Scouring has been known as one of the most frequent cause of failure observed in bridge infrastructures. Not to mention, the evaluation of scour mechanism sheds light on pile foundation design and helps to prevent scour induced structural deficiencies. Thus, the scouring mechanism around bridge pile foundations should be extensively evaluated in order to predict the bridge safety under critical multi-hazard environment. In this study, the local scour mechanism around bridge piles was appraised considering discrete element methods (p-y curves) in order to reflect the nonlinear nature of soil structure interaction (SSI). Following that, bridge seismic behavior and relevant failure mechanism was evaluated with regard to nonlinear time history analyses (THA). In the conducted research, river crossing 7 – span Boğaçay Bridge located in Antalya, Turkey was selected as the case study. After SAP2000 finite element modeling (FEM), the bridge was exposed to twelve incremental scour depths up to six meters at all piers and was subject to subsequent seismic effects as concordant to the site that mimics a probable earthquake occurs after scouring regarding the Turkish Earthquake Code (TEC-2018). The modal responses indicated a simultaneous increase in natural periods with augmenting scour depth. In the analyses, the influence of scouring on pier displacement demands, pier accelerations and the internal forces at piers and piles were investigated. The analysis results indicated a significant increase in pier displacement demands with increasing scour depth especially in the transverse direction of the bridge. Further, due to the migration and spreading of plastic hinging from piers to piles due to scouring, the internal forces that were resisted by the strong axis of the pier columns decreased significantly. This fact led to the increase in pile bending moments and rotations in both orthogonal directions of the bridge. Thus, it was concluded that the probable multi-hazard effects of scouring and earthquake in river crossing bridges should be considered in bridge substructure design.

冲刷是桥梁基础设施中观察到的最常见故障原因之一。更不用说，冲刷机制的评估为桩基设计提供了启示，并有助于防止冲刷引起的结构缺陷。因此，应该对桥桩基础周围的冲刷机制进行广泛评估，以预测在关键多灾种环境下的桥梁安全性。在这项研究中，考虑了离散单元法（py曲线）对桥桩周围的局部冲刷机理进行了评估，以反映土体结构相互作用（SSI）的非线性性质。之后，针对非线性时程分析（THA）对桥梁的地震行为和相关破坏机理进行了评估。在进行的研究中，位于安塔利亚的7 –跨Boğaçay桥跨河，土耳其被选为案例研究。在SAP2000有限元建模（FEM）之后，该桥在所有墩台处受到12级递增冲刷深度的影响，最高可达6米，并受到随后的地震影响，这与根据《土耳其地震法》进行冲刷后模拟可能发生地震的地点一致（TEC-2018）。模态响应表明自然期会随着冲刷深度的增加而同时增加。在分析中，研究了冲刷对墩台位移要求，墩台加速度以及墩台和桩上内力的影响。分析结果表明，随着冲刷深度的增加，尤其是在桥梁的横向方向上，墩台位移的需求显着增加。进一步，由于冲刷导致塑料铰链从墩到桩的迁移和扩散，墩柱长轴抵抗的内力显着降低。这一事实导致桩的弯矩和桥梁两个正交方向上的旋转增加。因此，得出的结论是，在桥梁下部结构设计中应考虑过河冲刷和地震可能产生的多灾种影响。