Collapse of Showa Bridge during 1964 Niigata Earthquake: a quantitative reappraisal on the failure mechanisms
Collapse of Showa Bridge during 1964 Niigata Earthquake: a quantitative reappraisal on the failure mechanisms
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DOI：
10.1016/j.soildyn.2014.05.004
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发表时间：
2014-10
影响因子：
4
通讯作者：
S. Bhattacharya;K. Tokimatsu;K. Goda;R. Sarkar;M. Shadlou;M. Rouholamin
中科院分区：
文献类型：
--
作者：
S. Bhattacharya;K. Tokimatsu;K. Goda;R. Sarkar;M. Shadlou;M. Rouholamin
昭和大桥在1964年新泻地震中的倒塌，多年来一直是证明液化破坏性影响的标志性案例研究。初始冲击期间的惯性力（在地面震动的前7 s内）或周围地面的横向扩展（在震动开始后83 s开始）不能解释昭和大桥的破坏，因为大桥在主震后约70 s和地面的横向扩展开始之前破坏。在这项研究中，进行定量分析的各种故障机制，可能导致失败。研究表明，在地震发生后70 s左右，桥梁的自振周期（由于土壤液化引起的无支撑桩长度的延长）与液化地基的周期一致，引起桥梁与地面运动的共振。这种调谐效应（共振）导致桩头过度偏转，导致桥面从支撑墩上脱落，从而引发桥梁倒塌。
Collapse of Showa Bridge during the 1964 Niigata earthquake has been, over many years, an iconic case study for demonstrating the devastating effects of liquefaction. Inertial forces during the initial shock (within the first 7 s of the ground shaking) or lateral spreading of the surrounding ground (which started at 83 s after the start of the shaking) cannot explain the failure of Showa Bridge as the bridge failed at about 70 s following the main shock and before the lateral spreading of the ground started. In this study, quantitative analysis is carried out for various failure mechanisms that may have contributed to the failure. The study shows that at about 70 s after the onset of the earthquake shaking, the increased natural period of the bridge (due to the elongation of unsupported length of the pile caused by soil liquefaction) tuned with the period of the liquefied ground causing resonance between the bridge and the ground motion. This tuning effect (resonance) caused excessive deflection at the pile head, resulting in unseating of the bridge deck from the supporting pier and thereby initiating the collapse of the bridge.