Probability based load combination criteria for design of shear wall structures

This report describes the development of probability-based load combination criteria for the design of reinforced concrete shear wall structures subjected to dead load, live load and earthquake. The proposed design criteria are in the load and resistance factor design (LRFD) format. The load and resistance factors are determined for flexure and shear limit states and target limit state probabilities. The flexure limit state is defined according to the ACI ultimate strength formula. The shear limit state is established from experimental results. In order to test whether the proposed criteria meet the reliability-based performance objectives, four representative structures are selected using a Latin hypercube sampling technique. These representative structures are designed using trial load and resistance factors. Then, a reliability analysis method is employed to assess their reliabilities. An objective function is defined and a minimization technique is developed to find the optimum load factors. In this study, the resistance factors for shear and flexure, and load factors for dead and live loads are preassigned to simplify the minimization. The load factor for SSE is determined for the target limit state probability of 1.0 x 10-6 or 1.0 x 10-5 with a lifetime of 40 years. 23 refs., 9 figs., 12 tabs