钢框架梁翼缘削弱型节点单元刚度矩阵及内力分析
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摘要
梁柱连接采用翼缘削弱型节点(RBS)可促使节点塑性铰外移,提高结构延性,达到节点抗震设计目的。采用能量法推导出梁翼缘削弱型节点的单元刚度矩阵和转角位移方程,通过实例进行内力分析。研究结果表明:RBS节点导致梁的抗弯刚度、刚架的抗侧刚度降低,使梁的固端弯矩减小,跨中弯矩增加,反弯点位置前移;梁单元刚度矩阵中各元素较普通节点有所减小,减小范围与梁的跨度、削弱深度、削弱长度及削弱起始点至柱翼缘表面距离等因素有关;梁翼缘局部削弱后主要影响梁的单元刚度,对内力值影响相对较小。建议在简化计算中仅考虑梁刚度变化,忽略内力值变化影响。
Reduced beam section connection(RBS) can make plastic hinge away from the beam and column interface,improve ductility of the structure and reach the purpose of seismic design of the connections.Element stiffness matrix and rotational displacement equation of the beam with RBS were derived using energy method,and then internal forces were analyzed by example.The results show that RBS leads to decreasing beam bending stiffness and lateral stiffness of rigid frame,the location of the point of inflection moves forward,but the moment of RBS beam fixed-end decreases and midspan moment increases;all the elements in the stiffness matrix decrease as compared with the ordinary connections,the reduction is related to the length of the beam,cutting depth,length of the cuts and distance from end of beam to initiation of the flange reduction.The beam flange reductions have main effect on beam stiffness,relatively small effect on internal force.Simplified calculation just to consider changes in stiffness and ignore the effect of changes in internal force was presented in the paper.
Reduced beam section connection(RBS) can make plastic hinge away from the beam and column interface,improve ductility of the structure and reach the purpose of seismic design of the connections.Element stiffness matrix and rotational displacement equation of the beam with RBS were derived using energy method,and then internal forces were analyzed by example.The results show that RBS leads to decreasing beam bending stiffness and lateral stiffness of rigid frame,the location of the point of inflection moves forward,but the moment of RBS beam fixed-end decreases and midspan moment increases;all the elements in the stiffness matrix decrease as compared with the ordinary connections,the reduction is related to the length of the beam,cutting depth,length of the cuts and distance from end of beam to initiation of the flange reduction.The beam flange reductions have main effect on beam stiffness,relatively small effect on internal force.Simplified calculation just to consider changes in stiffness and ignore the effect of changes in internal force was presented in the paper.
引文
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[9]郁有升,王燕,刘秀丽.钢框架梁翼缘削弱型节点循环荷载作用下的有限元分析及试验研究[J].工程力学,2009,26(9):162-169.
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[2]闫丽梅,范子芳.日本阪神地震对钢框架节点设计的影响[J].沈阳工业大学学报,2005,27(1):107-110.
[3]Chen C C,Lu C A,Lin C C.Parametric Study and Design of Rib-Reinforced Steel Moment Connections[J].EngineeringStructures,2005,27(5):699-708.
[4]Park J W,Huang I K.Experimental Investigation of Reduced BeamSection Connections by Use of Web Openings[J].EngineeringJournal,AISC,2003:77-88.
[5]Chen C C,Lin C C,Lin C H.Ductile Moment Connections Used inSteel Column-Tree Moment-Resisting Frames[J].Journal ofConstructional Steel Research,2006,62(8):793-801.
[6]Engelhardt M D,Sabol T A.Reinforcing of Steel MomentConnections with Cover Plates:Benefits and Limitations[J].Engineering Structures,1998,20(4-6):510-520.
[7]Chen S J.Dynamic Behavior of Frames with Beam Flanges ShavedAround Connections[J].J.Construct.Steel Res,1997,42(1):49-70.
[8]郁有升,王燕.钢框架梁翼缘削弱型节点力学性能的试验研究[J].工程力学,2009,26(2):168-175.
[9]郁有升,王燕,刘秀丽.钢框架梁翼缘削弱型节点循环荷载作用下的有限元分析及试验研究[J].工程力学,2009,26(9):162-169.
[10]FEMA-350.Recommended Seismic Design Criteria for New SteelMoment-Frame Buildings[S].2003:39-42.
[11]王燕,郁有升.钢框架梁端翼缘削弱和扩翼型节点的受力性能分析[J].力学与实践,2010,32(1):46-53.
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