【作者】 傅剑平；

【导师】 白绍良；

【作者基本信息】 重庆大学 ， 结构工程， 2002， 博士

【摘要】 本论文进行了以下三方面的研究工作： ①进行了8组共16个矩形柱中间层中节点和4个圆柱节点组合体的低周反复加载试验。通过对节点区水平箍筋以及贯穿节点梁、柱纵筋在不同受力阶段应变的精细量测，对节点的传力机理以及影响抗震性能的因素进行了分析研究；对不同剪压比条件下轴压比对节点抗震性能的影响规律进行了分析研究；对不同受力阶段梁筋的粘结退化规律以及节点区的剪切变形进行了分析研究；对节点的静力抗剪与建立在能力设计思路上的抗震抗剪问题进行了深入研究，提出了建立在新思路基础上的节点抗震性能控制准则和控制条件。 ②根据本文建立的考虑轴压比和位移循环次数影响的梁筋平均粘结应力退化模型和考虑软化效应、约束效应的核心区混凝土应力应变关系，通过在试验中得出的节点核心区混凝土、箍筋、节点正面、背面柱筋在反复荷载下的受力特点，利用斜压场理论模拟节点核心区在反复受力过程中的受力状态。通过本文编制的程序JAP对本文试件和收集到的数据较完整的国内外试件进行了电算分析，电算结果与试验结果符合程度较好。进一步利用JAP程序预测了不同剪压比，不同配筋特征值及不同轴压比条件下节点区的延性变化规律。 ③对收集到的顶层中节点、中间层端节点以及顶层端节点的国内外试验结果进行了整理分析。明确了这三类节点的主要传力机构。根据不同部位节点之间存在的受力差异，对三类节点在整个受力过程中的传力机理进行了分析研究。此外重点对不同条件下中间层端节点梁筋带90°弯折锚固端的试验结果、顶层中节点采取不同柱筋构造方案的试验结果以及梁柱负弯矩筋采取不同搭接方案的顶层端节点的试验结果的延性和耗能性进行了对比分析。在充分听取国内专家意见的基础上提出了梁柱纵筋在节点部位有抗震要求的锚固和搭接方案。 本论文得出了以下有创新意义的成果： ①节点中箍筋的受力方向箍肢(对圆形箍筋为沿受力方向部位)与垂直受力方向箍肢(圆形箍筋为沿垂直受力方向部位)的作用不完全相同。沿受力方向箍肢(或部位)既作为桁架机构的拉杆参与抗剪又对斜压杆受压后沿受力平面侧向膨胀的水平分量起约束作用；垂直受力方向箍肢(或部位)原则上仅对斜压杆沿垂直受力方向侧向膨胀起约束作用。以上结果确认了节点中存在三种传力机构，即桁架机构、斜压杆机构和约束机构。前两个机构直接传递节点剪力，后一个机构则通过约束节点核心区混凝土的侧向膨胀提高节点的延性和耗能能力。 ②通过对梁柱组合体柱脱离体的平衡条件，首次明确了贯穿节点梁筋粘结应力和梁端受压混凝土的压力以相同的比例传入柱端以平衡柱端剪力，从而对节点区的传力机理 重庆大学博士学位论文结出了完整的和具有说服力的解释。本文研究表明，在不同受力阶段，传人节点区的水平作用剪力由流架机构和斜压杆机构承担的比例是不同的，约束机构发挥的作用也有所不同。当贯穿节点的梁筋未出现明显的粘结退化之前，节点作用剪力主要通过街架机构传递，斜压杆机构传递的剪力和约束机构发挥的作用较小；当梁筋全面出现粘结退化以后，行架机构传递的剪力明显降低，作用剪力主要由斜压杆机构传递。核心区混凝土双向交叉斜裂缝充分发育后，斜压杆倾向膨胀不断增大，约束机构逐步发挥出最大作用。 ③本文首次分清了构件的静力抗剪与框架结构根据能力设计思路确定的构件抗震抗剪具有不同的前提条件和不同的控制目标。即静力抗剪仅要求构件的承载能力高于作用剪力，是以承载能力作为控制目标的；抗震抗剪则是构件在承载能力不低于作用剪力的前提下，要求在反复作用的情况下，构件在达到一定的延性和变形能力之前维持其承载能力不出现明显退化。指出了目前进行抗震抗剪试验和确定构件抗震抗剪控制条件中存在的不正确概念。在此基础上，本文提出了以延性控制准则为基础的节点抗震抗剪控制公式。同时根据本文较系统的轴压比对比试验结果，指出了目前世界各国规范中节点抗剪承载力公式中的轴压比不分条件始终起有利作用的不合理性，在本文建议的公式中反映了在高剪压比的条件下轴压比对节点延性不利的特点。更多还原

【Abstract】 This paper includes three parts of research:(1)Cyclic loading tests of sixteen interior joints with rectangualr columns and four joint subassemblages with circular columns. Based on measurement of strains of both horizontal stirrups in the joint core and longitudinal reinforcement passing througth the joint, in different stages,transfer mechanism and factors affacting seismic behavior of the joint, were analysed. Under different shear compression ration, effect of axial force ratio on seismic behawior of the joint was also evaluated, static shear and seismic shear of the joint based on capacity design were investigated. On this basis,new governing criteria and conditions of seismic behavior of the joint were put forward.(2)Based on deterioration model of owerage bond stress of beam reinforcement accounting for effect of axial compression ration and number of displacement loops,and stress-strain relationship of the concrete in the joint core accounting for effects of both softening and confinement, the modified compression field theory was employed to simulate behavior of the joint core under loading reversals. Analysis by means of the program JAP on the tested specimens in this paper and those obtained from other researchers produced consistent results. Predictions were made on the ductility of the joint core when shear compression ratio,reinforcement contant and axial force ratio were different.(3)Experimental results of interior joints on the top story, exterior joints in the intermediate stories,and knee joints are collected and summerized. Force transfer mechanisms of the three categories of joints were identified and analysed. Besides,compariative analysis was carried out on ductility and energy comsumption of the interior joints on the top story with 90?bent hooks,exterior joints in the intermediate stories with different detailing of longintudinal reinforcement in the columns,and the knee joints with different lap splices in the beam and the column under negative moments. Seismic anchorage and lap splices schemes were presented for the longitudinal rebars in the joint core.The creative results are as follows:(1)Behavior of the stirrup legs in the loading direction in the joint core (along the loading direction for circular stirrups)is different from that perpendicular to the loading direction. The stirrup legs in the loading direction acts as the tension chords in the truss model to resist shear,in the meantime,they confine the compressed diagonal strut from lateral expam-sion. For the stirrup legs perpendicular to the loading direction, they usually confine the strut from lateral expansion. The findings above confirm that there exsists three transfer mecha-nisms in the joint,that is,the truss mechanism,the diagonal strut mechanism,and the confinement mechanism. The first two mechanisms transfer joint shear,while the third inecha-nism provide ductility and energy dissipation capacity by confining the joint core concrete from lateral expansion.(2)From the equilibrium conditions of the isolated segment from a beam-column sub-assemblage, it is clarified for the first time that the bond stress along the beam rebars passing through the joint transfers into the column end to balance shear at this column end at the same ratio as that of the compression force in the compressed concrete at beam ends. In the way, a convincing expression is prsented to force transfer mechanism in the joint core. The findings shew that in different stages,the horizontal forces transfered into the joint are by the truss and the diagonal strut mechanisms are different. Behavior of the confinement mechamsm is also different. Before obvious bond deterioration of the beam rebars passing through the joint core occurs,the shear is mainly transfered by the truss mechansim. When the bond deterioration occurs comprehensively, the shear transfered by the truss mechamism is reduced significantly,the majority of the shear is transfered by the diagonal strut. At the time when reversed diagonal cracks develop fully, later更多还原