帕劳国预应力连续箱梁长期下挠分析

发布时间：2018-11-13 15:54

【摘要】：帕劳共和国科罗尔岛-巴伦尔图阿普岛桥(简称KB桥)为主跨241 m的预应力混凝土箱梁,通车后KB桥发生长期下挠,严重影响其正常运营,最后垮塌,其教训值得反思。该桥于1977竣工,运营18年后挠度达到1.61 m,1996年对该桥进行了体外预应力加固,却在加固后3个月发生垮塌。挠度分析结果表明:传统的梁理论与三维空间分析相比,误差高达20%,且宽跨比越大,误差越大。三维有限元空间分析采用多种徐变收缩计算模型:美国ACI模型、日本JSCE模型、CEB-FIP模型和GL模型,其挠度计算值要比(18年后)实测值低50%~70%,预测的变形也与实测不符;预应力损失计算值为22%~24%,远低于实测值50%。唯一基于理论的B3模型,采用经验值参数计算得到预应力损失40%,18年后挠度计算值比实测值低42%。如果根据长期实测值调整输入参数,结果可与实际更符合。对于早期挠度及其预测,B3模型能够合理地考虑因截面厚度差异产生的收缩和干燥徐变的速率差异。此外,B3模型还可考虑温度差异和顶板可能发生的开裂。
[Abstract]:The KB Bridge of Koror Island in Palau Republic is a prestressed concrete box girder with a main span of 241m. After opening to traffic, the KB bridge has a long-term deflection, which seriously affects its normal operation and finally collapses. The lessons should be reconsidered. The bridge was completed in 1977 and its deflection reached 1.61 m after 18 years of operation. The bridge was strengthened with external prestressing force in 1996, but collapsed three months after strengthening. The results of deflection analysis show that the error of traditional beam theory is as high as 20% compared with that of three-dimensional space analysis, and the larger the ratio of width to span is, the greater the error is. Three dimensional finite element spatial analysis uses a variety of creep shrinkage calculation models: American ACI model, Japanese JSCE model, CEB-FIP model and GL model. The calculated deflection value is 500.70% lower than the measured value (18 years later). The predicted deformation is also inconsistent with the actual measurement. The calculated value of prestress loss is 22 and 24, which is far lower than the measured value of 50. In the only theoretical B3 model, the loss of prestressing force is calculated by using empirical parameters. The calculated deflection is 42. 2% lower than the measured value after 18 years. If the input parameters are adjusted according to the long-term measured values, the results can be more consistent with the actual results. For the early deflection and its prediction, the B3 model can reasonably take into account the shrinkage and drying creep rate differences caused by the cross-section thickness difference. In addition, the B _ 3 model can also take into account the temperature difference and the possible cracking of the roof.
【作者单位】：西南交通大学土木工程学院;
【基金】：国家自然科学基金资助项目(编号:51208430,51408501)
【分类号】：U441;U445.71

【相似文献】