高桩承台基础损伤状态服役性能仿真分析及损伤评价

Simulation analysis and condition assessment of service performance for damaged high⁃pile foundation

基于桥梁高桩承台基础典型损伤类型及其对基础竖向、水平向强度、刚度劣化的影响,建立了适用于该类型基础的损伤评价模型,包括损伤指标体系、损伤特征参量量化、损伤指数计算方法和损伤分级。以一座近海斜拉桥主墩为例,建立了有限元模型,研究了其在各种损伤类型和程度下,受波浪力、船撞、地震荷载作用时的服役性能。以某内河拱桥为工程实例,调查其高桩承台基础,并采用本文方法做损伤评价。研究表明:桩基和地基固结位置、主墩各构件连接部位是主墩的易损部位;本文损伤评价模型能够对高桩承台基础损伤程度做出合理估计,评价结论与基础的服役性能仿真结果相匹配;现场调查能够为本文模型提供必要的损伤特征参量计算依据。

In order to assess the condition of service performance for damaged high-pile foundation of bridges appropriately,a specific condition assessment method was first established,including damage indicator system,damage characteristic parameters,damage indices calculation and condition grading.The assessment method is based on typical damage types of high-pile foundation,and it quantitatively accounts the impacts of performance degradation in both horizontal and vertical direction of the piles resulting from each type of damage.Then,a three-dimensional(3D)finite elements(FE)model of tower-foundation for one offshore bridge was developed to simulate the service performance under action of earthquake,wave force and ship collision.Each typical foundation damage with different damage extent was considered separately in the FE model and was assessed by the condition assessment method. The simulation resultsshow that fixed position between piles and ground,and the member joints are the vulnerable parts. Thecondition assessment method proposed in this paper is able to reasonably evaluate service performance ofhigh-pile foundation with different extent of damages.