Load Distribution and Ultimate Strength of an Adjacent Precast, Prestressed Concrete Box Girder Bridge.

摘要

A decommissioned, adjacent precast, prestressed concrete box girder bridge constructed in 1967 was load tested to destruction in August and September of 2010. The bridge, which crossed Paint Creek approximately nine miles (14.5 km) northeast of Washington Court House, Ohio, consisted of three simple spans, each 47 ft. 10 in. (14.6 m) long. Each span was comprised of nine, 21 in. (533.4 mm) deep by 36 in. (914.4 mm) wide prestressed concrete box beams for a total width of up to 27 ft. 4 in. (8.3 m) with a 15° left-forward skew. Prior to testing, the bridge appeared to be in good condition, with the vast majority of deterioration limited to concrete spalling from the exterior webs of the fascia girders.;Of the three spans tested, this thesis details testing and analysis of the first two. In addition to environmental deterioration, the first span was damaged by researchers, whereas no additional damage was done to the second. Loads were applied via three, 350 kip (1557 kN) hydraulic cylinders supported by steel load frames. Test data collected from pressure transducers, wire potentiometers, and strain gauges were compared to predictions from a reinforced concrete modeling program. Beam capacity and bridge distribution factors were compared to values calculated from the AASHTO LRFD Bridge Design Specifications.;Data analysis shows that the response of the bridge was predicted well by the analysis program for both low-level destructive and ultimate destructive loads. It was determined that bridge capacity could be found by summing the capacity of each individual beam, as long as the calculated capacity is reduced for the effects of damage. The bridge maintained its ability to transmit load between girders even after cracking of shear keys, indicating that steel tie rods play a major role in transmitting load from one beam to the next.