I-75 / SR 826, RAMP A
The widening of Ramp A at the I-75/SR 826 Interchange was the first widening of a precast segmental concrete bridge in the United States. The single-lane ramp, constructed in the early 1980s, was widened from 29′-9″ to 37′-1″ to accommodate two lanes of traffic. All construction activities associated with the widening took place without interrupting traffic. Ramp A is a 3,027′ long precast segmental concrete box girder bridge with span lengths up to 217′ long. The ramp has 1,000′ radii curves at each end. Segments were erected in balanced cantilever by ground-based cranes.
Corven Engineering served as the prime consultant and engineer of record. Services included the development of three-dimensional construction analyses in determining the state of stress in the bridge, design of bridge strengthening using external longitudinal post-tensioning, load rating of widened bridge, shop drawing review, and engineering support during construction.