Mechanical Behaviour And Design Method Of End-Plate Connections With Special Configuration

With the increase of the structural span and the external load, the innerforce transferred by the connection is increased sharply, where the end-platewith conventional configuration could not satisfy the requirement of the bearingcapacity. And in some practical steel structure work, end-plate connections withsome configurations greatly different from the traditional ideas are needed. As aresult, end-plate connections with special configurations, including the largecapacity end-plate connections, have been already applied in many practicalprojects. However, researchers from domestic and abroad have only conductedelaborate and intensive investigations on the performance of conventionalend-plate connections in steel frame, while little research has been done on thebehavior of the aforementioned end-plate connections with specialconfigurations. What’s more, the domestic investigations in this area are still inits infancy, and notable differences could be found in the configurations of thesespecial end-plate connections between the domestic and the abroad. The maincontents and conclusions of this dissertation are:(1) Based on the finite element method of conventional end-plateconnections, the performance of the wide-type and the high-type large capacityend-plate connections used as the beam-column connections in steel frames isanalyzed, in which the thickness of the end plate, whether the compression sideof the end plate is extended or flushed, the bolt lay-out and the shape of theend-plate stiffener are considered. The distribution of the tension force in thebolt group, the transferred tension force by the bolt group and the shear force inthe bolt group, and the strain/stress state of the end plate tension part and theend-plate stiffener under ultimate loading are carefully investigated. Further,resistant capacity design approaches are proposed for both the wide-type and thehigh-type large capacity end-plate connection, which mainly include the designformulas of the tension force transferred by the bolt and the end plate thickness. And a parametrical analysis by the finite element method demonstrates that theproposed design methods are both safe and reliable.(2) Methods to calculate the joint rotation of end-plate connections in steel framesand the relationship between the joint rotation and the deformation of the jointcomponents are clear. Based on the ‘component approach’, formulae to calculate thestiffness and the ultimate resistant capacity of the typical components in end-plateconnections are suggested. By a stiffness spring model and a moment resistant capacityspring model, the initial rotational stiffness and the ultimate moment resistant capacityof both the wide-type and high-type large capacity end-plate connections are obtained,which show high accuracy compared to the corresponding finite element analysis results.Further, based on a modified moment-rotation curve model, the moment-rotation curvesof48large-capacity end-plate connections are adopted, which show high agreementwith the corresponding finite element analysis results. And this method could also beused to predict the moment-rotation curve of conventional end-plate connections.(3) To investigate the seismic behavior of a practical extended end-plateconnection without end-plate stiffener, three full-scale specimens are tested under cyclicloading. The loading capcacity, deformation, hysteretic curves, the ductility ratio andthe failure mode of the test joints are obtained, which demonstrate that the testedend-plate connections have excellent performance under cyclic loading.