Project Overview
The majority of the connector is located within the Rio Grande Flood Plain and below the design high-water level. In order to gain project approval from the International Boundary & Water Commission (IBWC), the structure depth needed to be as shallow as possible. The TxDOT slab beam, a 15-in.-deep solid precast, prestressed beam similar to a box beam, was what led to the project approval from the IBWC.
Because the majority of the bridge is below the design water level, the bridge was required to withstand flood forces of the river. Slotted holes were formed within the slab beams at the beam ends allowing threaded dowels embedded with the cap to pass through and anchor the beams down with bolted plates, holding the bridge superstructure in place in case of a flood. The precise fabrication of precast elements allowed the engineers to utilize complex geometric calculations that enabled the placement of these slab beams side by side on a tight horizontal curve with a vertical curve and cross slope.
Precast Solution
The TxDOT slab beam was used to minimize the superstructure depth, contributing to a minimal floodwater effect. Another impressive detail accomplished through the use of precast, prestressed concrete was the tight horizontal curve on the bridge.
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