PROBABILITY-BASED CODIFIED DESIGN FOR EARTHQUAKES

Current trends in code development in North America and Western Europe are toward the implementation of probability-based limit states desig n methods. Structural design of buildings and other facilities to with stand the effects of strong earthquake ground motion requires special considerations that are not normally a part of design for other occupa ncy, service and environmental loads. This paper reviews some of these special considerations specifically as they pertain to probability-ba sed codified design. The role of structural reliability methods in pro viding an improved basis for design provisions that are suitable for c ode implementation is evaluated, and the treatment of uncertainty in c ode safety checking is described. Difficulties experienced in implemen ting structural reliability principles in the first-generation probabi lity-based limit states codes are summarized. Prospects for improving current earthquake-resistant design procedures based on a more rationa l probability-based treatment of uncertainty are assessed.