Experimental Research On The Extended-End-Plate Connections And T-Connections Of Beam-to-Column

With the rapid development of economy and the dramatic increasing of steel productivity in our country, the clay-brick and empty-core clay-brick being prohibited, the policy of using more steel-structure building system was advocated by the Construction Department nation-widely. But the research on the function of fire-protection, beam-to-column connection, floor-plate forms, matched wall material, as well as economy and market for people to accept it, there were still many things to improve. In the traditional design and analysis on steel frames, it was often assumed that the connections between columns and beams were either rigid or pinned. In the analysis of steel frames under internal forces, the angel between the border upon columns and beams was keep invariable in the former. It was regarded that the joint can not transfer moment and can rotate freely in the latter. If the two ideal joints models were used to designing, the calculation would become simplified mostly, but the structural performance under load would not be factually reflected. Especially along with the high-strength bolts widely used in the steel-frame joints, the performance of connections was regarded between rigid and pinned. The connection was actually a kind of semi-rigid connection. The experiment on beam-to-column connections of steel frame was very important and meaningful, because it can provide foundation for theory and reference for practical projects in selecting the beam-to-column connections form in steel-frame structure residence system.The present findings of extended-end-plate and T-connections, the research methods of beam-to-column connections, the contents and methods of design and calculating about them in our country and other countries, the forms of beam-to-column, as well as the character about semi-rigid connections were briefly addressed in this paper. The M-θr relation curve of semi-rigid connections took on nonlinear character under load. The cause was briefly analyzed in this article. The simulated method of M-θr curve and the resilience model of beam-to-column semi-rigid connections were discussed in detail.On the basis of experimental research, the performances ofextended-end-plate bolted connections and T-connections were discussed in this paper. The influence of semi-rigid connections to the performance of steel frame was also discussed in this article. During discussing the performance of semi-rigid connections, a M -θr mathematical model was assumed at first. On the basis of mechanical analysis, a formula to express the M-θr relation curve was proposed by use of the known sizes of the connections in this paper. Then the destructive form, the influencing factors of initial rotational stiffness, hysteresis behavior(including the coefficient of ductility, the capacity of energy dissipation, the deterioration of strength and stiffness in the cycle of internal forces) and stress of key part of the two kinds of connections were discussed in this paper. Finally, the designing methods of the two kinds of connections were supposed. During discussing the influence of semi-rigid connections to the steel-frame structure, the unit stiffness matrix of partly obligation beam was set up at first, then the influence of semi-rigid connections to the steel-frame structural internal force, displacement and plastic limited load were discussed.