Residual stress measurements and modeling of built-up Box-T sections

Abstract

Increasing use has been made recently of special-shaped columns (i.e., L-shaped, T-shaped, and cross-shaped) in multistory and high-rise residential and official buildings, due to their advantages in avoiding column protrusion and enlarging the indoor space. The box-T section column, built up by one cold-formed box section and several welded or hot rolled T-sections, is a new special-shaped column type. In this paper we report an experimental investigation of the residual stress distributions of eight box-T sections using the sectioning method, including L-shaped and T-shaped columns. From the experimental results, new residual stress distribution patterns for welded box-T sections and rolled box-T sections are found. Based on the interaction analysis of the residual stresses in different components of box-T sections, reasonable assumptions and simplifications for the residual stress distribution patterns are obtained. Finally, residual stress distribution models are proposed for welded box-T sections and rolled box-T sections and they are verified by finite element (FE) analysis to meet the self-equilibrium condition. The proposed residual stress distribution models can be used in the buckling analysis of box-T section columns and the modeling concepts in this paper may be invoked in the processes for modeling residual stress distributions in other complex built-up sections.