Investigation of Load Transfer in Multi-Beam Prestressed Box Girder Bridges

摘要

The report describes a series of field tests of multi-beam prestressed box girderbridges. The objectives of the tests were to investigate the in situ performance of the grouted shear keys, located at the joints between adjacent girders, and to identify causes for joint distress observed on some bridges of the type. The tests consisted of monitoring relative displacements occurring across the intergirder joints, as well as bending strains in the girders themselves, during passages of a preweighted test vehicle. The test vehicle consisted of a fully loaded tandem axle dump truck, with axle loads typically in the range of 18 kips (80 kN). Relative displacements were measured with an especially designed transducer, having a resolution on the order of 0.1 mils (.00254mm), which was bonded to the underside of the bridge across the intergirder joints.