Interfacial Bond Performance of Concrete-Filled Steel Tubes under Fire and Postfire Conditions: State-of-the-Art Review

Abstract

The critical influencing factors of the interface bonding properties of concrete-filled steel tubes (CFSTs) under fire and postfire conditions are analyzed. This paper analyzes and summarizes the existing research related to the bonding performance of CFST interfaces under fire and postfire conditions at home and abroad, which includes the bonding mechanism of CFST structures, the bonding strength of CFSTs during and after fire exposure, and the main factors influencing bond strength. The analysis results indicate that the temperature has noticeable influences on the bond strength of a CFST during and after fire exposure. The bond strengths of the specimens are reduced more severely under high-temperature conditions than after high-temperature cooling. Shear connectors can significantly improve the bonding performance of CFSTs and effectively reduce the relative slip between steel tubes and concrete. The paper concludes with an analysis of the deficiencies in bond-slip research on the bonding properties of the CFST interface during and after fire exposure and future research directions. First, we can study the use of new technologies and materials to solve the problem of bonding and slipping of CFSTs during and after fire exposure. Second, we can perform extensive experimental research and theoretical simulation analysis to enrich the research in this field, which can provide a reference for engineering practice.