Demountable connections for enhanced resilience: An analytical and numerical assessment of steel-concrete composite beams

To improve the increasingly serious environmental pollution problems such as construction dust and waste in the process of construction and reconstruction phase, the full life-cycle demountable structures have attracted increasing interest in earthquake engineering. This paper describes a new type of demountable shear connection for the steel-concrete composite beams to realize reuse in full-life cycle at service loads and rapid return to occupancy after damage under seismic actions. The structural configuration and mechanical feature of this composite beam were first introduced. After the nonlinear finite element (FE) models using the Abaqus software had been validated against experimental data, a parametric study was carried out to understand the effect of bolt diameter, bolt strength grade, precast concrete plug size, strength of precast concrete plug and slab on the shear behavior of demountable shear connections at the component level. The results show that bolt diameter and strength grade have a significant effect on the shear capacity and stiffness, respectively. Besides, bolt strength grade and concrete plug size can improve the performance level of reuse and occupancy. Based on the FE analysis results, simple design calculation method for demountable shear connection is proposed. Finally, behavior of the proposed steel-concrete composite beam was also evaluated under two-point loading to exhibit the performance of reuse and replaceability in engineering practice. •The proposed composite beam consisted of steel beam, prefabricated concrete slab and demountable shear connections.•Bolt diameter and strength grade have a significant effect on the shear behavior of demountable shear connections.•Bolt strength grade and concrete plug size can improve the performance levels of reuse and occupancy.•The composite beam with demountable shear connections can achieve the behavior of reuse and replaceability.