PermaTrak® Boardwalk Construction Process
The PermaTrak system is manufactured by pre-qualified regional precasters throughout the country. We own and maintain these steel production forms to ensure consistent quality control.
While the PermaTrak boardwalk system is comprised of individual precast concrete components - that doesn't necessarily mean that the boardwalk's foundation must also be precast concrete.
In fact, the PermaTrak system can be installed on many different foundation types - precast concrete piers, timber piles, cast-in-place concrete caissons, steel piles, precast concrete piles, etc. In all cases except the precast concrete piers, PermaTrak directly supplies only the precast concrete boardwalk components (caps, beams and treads) that go on top of the foundation system.
Several factors guide the decision process for selecting a boardwalk foundation type. The designer can calculate the dead load of a timber or composite structure. For a precast concrete boardwalk, PermaTrak is able to calculate dead load and forward to the designer. The live load should be the same regardless of the type of boardwalk specified, timber or precast concrete.
The foundation system for a PermaTrak structure is a function of the site's soil conditions and geotechnical recommendations.
For more on determining the most cost-effective and durable foundation type for your boardwalk project, see "Boardwalk Foundations: Which Type Is Right for My Project?"
1. Foundation
PermaTrak® on Precast Concrete Pier Foundation
Depending on the soil conditions and layout of the project, PermaTrak's precast concrete piers can serve as a low-impact, cost-competitive foundation option. Precast concrete piers supplied by PermaTrak consist of three stackable components: bases, risers, and caps. Excessive excavation of the project site is eliminated, providing owners with a boardwalk foundation suitable for minimal tree root disturbance.
The base component of our concrete pier foundation option spreads the load to the sub grade. Weighing 130 lbs. each, bases can be maneuvered by hand into position.
"Riser" components can be stacked for elevation changes, without any hardware required. Lifting inserts allow contractors to move these pieces by hand (~80 lbs. each).
"Cap" components transfer the load from the pier to the precast concrete beams. The dimples on the top of the caps accept the spherical polyurethane pins. This pier is installed on a compacted granular base.
Spherical, polyurethane "mushroom" pins connect the precast beams to the foundation elements.
PermaTrak® on Concrete Pier or Concrete Pile Foundation
You may be familiar with the terms concrete pier, concrete caisson or concrete pile. While these terms are often used interchangeably, technically, a concrete caisson is one type of a concrete pier; these are typically formed in place. Precast concrete piles are typically driven or vibrated in to place.
Concrete offers durability and longevity for boardwalk construction over lakes or streams, through wetlands or floodplains. If the geotechnical report calls for a deep concrete pier, these can be constructed as an augered hole or drilled shafts with a casing used to pour the cast-in-place deep footing.
The boardwalk's beginning and ending stations typically utilize our precast abutment piece, on an unreinforced concrete leveling pad. Lift inserts allow for easy handling.
Sonotube casings can serve as temporary forms as cast-in-place reinforced concrete piers are constructed. Concrete piles may also be precast, shipped to the site, and driven into place.
PermaTrak® Boardwalk Construction On Helical Piles
Helical piles, sometimes referred to as screw piles, can make for a durable and environmentally friendly boardwalk foundation. As a pre-engineered foundation system, helical piles require small installation equipment and can be easily modified in the field.
Helical piles may be a good foundation solution for project sites with:
- restricted access
- high water table
- limited vertical head room, or
- weak surface soils
They consist of one or more helix plates attached to a central steel shaft.
With a PermaTrak's concrete boardwalk system installed on a helical pile foundation system, owners can benefit from a very durable, maintenance-free structure overall.
Once a pile is installed to the specified capacity, a steel plate is secured to each pile, setting the template for the rest of the PermaTrak boardwalk construction process.
The boardwalk's beginning and ending stations typically utilize our precast abutment piece, on an unreinforced concrete leveling pad. Lift inserts allow for easy handling.
Steel helical piles are installed or "screwed" into soil to a specified torque.
A steel cap plate with gusset supports is attached to the top of the helical pile.
In plan view, the helical pile foundations with attached steel cap plates set the template for the PermaTrak beams and treads to be installed.
PermaTrak concrete beams sit directly on helical steel cap plate.
PermaTrak® Boardwalk Construction On Timber Piles
In applications through a wetland or over water, timber piles may be the most cost-effective foundation option.
Our PermaTrak system is easily installed on a timber pile foundation, as is common with timber or composite boardwalk construction. Once a pile is driven to the specified depth a precast concrete cap is secured to each pile with a lag bolt, setting the template for the rest of the boardwalk construction process.
The boardwalk's beginning and ending stations typically utilize our precast abutment piece, on an unreinforced concrete leveling pad. Lift inserts allow for easy handling.
Caps are secured to timber piles, setting the template for the rest of the boardwalk. Cap components transfer the load from the PermaTrak boardwalk components to the timber piles.
Caps are aligned and measured for correct spacing per the installation drawings. A lag bolt is drilled through the center precast hole down into the pile for a secure connection.
A non-shrink grout fills the pile-cap connection for long-term durability. The dimples on the top of the caps accept spherical polyurethane pins.
Spherical, polyurethane "mushroom" pins connect the precast beams to the foundation elements.
2. Beams & Treads
Once levelness and position of the foundation piers have been verified, PermaTrak's beams can be set. Typically a 1/2" gap is left between ends. Shim and grout may be required under the beam to ensure proper slope.
Beams may require a mechanical connection to the pier, depending on specific project requirements.
A 1/8" rubber bearing pad strip is laid on the beams to eliminate any potential uneven bearing.
Curved alignments are easily accommodated by adjusting the beam lengths of the inside and outside runs.
Precast treads are easily maneuvered into place with small construction equipment. Spud bars or crow bars used from underneath the boardwalk allow installers to adjust the treads' final position on the precast beams without damaging the finished walking surface.
Tread installation continues by aligning PermaTrak’s interlocking keyway system and maintaining 1/8”-3/8” joint spacing between treads.
Curved alignments are formed by use of tapered boardwalk tread components. See our Engineering Layouts page for more information on horizontal alignment and minimum radii.
3. Railings & Curbs
Precast concrete curbs (supplied by PermaTrak) are also popular choices as an add-on feature. Connecting hardware is hidden from view and curbs attach without any field drilling.
PermaTrak's steel brackets are manufactured with a galvanized steel finish. A 4'' x 4'' timber post fits into the bracket to allow for a variety of timber railing designs. Bolts connect to a bottom plate on the underside of the walking surface.
Railing options with the PermaTrak boardwalk system span a wide range. See Railings for pricing and design information.
Aluminum railings can also be supplied as a cost-efficient boardwalk railing. See "What Types of Railings Does PermaTrak Offer?" for more information.
A stainless steel railing with cable strands offers a transparent look, but is one of the more expensive options to complete a boardwalk project.