柱截面形状对板柱节点受冲切性能影响的试验研究

发布时间：2018-05-03 05:36

本文选题：板柱节点 + 柱截面形状　；参考：《湖南大学》2015年硕士论文

【摘要】：钢筋混凝土板柱结构是一种常用的结构形式,它具有施工支模简单,结构本身高度较小,可以减少建筑物的层高,从而降低建筑物的造价等优点,多用于车库、住宅等建筑,在欧美等国得到广泛的应用。为满足使用者对房屋结构的建筑功能、结构布置等方面的不同需求,实际结构中可能出现平板由矩形或者圆形柱头支撑的情况,另一方面,板柱-剪力墙结构中的平板则可能由短肢剪力墙支撑。目前,国内外学者对于矩形柱、圆柱板柱节点受冲切性能的试验研究相对较少,而纵向配筋率对板柱节点受冲切性能的影响也众说纷纭,各国规范条文的受冲切承载力计算公式大多建立在半理论半经验的基础上,而并非基于失效机理层面的理论模型,进一步完善对柱截面形状、纵向配筋率对板柱节点受冲切性能影响的认识是非常有必要的。为研究柱截面形状及纵向配筋率对板柱节点受冲切性能的影响,本文在总结前人研究的基础上,完成了10个轴心荷载作用下的板柱节点冲切破坏试验研究。试件尺寸为2550mm×2550mm×180mm。试验变量包括柱截面形状和纵向配筋率:五种柱截面形状(包括圆形、六边形、方柱和矩形截面)、纵向配筋率取1.28%、0.86%两种,单层双向配置。通过试验获取了荷载-中心挠度曲线、破坏形态、局部应变分布和板内斜裂缝发展过程数据等信息。结合试验结果和历史试验数据进行分析,主要结果表明:提高纵筋配筋率较为明显的影响板柱节点试件的变形性能,能在一定程度上提高板柱节点受冲切承载力,试件在最大弯矩部位纵筋屈服后发生冲切破坏;加载短柱长宽比在1到4之间变化时,对冲切承载力无明显影响,柱截面形状对受冲切承载力的不利影响的根本原因是冲切截面计算周长与板截面有效高度之比增大导致的应力集中现象;现行GB50010-2010规范的冲切锥面倾角、圆柱板柱节点的受冲切承载力计算方法存在不合理之处;板内斜裂缝首先在靠近柱边的中上部区域形成,然后向上下发展发生冲切破坏,冲切破坏过程并非呈理想塑性。综合比较国际上广泛应用的四种规范可以认为,欧洲规范和欧洲模式规范能较好的反映纵筋配筋率和柱截面对板柱节点受冲切破坏承载力的影响。本文基于双剪强度准则和刚塑性理论推导了板柱节点受冲切破坏承载力计算的理论公式,公式计算值与本文试验值吻合良好,将该理论公式与收集到的历史数据对比,也吻合良好。
[Abstract]:Reinforced concrete slab-column structure is a kind of common structural form. It has the advantages of simple construction formwork, small height of structure itself, which can reduce the floor height of buildings and thus reduce the cost of buildings, etc. It is often used in buildings such as garages, residential buildings, etc. In Europe and the United States and other countries have been widely used. In order to meet the different needs of the users on the building function and layout of the building structure, the actual structure may be supported by rectangular or circular columns, on the other hand, The plate in the slab-column-shear wall structure may be supported by the short-leg shear wall. At present, there are few experimental studies on punching behavior of rectangular column and cylindrical plate-column joints, and there are different opinions about the influence of longitudinal reinforcement ratio on punching shear performance of plate-column joints. Most of the calculation formulas of punching shear capacity of national specifications are based on semi-theoretical and semi-empirical, but not on the theoretical model of failure mechanism to further improve the cross-section shape of columns. It is necessary to understand the influence of longitudinal reinforcement ratio on punching behavior of plate-column joints. In order to study the influence of column section shape and longitudinal reinforcement ratio on punching shear behavior of slab-column joints, the experimental research of punching shear failure of slab-column joints under 10 axial loads has been completed on the basis of summarizing previous studies. The size of the specimen is 2550mm 脳 2550mm 脳 180mm. The test variables include column section shape and longitudinal reinforcement ratio: five column cross-section shapes (including circular, hexagonal, square column and rectangular section), longitudinal reinforcement ratio of 1.28% 0.86%, single-layer two-way configuration. The information of load-center deflection curve, failure pattern, local strain distribution and the development process of inclined cracks in the plate were obtained by experiments. Combined with the test results and the historical test data, the main results show that increasing the reinforcement ratio of longitudinal reinforcement significantly affects the deformation performance of the slab-column joints, and can improve the punching capacity of the slab-column joints to a certain extent. When the ratio of length to width of the short column changes from 1 to 4, the shear capacity is not affected obviously. The fundamental cause of the negative effect of column section shape on the punching capacity is the stress concentration phenomenon caused by the increase of the ratio between the calculated circumference of the punching section and the effective height of the plate section. The calculation method of punching capacity of cylindrical plate-column joints is unreasonable, and the inclined cracks in the plate are formed in the upper and middle parts near the column edge, then the punching failure occurs up and down, and the process of punching failure is not ideal plastic. Compared with the four codes widely used in the world, it can be concluded that the European Code and the European Model Code can better reflect the influence of the reinforcement ratio of longitudinal reinforcement and column section on the punching shear failure capacity of plate-column joints. Based on the double shear strength criterion and rigid-plastic theory, the theoretical formula for calculating the punching failure capacity of plate-column joints is derived in this paper. The calculated value of the formula is in good agreement with the experimental value in this paper. The theoretical formula is compared with the historical data collected. It also fits well.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375

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