EXPERIMENT ON CYCLIC BEHAVIOR OF ENLARGED BEAM FLANGE REINFORCED CONNECTION OF STEEL MOMENT-RESISTING FRAMES

摘要

Enlarged beam flange reinforced connection of steel moment-resisting frame is one of reinforced forms to improve its seismic performance. Based on the suggestion of "Recommendation for Design of Connections in Steel Structures" of Japan, the details and design formulae of steel moment resistant frame connections reinforced by haunch enlarged beam flanges welded to the column diaphragm were put forward in this paper. Then, four half-scale T-shape specimens were designed based on the Chinese relevant codes and above formulae with enlarged flanges of H-shape beam welded to the diaphragm of diaphragm-through type box-section columns, with the variety of the width-to-thickness ratio of beam flange and web, and different types of reinforcement considered.The experiment was carried out under cyclic beam bending with constant axial compression on column. The test results revealed that the connections of this reinforcement type had a good performance of the strength and rigidity, and satisfied the demand of current Chinese Code on Seismic Design of Buildings. However, the plastic rotation was limited and could not fully satisfy the demand of special moment resisting-frames, so the details of this reinforced type of connections need further improvement when used in high seismic region.