Location: Titusville, FL
Application: Temporary retaining wall for a new bridge approach
Project Scope: Temporary wire walls for stage construction
Products Used: StrataGrid, SGU 40, SGU 60, and SGU 80
Contractor: RWH Construction Services Company
Client: FDOT – Orion Marine – Prime, RWH – Sub-Contractor
Date Constructed: June 2022
Initially, an aging causeway linked Titusville, FL, to the high-profile NASA Kennedy Space Center. The goal was to construct a modernized replacement bridge that required approaches on both sides of the bridge. According to the project drawings, one of the approaches needed to be located along the causeway road. One of the challenges in building this approach was that NASA required the road to remain open during construction since access was needed to the Space Center for its employees, scientists, researchers, and general staff, along with the public and dignitaries that travel in to watch the space launches and tour the facility.
Because the road needed access, the project took place in two parts. While one part of the road would be closed for construction of the bridge approach, the other part would remain open for traffic. After completion of the initial section of the approach, it would be opened for traffic while the latter portion was taken up to complete the width of the approach.
The engineering of the project carefully considered several areas, including the marshlands and surrounding environment, cost, speed of construction, and the need for a flexible structure. The final structure resulted in a mechanically stabilized earth wall with soil reinforcement and black steel wire forms. The length of the approach was 1005’ (305 m), with a maximum height of 27.5’(8.4 m).
Construction is always a challenge in this sensitive marine environment in South Florida. The system to be adopted needed to be rapidly constructed to minimize any jobsite downtimes, like those that occur in the frequent and hazardous thunderstorms common to the region. Additionally, even though temporary, the façade facing the truncated road needed to be appealing to the eye because of the high-profile traffic to the center.
Several conventional options were considered, such as soldier piles and sheet piles, but these methods were not suitable for the project’s needs. What was needed was a flexible system that was easy to install and permitted the option to remove it at the conclusion of the project, and most importantly, one that paired well with the bridge approach. And so, a temporary Strata reinforced soil retaining wall was chosen to support the temporary approach.
The temporary reinforced soil wall consists of PET uniaxial StrataGrid, SGU 40, SGU 60, and SGU 80, and locally available backfill material from the project site. These geogrids are wrapped around and protected by a face wrap of nonwoven geotextile, Strata’s ST 160. The fascia is formed by a welded steel form (see picture), which is placed to line up and level with the forms to provide an aesthetic façade. The temporary reinforced soil retaining wall supporting the access is raised simultaneously to match the height of the progressively constructed approach.
The approach was constructed to its final level and opened for traffic. The temporary reinforced soil wall by Strata was designed for the full traffic load that is expected over the bridge approach. The design life of the temporary Strata reinforced soil wall is a minimum of three years, which is well in excess of the expected time taken to complete the other portion of the approach.
It is significant to note that there was a large-diameter pipe that penetrated the face of the structure, and the temporary Strata reinforced soil wall could accommodate the obstruction in its design and detailing.
5 advantages the temporary Strata reinforced soil wall solution provided: