Residual ultimate strength of large opening box girder with crack damage under torsion and bending loads

摘要

This paper numerically investigated the residual ultimate strength of large opening box girders with crack damage under individually or jointly applied torsion and bending loads. Series of nonlinear finite element analyses were carried out with varying the crack length, location, and orientation angle to assess their effects on the residual ultimate strength of large opening box girders. Three types of cracks, namely longitudinal crack, transverse crack and inclined crack, are considered in this paper. The residual ultimate strength are obtained and discussed for the three types of cracks under torsional or bending moment loading condition. Based on the numerical results under individually applied torsion or bending moment, two of the most dangerous crack damage situations are adopted for analyzing the residual ultimate strength of large opening box girders with crack damage under combined loads. An interaction equation is proposed for predicting the residual ultimate strength of large opening box girders with crack damage under combined loads. The validity of this simple equation is verified by some crack damage cases of varying crack length.