The St. Johns Heritage Parkway and I-95 interchange project was a design-build project that created a new interchange between a new roadway alignment for St. Johns Heritage Parkway and Interstate I-95 in Palm Bay, Florida.
Improved Safety and Efficiency
The WGI team produced an innovative alternative technical concept (ATC) that converted the preliminary design concept from a partial cloverleaf to a diverging diamond interchange. This conversion improved the safety and efficiency of the interchange due to the reduction of signal phasing from three phases to two phases.
The conversion to a diverging diamond also allowed the team to provide two narrow bridges in lieu of the preliminary concept’s one wide bridge, resulting in a reduction of bridge deck area.
The eastbound bridge features 4~12’ travel lanes, a 7’ bicycle lane, a 2’-6” shoulder and a barrier protected 12’ shared-use path. The westbound bridge features 3~12’ lanes, a 7’ bicycle lane, and a 2’-6” shoulder. Span lengths provided are 2 @ 115’-3” and one at 99’. Span 1 of the two bridges was required to span over a Florida gas transmission easement parallel to I-95. The bridge abutments are supported on mechanically stabilized earth walls.
The project also included extensive drainage modifications, including reinforced concrete box culverts and two drainage ponds.
Innovative Concepts
One innovative concept incorporated into the project was the design of the piers in the median of I-95. The foundation piles were designed to straddle an existing drainage trunk line that runs down the middle of the median. This design solution eliminated deep excavation that would have been required to re-route the existing trunk line around the bridge piers.
Protecting The Environment
During the project, our team carefully mitigated impacts to the surrounding environment. WGI performed gopher tortoise survey and relocation, and the construction team scheduled activities around the breeding season of the Florida Scrub Jay.
Eliminating Delays
Signing and signals were also included as part of the project. The project team was successful in avoiding a delay as the adjacent project that was to supply the proposed power for the new interchange lighting and signals, was behind schedule. The WGI team proposed a different power source a mile to the south of the proposed interchange to eliminate this delay.
