Fire Performance of CFST Triple-Limb Laced Columns

AbstractThis paper investigates the fire performance of concrete-filled steel tubular (CFST) triple-limb laced columns. Six CFST triple-limb laced columns are tested to measure their fire resistance. The influence of column load ratio and steel type on fire resistance are investigated. For comparison, four CFST single-limb columns in fire are tested. The test results indicate that the three CFST chords in CFST triple-limb laced columns can work together very well in fire because of the binding effect provided by the steel lacing tubes. Finite-element analysis (FEA) models are developed to simulate the CFST triple-limb laced columns in fire. The mechanical behavior, including failure modes, deformation, and load distribution, are discussed. Parametric analysis based on the established FEA model is conducted, and a simplified equation is proposed to predict the fire resistance of CFST triple-limb laced columns.