摘要
多次地震灾害表明,采用现浇楼板的钢筋混凝土框架很难实现原抗震设计所期望的"强柱弱梁"延性屈服机制,绝大多数的裂缝损伤或塑性铰发生在框架柱的端部而非梁端。基于国内外研究现状与设计规范中的规定,针对钢筋混凝土梁柱节点中的楼板贡献、柱端抗弯承载力之和与梁端抗弯承载力之和的比值选取、水平地震作用方向的影响、所用材料性能强化以及框架柱所承受轴向力的动态变化影响进行分析,进一步了解"强柱弱梁"屈服机制未能实现的多方面因素。鉴于目前此类问题常用抗震加固方法的不足,介绍一种有效可行的框架梁端部负弯矩承载力弱化的抗震加固措施,可以使得既有带现浇楼板的钢筋混凝土框架易于出现梁端塑性铰,提高钢筋混凝土框架整体的延性能力。
During existing earthquake excitations,some reinforced concrete（RC） moment-re sisting frame systems with cast-in-place slab were very hard to realize ductil e yielding mechanism with strong column-weak beam as desired at initial seismic design,and most cracks damage or plastic hinges formed at column ends rather t han beam ends.Based on some research results and stipulations provided in desig n codes,flexural strength contribution of slab located at beam-column joint,d efinition of ratio about the sum of the nominal moment capacities of the columns at a joint to the sum of the moment capacities of the beams framing into that j oint,influence of acting direction of lateral seismic forces,influence of dyna mic variation of axial force acting on the column,and the enhanced properties o f materials used are analyzed for understanding the factors that prevents a RC m oment-resisting frame from forming a structural yielding mechanism.Consider th e shortages of existing seismic strengthening methods,an effective means by wea kening the negative flexural strength of the beam is provided,which could facil itate forming plastic hinges at beam ends and improve the ductility capacity of a RC moment-resisting frame.
出处
《土木工程与管理学报》
2011年第3期254-258,共5页
Journal of Civil Engineering and Management
基金
国家自然科学基金(51008070)
关键词
钢筋混凝土框架
强柱弱梁
塑性铰
楼板
延性破坏
RC moment-resisting frames
strong columnweak beam
plastic hinge
slab
ductile failure
