7 - Analytical model for compressive arch action and catenary action in reinforced concrete beams against progressive collapse

Abstract

This chapter presents the development of analytical model for prediction of compressive arch action (CAA) in reinforced concrete (RC) 2D substructure specimens against progressive collapse, which was derived based on Park’s assumption, and test results from previous experimental studies, which could also take into account the tensile strength of engineered cementitious composites (ECC). The mechanical model calibrated against test results from conventional concrete beam-to-column 2D substructure specimens was further employed to predict the structural performance of ECC 2D substructure specimens subjected to removal of column. Eventually, investigation on several critical parameters governing the CAA behaviour in RC 2D substructure specimens was conducted via a series of parametric studies. Analytical studies on catenary action (CA) in RC beams were also presented in this chapter. The CA model involves formulation of compatibility and equilibrium of beams, followed by correlating the strains of steel reinforcement to global beam deflections to obtain the development of vertical load and axial tension force with increasing central joint vertical deflection. The validated analytical models (showing good agreement with test results) are further employed in studying the influences of axial restraint stiffness on CA. Finally, a design method based on the analytical studies is proposed to evaluate the vertical capacity of CA and its corresponding tension force.