Xianghe Dai

Effect of Concrete Strength and Stud Collar Size to Shear Capacity of Demountable Shear Connectors

AbstractIn this paper, a group of demountable shear connectors have been developed and tested to assess their potential and suitability in terms of replacing welded shear studs. The experiments showed that these demountable shear connectors can be easily demounted after testing and have similar capacity and behavior to those of welded shear connectors. After the numerical simulation method had been validated against experimental observation, a parametric study was carried out to understand the effect of concrete grades and stud collar sizes on the shear resistance of demountable shear connections. Simple design calculation methods for welded shear connections or anchoring connections provided in European and American standards were checked to the suitability for assessment of this headed demountable shear connector.

Performance of recycled aggregate concrete-filled square steel tubular columns exposed to fire

Experimental and theoretical investigation on the fire performance of concentrically loaded recycled aggregate concrete–filled square steel tubular columns with or without fire protective coating is reported in this article. Tests of nine specimens were conducted with the variation in the recycled coarse aggregate replacement ratio, axial compressive load ratio and thickness of fire protective coating. The failure pattern, typical temperature development, axial displacement and fire resistance of the tested specimens are presented and analysed. The experimental results reveal that the temperatures of the core concrete decrease with increasing recycled coarse aggregate replacement ratio and decreasing thickness of fire protective coating under the same fire exposure time. In general, the specimens with the recycled coarse aggregate replacement ratio of 50% have a similar behaviour as the corresponding specimen with normal concrete; however, the performance of specimens with the recycled coarse aggregate replacement ratio of 100% is clearly different from the reference specimen with normal concrete. Moreover, the fire resistance of recycled aggregate concrete–filled square steel tubular columns increases with an increase in the thickness of fire protective coating and a decrease in axial compressive load ratio. A finite element analysis model was developed for simulating the performance of recycled aggregate concrete–filled square steel tubular columns exposed to fire, and the finite element analysis model was validated against the experimental results.