Internal force redistribution caused by cracking of concrete in composite frame structures under lateral load

Abstract

The internal force distribution of composite frame structures governs their economic performance and failure modes. In practice, redistribution factors are generally used to measure the difference between real bending moment distribution and bending moment distribution calculated using the elastic method. However, most of the studies have focused on the redistribution factors of continuous beams under a vertical load. There are only a few studies on the redistribution factor of composite frame structures under lateral loads caused by the cracking of concrete slab. This study focuses on the redistribution of composite frames under lateral loads owing to concrete slab cracking; the shell–solid model is adopted in this study. First, the numerical results of different finite element models are compared. Second, through theoretical analysis and numerical simulation of a composite frame beam, the analysis of the redistribution factors is performed, and the yield point is defined. Thereafter, the shell–solid finite element models considering the cracking of concrete are established to simulate the entire process under lateral loading, and several key parameters are identified; the influence of each parameter on the redistribution factors is analysed. Based on single-parameter analysis, finite element analysis using the shell–solid model is conducted to propose formulae for calculating redistribution factors, and the corresponding accuracy and errors are analysed. Finally, engineering design suggestions are proposed for internal force redistribution caused by the cracking of concrete in composite frame structures under a lateral load.