9711084 Hsu Evidence from structural failures in past earthquakes clearly shows that shear walls offer excellent protection to buildings in seismic regions. This project is to develop a rational approach to understanding and predicting the behavior of low-rise shear walls and framed shear walls under cyclic loading. The overall concept behind this approach is that the complicated behavior of shear walls as a whole system, can be elucidated by integrating what can be learned, experimentally, about its parts and components, visualized as being an assembly of membrane elements (panels). The stress-strain behavior of individual membrane elements will be studied to establish physical and analytical models. The resulting models will then be integrated into a finite element program to compute and predict the load- deformation behavior of whole shear walls under specified conditions. A unique universal panel tester was constructed at the University of Houston in 1988 which is especially suited for the intended testing. A test program of 25 wall panels subjected to cyclic loading will be carried out. The results from the cyclic tests on membrane elements will be used to establish the cyclic constitutive laws of concrete. Concrete behavior such as stiffness deterioration, strength deterioration, and "pinching" of hysteretic loops will be determined and then used to calibrate their corresponding parameters in an analytical model established by El-Borgi. The calibrated hysteretic models will then enable a nonlinear finite element computer program be formulated, which can be used to predict the behavior of whole shear walls. The University of Houston in the United States and the Polytechnic School of Tunisia in Tunisia will jointly carry out this research. ***
