Fire Performance of Shear Studs in Transverse Deck Slabs

Abstract

Steel and concrete composite structures are frequently utilised in multi-story buildings, as they maximise the material merits via composite action, which is achieved by a shear connection between the steel and concrete sections. The fire performance of the shear connection is a primary parameter in composite beam design, which has been investigated with a focus on adopting solid concrete slabs. Despite the popularity of embracing profiled steel sheeting in composite construction, the fire behaviour of shear studs embedded in a transverse deck slab remains to be confirmed.
This thesis presents experimental and numerical studies on the behaviour of the shear connection when headed shear studs are incorporated with a transverse deck slab both at ultimate and fire limit states. High-temperature push-out tests were experimentally conducted, and finite element models were developed using a commercial package, Abaqus. Concrete plasticity parameters for high-temperature applications were proposed to simulate a concrete-dominated fracture in the push-out test models. The accuracy of the developed numerical models was verified using experimental data, which demonstrate a strong correlation in the shear resistance and failure modes at different temperatures.
The failure mode transforms from a concrete pull-out into stud shearing as the temperature increases in the transverse deck specimen owing to a higher thermal degradation of stud material. The shearing location also approaches the bottom of the shear stud as fire exposure time increases. Parametric studies using the developed numerical models were conducted, including several variables such as the stud welding method, deck thickness, stud location, and number of studs in a trough. Although all the mentioned variables influence the shear resistance in the ultimate limit state, their effects decrease with increasing temperature. Since the current design code of EC4-1-2 (2014) shows a different response in comparison to experimental data, modified design rules for shear resistance calculation in the fire limit state have been proposed herein depending on failure modes.

Date of Award	Apr 2020
Original language	English
Supervisor	Seng-Kwan Choi (Supervisor) & Jianping Zhang (Supervisor)