Calculational Unified Theory for Calculation of Shear Strength of Linear and Planar Members

本研究讨论了四个主题。得到的主要结果如下。1) RC深板抗剪破坏的有效宽度从试验结果出发，讨论了RC深板抗剪承载力的有效宽度。加载板长度对有效宽度的影响大于支撑板长度。如果考虑有效宽度与荷载与支承板之间形成的受压混凝土支撑的膨胀有关，则剪跨比是影响膨胀的重要因素。2)抗剪配筋对RC板局部抗剪破坏的影响对单向和悬臂梁RC板进行了抗剪配筋试验研究。冲剪破坏时，抗剪承载力随配筋的增加而增加。在梁剪力破坏情况下，承载力略有提高。在一定荷载作用下，抗剪钢筋的应变开始突然增大，但在板达到极限状态时，应变未达到屈服应变。3)钢筋混凝土构件受剪破坏时纵筋的销钉和粘结作用建模对抗剪机构纵筋进行了建模。沿纵杆的开裂是由销钉和粘结作用的共同作用引起的。钢筋的变形可以通过将周围混凝土建模为弹塑性弹簧来描述。裂缝的判据与杆的竖向位移和滑移位移有关。4)轴对称钢筋混凝土板的解析研究抗剪配筋对轴对称钢筋混凝土板抗剪承载力的影响可以用非线性有限元分析来描述。通过分析，阐明了受拉筋和受剪筋对构件刚度的影响。

In this study four topics are discussed. The major results obtained are as follows.1) Effective Width for Shear Failure of RC Deep SlabsThe effective width to the shear capacity of RC deep slabs was discussed from the experimental results. The effect of the length of loading plate on the effective width is larger than that of the supporting plate. If it is considered that the effective width is related to the swell of the compressive concrete strut formed between the loading and supporting plates, the shear span ratio is a factor of great importance to the swell.2) Effect of Shear Reinforcement on Local Shear Failure of RC SlabsFor one way and cantilever RC slabs, the shear reinforcing effects were experimentally investigated. In case of the slabs with a punching shear failure, the shear capacities increase with shear reinforcement. In case of the slabs with a beam shear failure, the capacities increase a little. The strain of the shear reinforcement starts to increase suddenly at a certain load, however, the strains do not reach its yield strain when the slabs reaches its ultimate state.3)Modeling for Dowel and Bond Actions of Longitudinal Bars in Shear Failure of RC MembersModeling for the longitudinal bars in a shear resisting mechanism was conducted. The cracking along a longitudinal bar is caused by a combined effect between the dowel and the bond actions. The deformation of the bars can be described by modeling the surrounding concrete as an elasto-plastic spring. The criteria of the cracking is related to a vertical and a slip displacements of the bars.4)Analytical Study on Axisymmetrical RC SlabsAn effect of the shear reinforcement on the shear capacity of axisymmetrical RC slabs can be described by using a nonlinear finite element analysis. The effect of the tensile and shear reinforcing bars on the member stiffness is clarified by the analysis.