The performance of composite beams with X-HVB shear connectors after being subjected to fire exposure

Abstract Composite construction has emerged as a highly effective methodology for construction in recent decades, typically involving hot-rolled steel beams, profiled seel decks, welded bolts, and an in-situ concrete slab reinforced with a steel mesh. This construction method offers numerous benefits, including damage resistance, good service response, and low cost. The advantages can be further enhanced through the use of X-HVB shear connectors instead of traditional weld-on bolts. X-HVB connectors offer two additional benefits: they can be used in cold rolled profiles, wet sections or rehabilitation elements, and their installation is simple and safe. The connectors are made of cold-rolled steel and come in a range of nominal heights from 40 to 140 mm. However, little previous research has focused on how the X-HVB connectors behave and affect composite beams during a fire. To investigate this, an experimental study was conducted that focused on the effect of fire exposure, the orientation of the corrugated steel plate to the steel beam, and the side of exposure to fire (from the concrete slab or steel beam). Six composite beam specimens were prepared to investigate shear strength, stiffness, and ductility, with load-deflection results obtained from the experimental work validated with proposed Digital Image Correlation (DIC) based technique results. The experimental results indicate that the capacity, stiffness and ductility of composite beams decreased upon exposure to firing, especially for those with transverse corrugated steel plates. The direction of fire exposure also had a significant impact. The DIC technique results aligned well with the test results.