刚性钢框架焊接梁柱连接的损伤累积破坏机理
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摘要
采用考虑损伤累积的有限元本构模型,分析了焊接刚性钢框架梁柱连接在循环荷载作用下的受力性能和破坏机理,研究了梁柱连接中的损伤发展和分布,以及材料损伤对梁柱连接受力性能的影响。计算结果表明,在地震荷载作用下,遗留在结构上的焊接衬板造成了比较严重的应力集中和三向拉应力状态,使梁翼缘对接焊缝的损伤发展很快,影响了节点的变形能力。移去焊接衬板,可以有效地改善梁柱连接的受力性能,提高其延性和耗能能力。
To analysis the performance and collapse mechanism of the welded beam-to-column connections in moments-resisting frames under seismic loading,a FEM model considering damage accumulation is adopted.Evolution and distribution of damage of the material and its affect to the performance of the beam-to-column connections are studied.It is concluded that severe stress concentration and tri-axial pull stress are conducted by the backing bar left on the structure after the weld proceeding,which lead damage in weld metal and vicinity steel growing rapidly even plastic strain there is under a very low level.Then the ductility of the connection is decreased.The ductility of the beam-to-column connections can be improved significantly by removing the backing bar from the structure.
To analysis the performance and collapse mechanism of the welded beam-to-column connections in moments-resisting frames under seismic loading,a FEM model considering damage accumulation is adopted.Evolution and distribution of damage of the material and its affect to the performance of the beam-to-column connections are studied.It is concluded that severe stress concentration and tri-axial pull stress are conducted by the backing bar left on the structure after the weld proceeding,which lead damage in weld metal and vicinity steel growing rapidly even plastic strain there is under a very low level.Then the ductility of the connection is decreased.The ductility of the beam-to-column connections can be improved significantly by removing the backing bar from the structure.
引文
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[5]宋振森.刚性钢框架梁柱连接在地震作用下的累积损伤破坏机理及抗震设计对策[D].西安:西安建筑科技大学,2001
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[7]FEMA.Interim Guidelines:Evaluation,Repair,Modificationand Design of Steel Moment Frames[R].FEMA-267,Rep.No.SAC-95-02,SAC Joint Venture,Calif.,1995
[8]FEMA.Interim Guidelines Advisory No.2.Supplement toFEMA-267[R],Report No.SAC-99-01,SAC JointVenture,Calif.,1999
[2]Nakashima M,Inoue K and Tada M.Classification ofDamage to Steel Buildings Observed in the 1995 Hyogoken-Nanbu Earthquake[J].Engrg J,1998,(4~6):271~281
[3]Lemaitre J.A Course on Damage Mechanics[M].Berlin:Spring-Verlag,1992
[4]宋振森,顾强,苏明周.考虑混合强化和弹塑性损伤的有限元模型[J].西安交通大学学报,2000,34(11):95~98
[5]宋振森.刚性钢框架梁柱连接在地震作用下的累积损伤破坏机理及抗震设计对策[D].西安:西安建筑科技大学,2001
[6]ECCS-Technical Committee.Study of Design of Steel Buildingin Earthquake Zones[R].Doc.ECCS-TWG 1.3,No.47,1986,3/1~3/71
[7]FEMA.Interim Guidelines:Evaluation,Repair,Modificationand Design of Steel Moment Frames[R].FEMA-267,Rep.No.SAC-95-02,SAC Joint Venture,Calif.,1995
[8]FEMA.Interim Guidelines Advisory No.2.Supplement toFEMA-267[R],Report No.SAC-99-01,SAC JointVenture,Calif.,1999
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