An Equivalent Single-Degree-of-Freedom System to Estimate Nonlinear Response of Semi-fixed Flexural Members Under Impact Load

Abstract

A quick and reliable method to estimate the nonlinear dynamic response of a structure is replacing it with an equivalent single-degree-of-freedom system. To analyze the equivalent system, determination of the load and mass transformation factors is essential. So far, these factors have been calculated just for elements with completely fixed or hinged supports. However, so many supports and connections behave as semi-fixed or semirigid and the assumption of being fully fixed or hinged does not comply with current practical conditions. The purpose of this study is to determine load and mass factors, ultimate resistance and nonlinear dynamic response for one-way flexural members with semi-fixed supports or a member of a frame with semirigid connections under impact (blast) load. The results of the proposed model are verified with available codes and references. Also, the importance of considering the members with semi-fixed supports in obtaining accurate responses is demonstrated.