Comparison of a quasistatic seismic strain range method with test and detailed transient analysis

A recently developed method for estimating the maximum strain range of a structure subject to seismic excitation has been applied to a one inch pipe test configuration. The method uses the concept of a simple substitute structure with physical constants developed from quasistatic plastic analysis of the full structure. Loads for the quasistatic analysis are model loads gradually scaled to cover strain levels of interest. The substitute, subjected to the same excitation as the structure, represents the structure's important characteristics of strain concentration, structural system hardening and hysteretic damping. From test data, maximum strain ranges from 0.5% to 1.0% were obtained for four levels of strong sinusoidal shaking. The quasistatic method gave conservative predictions at all levels, on an average by about 30% of the test results. Reapplication of the method to detailed transient analyses of the same piping configuration also gave conservative results