Boardwalk Construction at Allen Water Station (Texas)
PermaTrak boardwalk construction at Allen Water Station in Allen, TX will be completely finished by the end of August. The walkway overlooks Allen’s historical Old Stone Dam and connects to a new steel truss bridge that extends over Cottonwood Creek, allowing visitors access to enjoy the scenic view of the waterway and surrounding trees.
The PermaTrak boardwalk construction at this unique location is part of an improvement phase on the Cottonwood Creek Hike & Bike Trail. Allen’s Community Development Corporation and Collin County grants funded the project.
PermaTrak boardwalk and pedestrian bridge designs typically feature softer curves using tapered treads. This unusual layout with sharp turns and more angular edges is a first, unlike any other PermaTrak boardwalk project to date. The project owner, the City of Allen, wanted the boardwalk to have a zig-zag layout with sharp angles to follow the bank of the Cottonwood Creek where water flows from the dam reservoir. 
The design team at Halff Associate’s main office in Richardson, TX accomplished this by creating a layout that included trapezoidal shaped PermaTrak precast concrete panels. The pieces range from 3’-0” wide to 5 ft. 2 in. width (in the direction of travel) and include reveals to replicate thinner treads.
PermaTrak’s boardwalk system is often specified for use on busy thoroughfares, multi use trail systems and elevated greenways where walkers, runners, rollerbladers, cyclists, and skateboarders share the same space. But this application in Allen, TX is intentionally different.
The walking trail where PermaTrak was specified in Allen overlooks the historical stone dam in a shaded area of the tributary, where sharper PermaTrak boardwalk turns designed by Halff Associates are used to enhance the walking experience.
The zig-zagging PermaTrak boardwalk is 255 LF, at 9 ft. wide with a 42 in. tall galvanized vertical picket railing. The walkway offers roughly 8 ft. of usable space for the site’s walkers.
The boardwalk sits atop the water station’s newly enhanced gabion wall, which was recently upgraded to reduce future erosion. The site also features crushed granite trail leading up to the PermaTrak boardwalk segments. 
Halff Associates’ design services included a conventional piling design for the boardwalk, based on geotechnical analysis. Expansive soils are common in the Dallas/Ft. Worth area, and the geotechnical engineer recommended a drilled shaft foundation system- which ends up being a cast-in-place concrete pier column. Boardwalk construction followed with PermaTrak’s precast concrete beams and treads.
The installing contractor, North Rock Construction, has shown a high level of workmanship during this boardwalk construction phase. “North Rock Construction would come highly recommended as they have proven to be very qualified and capable of handling such an install. I imagine this is one of the more involved alignments, but as I stated the contractor is doing an excellent job!” added Matt McComb, City of Allen Landscape Architect.
The City of Allen, TX liked the durability aspect of PermaTrak's system, as well as the cost savings from lack of required boardwalk maintenance. Project managers from the City of Allen are now working through the design process for a second PermaTrak installation in the area: a retrofit boardwalk construction project on an elevated walkway.
Allen Water Station – a historic treasure
The City of Allen’s dam stabilization and trail project is one of many recent steps in their effort to improve infrastructure to keep up with population growth. 
The bustling City of Allen has enjoyed rapid growth in the past several decades, with the population increasing from just 400 to at least 86,000. One of the country’s only stone dams still in existence, the Allen Water Station was originally built in the 1870s as an integral water station fill-up spot for the H&TC railway.
According to the City, "new informative panels will draw attention to the old pump facility, water tower piers and stone dam that helped power steam engines along Allen’s train line. It is thought to be the only such dam remaining in the United States."
With the train station, high school and event center nearby, the Allen Water Station serves as an oasis amidst this modern and expanding town. The twisting layout of the new PermaTrak boardwalk serves as a perfect pathway for site-goers to leisurely meander and enjoy the natural beauty of Allen’s tranquil and historic gem.
See this article for more information from the City of Allen on this project. 2nd photo by Robert Nunnally.
Stay tuned - more photos and videos to come!
