Field Vibration Tests and Proposition of Safety Measures for Dynamic Instabillity of Folsom-Dam Tainter-Gate

Folsom-Dam Tainter-Gate 动态失稳现场振动试验及安全措施建议

基本信息

批准号：
15360127
负责人：
ISHII Noriaki
金额：
$ 8万
依托单位：
Osaka Electro-Communication University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Tainter gates (radial gates) are frequently used as a crest gate of dam for a flood release. A huge Tainter gate installed on Folsom dam in California, induced vibrations and failed, early in the morning of July 17,1995. A possibility that vibration participated in its failure was pointed out from just after the accident, and some failure analysis studies have been performed by applicants.In this study, verification studies of theoretical analyses developed for a possible coupled-mode flow-induced vibration of Tainter gates were made by conducting vibration tests for 45-ton Tainter gate and 3-D 1-13-sclaed model gate. In addition, failure analyses of Folsom dam Tainter gate were made and suggestions for dynamic stability were presented. Research results are summarized as follows :1.Field vibration tests of Folsom-dam Tainter-gate which was being planned to conduct at the beginning of this research project was not able to be conducted because of severe cautions to terrorism in USA. In t … More his study, thereupon, field vibration tests were conducted for a 45-ton full-scale gate under practical uses in Japan, to determine its in-air and in-water natural vibration characteristics, where steel bar breaking tests were first adopted to excite the huge gate to vibrate. Detailed measurements of responding vibration acceleration were made to identify the frequencies and modes of natural vibrations. In in-water vibration tests, hydrodynamic pressure also was measures, where a small pressure hole was made directly through the skinplate. The measured data were incorporated into the theoretical analyses to calculate the in-water vibration frequency and the dynamic instability curve. As a result, the theoretical analyses were well verified for its validity.2.Three-dimensional 1/13-scaled model of Folsom dam Tainter-gate was made, where the vibration modes and its in-water vibration frequencies were carefully designed to be exactly same as those of failed Folsom Tainter-gate. The 3-D model gate was installed in a large flume of water circulation type. As a result, the 3-D model gate definitely re-realized the same type of violent coupled-mode self-excited vibration that must have caused the Folsom gate failure. The theoretical analyses were well verified for its validity by the 3-D model gate tests also.3.Folsom gate Failure was made by applying the developed theoretical analyses, where the dynamic instability of the Tainter-gate is theoretically examined and the major characteristics of this instability were presented, and an FEM analysis of the structure was incorporated to reveals that the small vibration amplitude of at most 11.9mm at the spanwise center and bottom end of the skinplate induced the excessive hydrodynamic pressure load of about 1.6 times the static load, thus causing incipient failure of 4 bolts connecting a diagonal member to the main struts. Less

tainter大门（径向门）经常用作洪水释放的大坝的波峰大门。 1995年7月17日清晨，在加利福尼亚的Folsom大坝上安装了一个巨大的门，引起了振动，并失败了。事故发生后，申请人进行了一些失败分析研究，并进行了一些故障分析研究。在这项研究中，针对对45-ton Tainter Gate和3-D-1-1-1-1-1-1-1-1-13-DED的模型进行了振动测试，对辅助模式流量振动进行了可能的耦合模式振动而开发的理论分析进行了验证研究。此外，对Folsom坝tainter门进行了故障分析，并提出了动态稳定性的建议。研究结果总结如下：1。FOLSOM-DAM TAINTER GATE的场振动测试，该测试计划在该研究项目开始时进行，因为在美国对恐怖主义的严重警告，无法进行。在……更多的研究中，在日本实际用途下，对45吨的全尺寸门进行了现场振动测试，以确定其空气内和水的自然振动特性，首先采用了钢筋破裂测试，以激发巨大的振动门。对响应振动加速度进行了详细的测量，以识别自然振动的频率和模式。水内振动测试，水力压力也是测量，其中直接通过皮肤板制成一个小压力孔。将测量的数据纳入理论分析中，以计算水内振动频率和动态不稳定性曲线。结果，理论分析的有效性得到了很好的验证。2。三维1/13尺度的folsom dam dainter-gate模型，在此，振动模式及其水中振动频率仔细设计为与失败的人的振动频率完全相同。 3-D模型门安装在大量水流液类型中。结果，3-D模型门无疑重新实现了相同类型的暴力耦合模式自激振动，该振动必须导致Folsom Gate失败。 3-D模型门测试还通过应用开发的理论分析进行了理论分析的有效性。皮肤板诱导多余的流体力压力负荷约为静态负荷的1.6倍，从而导致4个将对角构件连接到主支撑杆的螺栓的影响。较少的