Many popular trails and boardwalks have been built in beautiful settings that draw visitors regularly.
Those sites include timber or composite structures that are outdoors and in harsh environments. The trails and boardwalks eventually become worn and may exceed safe structural design guidelines and become functionally obsolete.
There are trails that have deteriorated decks, substructures and foundations (the photo on the right is an extreme example of this). Designers and their clients are often faced with the need to replace portions of trails and boardwalks. In some cases, even the complete structure must be replaced.
When We Cannot Use Existing Foundations
Many times, we are unable to install our concrete boardwalk system on top of existing foundations because support beams and foundations are not designed to handle the loads of a concrete deck.
For example, Southern Yellow Pine has a density of about 52 pounds per foot with decking made from 2x4s which are approximately 1.5" thick. Our decking pieces have a density of 150 pounds per cubic foot, and are either 4" or 5.5" thick (depending on load requirements and structure width), which means that the weight of a concrete deck is 8-11 times heavier than that of a typical timber deck. Timber support beams are typically not designed to handle the loads of a concrete deck.
When It CAN Work: Retrofitting Application Examples
However, there are times that we CAN install our boardwalk system on an existing foundation.
It all comes down to the foundations. Structures built with substantial foundations can be an excellent PermaTrak retrofit opportunity.
Concrete pilings or caissons have been used on some structures, particularly near or over water. Steel or concrete can be used as well. Even treated wooding pilings can be found to be quite suitable for many years of use.
A good policy would be to survey the potential foundation system that is in place. If a survey proves the foundations are worthy of pairing with a new deck or boardwalk system, then PermaTrak can be an excellent long term addition.
Important! A structural engineer needs to perform a site inspection and evaluate the piles to ensure their quality and whether or not they can handle the loads of a concrete deck.
If the foundations pass the inspection, PermaTrak has the design capability and experience to be counted on to provide a solid joining of strong, existing foundations with the attractive, durable PermaTrak components.
Here are a few examples of this type of application:
Rails to Trails and Train Trestles
There are transportation structures all over the US that are particularly well suited to be retrofitted with the PermaTrak precast boardwalk system.
Those structures are the many obsolete train trestles that are found at sites, both urban and rural. These bridge trestles tend to be heavily built, they have many years of design life remaining when used for multi-purpose trails and elevated observation decks.
PermaTrak precast components are perfectly suited to be used with these sturdy structures. Once the old railroad track and ties are removed, the hearty bridge structure allows the longitudinal precast beams to work in harmony with attractive PermaTrak boardwalk treads. These are practically natural retrofit projects that will be in place for decades.
PermaTrak Retrofit with Sabal Pines, FL
Here's a recent example of retrofitting in Sabal Pines, Florida. For this project, the existing wooden boardwalk beams, treads, and railing were deteriorating and needed to be replaced.
However, the existing timber piles were still in good enough shape to support precast concrete.
PermaTrak Retrofit with City of Sarasota, FL - Piers at Van Wezel
In the past, we have been able to reuse existing piles and replace the beams and decking with PermaTrak. This option involves extensive investigating and engineering.
Existing piles would need to be load tested by a structural engineer to ensure that they are capable of handling expected loads, and the site would need to be surveyed to determine the exact locations of existing piles.
PermaTrak provided the City of Sarasota with the design and material that allowed the City to utilize existing concrete piling and durable PermaTrak precast beams and treads to give the City (4) brand new observation decks right on the shoreline of Sarasota Bay adjacent to the Van Wezel Performing Arts Center.
The previously installed weathered timber decks are gone and the new concrete PermaTrak decks enhance the spectacular views of the bay.
Conclusion
Yes, PermaTrak boardwalk systems can be a terrific answer for use in retrofit applications.
PermaTrak can extend the life of previously well designed foundation systems or of proud, older transportation structures.
Retrofitting structures is a sound plan for communities when replacing trails or boardwalks with foundations that have enough capacity to handle PermaTrak.
2nd photo by Charles Haynes, 4th photo by Len Matthews
Note: visit our Florida boardwalk photo gallery for more photos of the Van Wezel Piers by PermaTrak
