突加荷载下钢筋混凝土框架梁性能试验研究  

Experimental research of reinforced concrete frame beam under a sudden load

作　　者：苏幼坡[1] 张玉敏[1] 许琳琳[1] 任延庆[1] 明伟[1] 

机构地区：[1]河北理工大学建筑工程学院,河北唐山063009

出　　处：《建筑结构学报》2009年第S2期92-97,共6页Journal of Building Structures

基　　金：国家自然科学基金资助项目(50478114)

摘　　要：为研究框架梁在其支撑柱遭到破坏之后的反应及其性能,进行了9根钢筋混凝土框架梁在突加荷载(加载时间小于0.01s)下的试验,试件分别按"常规抗震设计"、"强剪弱弯"和"强弯弱剪"设计,重点研究框架梁在突加荷载作用下的破坏形态和动力响应,以及"拱效应"对框架梁的弯、剪承载力的影响。并依据试验结果提出考虑"拱效应"影响的承载力计算方法。研究表明:由于支座的约束作用,框架梁在受力过程中会产生水平轴向压力即"拱效应",使梁的刚度增加、自振周期减小,并可显著提高梁的受弯承载力;从而可能使没有考虑"拱效应"影响的框架梁最终的破坏形态由预期的延性弯曲破坏转变为脆性剪切破坏。框架梁在突加荷载作用下,可能发生弯曲、斜弯和剪切三种破坏形式;斜弯和剪切破坏均会造成轴力的突然降低,使框架梁承载力降低。试验结果证明了在进行钢筋混凝土结构抗倒塌设计时宜考虑"拱效应"的影响。The reaction and properties of frame beams supported by broken frame columns were experimental researched.Respectively,used 3 design modes,which are 'common anti-seismic design' 'strong shear and weak moment' and 'strong moment and weak shear',9 beam specimens were designed and loaded with sudden force(the loading time is shorter than 0.01s) during the experiment.The experiments focused on researching the failure forms and dynamic responses of beams with sudden loading,and the influence of arching action on bending and shear capacity of the frame beams.By considering the arching action and analyzing the experiment results,the method for calculating limit load of the beams' was suggested.The research reveals that horizontal axis force can be produced by the support restriction when beam is loading.Beam stiffness and natural frequency can be improved by this horizontal force,so the beam′s anti-bend strength is enhanced obviously,which is arching action.The final failure forms of frame beams without considering 'arching action' may be changed from ductile bending failure to brittle shear failure.Under the sudden loading,3 failure modes may be happen,they are bend failure and tilt-bend failure and shear failure.Both of the last 2 failures can reduce the axis force suddenly,following the axis force,the beam's limit load is reduced,too.According to the experiment results,'arching action' should be considered in the RC frame anti-seismic design.

关 键 词：钢筋混凝土框架梁 突加荷载 试验研究 框架梁破坏形态 拱效应 动力响应 

分 类 号：TU375.4[建筑科学—结构工程]