Failure Mechanism of Concrete Pile

桩承式钢筋混凝土房屋抗震性能分析在进行结构计算时，一般将建筑物分为地上部分和地下部分。如前所述，检查地下部分的极限强度不是法律的义务。所以，地下部分的最终实力，还是未知数。因此，在1995年兵库县南部地震中，许多钢筋混凝土建筑物在地下部分受损，而地上部分没有受损。为了模拟轴力和弯矩的相互作用，本文引入了多弹簧模型。对一栋7层钢筋混凝土房屋进行了分析。一开始，我们只分析了这座建筑的地上部分。屈服发生在几乎所有梁的末端。这是理想的铰链机构。其次是地上部分和地下部分 ...更多信息 部分作为一个整体进行分析。在梁到达屈服曲率之前的早期阶段，桩顶已经发生屈服。高强混凝土预制桩的抗剪强度这是分析结果与试验最大抗剪强度的比较。横轴表示轴向应力、预应力和外部轴向应力的总和。当轴向应力之和较小时，解析结果比实验结果大。该公式是由柴田和Joh提出的，用于计算方形截面柱的极限抗剪强度。本文将此方程应用于圆柱形截面桩。轴向应力之和越大，安全系数越低。我们研究的可能性，桩剪切失败之前，屈服已经开始在桩顶。在大多数情况下，抗剪强度小于桩顶开始屈服时的抗剪力。日本目前使用的PHC桩容易产生剪切破坏。少

Analysis on the Seismic Behavior of Reinforced Concrete Building supported by PileIn making structural calculation, a building is commonly divided into two parts, aboveground part and underground part. As already mentioned, it is not legal obligation to examine the ultimate strength for the underground part. So, the ultimate strength of the underground part was left unknown. Therefore, many reinforced concrete buildings were damaged at the underground part due to the 1995 Hyougoken Nanbu Earthquake without damage of aboveground part.Here, we analyzed the damage considering the interdependence of aboveground part and pile. In order to simulate the interaction between axial force and bending moment, the multi spring model is introduced here. A 7 storied reinforced concrete building is analyzed. At first, we analyzed only the aboveground part of this building, alone. Yielding has occurred at the end of almost beams. This is ideal hinge mechanism. Next the aboveground part and underground … More part are analyzed together as a body. The yielding has occurred at the top of pile in the early stage before beams reach at the yield curvature. This agreed with the damage due to the earthquake.Shear Strength of Pre-cast High Strength Concrete PileThis is the comparison between analytical result and experimental maximum shear strength. The horizontal axis shows the sum of the axial stresses, pre-stress and external axial stress. When the sum of axial stresses is low, the analytical results are larger than the experimental one. The equation was proposed by Shibata and Joh in order to calculate the ultimate shear strength of column with square section. We apply this equation to the pile with cylindrical section. The higher the sum of axial stresses becomes, the lower the factor of safety is. We examine the possibility that the pile fails by shear before the yielding has begun at the top of pile. In almost cases, the shear strength is smaller than the shear force when yielding has begun at the top of pile. The PHC pile now in use in Japan tends to cause the shear failure. Less