The NW 25th Street project involved two major components: the roadway reconstruction and widening of NW 25th Street from the SR826 (Palmetto Expressway) to NW 89 Court and the construction of a viaduct (an elevated bridge). The viaduct, elevated about 30 feet, was situated mainly along the north side of NW 25th Street and would connect with an existing east viaduct.
In order to widen NW 25th Street in Miami-Dade County, Florida, the contractor, Astaldi Construction Corp., decided that the best solution to present to the Florida Department of Transportation (FDOT) as a Value Engineering proposal was Contech Engineered Solutions’ BridgeCor® structural steel plate. The solution was to encase the existing canal and extend the viaduct to the west, and FDOT accepted the proposal. With an advanced profile of 15” x 5.5”, BridgeCor offers nine times the stiffness and three times the strength of standard plate structures. Using BridgeCor was substantially less expensive than the concrete deck bridge that had originally been considered, and the construction time was also considerably less.
Nick Reynolds, Assistant Project Manager with Astaldi Construction Corp. had this to say, “Astaldi selected Contech’s 48S BridgeCor horizontal ellipse culvert pipe (24’-6” span x 15’-3” rise) during the design phase of a value engineering initiative to eliminate a proposed low level concrete girder bridge and replace it with an earthen supported roadway built over Contech’s BridgeCor pipe structure. Contech’s culvert pipe proved to be an astonishing structure that never failed to maintain its shape and integrity throughout the rigors of assembly, hoisting and in-the-wet canal installation.”
This was an extremely unique challenge given the tight site constraints, the large structure size, the underwater installation and the minimum cover requirements. As the canal enclosure was the project’s critical path, a tight adherence to Astaldi’s schedule needed to be maintained.
The partially perforated BridgeCor structure was fabricated in 75’ sections with multiple gages to meet the various loading requirements. Using a crane to install each section in the water, the completed structure was assembled and installed in just over a year – well within the projected timeline. The installers, Straight Ahead Construction, Inc., played a crucial role in making sure the installation went smoothly and that the deadline was met.
Overall, this was a successful installation, due in part to the excellent communication by the contractor, Contech engineering and manufacturing, plate assemblers and installers.