Structural Behavior of SRC Beam-to-Column Joints Subjected to Simulated Fire Including Cooling Phase

Abstract

This paper presents the test results of three steel-reinforced concrete (SRC) columns to SRC beam joints under combined loading and fire. Simulated fires, including heating and cooling phases with different heating times, were applied to the lower part of the three composite joint specimens. Failure modes, concrete cracking, concrete spalling, and deformation development were observed or measured. The test results indicate that heating time affects the postfire residual bearing capacity significantly. A finite-element analysis (FEA) model was developed to simulate the response of SRC beam-to-column joints in whole loading sequences, including initial loading, heating, cooling, and postfire loading. Some key influencing factors, such as the creep of steel at high temperatures, slippage between the steel and concrete, and residual stresses in the H-shaped steel, were considered in the model. On the basis of the verified FEA model, the development of the rotation angle between the beam and column, which cannot be measured by testing, was calculated and discussed.