Owner: MTA Bridges & Tunnels
Contractor: Perini Corporation
Contractor’s Engineer: HNTB
Designer: Steinman, Boynton, Gronquist & Birdsall Consulting Engineers
The Triborough Bridge in New York City continues to experience major rehabilitation. The contractor proposed the use of the precast concrete Inverset Bridge System to save time and reduce the revenue disruption to the owner. The project utilized (254) Inverset units (144,000 sf) in lieu of the specified concrete grid-filled deck. The installation, which reached placement rates of (15) units per shift, was accomplished during evening and off-peak hours and resulted in saving a year on the project schedule.
Inverset units were designed to fit on top of the existing substructure requiring many specially shaped units. Some precast concrete Inverset units actually were framed into other Inverset units while others were heavily tapered to accommodate the highly complex geometry. Units were erected from above and below the existing structure to minimize interference with traffic.