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

摘要

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.