Numerical Simulation of Steel Pipe Column with Outer Pipe for Seismic Retrofit

Abstract

Regarding the seismic retrofit of a steel pipe column by attaching an outer pipe with clearance at the portion where local buckling occurs, we investigated the effects of various factors of the outer pipe (clearance between outer pipe and steel pipe, wall thickness and mechanical properties of outer pipe) on the ductility of the steel pipe column, by conducting an elasto-plastic FEM analysis using shell elements as parameters, in a test similar to that which reproduces quasi-static cyclic load on a cantilever model test specimen. And using the analysis results thus obtained, we proposed the guide specifications for structural reinforcement to attain necessary ductility and a formula for estimating the ductility ratio of the reinforced steel pipe column with various types of outer pipe.