Research On Seismic Behaviour Of The Fully-bolted Diaphragm-through Connection Between Rectangular Concrete Filled Tube Column And H-shaped Steel Beam

In general, the four types of connections used in China，which are the innerdiaphragm connection, the vertical stiffener connection, the exterior diaphragmconnection and the diaphragm-through connection are all weld flange-bolted webconfiguration. However, the typical welded steel moment frame connection failed toprovide the expected ductile behavior in the1994Northridge earthquake in LosAngeles, California. Damage occurred at the beam-to-column connections. Thedamage included fractures of full penetration welds, cracks in beam flanges, andcracks through the column sections. Increasing research in bolted connections hastried to address some of the technical issues, such as the end-plate connections, thebolted-angle connection, the split-tee stub connection, the through-column bolts-stiffened end plate connection and double plates connection. In this paper, the fullybolted diaphragm-through connection between rectangular concrete filled steel tubecolumn and H-shaped steel beam are invented on the bases of researches above boltedconnections. as the main type of the steel frame construction is selected in China, thediaphragm-through connection with fully-bolted methodology received less attention.In order to study the fully bolted diaphragm-through connection and obtain sufficientinformation for structural design, an experimental and analytical research on fourfull-scale connections under cyclic loading is presented in the paper.In order to study the seismic performance of the fully-bolted diaphragm-throughconnections between rectangular concrete filled steel tube column and H-shaped steelbeam, an experimental research on six full-scale connections under cyclic loading isconducted. The failure mode and seismic characteristics are described. Seismicperformance, is also evaluated in terms of bearing capacity, ductility, energydissipation capacity and stiffness degradation. Experimental results show goodductility and energy dissipation capacity of the connections in the case of allowing thesliding of bolts. The eccentric connection and the welded diaphragm-throughconnection are used safety, reliability and economically in the practical engineering;The plastic hinge of the connections occurs at the flange of the beam, close to the endof the overhanging diaphragm, thus achieving the outward shift of the plastic hinge.The shear deformation in the connection core region is slight, and the seismic design principle of "strong column and weak beam" and "strong connection and weakmember" is satisfied.In order to study the seismic performance of the fully-bolted diaphragm-throughconnections between rectangular concrete filled steel tube column and H-shaped steelbeam, four solid finite element models were developed by Abaqus to analyze theseismic performance of the diaphragm-through connections. The research results aredescribed in the paper. Good agreement was found between the experimental resultsand the finite element results. It indicates that the proposed column-to-beamconnections exhibit excellent seismic behavior. The stress at the corner of thediaphragm and the beam flange close to the end diaphragm are larger than that atother location. The plastic hinge of the connection occurs at the flange of the beam,thus achieving the outward shift of the plastic hinge. The stresses of the high-strengthbolts placed in different position are different when the connection is subjected to theload, even the stresses at both sides of the high-strength bolts are difference. Thenonlinear finite element models can simulate the mechanical performance of thefully-bolted diaphragm-through connections, meanwhile the modification hystereticcurves combining the finite element models and theory coincide with the experimentalhysteretic curves. The eccentric specimen and the welded through-diaphragmspecimen can be used in the practical engineering safely, reliably and economically.