TENNESSEE STATE ROUTE 385 OVER THE WOLF RIVER WETLANDS: A PRECAST SOLUTION

摘要

Environmental considerations necessitated a change in the bridge required on State Route 385 over the Wolf River in West Tennessee. During preliminary design a 5-span, 720-ft long structure was proposed for the crossing. This evolved into a 33-span, 3,250-ft long structure composed of 4 continuous units which bridged not only the Wolf River, but adjacent wetlands as well.rnTo optimize economies of the major structure, both prestressed concrete and steel rolled shape girders were included as alternates in the contract plans. Both girder systems were designed incorporating simple for dead load, continuous for live load (SDCL) details.rnThermal displacements at 3 out of the 31 pile-bent substructures were accommodated with strip seal expansion joints located between “double-bents”. Pipe piles were designed for seismic loading and extended beyond liquefiable layers. Out-of-phase transverse seismic deformation of the “double-bents” was prevented with pipe restrainers to protect the expansion joints.rnThe bid cost of the bridge was $14,220,000 resulting in a unit price of $50 per square foot for the dual, 44-ft wide structures. All five bidders opted for the precast, prestressed girder alternate.