SR 924 WB Extension PD&E
The Project Development and Environmental Study (PD&E) report consists of the extension of SR 924 (Gratigny Parkway) from SR 826 (Palmetto Expressway) to the Homestead Extension of Florida’s Turnpike (HEFT) in Miami-Dade County, Florida. In addition to other environmental impacts, the PD&E study considers the construction of new bridge structures, existing bridge widenings, connector ramps, retaining walls, existing roadway widening, drainage improvements and milling and resurfacing.
There are three (3) proposed alternatives along the NW 138th Street Corridor that extend SR 924 West to Florida’s Turnpike. The alternatives consider an at grade solution along NW 138th Street with both a full and partial connection at the Turnpike and an elevated option with an intermediate access at 107th Avenue and a partial (SB) connection at the Turnpike. These alternatives incorporate the construction of up to ten (10) new bridges and the widening of three (3) existing bridges.
BPA is providing services for the preliminary design and evaluation of the proposed bridges and related structures for this project. For the proposed bridge structures, this study considers four different superstructure alternatives including concrete segmental box girders, composite steel box girders, concrete U-beams and composite steel plate girders. Substructure types being studied include integral post-tensioned single column piers, integral piers, and post-tensioned straddle bent caps supported on drilled shafts or prestressed concrete pile foundations. Other tasks include preparation of cost estimates and constructability analysis of each alternative superstructure type.