Seismic performance evaluation of reinforced concrete columns using finite element-based nonlinear dynamic analysis

Abstract

As ensuring seismic safety for mid- and low-rise reinforced concrete (R/C) buildings with non-seismic details has become increasingly pressing, numerous studies have carried out seismic performance evaluation based on experimental and analytical research, considering structural characteristics. However, there are limitations to experimentally evaluating seismic performance. Experimental research incurs high costs due to expenses associated with equipment, materials, labor, and the fabrication of full-scale structures or scaled models for testing. Additionally, large complicated structures can be challenging to reproduce in a laboratory setting, and it is difficult to replicate various conditions associated with load, material properties, and constraints. In contrast, most nonlinear dynamic analysis studies conducted for seismic performance evaluation assume that the beams and columns of R/C buildings are linear members with springs at their ends and midsections, where nonlinear hysteretic behavior occurs. However, nonlinear dynamic analysis based on a spring model for member substitution is not sufficient for detailed seismic performance assessment, as it does not fully represent the full progression of cracks and failures in all members, the final failure shape, or the stress–strain distributions. In this study, a methodology for evaluating seismic performance using finite element-based nonlinear dynamic analysis is proposed based on a material model that reflects the structural characteristics of column members, which are critical seismic components in R/C buildings, for a more precise evaluation compared to that of traditional member-substitution spring models. Using our proposed approach, seismic performance was evaluated for real R/C columns, with a focus on three column types: pilotis columns and columns affected by shear and flexure. To verify the validity of our method, we compared the finite element-based nonlinear dynamic analysis results with those obtained using pseudo-dynamic testing with respect to the three R/C column types. Our findings revealed a high degree of similarity in seismic performance evaluation between the proposed approach using finite element-based nonlinear dynamic analysis and pseudo-dynamic testing in terms of crack patterns, load–displacement response, displacement–time hysteresis, cumulative dissipated energy, and reinforcement strain.