【作者】 马颖；

【导师】 贡金鑫； 赵顺波；

【作者基本信息】 大连理工大学 ， 结构工程， 2012， 博士

【摘要】 钢筋混凝土柱、墩作为房屋、桥梁等结构的重要竖向承重构件,地震作用下极易发生破坏。我国是地震多发国家,许多结构都处于高烈度地震区,从抗震防灾的角度考虑,如果承重柱破坏严重且难以修复,即使结构未倒塌,但仍需要拆除重建。所以有必要研究钢筋混凝土柱地震破坏方式及性能,保证其具有足够的承载力和良好的延性,避免在地震作用下发生破坏。基于此,本文对地震作用下钢筋混凝土柱的性能进行了试验研究和理论分析,主要内容及结论如下：1.对10根钢筋混凝土柱进行了水平单调加载试验和24根钢筋混凝土柱进行了低周反复试验,研究了钢筋混凝土柱的地震破坏方式及性能,测量、计算了弯曲变形、剪切变形和端部钢筋拔出滑移变形及3种变形占总水平变形的比例。研究表明,低周反复荷载作用下,钢筋混凝土柱主要发生3种形式的破坏,即弯曲破坏、弯剪破坏和剪切破坏。随着剪跨比减小或轴压比增大或配箍率减小,试件趋向于发生弯剪或剪切脆性破坏,柱的滞回曲线捏缩,耗能能力和延性降低；随着总变形的增大,弯曲变形在总水平变形中所占比例减小,剪切变形所占比例增大,钢筋拔出滑移变形所占比例约为30%-40%。2.根据本文试验和美国太平洋地震研究中心钢筋混凝土柱抗震性能试验数据库(PEER-Structural Performance Database)低周反复荷载下钢筋混凝土柱的试验资料,分析了剪跨比、轴压比、配箍率、纵筋配筋率、混凝土和钢筋强度对钢筋混凝土柱破坏方式的影响规律,给出了钢筋混凝土柱破坏方式判别参数的计算公式,提出钢筋混凝土柱弯曲破坏、弯剪破坏和剪切破坏的概率判别方法。3.根据试验结果,分析了剪跨比、轴压比、配箍率对钢筋混凝土柱弯剪破坏时抗剪承载力和位移延性的影响,提出钢筋混凝土柱弯剪破坏时抗剪承载力和位移延性系数的计算公式。4.给出了发生弯剪破坏的钢筋混凝土柱开裂荷载、屈服荷载、弯剪破坏荷载及其相应变形的计算方法,提出了地震作用下钢筋混凝土柱弯剪破坏时恢复力模型骨架曲线的简化方法。5.对受腐蚀钢筋混凝土圆柱进行了低周反复试验,分析了钢筋锈蚀率和轴压比对柱破坏方式和抗震性能的影响,建立了锈蚀柱荷载、刚度、延性和耗能等抗震性能退化模型。研究表明,随着钢筋锈蚀率或轴压比的增大,柱的延性和耗能能力逐渐降低,当箍筋受到严重锈蚀时,柱可能会由弯曲破坏转化为弯剪或剪切破坏。更多还原

【Abstract】 Reinforced concrete (RC) columns are often used as the main vertical load-bearing elements in building structures, highway bridges and so on. They play a crucial role in overall structural performance and easily fail in earthquake. In China, which is a multi-earthquake-happening country, many structures are located in regions with moderate and high seismicity. From the view of earthquake disaster prevention, the structure still need reconstruction even if it does not collapse because the damage of support columns in structure is so serious that it is difficult to get them repaired. Therefore, investigations on the failure modes and seismic performance of RC columns are necessary. Effective measures should be taken to ensure that the columns develop sufficient bearing capacity and ductility to prevent failure in earthquake. The seismic performance of RC columns is studied in the paper by experimental and theoretical analysis. The main content and conclusion are listed as follow:1. The monotonic loading tests on ten RC columns and cyclic horizontal loading tests on twenty-four RC columns were carried out. Failure modes and seismic performance of RC columns were studied. Also the contributions of flexura deformation, anchorage slip deformation, and shear deformation, to the total deformation of columns were measured and investigated, respectively. Experimental results show that RC columns under cyclic loading may exhibit three failure mechanisms:flexural failure, flexure-shear failure and shear failure. With the decrease of span-to-depth ratio or transverse steel ratio, or the increase of axial load ratio, specimen failure models are changed from flexural to flexure-shear and shear with poor energy dissipation capacity and ductility, and more obvious pinch can be seen from the hysteresis loops. With the increase of total displacement, the contribution of flexure deformation to the total deformation is reduced; the contribution of shear deformation is increased; and the contribution of anchorage slip deformation keeps at about30%-40%2. According to the anti-seismic test data of RC columns at home and abroad, the influences of span-to-depth ratio, axial load ratio, transverse reinforcement ratio, longitudinal reinforcement ratio, concrete compressive strength and reinforcement strength on failure modes of column were analyzed. Considering these influence factors, a probabilistic estimation method was developed to identify column failure mode, and an equation of discriminant parameter for columns failure modes was proposed. 3. Based on test results of columns failed in flexural-shear, the effects of axial load, span-to-depth ratio and stirrup ratio on shear capacity and displacement ductility were estimated, and equations for predicting shear capacity and displacement ductility factor were proposed.4. Based on analytical and experimental results, approaches were developed for predicting the cracking, yielding and failure loads, as well as corresponding deformations, for RC columns failed in flexural-shear. And then according to three feature points, a simplified method was proposed to describe the backbone curve of restoring force model for RC columns in flexural-shear under seismic loads.5. RC circular columns were tested under combined cyclic lateral displacement excursions and constant axial load after being subjected to accelerated corrosion tests. The controlled variables in the test were corrosion level and axial load ratio. Based on the test results, degradation models for loading capacity, stiffness, ductility and energy dissipation capacity of columns were proposed. Test results show that higher corrosion levels or higher axial loads may result in worse energy dissipation capacity and ductility, and the failure mode of columns damaged seriously by reinforcement corrosion may change from flexure to flexure-shear or shear.更多还原