钢管桩加支撑前后涡振比较研究

针对最近几年来,我国几座代表性大桥在施工过程中钢管桩断裂的急需解决问题,对在水流、波浪力作用下钢管桩搭设支撑前、后所产生的涡振进行研究。采用伽辽金法分别对2种支撑体系的振型、响应、自振频率、临界弯矩、临界应力进行计算比较,同时对2种支撑体系所对应的大波数区、小波数区频率进行比较分析。通过比较分析、计算2种支撑体系的振动情况,得出钢管桩在支撑前更容易产生涡振破坏的结论。结果表明通过改变钢管桩 EI 值或采取一些特殊措施,增加桩的自振频率,来避免其在施工过程中产生的涡振破坏,对实际工程具有重大理论价值。

COMPARATIVE STUDY ON VORTEX VIBRATION OF OFFSHORE STEEL-PIPE PILE WITH SUPPORT AND WITHOUT SUPPORT

Several representative bridges have ruptured during construction in the last few years in our country.The mentioned problem should be solved urgently.The vortex vibration on steel-pipe piles with support and without support under current and wave is studied.For two support system,the method of Galerkin was employed to compute the mode,response,natural frequency,critical moment,critical stress respectively.At the same time two kinds of support system's corresponding frequency of the high number of wave and low number of wave were analyzed.The vibration about two kinds of structure systems were analyzed and calculated by comparative.A conclusion was drew that steel-pipe pile without support was apt to produce destroy of vortex vibration.The result seems to suggest that the EI value of steel pipe piles are changed or some special measures are adopted to increase the free vibration frequency,so as to avoid it yield vortex destroy in the process of construction.This is an important value theory to actual engineering.