Theoretical study on progressive collapse of truss string structures under cable rupture

Abstract

Cables are critical components of truss string structures and cable failure can cause serious damage to the structure or even progressive collapse. However, little theoretical research work deals with this phenomenon. In this study, a rapid analysis method for the progressive collapse of truss string structures based on the nonlinear buckling material model was proposed. The results showed that the rapid analysis method could reduce the computational time by at least 30% and effectively improve computational efficiency. Based on the validated rapid analysis method, the progressive collapse failure mechanism of truss string structures under cable rupture was analyzed. The results showed that progressive collapse failure mechanisms could be divided into two categories. In one category, compression buckling of the upper chord member leads to a loss of load capacity and a rapid increase in deflection without convergence, resulting in progressive collapse of the structure. In the other category, tensile yielding of the lower chord member results in a gradual loss of stiffness and a slow increase in deflection without convergence, leading to progressive collapse of the structure. Moreover, a series of assumptions and simplifications were made, followed by the establishment of calculation equations for the progressive collapse load capacity and deflection of truss string structures under cable rupture. By comparing the theoretical values with the finite element values as well as test values, the accuracy of the equations proposed in this study for calculating the progressive collapse load capacity and deflection of truss string structures was verified.