Building a boardwalk over wetlands is a great way to add value to a community. Wetland boardwalks give the public a way to enjoy the beauty of nature, in place that would otherwise be off-limits. But building a walkway in such a fragile environment brings many challenges. Especially in environmentally protected areas, there are a number of factors that need to be considered in wetland boardwalk construction.
One of our recent boardwalk construction jobs in Fall River, Massachusetts is a perfect example of how a great site plan, combined with a little creativity and lots of experience can result in a breathtaking natural sanctuary for the public to explore.
The Quequechan River Rail-Trail
For over 30 years the Rails to Trails Conservancy® has been helping to transform unused railroad corridors into vibrant public places to be enjoyed by the community. The initiative has been so successful that public and private funds have poured into new, local projects all over the country.
Conte Company had a great opportunity to work on just such a project last year in Fall River, Massachusetts. The beautiful landscape, full of wildlife in a robust wetland sanctuary challenged us to complete a highly-sensitive, environmental project using our highly adaptable, helical pile expertise.
Now completed, we are extremely proud of this project and happy to bring the story of its construction to our readers. Like us, most of you love being outdoors, enjoying what nature has to offer while maintaining its pristine beauty. Fall River wanted the same for their residents and decided to complete part of a hiking and biking trail that followed the old Fall River Rail Line. The rail bed was being recycled with help from the Rails to Trails folks, who sponsor these kinds of projects all over the USA.
A Boardwalk Foundation Supported by Mud
In a nutshell, we were asked to connect a trail that ran down the center of a few tiny islands while making the island trails accessible from each river bank. The islands were separated by stretches of the flowing water, swampy wetlands and various grades of soft wet soil. Our mission was to develop a support system for four bridges which would seamlessly connect the trails running through these islands.
Using helical piles to build or repair a boardwalk is not uncommon. In fact, for building on wetlands, helical piers are the most effective solution to support paths, bridges and walkways. So when we first heard about this boardwalk construction project in Fall River, we knew it had our name all over it. We had the expertise, the experience and the attention to detail to do the job right.
We live to find new and better ways to build stronger foundations, which is why we are the #1 installer of Chance® Helical Piles in New England! After a few references from previous projects, the general contractor knew that our construction footprint would be nowhere to be found once the pathway was complete. And so, the job was ours.
Working in a Protected Eco-System
To dig right in, this project pitted a variety of environmental challenges against the special requirements of the boardwalk. First and foremost, protection of the wetland plants and animals inhabiting the river and surrounding marshes topped the priority list. A tricky work environment, unpredictable soil conditions and a litany of environmental regulations would be enough to scare off most contractors, but not Conte Company.
“Conte Company’s experience with environmentally sensitive areas, and the regulations protecting them, was invaluable to the success of this project.”
Strong Enough for Semis
The boardwalk requirements were challenging in-and-of itself. In short, a total of 4 bridges were needed, which had to be H20 loaded. That means they had to be strong enough to support 18 wheeler trucks! In our experience, the best way to accomplish this type of necessary support was to space the piles more closely together and use batter piles (angled supports) to resist lateral loads.
The need for this added structural strength is unusual. Most boardwalks we build are pedestrian rated and we can bring in our smaller equipment to install the piles. In this case, however, it was mandatory that the popular walking, running and biking path had access for emergency vehicles. The Quequechan River Boardwalk was designed for pedestrians, but also needed to be able to support ambulances and other first responders, which would require much bigger helical piles sizes than we would normally install. Ultimately, this job required us to bring in the big excavator in order to drive the large diameter piles into the soil beneath the water.
With all of these ingredients and the big equipment necessary to install a heavy-duty boardwalk, the project had all the ingredients for disaster… that is if a less experienced company had been hired for the job. But Fall River hired Conte Company and we’re proud to take on the most complicated wetland boardwalk construction projects.
Barges are the Answer
Given the nature of the delicate eco-system in which we need to work, the first major question that came up was:
“How do you get the big equipment where it needs to go, to do what it needs to do, without compromising the eco-system or the safety of the workers?”
The solution was barges! We’ve used barges in helical pile installations before, and they’ve worked really well. We decided that floating pontoon barges to transport equipment and materials was the way to go. The big excavators could reach over the side of the barge, lower the helical piles into the water and screw them into the ground. Our guys, on free-floating docks, would guide the helical piles into position and bolt on the extensions so they could be driven deep into the soil. Our experienced crew could focus on this intricate task because we’ve done it before. We have a lot of experience around water and didn’t forget the bug spray). At Conte Company, safety is always first!
Boardwalk Bridges, Made To Order
Two of the longer bridges were to stem from opposite shores and meet on the biggest island, allowing pedestrians to cross from one side of the river to the other. The two shorter bridges were to span a few smaller gaps over the water. The longest bridge was to be 500 feet, the shortest 100 feet, and we would have to use a grand total of 600 helical piles to make everything hook up — and stay up.
The boardwalk’s roadbed was to be lined with 10-inch wide timber sections. Each section would require us to fabricate custom, galvanized beam saddles to secure the boardwalk to its helical pile system.
The general contractor fabricated each timber boardwalk section based on measurements of the piles as we installed them. And each boardwalk section was attached to the foundation as it was completed. You can think of it like a custom boardwalk assembly line. As we go, so go the boards. This requires meticulous care to ensure that each and every pile was plum, secure and properly aligned with each of the other piles.
“Helicals were really the only option on an environmentally delicate job like this.”
Using Helical Piles for Boardwalks
There are three reasons why helical piles are the perfect solution for wetland boardwalk construction: Logistics, Structural Stability and Environmental Impact…
Compared to other types of pile foundations, helical pile systems are easy to install and require less maneuvering room to do it. The arm of the pile driving excavator can reach out away from the machine, whereas other types of piles systems need to be drilled or driven straight down.
One-path-in and one-path-out means there’s not a lot of room for extra machinery. Fortunately, to install helical piers, you really only need the one excavator. No other pile system could be installed faster or more efficiently than helical.
High Structural Stability
As we mentioned, construction of the boardwalk itself was being measured, fit and installed right in our footsteps. This meant the foundation needed to be secure and able to hold capacity immediately. That’s sort of a trademark of screw pile systems, as they do not require concrete.
Screw piles are also incredibly stable in soft soils, like mud and riverbed. In this case we used round shaft helical piles to accommodate the potential trailer truck loads. Even if another pile system were easier to install (which it wasn’t), a helical foundation was the correct choice for the project.
Low Environmental Impact
As we mentioned, protecting the eco-system in which we were working was one of the most important aspects of this job. And helical pile systems have very little impact on their environment, even feet from where they’re being installed.
- No Grout Necessary – No contamination to the water or the habitat.
- No Spoils from Drilling – No dirt or mud was pulled up from screwing the piles into the ground.
- Only Piles Remain – Nothing goes into the water except for shiny, galvanized, steel piles.
- No Danger to Wildlife – Piles are screwed deep underground, posing no threat to living things.
- Finished Fast – Completed in just a few months, the environment was to back to normal before Springtime!
“All of this had to be done in real time, while working on a barge, floating in 6 feet of water, in an environmentally protected area, alongside birds, fish and turtles. This job was interesting, to say the least.”
All-in-all we couldn’t be happier with how this project tuned out. If you’ve got a boardwalk project and need some expert advice, give us a call. Our experience with wetland boardwalk construction and pile foundation systems makes us one of the most qualified contractors in the country.
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