Study On Seismic Performance Of PEC Column And Steel Beam Frame Articulated By End Plate

The merit of partially encased concrete composite column is combined by that of steelstructure and concrete structure, and it has been used for engineering abroad. Framearticulated by end plate belong to classical semi-rigid connection, and there are manyresearches on the steel frame articulated by end plate both at home and abroad. However,there is few relevant research documentation about PEC column-steel beam frame articulatedby end plate and the failure mode and structural behavior about the frame have not beenstudied very well. It has very important theoretical and engineering significance to studythe failure mechanism of PEC column-steel beam frame articulated by end plate under lowfrequency cyclic loading.Three frame specimens were designed to explore how the changing of thickness ofend plate and column flange influenced seismic behavior of the frame. It was found thatfailure mode containing beam end flange buckling, beam flange and end plate weldingcrazing, beam web plate tearing and column flange buckling according to the testphenomenon; the stiffness degradation, ductility, ultimate bearing capacity and energydissipation of the specimens were obtained according to data analysis. The results showthat ultimate bearing capacity and initial stiffness of framework are markedly increasedwhen thickness of column flange changes from12mm to16mm, which increasing are13%and50.77%respectively; the ultimate bearing capacity and initial stiffness of frameworkare increased2%and22.44%respectively when thickness of end plate changes from12mm to20mm, and ductility is increased14.77%. The ductility of the three specimens isbetween4.4and5.1, which proves that PEC column-steel beam frame articulated by endplate has very good seismic behavior.Comparison and expansion analysis were done by using ABAQUS finite elementsoftware on the basis of experiments. It showed that the simulation and experiment datawere in good agreement and the damage form was basically the same; expansion analysistook beam flange thickness and axial compression ratio as variable parameters, which wasfor further researching on seismic performance of the frame. The results show that when thickness of end plate increases from8mm to12mm, ultimate bearing capacity increasesby4.23%and ductility coefficient increases by17.14%; when the thickness of the beamflange increases from8mm to12mm, ultimate bearing capacity increases by6.25%andductility coefficient reduces by17.07%; when frame column axial compression ratioincreases from0.25to0.35, the ultimate bearing capacity raises and ductility decreasesobviously. From the perspective of economics, the best combination of thickness ofcolumn flange, thickness of end plate and thickness of the beam flange is3:3:2.According to the text and FEM results, the framework destruction occurred in beamcolumn joints. Therefore, in order to improve the ability of energy dissipation of this kindof frame, it is suggested to install stiffeners at the weld in the end plate and the steel beamto increase the energy dissipation capacity of frame.