Axial compressive behavior of the middle-supported irregular-shaped columns in modular aluminum houses

Abstract

Modular folding aluminum houses (MFAHs) are new modular structures that can be folded, transported, and built directly on-site. In this study, the axial compressive behavior and design method of the middle-supported irregular-shaped columns (MICWs) with a single-cavity open section in an MFAH were investigated. Tests were conducted on 12 MICWs and obtained the indexes of bearing capacity and ductility under different slenderness ratios from 27 to 93. Within this range, the bearing capacity of the specimens decreased by approximately 7% for every slenderness ratio 7.32 increase. A refined finite element model (FEM) was established and verified against the corresponding experimental results, which were in good agreement. Furthermore, FEM was used for an extensive parametric study that consisted of specimens with different initial bending values, initial eccentric values, cavity thickness values, and column lengths. The ultimate strengths were employed to evaluate the current design methods. It is demonstrated that the European code (Eurocode 9) and Chinese code (GB 50429) underestimate the bearing capacity by approximately 20%–30%, whereas the American code (AA-2015), Australian code (AS/NZS-1997) and the Direct Strength Method (DSM) overestimate the bearing capacity, which is unconservative. Based on Perry's formula, an equation for calculating the axial compressive bearing capacity of MICWs was proposed. The theoretical design method was verified by comparing the theoretical results with the experimental and numerical results, and the proposed method was found to be accurate and conservative to some extent.