钢筋混凝土框架变梁中节点破坏机理研究  

Failure mechanism of reinforced concrete interior joints with variable depth beams

作　　者：邢国华[1,2] 吴涛[1] 刘伯权[1] 

机构地区：[1]长安大学建筑工程学院,陕西西安710061 [2]西安建筑科技大学土木工程学院,陕西西安710055

出　　处：《建筑结构学报》2011年第10期139-145,共7页Journal of Building Structures

基　　金：国家自然科学基金项目(50608004;51078037;51108032);教育部高校博士点基金项目(20100205110010);中央高校基本科研业务费专项资金项目(CHD2011JC037;CHD2010JC005)

摘　　要：根据10个梁高不等的钢筋混凝土框架中节点试件在低周反复荷载作用下的试验结果,重点分析了该类非常规节点的破坏过程和破坏特点。试验结果表明:变梁中节点试件通裂阶段与极限阶段非常接近,试件达到通裂阶段后,剪切变形急剧增大,强度、刚度退化显著加剧,试件破坏时节点区斜裂缝主要集中在大核心区(柱与大梁构成的区域)平行对角线方向的2/3范围内,按常规节点设计的变梁中节点不能满足刚性节点的要求。在斜压杆机构和桁架机构的基础上,结合该类非常规节点核心区两侧梁高不等的特性提出变梁中节点的等效斜压杆破坏机理,并应用等效斜压杆机理对变梁中节点的受剪性能进行理论分析,计算得到的节点区剪应力-剪切变形曲线与试验结果吻合良好。Ten specimens of interior joints with variable depth beams were tested under reversed cyclic loading.The failure characteristics and failure process of the interior joint specimens were analyzed.Test results indicate that the through-section cracking stage is quite similar to the ultimate loading stage of the irregular interior joints.The shear deformation of joint core increases greatly after the specimens reach the through-section cracking stage.Strength degradation and stiffness degradation of the test specimens obliviously occur too.At failure the joint diagonal cracks mainly concentrate within 2/3 of the greater core zone（joint of the column and girder） in the direction parallel with the diagonal line of the joint.The test specimens which were designed under the guideline of current code can not ensure the structural integrity and satisfy the strong joint demand.By developing the diagonal strut mechanism and the truss mechanism,an equivalent strut mechanism for this type joint is proposed.In addition,the curves of shear stress versus shear angle of the joint core of tested specimens were calculated using equivalent diagonal compression strut.Good agreement between experimental results and prediction results was achieved.The results can be served as a basis for further study on failure mechanism of reinforced concrete frame joints.

关 键 词：中节点 抗震性能 破坏机理 等效斜压杆机构 

分 类 号：TU375.401[建筑科学—结构工程]