless Construction in Your Community (26:18)
Wes Farrand white circle cutout headshot

Wes Farrand, P.E.

Civil Engineer

Wes Farrand, P.E.

Civil Engineer

Combined Sewer Planning & Design, Hydrologic & Hydraulic Analysis, Water Main design

Patrick Williams Contact Box White Circle Headshot

Patrick Williams, EI

Civil Engineer

Patrick Williams, EI

Civil Engineer

Combined Sewer Planning & Design, Hydrologic & Hydraulic Analysis, Water Main design

Why Trenchless Technology Demand Has Increased

Wes Farrand (0:15)

Today we’re talking about limiting impacts through trenches technologies. This podcast focuses primarily on municipal infrastructurewaterwastewater infrastructure, and how we can limit impacts when it comes to new construction and also rehabilitating old systems as well. My name’s Wes Farrand. I’m a Senior Engineer with Snyder & Associates out of Ankeny, Iowa. I’ve been working in the wastewater business for a couple of decades now. I’ve done quite a few projects of this nature, and today we’re going to talk with Patrick Williams out of our Cedar Rapids office. I’ll let him introduce himself.

Patrick Williams (0:47)

My name is Patrick Williams. I’m a Civil Engineer in Cedar Rapids. I’ve primarily done projects in water mains, sanitary sewer, and treatment plants, and a lot of those projects do involve the trenchless installation of pipes, so I’m here to help talk about my experiences with that.

Wes Farrand (1:05)

It would seem to me like the trenchless aspect of construction in the infrastructure business is increasing. We seem to see it a lot more lately. I think for good reason. It has some positive benefits and some aspects of it that make it appealing both financially and some of the intangible things. Patrick, in your experience, are you tending to see more of it than what we used to see in the past?

Patrick Williams (1:29)

I would say we are seeing more of it because, as time goes on, there’s more and more infrastructure above ground being built. When you’re putting pipelines in these areas that are already established, you don’t want to tear all that up. We go with trenchless because it limits the disruption above ground and keeps the pipe underground without excavating recently paved streets or railroads and such. So yes, as areas are developed more, trenchless is becoming more necessary to use as a method of pipe installation.

Wes Farrand (2:00)

That’s exactly right from what I understand too. I think in recent years, technology has improved quite a bit. There’s more and more technology out there. There are more and more people using technology. That’s helped the prices come down to where we’ve had some bids, where we had some trenchless and some open cut trenched water mains similar sizes, and the trenchless were cheaper foot per foot. Not even considering all the intangibles of the driveway replacement and street replacement just because of the ease for the contractor, he was able to tunnel it in cheaper than anybody could dig it in. I think that’s probably what’s contributing a lot to the more prevalence of it.

Intangible Community Benefits

When it comes to the construction industry and infrastructure, the adage of you have to break a few eggs to make an omelet couldn’t be more true. When we go to do a project, we mess things up pretty well. We’re digging, we’re making a mess, we’re piling things up, we’re breaking things before we can put it back new and good. When it comes to the impacts of a construction project, it can get pretty extensive. As you said, when we’re in an area that’s built up, and things are real tight and close, and so the ability to do the work we need to do without digging could be a huge benefit to the community and the people adjacent to the project.

Patrick Williams (3:08)

In addition to minimizing site restoration needs such as paving or habitat restoration, I’ve also seen public views on projects change for open-cut versus trenchless. When you’re putting a pipe in someone’s backyard, and you have a big open cut trench and their backyard’s getting torn up, we tend to get a lot more calls from the public asking, “What’s going on? When is it going to get fixed, and why is no one working?” Even though they’re working at a perfectly reasonable pace. When we have the trenchless, those calls seem to decrease. There’s less traffic, noise, and pollution, etcetera when you go through the trenchless method as well.

Wes Farrand (3:47)

That’s exactly right. I think that’s some of the intangibles that should be factored into the PR cost savings, even just the right-of-way acquisition from the property owner.

Understanding Possible Downfalls of Trenchless Construction

Patrick Williams (3:56)

Do we want to talk about the cons?

Wes Farrand (3:57)

Yeah, what cons have you run into, Patrick?

Patrick Williams (4:02)

I’d say the most common con of using trenchless from a client standpoint is the cost. Pipe materials, for example, like an eight-inch water main open cut, maybe five years ago, you’d be looking at $20 – $30, $20 – $40, depending on where you are per linear foot of water main. Then when you upgrade that to trenchless and, even further, trenchless with a casing pipe, you’re looking at like a hundred dollars plus per linear foot. While trenchless does have a lot of benefits in terms of rehabilitation, it is worth understanding that if you did your whole project trenchless, instead of cutting in some trenchless with some open cut, you’d be having a much more expensive project for the same end result of having a pipe in the ground. It is prudent to choose those areas wisely. Use your existing survey: we know this area is dense with utilities, and we know that this road is driven a lot, let’s not disturb it. But not just go through an open field trenchless because you like watching the machine run.

Wes Farrand (5:01)

Yeah, you’re exactly right. You do pay for what you get. It has to be weighed into both the monetary and the non-monetary benefits of it. Because you’re right, it is two to three times more expensive or even more depending on the size that you’re getting to. I will say on the rehabilitation side, it’s about two to three times cheaper to do a sewer lining versus reconstructing the whole sewer. On the rehabilitation side, the advantage is the money advantage side. I think the cons on the rehabilitation side for the trendless rehabilitation, it does extend your sewer life, and it might not be as long as a brand-new sewer, but it might be the problem is we don’t have fifty to a hundred years of some of these new liner technologies in the ground.

There’s a little bit of risk there on how long it’ll last. The other con that can come up with a trenchless, too, is you want to think, “Oh, there’s just no impact.” Then there are some impacts, especially with new construction. You do have entry and exit points you’ve got to deal with, so there are some impacts.

Patrick Williams (5:53)

Another conflict is unknown utility. Sometimes there’s unknown stuff in the ground, such as large boulders or existing utilities that have been in there for a long time, and no records were provided during design, and the contractor bores right through it. That’s always a possibility and a risk. If you hit something 200 feet into your bore, that’s going to cause the whole project to kind of stop, and you’re going to have to investigate what that utility is. Hopefully, it’s something that you can deal with quickly. But if it’s a major sewer, you’re going to have to go back and re-bore it to avoid that utility conflict. Those are just risks, not necessarily a con that you’re going to run to every time, but it’s kind of a gamble when you’re boring underground that you’re not going to hit something crazy.

Wes Farrand (6:34)

Yeah, you are right. There is a risk that you can’t see what’s ahead of you. If you can open cut, you can usually see that and can deal with it. But with trenchless, there is a risk.

Patrick Williams (6:43)

That reminds me of the idea of unknown conflicts. We had a Cedar Rapids sewer project where we were going under a roadway that was an old landfill, and there was a bunch of stuff buried under the road. The joke during design was that, hopefully, we don’t hit a car. We just weren’t sure what was under there. We were about 50, 40 feet under the roadway, but there was no car.

Wes Farrand (7:04)

As you said, nobody had any idea they were there, so there’s always that risk. That is the con I think to trenchless, but I think the benefits outweigh it. You just have to be flexible at the back end. Part of the upfront that you need to take into account when doing a trenchless project is it takes a little extra level of due diligence to research and figure out what utilities are there or do some test holes, kind of a hydro excavation to identify the exact location of some of those other pipelines or determine that it’s clear.

New Trenchless Insertion Technologies

Wes Farrand (7:36)

Trenchless has a wide range of technology and applications. We’ve touched on a little bit where there’s trenchless new construction, and there’s trenchless rehab. They’re different technologies, but both of them have the goal of limiting the impact to the surface and to surface features.

trechless installation pull laying on the side of the road

A pull head and pipe are ready to be inserted through trenchless construction.

and avoiding conflicts.

Horizontally Directionally Drilled Trenchless Construction

Getting a little bit into some of the new trenchless technologies and options that are out there. Probably the most common that we see is the horizontally directionally drilled trenchless. They send a pilot bore through, and then they back ream and pull the pipe in from the tail pit up, back where they started. This is something that’s primarily used for force mains or water mains.

The grade control is not quite as precise in my experience, and most recommendations are from guidelines. For the force mains and water mains, it’s really handy. It doesn’t require a casing pipe. They can pull directly into the main carrier pipe. This is what we see a lot for water mains and force mains. Patrick, you’ve used HDD on a few things before, haven’t you?

Patrick Williams (8:35)

Yeah, I’ve done several projects using HDD, and what you were saying it’s not a direct, straight line. It can kind of go up and down to the side, so you kind of got this weird shape, avoiding whatever existing conflicts underground maybe or getting under a culvert. I know in one of my projects, there was an 18-foot deep and 40-foot-wide box culvert that was at a creek. Our water main was supposed to be generally about six feet underground, but we had to go deep to avoid that and go directly underneath the culvert. The contractor set up his bore machine on one end and did almost a U-shape and got 60 feet underground with that water main to the other side and pulled that water through with some PVC pipe.

Wes Farrand (9:25)

That’s probably where I’ve seen the biggest advantage and shine is under creeks and drainage ways and under box culverts and things where if you had to dig that up to get the depth you needed to get underneath some of those drainage ways, or just like the advantage of being able to go deep with it when you had to is pretty handy.

Patrick Williams (9:40)

Yeah, they also have some sort of a sensor at the tip of their bore where they’re able to get a 3D report. So, when you’re doing your as-built drawings, you’re able to provide accurate horizontal and vertical location information of where that pipe is underground.

Wes Farrand (9:56)

Yeah, and there are some steerable capabilities to that as well that makes it pretty handy for both vertical and also a little bit of horizontal. We had one where they were able to take some horizontal alignment changes to avoid an intermediate pit or open-cut construction on a project and just keep boring through because they were able to deviate horizontally and track that. I think probably the con or risk with the HDD is it doesn’t really like different soil materials, and soil testing is a big thing to make sure that you’ve got some investigation done there to know what you’re digging through. When you have to go from maybe sand into bedrock, that causes problems. From what I’ve been told and seen, if you’re going from sand to bedrock, more than likely, it’s just going to bounce along the top of the bedrock. They have to use different cutterheads, and it doesn’t like to make that transition. You can bore through rock, and you can bore through the sand. Going from one to the next can cause issues. I don’t know if you’ve ever run into that, Patrick.

Patrick Williams (10:47)

The only issue I’ve ever seen on the HDD method was we were boring in a 12-inch force main in Anamosa, and they pump in this lubricating gel to allow the pipe to slide in. There was something wrong with the soil where we were going, and there was bore gel spilling out of the crack between the curb and the asphalt roadway. It was like, okay, we need to get some filter socks down or on that. Generally, it’s always a pretty smooth process, but now and then, you get weird soil conditions and can get some unexpected results.

Wes Farrand (11:21)

You’re right. The drilling fluid that they use for that, there’s a science and an art to that. Here in Iowa, where we have pretty heavy clay soils, that generally helps us because that drilling fluid is contained within the clay that we’re boring through, so it doesn’t blow out too often. But if you get a sand seam or some kind of different soil interface and if you’re running too high pressures, that path of least resistance it’s going to squirt out, so that is something to keep in mind.

Trenchless Auger Boring

Another technology that I want to touch on a little bit is the auger bore, that’s a casing pipe with an auger soil removal down the middle of the casing pipe. Patrick, have you had experiences with auger boring?

Patrick Williams (11:55)

From what I understand, the auger is just a big screw.

Wes Farrand (11:59)

Yeah, they have to dig down a jack pit, and they dig down a tail pit or receiving pit. Then they set up rails and a push system that pushes the casing pipe in. The auger in the middle of the casing pipe pulls the material out. They drive the casing pipe through. Your receiving pit is a lot smaller for this because it’s just the open-cut trench that you’re going to keep going with your pipe on the far end. Your bore pit tends to be a little bit bigger impact, so that’s something that we have to watch out for. Make sure you got the footprint to be able to drive that in, but they can hold pretty tight tolerance grades with auger and auger boring in that casing pipe. Then they run the carrier pipe through the casing pipe with spacers and other items.

That one’s pretty common around here. We see this a lot for sewer construction. The carrier pipe can be any pipe material, the same pipe material you run an open cut on either end. It can take any kind of carrier pipe, and it’s pretty foolproof. That casing pipe will hold your tunnel hole, which is kind of nice. If it’s a large enough tunnel, and we had one that was going underneath the railroad, that was a 72-inch diameter pipe, so the casing was 96 inches, so you could walk in it.

If you had to remove cobbles at the face of that, you could go in there and remove cobbles to some extent up there, so it does have some little bit of the risk taken out of that because you can pull the guts out of the tunnel and access it to address anything you might hit. They can change augers: a rock bit to a soil bit to some extent, so it gives some flexibility.

Microtunneling Trenchless Construction Method

Another one for the new trenchless is micro tunneling.

Patrick Williams (13:16)

When it comes to micro tunneling, essentially, you have a large machine that pushes the steel casing pipe inch by inch. It pushes the pipe, goes back, they add more pipe, and it keeps pushing it under. At the head of that pipe, they have a machine with a bunch of digging gears that rotates and upsets the head of the bore, and they’re able to remove the material that’s in the way in their large tunnel.

Wes Farrand (13:42)

Most people think of this when they think of the English Channel. That was a giant one.

They make those on a smaller scale too. Same kind of thing. Sometimes they’ll pilot bore a small pipe through, and then the TBM or the micro tunnel machine will follow it. Sometimes it’s online and grade with a jack system behind it, pushing through either casing pipe, or you can use this to direct the jack. Storm sewer concrete pipe can be used to direct jack with this where you don’t have to have a casing pipe. We did this with a 72-inch concrete sewer. A 72-inch pipe to put in a steel casing, that’s a pretty big casing, adds quite a bit of cost. Being able to get a little bit beefier concrete pipe and then jack it directly in was able to save some cost there, and it had some options. Patrick, have you used micro tunneling of any scale on a project of yours?

Patrick Williams (14:28)

Yeah, one of my first projects was a 66-inch diameter trunk sewer through Cedar Rapids, and we had about 400 feet micro tunneled under the Iowa 380 highway. We were able to avoid any disturbances on the most traveled road and in Cedar Rapids.

Wes Farrand (14:46)

Going back to what we talked about before, that’s expensive for pipe, but it doesn’t factor in what it would cost in traffic control and diversions and detours and headaches for all the thousands and thousands of travelers that use 380. The cost was taken into account. I’m not sure what the other impacts would’ve been for that project.

Patrick Williams (15:04)

Yeah, it was one of the coolest projects I’ve worked on because mostly what we work with is like a 12-to-24-inch pipe around there. 66-inch presented some interesting challenges with the trenchless because there’s a lot of stuff you can hit.

Wes Farrand (15:18)

Those are really neat projects when you get those that size.

Pipe Material & Application Considerations

Patrick Williams (15:22)

One other thing when you’re considering the trenchless installation of pipe is the application of the pipe and the material of the pipe.

Typically, when you’re dealing with water main or sewers, PVC is the most common material, but I’ve been recently using a lot of HDPE on different projects because of its bending flexibility. Normally if you have a bend in a water main or a sewer, you can either put the sewer at a manhole or you can put a 90 or 45-degree fitting. But sometimes, that isn’t necessary, and you can get the HDPE material, which has a tight bending radius. You can bend that pipe around at a lot of crazy angles. When you’re doing trenchless, if you have to add a manhole or a fitting, that’s just another open pit that you’re going to have to do. If you’re able to do all those bends all underground, all trenchless, it can save a lot of time and money for the project overall.

But, if you’re trying to do sewer, especially gravity sewer, you want to stay away from any bends. You want that pipe to be straight. When you’re talking about a pressure pipe, like a water main or a force main, something that’s under pressure, you can get a little bit more creative with the alignment of the pipe. HTPE has just been a fun material to work with because it’s less rigid in the rules that you typically have to follow when you’re doing a concrete or a ductal iron or PVC pipe. PVC pipe is flexible, but only to a fault, and I think you get like maybe a few hundred feet of bending radius before that thing will burst underground, and you’ll have to go dig it up and replace it. HTPE, it’s the way of the future.

Trenchless Construction Methods for Rehabilitation Projects

Slip Lining Trenchless Construction

Patrick Williams (17:07)

We were just talking about new trench insertions, which is virgin soil, a new pipe going in, brand new. Everything is different. Now I want to transition to the rehabilitation of existing infrastructures with trenchless technology. There are a couple of different ways we can rehabilitate a pipe through trenchless. One of them is slip-lining. What’s your experience with slip-lining, Wes?

Wes Farrand (17:30)

Slip lining has always been one of those things that we evaluated as one of the potential options. In most cases that I’ve been involved with, it turns out that it doesn’t end up being the preferred option. The pros of it are its trenches for the most part, but the cons are it does require an excavated pit to access the pipeline, to be able to put the slip lining pipe in and push it through the pipe. Generally, where we’ve been evaluating it, other technology or options have better pros, if you will. While we always look at it as an option, it’s not one that we typically get into as the actual final solution that’s been used, but it does have its applications.

Patrick Williams (18:06)

Can you briefly explain what slip lining is?

Wes Farrand (18:09)

Yeah. Slip lining is where you take a slightly smaller diameter pipe than the pipe that you’re going to rehab. You make an excavation down to the existing pipe, cut into the existing pipe, and then you push the new, smaller pipe inside of the old pipe, and it lines the inside of the pipe with this new one inside. You drop a piece in, push it down, you connect the next one to it, and push it down until the pipe is lined. Then you patch the hole where you cut in and backfill your excavation and get out so that excavation tends to be what slips this one out.

It does have its place, and it can be used effectively. Probably, its best application is where you don’t have any connections, and it’s a long straight run. You get into too many bends, and it doesn’t work if you have to do any service taps, so small-diameter stuff doesn’t work so well because there are better options, and you have to dig up every place where you have a connection, that kind of drives it out. But long, straight runs, large diameter pipe.

The pro that I’ve seen is it can be done under some live flow, which, when it comes to doing any kind of sewer rehab, bypassing and dealing with the existing sewer flow is always one of the big things that are often forgotten about, but it’s almost always a big factor, and it can be a big cost too. It’s not like you can tell the whole town just to, “Hey, stop flushing for a day or two, would you?” Slip lining can be done under some flow, which can help.

Patrick Williams (19:26)

I would also think you’re putting in a smaller pipe. You’re also lowering the capacity of what was existing to a certain extent.

Wes Farrand (19:33)

Yeah, a little bit. That’s something to take into account. Sometimes you can accommodate that with the different Mannings Coefficient, which is the smoothness of the pipe. A rough pipe is going to be able to carry less flow than a smooth pipe just because of the friction and the resistance of the water, so you can sometimes account for that. The other thing is sometimes those large diameter pipes, you’re already in a surcharge condition under most high flows. So the system can account for some surcharging, and a little bit of surcharging that you might add with a slightly smaller pipe diameter doesn’t add up to be significant, but it is something to keep in mind.

Trenchless Pipe Installation with CIPP Lining

Patrick Williams (20:05)

Speaking of lining, there’s another type of rehab called CIPP that uses a bit of the lining method, but it’s fundamentally different. From what I understand, CIPP is usually used when there’s infiltration of groundwater into the sewer. They use that to kind of rehabilitate the integrity of the existing pipe to prevent I&I, as we call it in the industry, infiltration into that pipe and prevent overloading that pipe with flows that you don’t want to get into your pipe.

Wes Farrand (20:35)

Yeah. CIPP is a cured-in-place pipe. It’s the most common trenchless rehab, especially for small-diameter pipes. It’s getting used everywhere, and it has a lot of pros and very few cons, I think. It’s essentially an inverted felt bag that they soak in an epoxy-type resin. Then they use steam or hot water to turn it inside out inside the pipe. They start at one end of the pipe, they blow it in, it turns inside out, and the pressure of the steam or the water holds it to the outside of the pipe. At the same time, that heat from the steam or the water cures the resin and hardens it so that it essentially turns into a brand new, hard pipe that can carry the soil load and the structural load of the pipe all by itself inside of that old pipe. They send up machines that can recut the service connections.

If it’s a collector along the residential street, they put the sewer liner in. You do have to ask people to stop flushing for a little bit on this project. It will back up because it will be plugged in for an hour or two, but they go in, and they recut those holes open. Once the holes are cut open, the work’s done, and the sewers back live again.

There’s zero digging. It’s just a few trucks on the surface. They do it in a few hours, and they move on to the next one. Most people will get their sewer lined while they’re gone at work, and they’ll never even know it happened other than the door hanger that says, “Hey, don’t flush for this time period.” A neat product and a great way to extend the life of our sewers.

We see that used a lot, and there are even some new technologies out there that are UV cured, rather than steam or hot water cured, which have some added benefits of the flexibility of putting in and taking out before it gets cured. That’s the new technology that’s currently getting out there that has some benefits as well. I do have a different webinar presentation that we’ve done on CIPP, so if you’re interested, feel free to check that out.

Pipe Bursting Trenchless Construction Technology

Wes Farrand (22:26)

Then there’s another technology for rehabilitation out there that’s been around a while, pipe bursting. This one is kind of like slip-lining. It gets tossed out there as an option but then never really comes to fruition. Patrick, have you done any pipe bursting?

Patrick Williams (22:40)

Coincidentally they’re starting a project out in Robins, Iowa, this week with some pipe bursting. It’s very similar to slip lining in that you’re utilizing an existing pipe as the alignment for a new pipe, but where slip lining, you’re pulling a smaller pipe through the existing pipe, and pipe bursting, you’re pulling a bigger or same size pipe and where the bursting in the name comes from is when they pull the pipe back, it will cut open and destroy the existing pipe, making way for room for the new pipe that’s following. Essentially, what we’re using this project for is we’re expanding the capacity of Robin’s trunk sanitary sewer system. They had a 12-inch, which could do about 1.9 cubic feet per second, but we’re pulling through a 16-inch, so they’re effectively doubling their trunk sewer capacity to four cubic feet per second.

Wes Farrand (23:35)

That’s trenchless, where you’re increasing that capacity and have the option to go with a bigger pipe size, which would be different than all the other rehab projects that we’ve done.

Patrick Williams (23:43)

Yes, and the reason why we chose to go with pipe bursting rather than just open cutting or a more typical method was in that sewer easement, several residents had installed fences, sheds, and landscaping, not to mention existing electrical and communication lines. It was a messy area, so I looked into it and saw that pipe bursting was an option we could do. Even though their residents built their fences and sheds within an easement and the city is perfectly within their right to tear it down in the name of infrastructure, we decided to be nice and, at the end of the day, everyone’s going to be happy. The city’s going to have a brand new, bigger sewer pipe, and their residents get to keep their flower bed and utility shed.

Wes Farrand (24:30)

Nice. I’ve heard that there are some limitations on what materials can be burst. I think cast iron pipe or steel pipe would be ones that maybe couldn’t be. But I know for certain that clay tile pipe, you could burst. I’m curious to see how that comes out for you, Patrick.

Patrick Williams (24:44)

Definitely. Just one more thing on the pipe bursting that we had to look into was kind of poor records of the existing sewer and services, and we weren’t sure if there was anybody hooked onto that. We had to do some sewer televising to make sure we weren’t going to blow up someone’s service when we did the work. Luckily, there was nobody on there.

Wes Farrand (25:02)

Yeah. Something to think about when using that technology is as being able to re-hook up any services that are along the way is going to take some excavation, more than likely.

Manhole Recovery as a Secondary Rehabilitation Option

Wes Farrand (25:09)

I think one thing, though, on the sewer rehab, we tend to focus on the pipeline. But there’s also the manhole accesses. Depending on what your goals are, and I always say this, when we look at rehabilitation, what’s your goal? Are you looking to restore the structural stability of the pipe? Are you looking to stop I&I? That can play into what technology you use.

One thing that often gets overlooked is the manholes, which can be a source of I&I if infiltration and inflow are one of your concerns. There are some technologies, products, and methods out there to line manholes as well as the pipe without doing any kind of digging. You can leave the old manhole there; you can get a new liner in it. You can coat it, line it, and cast in place a new concrete one inside the existing manhole, polyurethane liners, and plastic liners. There are lots of different options out there, but something to always make sure that when you’re evaluating your pipeline to evaluate the manholes too because it would stink to put all that money into the pipeline and then realize that you haven’t issued the manhole too and hadn’t been planned for.

In my experience, when you end up having to do manhole rehabilitation, it’s only about 10 to 20% of the time versus when you’re doing the sewer work. Usually, they’re in pretty good condition, but we have run into some pretty crazy poor old brick manholes, and sometimes they just can’t be rehabbed.

Utilizing Trenchless Construction in Your Community

Wes Farrand (26:18)

That goes through quite a bit of the trenchless technologies. We touched on probably some of the more basic ones. There are still other ones out there, especially with rehab. There are some other up-and-coming trenchless, new construction technologies, some laser-guided stuff. It’s a moving industry, but all towards the goal of being able to build new or rehabilitate the old stuff to get it like new but, at the same time, limiting the impact, both cost-wise for surface features and also the intangible impacts of disruptions to properties, to trees, to driveways, streets, traffic anything that’s on the surface to avoid that and the benefits that come along with that. Patrick, anything else you had on limiting impacts by trenchless methods?

Patrick Williams (26:57)

I don’t have too much to add, but I do like seeing trenchless in the field because if no one even knows the project happened in the first place, I consider that a success.

Wes Farrand (27:06)

Yeah, sometimes you have to make a mess, but sometimes it’s nice to not have to make a mess. If you can get it done and keep the property owner happy because you’re able to save their tree or their fence or their backyard, or their access and not have to park a block away every day for a month. That’s a good win in my book. It’s nice to have these options to be able to do that when we can.

Patrick Williams (27:24)

Definitely. Alright, Wes, I think that about wraps it up for our discussion today on different trenchless technologies. If anybody listening to this has any inquiries on how trenchless installation of pipe can benefit their community, feel free to reach out, and we’d be happy to help.

Wes Farrand (27:39)

Definitely. Thanks, Patrick.

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