A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1989

Experimental data from previous studies were analyzed to model a shear resistance mechanism of concrete members. Using Li and Maekawa' s Contact Density Model for Cracks in Concrete, forces transferred at cracks for loading and unloading paths were obtained. Forces in the shear reinforcement and shear force in the compression zone were also quantified and summed up with forces transferred at crack to balance the external shear force . Beam tests were also carried out to study the contribution of the individual internal force components to resisting external shear force at loading and unloading stages. Measurements of crack dis placements, concrete strains in between shear cracks as well as compressive strains in the compression zone of the tested beams, which are of ordinary reinforced concrete and concrete sandwiched by steel plates , were meticulously taken using Demecgauge. While the internal forces balanced the external shear force for monotonic loading case , they did not perform as expected for the unloading case due to presence of residual forces in each component and positive strut angles at complete unloading . The shear resistance mechanism model derived for the monotonic loading case was proposed with a reducing factor in the concrete component .