The newly completed Selmon West Extension is an elevated 1.9-mile two-lane roadway located in Tampa, FL, which connects to the Selmon Expressway. The Tampa Hillsborough Expressway Authority (THEA) began construction of the $230 million project in December 2017 and completed it in April 2021.

The Selmon Extension offers drivers a choice to either stay on Gandy Boulevard for local destinations or use the Extension for regional "pass-through" trips. The opening marks the second time in 15 years that THEA has built a first-of-its-kind superstructure in the United States. In 2006, THEA completed the Selmon Expressway's Reversible Express Lanes (REL), an all-electronic, elevated express lane project.

Gandy Boulevard (State Road 600/U.S. 92) in South Tampa is heavily utilized by drivers who commute to or from neighboring Pinellas County, making this road extremely congested, particularly during peak hours. Over the years, there were various proposals to widen the roadway, but these attempts failed due to public opposition, additional right-of-way requirements, and funding constraints.

Recognizing that regional and local traffic volumes would continue to increase due to large-scale migration to Tampa Bay, THEA proposed an alternative to widening the existing roadway.

The Selmon West Extension is elevated and constructed within the 30-foot median located in Gandy Boulevard. All work is within the existing THEA and Florida Department of Transportation (FDOT) right-of-way. By removing the "pass-through" traffic coming to and from the Gandy Bridge, the Selmon Extension creates at least 35% greater capacity on Gandy Boulevard for neighborhood traffic and customers of Gandy Boulevard businesses. The project was advertised as an adjusted score (best value) design-build project on January 20, 2017. THEA's Board of Directors approved the selection of the Kiewit Corporation/AECOM team on July 24, 2017, and the design-build firm was issued a Notice to Proceed by THEA on September 25, 2017.

The Kiewit team proposed an elegant extradosed tendon concrete segmental viaduct for most of the length along Gandy Boulevard, transitioning to steel tub girders shaped and painted to match the segmental portion at the interchange on the east end of the project. The bridge foundation consists of 55 piers and caps supported by four redundant drilled shafts for each pier. The extradosed tendons (similar to a cable-stayed bridge with the cables encased in concrete finbacks) allow a shallow superstructure and longer spans between piers, which is particularly critical at the Westshore and Manhattan intersections. The elevated bridge is three different bridge types combined. These include precast concrete segments, steel tub girders, and prestressed concrete beams. A total of 744 segments were precast offsite and transported to the
95 project site for erection and post-tensioned into the viaduct structure. Over 1400 ground improvement piles were installed within the interchange area to support the ramps and MSE walls.

The Selmon Extension has a unique design that has never been built in the United States. These fins are not just for aesthetics, they help support the bridge deck that enables longer span lengths between pier columns and allows a reduced height cross-section for the precast segments.

Back in 2017, THEA asked the community to vote on the Selmon Extension's aesthetic design. The Tampa Bay community overwhelmingly chose the "Estuary" design for the Extension's columns and fins, the cream-and-blue pattern representing nature envisioned in the form of a river delta.

THEA also listened to the business community's concerns and designed a 30' bridge, double the height of a standard bridge, to ensure the visibility of the businesses on both sides of Gandy Boulevard. The Construction Engineering Inspection (CEI) and Public Involvement Team personally visited approximately 70 Gandy Boulevard businesses and continued ongoing communications throughout the project with existing and new businesses. Since construction, 13 new businesses have opened along Gandy Boulevard. THEA listened to the community and kept its promises from ensuring easy access and visibility for businesses along the Gandy Corridor to keeping a commitment to the project renderings and final superstructure.

Learn more about the promises kept and made - a rarity in big projects like this - at https://www.tampa-xway.com/promises-made-promises-kept/, including how toll revenues and bonds fully funded the Selmon West Extension without using any taxpayer dollars.