Effect of Concrete Slab on Shear Capacity of Composite Plate Girders under Positive Moment

Abstract

To evaluate the contribution of the concrete slab to the shear resistance of composite concrete-steel plate girders, two tests were carried out on one full-scale composite plate girder. The tested specimen was loaded to failure under shear load and positive moment. Vertical deflection of the girder and out-of-plane deflection of the web panels were monitored during each test. Principal strains and their inclination were obtained by instrumentation on the web, flanges, stiffeners, and concrete slab. The observed failure mechanism of the tested specimen is presented using the test results. Nonlinear finite-element analysis of the tested specimen was carried out and calibrated using the tests results. To study a wider range of composite girders, further finite-element models were built with different concrete slab and steel web thicknesses. The experimental and analytical results indicate that the ultimate capacity of the tested composite specimen is higher than what is predicted by the current AASHTO design specifications for a bare steel plate girder.