Behavior of Reinforced Concrete Membrane Elements Subjected to Bidirectional Shear Loads

The shear design and behavior of a typical membrane reinforced concrete (RC) element has been extensively studied in the past several decades. Such design requires knowledge of the constitutive behavior of reinforced concrete elements subjected to a shear stress acting along its plane (in-plane shear). These constitutive models were accurately derived from experimental test data on representative reinforced concrete panel elements. The true behavior of many large complex structures, however, involves interaction between the in-plane and out-of-plane shear stresses acting on the RC element. To investigate this interaction, large-scale tests on representative concrete panels need to be conducted. The University of Houston is equipped with a unique universal panel testing machine that was used for this purpose. The panel tester enhanced the understanding of the in-plane shear behavior of reinforced concrete elements. Recently, 10 additional hydraulic jacks were mounted in the out-of-plane direction of the universal panel tester to facilitate testing of concrete elements subjected to bi-directional and tridirectional shear stresses. The experimental program included designing, fabricating, instrumenting and testing full scale reinforced concrete elements. The elements were subjected to different combinations of in-plane and out-plane shear loads. Strong interaction between in-plane shear strength and out-of-plane shear stresses was observed.