Research On Mechanical Behavior Of New-type Steel T-stub Connections With Slotted Holes

This paper has a research on the new-type steel T-stub connections with slotted holes. In order to understand the mechanical behavior of new-type steel T-stub connections and propose design recommendations for engineering application, the following work has been completed:Firstly, on the basis of the technical standards about steel T-stub connections at home and abroad,we put forward a preliminary design method of new-type steel T-stub connections and designed the new-type steel T-stub connections according to the method. Secondly, quasi-static experiment research of full size connections which were designed by the preliminary design method was performed. Experimental specimens included three new-type steel T-stub connections with different sizes of slotted holes, an ordinary steel T-stub connection, and a dog bone connection. Thirdly, the finite elements software ABAQUS was adopted to establish the three-dimensional finite element models of experiment specimens. The finite element models were used to study the stress distribution, law of force and deformation characteristics of the new-type steel T-stub connections. Lastly, in terms of existential defects in the preliminary design method, a recommendation for the practical design of the new-type steel T-stub connections was proposed, aiming to provide reference for engineering application.Through the research of this paper, the main conclusions are shown as follow:(1) Compared with the dog bone connection and the ordinary steel T-stub connection, the plastic rotation angle, ductility and energy dissipating of the new-type steel T-stub connections are significantly improved:1) the plastic rotation angle of the new-type steel T-stub connections are 1.1～1.5 times than that of the ordinary steel T-stub connection, and 1.8～2.5 times than that of the dog bone connection; 2) the ductility of the new-type steel T-stub connections are 1.2～1.5 times than that of the ordinary steel T-stub connection, and 2.2～2.6 times than that of the dog bone connection; 3) the energy dissipating of the new-type steel T-stub connections are 1.7～2.1 times than that of the ordinary steel T-stub connection, and 6.3-8.0 times than that of the dog bone connection; 4) the new-type steel T-stub connections can improve the energy dissipating by friction sliding. The maximum friction energy dissipating can reach to 25% of the total energy dissipating of the new-type steel T-stub connections.(2) The finite element analysis results were consistent well with the experimental results. So the finite element models could be used for further study. Simulation results showed that:1) each T-stub bears more than half of the shear force within the beam end; 2) Existing technical standards can not calculate the prying force under the limit state.This paper proposed a formula to calculate the prying force and the prying force calculated by formula is 1.16 times than that achieved from FEM results.In conclusion, slotted hole on the web of T-stub can improve the ductility and energy dissipating of the steel T-stub connection significantly. The ductility and energy dissipating can be controlled by the size of slotted hole. The new-type steel T-stub connections proposed in this paper can provide new ideas for the structure of the seismic performance-based design.