Control of Random Yield‐Strength for Mechanism‐Based Seismic Design

Abstract

A weak‐beam‐strong‐column philosophy is generally recommended for the design of earthquake‐resistant multistory structures, because the associated overall collapse mechanism exhibits a high ductility against a strong ground motion. Some uncertainty factors, however, are considered to impair the overall collapse mechanism, such as randomness in members' yield strengths, randomness in earthquake motions, and randomness in mass‐distribution over the height of the building. Static and dynamic simulations on the inelastic performance of a six‐story rigid frame using a Monte Carlo method showed that the randomness in the yield strengths has a predominant influence on the failure mechanism and consequently on the system ductility. In practice, weak‐beam‐strong‐column structures will be realized only when the randomness in the yield strengths is reduced by means of a higher quality control in manufacturing and construction processes, otherwise a considerably high margin should be provided to column strengths.