Experimental study on the axial compression performance of pultruded GFRP tubes for emergency bridges

Glass fiber reinforced polymer (GFRP) tubes exhibit significant potential in the design and construction of emergency bridges owing to their high strength-to-weight ratio. Axial compression tests were conducted on 13 pultruded GFRP tubes with varying slenderness ratios (11.9, 14.3, 21.4, 28.6, and 35.7) and diameter-thickness ratios (37.2, 46.5, and 86.2). Furthermore, a nonlinear finite element model was applied to analyze the failure characteristics and load-bearing capacity of the GFRP tubes when subjected to axial loads. A modified Perry formula was proposed based on this analysis. The results indicate that the GFRP tubes are prone to experiencing brittle failure. With the slenderness ratio increases from 11.9 to 35.7, the failure mode tends to change from crushing to local buckling to global buckling. The modified Perry formula displays a high degree of agreement with experimental results, with an average error of 9.38%, and offers a more precise prediction of the capacity of composite tubes. The findings have practical implications for the design of composite truss bridges.