Investigation On The Performance Of The Connection With Shearheads Of CFT Column To Flat Slab

Flat slabs are frequently used in practice due to the advantages of reduce story height, ease to construction and improving economic efficiency. However the node region is prone to brittle fracture when subjected to gravity loads and lateral loads. Punching and Seismic of slab-column connections has been the focus of many scholars continue to study. Concrete-filled tube(CFT) columns can improve the bearing capacity of members, to change the ductility and toughness of structures. The CFT can ensure the structure has a good seismic performance under earthquake, because the better energy dissipation capacity under lateral repeated loads.This paper use the shearheads to combine the advantages of flat slabs and CFT, as the shearheads can improve the punching shear capacity and change the ductility of the joint. In this study, finite element analysis of full-scale RC slab-CFT column connections with shearheads reinforcement is conduced to investigate the contribution of the connection to slab punching shear capacity, to research the influence of different shearheads parameters on the punching shear capacity and find the appropriate design equation of the connection.In this paper, the failure pattern of the slab-column joint has been summarized first. It explained the failure mechanism of the punching shear under gravity loads, and the shearheads has been proposed as the effective connection to improve the punching shear capacity.Then, the paper introduced the finite element analysis program and material models briefly. It also showed shearheads is a viable option for shear reinforcing of flat plat connections with CFT column and prove the effectiveness of finite element analysis by comparing with the test.Third, the research focused on the punching shear capacity of the connection under gravity loads. The results shows the shearheads can improve the punching shear capacity significantly, and the failure model has changed from punching to bending failure. As the shearheads arm length and web area increased, larger punching shear strength was obtained. The minimum shearheads arm length and height was proposed as 02(b ?2h) and 0h2. The punching capacity formula was proposed through multiple linear regression analysis reflecting the influence of shearheads.At last, the paper has evaluated the ductility of the connection under lateral repeated loads. The results show that the CFT column can improve the anti-lateral capacity compared with RC column, but the ductility will reduce when the shearheads arm length and web area increased.