A Study on Simplification of Seismic Design Method Considering In-elastic Behavior of Equipment and Piping Systems

Abstract

The applicability to Japan of the American Society of Civil Engineers seismic design standard (ASCE/SEI 7-22) is examined with respect to a simple seismic design method considering the plastic region of machinery and equipment. Response analyses were conducted for seismic waves recorded in Japan using a simple, end-supported, 5-Masses model with bilinear force-deflection characteristics, and the following results were obtained: (1) When the yield capacity is set using the maximum acceleration value of the input wave as the static load, an element ductility factor of 3 to 5 is expected. (2) The standard’s recommends value of 2/3 of the response reduction factor can be appropriate for flexible systems, but for systems with high natural frequencies, it is necessary to consider the other effects such as an overstrength factor in addition to the effect of energy absorption by plasticization.