基于极限承载比的大跨桥梁结构内力监测方案设计

Internal Force Monitoring System Design for Long Span Bridges Based on Ultimate Bearing Capacity Ratios of Structural Components

大跨度桥梁结构内力监测方案设计提供理论方法和依据,提出了基于构件极限承载比的大跨度桥梁结构内力监测方案设计理论和方法。通过对不同荷载组合作用下的大跨度桥梁结构的极限能力分析,以及结构极限状态下的受力和构件本身的极限承载状态,定义了构件极限承载比、极限承载比均匀度和基准极限承载比等特征参数。进而根据构件极限承载比与基准极限承载比确定结构中的高承载构件,并对高承载构件进行内力监测方案设计。最后,以芜湖长江公路二桥为工程背景,通过对六种荷载组合作用下的极限承载能力分析,找出结构中的高承载构件及破坏路径,进而提出了芜湖长江公路二桥内力监测设计初步方案。结果表明:基于构件极限承载比的大跨度桥梁结构内力监测方案设计,为桥梁结构内力监测设计提供定量化评价基准;通过基于构件极限承载比的结构内力监测所选取的监测构件与结构的真实破坏过程一致,可以减少低承载构件的监测,对于芜湖长江公路二桥内力监测的构件可以从原方案178个测试构件减少至59个测试构件,减少了低承载的监测构件,降低了监测费用。

In order to provide a novel strategy for long-span bridge health monitoring system design,this paper proposes a novel bridge internal force monitoring system design method based on the ultimate bearing capacity ratios of structural components.Through the analysis of the ultimate capacity of the long-span bridge structure under various load conditions,the stress of the structural components under the limit state is obtained.Then,the component ultimate bearing capacity ratio,the uniformity of ultimate bearing capacity ratio,and the reference of component ultimate bearing capacity ratio are defined.Based on the analysis of these indices,the high bearing components can be found.The internal force monitoring system can then be designed based on the high bearing components.Finally,the internal force monitoring system of the second bridge of Wuhu Yangtze river highway bridge is designed based on the proposed method.The results show that the proposed method can provide quantitative criteria for the internal force monitoring system design;The monitoring components selected by the proposed method are consistent with the actual failure process of the bridge,and can reduce the monitoring of low bearing components;For the second bridge of Wuhu Yangtze river highway bridge,only 59 components are designed to be monitored.Therefore,the bridge internal force monitoring system based on the proposed method can decrease the number of monitored components and the cost of the whole monitoring system.