Experimental and theoretical study on the eccentric compression performance of novel L-shaped composite columns composed of HGM-filled square steel tubes

Abstract

This study investigates the mechanical properties of novel L-shaped composite specimens composed of high-strength grouting material filled square steel tubes (L-shaped HGMFSST composite specimens) under eccentric compressive loading. In this study, an experimental program involving twelve L-shaped composite specimens was carried out to evaluate their failure modes, bearing capacity, deformation characteristics, and strain development patterns. The research results demonstrated that the primary failure mode of the L-shaped composite specimens was overall bending failure. The incorporation of high-strength grouting material (HGM) significantly enhanced the ultimate bearing capacity, with improvements ranging from 65.2 % to 104.3 %. The horizontal deflection development curve during loading exhibited a characteristic half-sine wave distribution. During the initial loading phase, the entire cross-section was under compression. A three-dimensional numerical model was established using the finite element software ABAQUS to simulate the nonlinear behavior of the composite specimens. The validated numerical model revealed the failure mechanism of the L-shaped composite specimens under eccentric compression. Finally, based on parameter analysis, a calculation method was proposed to predict the eccentric bearing capacity of L-shaped HGMFSST composite specimens. The eccentric bearing capacity of the specimens was predicted using the proposed method and existing design codes. The comparative results showed that the average and standard deviations of the ratio between the calculated results from the proposed method and the experimental values were 0.916 and 0.049, respectively. It indicates that the proposed method can predict the eccentric bearing capacity of the novel L-shaped HGMFSST composite specimens more accurately. Compared with the calculation methods of the other three codes, the proposed method is simpler and more applicable. Overall, this study reveals the mechanical properties of this innovative composite specimen under eccentric compression and provides significant reference value for engineering design and practice.