This proposal requests funds to permit Dr. Franklin Y. Cheng, Department of Civil Engineering, University of Missouri-Rolla, to pursue with Dr. Chang-Koon Choi, Department of Civil Engineering, Korea Advanced Institute of Science and Technology (KAIST) for a period of 24 months, a program of cooperative research on nonlinear behavior and marginal safety of low-rise reinforced concrete shear wall systems against interacting ground motions. Low-rise civilian buildings comprise the overwhelming percentage of building construction in the U.S. and Korea. For such structures with reinforced concrete walls, the height-to-width ratios are small. Under seismic loads, these walls experience shear deformation rather than the bending experienced by walls in taller structures. Research currently in vogue deals mainly with bending deformation of high-rise structures within the elastic limit. The present cooperative research, on the other hand, will consider the amount of reserve strength between the elastic limit and failure for walls of low height-to-width ratios. Structural behavior in this range is nonlinear, and new analytical models must be developed to predict the behavior of new and repaired structures. These models will be tested and verified against experimental results. Damage studies will be based on experimental behavior and calculated results. In addition, building code specifications will be assessed. Considerable progress has been made in predicting the behavior of high-rise structures subjected to multicomponent seismic input. Much remains to be done toward predicting the behavior of low-rise structures, improving their ability to withstand earthquake loads, and the strength of rehabilitated structures. The collaborators on this project are well suited to undertake such work. The U.S. PI's previous work has dealt with a model of macro-element formulation which reliably predicts the response of structural systems but does not yield detailed information on localized deformations of individual walls. The Korean PI has experience in micro-element analysis which can be used for observing localized deformations. Their models are complementary for examining the relationship between system and element deformations. The solution to the problems addressed by this project would be beneficial to the United States and Korea. This project is relevant to the objectives of the U.S.-Korea Cooperative Science Program which seeks to increase the level of cooperation between U.S. and Korean scientists and engineers through the exchange of scientific information, ideas, skills, and techniques and through collaboration on problems of mutual benefit.
