Bearing Restraint in Slab‐on‐Girder Bridges

Abstract

It is well established, as a result of many field tests, that slab‐ongirder bridges are usually stiffer in flexure than is predicted by normal deflection analysis. An example is given in the paper to support this contention. Restraint to horizontal movement at girder supports is identified by field tests on actual bridges as the main reason for this enhanced stiffness. Simple expressions are derived in the paper, by use of which the beneficial effect of girder support restraint can be taken into account in the evaluation of the load‐carrying capacity of single‐span existing bridges. These simple expressions relate to girder deflections and moments, and to the stresses in the bottom flanges of the girders, all of which reduce differently as a consequence of bearing restraint. It is shown that girder restraint can reduce live load moments in existing single‐span slab‐on‐girder bridges by up to 20%