Abstract
This paper suggests a method to evaluate seismic resistivity of low steel structures by comparing characteristics of plastic energy absorption response obtained by the present analysis of lumped mass models with energy absorption capacity previously obtained by the experiment as shown in ref. 20. The earthquake response analysis shows that plastic energy absorption response can be a more appropriate parameter to appreciate the response characteristics than displacement response. It has been pointed out that the sum total of plastic energy absorption response in multi-mass system can be approximated by that in one mass system, but the distribution yields scatter due to the difference in characteristics of system and earthquake motions. We suggest the factor of safety in aseismic design against such scatter having indicated its sufficiency in the analyzed examples. We also suggest to evaluate seismic resistivity by cumulative damage factor. This factor can be obtained in the present manner, that is, by comparing energy response with energy absorption capacity with the application of plastic energy absorption as a parameter to cumulative damage rule (ref. 21). For the practical application to aseismic design, we have derived formulae to calculate the base shear coefficients in establishing the aimed value of cumulative damage factor and the intensity of earthquake motions defined by the maximum velocity and power of wave. The results of analysis in some examples have proved their adequake accuracy.
