Performance of Prefabricated Hollow Concrete-Filled Steel Tube Bracings on Transverse Bending: Experimental and Numerical Analyses

Abstract

Due to the complex hydrogeological conditions in coastal regions, the use of internal bracing systems is necessary for supporting coastal foundation pits. This paper introduces a novel prefabricated foundation pit bracing system based on Hollow Concrete-Filled Steel Tube (H-CFST) structures that can be reused, offering significant economic and societal benefits. However, there is a severe lack of research on the application of H-CFST bracing systems. Through model tests and finite element simulations, the load-displacement characteristics and failure modes of prefabricated H-CFST bracing under transverse bending were investigated. The study revealed that when a wall thickness of 1.5 d was chosen, the self-designed hoop effectively mitigated strength and stiffness reduction at the bracing connection point. When the load reached 150 kN, the outer steel tube of the H-CFST components experienced localized yielding, and when the load was increased to 300 kN, the end supports exhibited cracking. Finite element analysis provided a more accurate prediction of bracing failure at 147.18 kN, and it offered valuable insights for optimizing the bracing design. Based on the above research, theoretical methods for calculating the bearing capacity of each bracing component under transverse bending conditions have been proposed and validated against experimental results.