ABSTRACT

This paper proposes a comprehensive analysis framework, combining three-dimensional (3D) numerical modelling and metamodeling, to investigate the probabilistic performance of retrofit actions on coastal bridges subjected to extreme wave forces. Specifically, a 3D Computational Fluid Dynamics (CFD) model is developed to calculate extreme wave load on the bridge superstructure. The established 3D model is validated by laboratory experiments. The characteristics of wave forces are parametrically investigated, and an Artificial Neural Network (ANN) metamodel is utilised to quantify the loading effects with multiple surge and wave parameters. Such a numerical-based ANN metamodel could predict wave forces under variable scenarios accurately, and significantly reduce the high computational cost of the 3D numerical model. Based on the numerical and metamodeling results, the bridge fragility curve is derived by considering uncertainties associated with structural demand, capacity, and hurricane hazard. Long-term failure risk is assessed under different climate change scenarios. Furthermore, different retrofit methods to improve structural performance and reduce failure risk are examined according to the proposed framework, including inserting air venting holes, enhancing connection strengths, and elevating bridge structures. The proposed framework could facilitate the optimal and robust design and maintenance of coastal infrastructures under hurricane effects in a long-term time interval.

摘要

本文提出了一个综合的分析框架，将三维（3D）数值建模和元建模相结合，以研究在极端波浪力作用下沿海桥梁的加装动作的概率性能。具体来说，开发了3D计算流体动力学（CFD）模型来计算桥梁上部结构上的极限波浪载荷。建立的3D模型已通过实验室实验验证。对波浪力的特性进行了参数研究，并利用人工神经网络（ANN）元模型来量化具有多个浪涌和波浪参数的载荷效应。这种基于数字的ANN元模型可以准确预测可变场景下的波浪力，并显着降低3D数值模型的高计算成本。根据数值和元建模结果，通过考虑与结构需求，承载力和飓风危害相关的不确定性，得出桥梁的脆性曲线。在不同的气候变化情景下评估长期失败风险。此外，根据提出的框架，研究了用于改善结构性能和降低故障风险的不同改造方法，包括插入通风孔，增强连接强度和提升桥结构。拟议的框架可以在长期影响下，在飓风影响下促进沿海基础设施的优化，健壮设计和维护。在不同的气候变化情景下评估长期失败风险。此外，根据提出的框架，研究了用于改善结构性能和降低故障风险的不同改造方法，包括插入通风孔，增强连接强度和提升桥结构。所提出的框架可以在长期的时间间隔内，在飓风的影响下促进沿海基础设施的最佳，稳健的设计和维护。在不同的气候变化情景下评估长期失败风险。此外，根据提出的框架，研究了用于改善结构性能和降低故障风险的不同改造方法，包括插入通风孔，增强连接强度和提升桥结构。所提出的框架可以在长期的时间间隔内，在飓风的影响下促进沿海基础设施的最佳，稳健的设计和维护。