A Review of Ship Collision and Seismic Impacts on Scour-Affected Bridge Pile Foundations

Abstract

In recent years, the frequent collapse of bridges has underscored the severe threats posed by ship collisions and seismic forces to bridge pile foundations, particularly under scour conditions. Scour significantly increases bending moments, weakens foundation stability, and exacerbates damage under ship impacts and seismic loading. This review systematically examines the dynamic responses of bridge pile foundations subjected to multi-hazard scenarios, focusing on how scour-induced degradation exacerbates the impacts of ship collisions and seismic events. The synthesis covers experimental studies, numerical simulations, and theoretical approaches, providing a comprehensive evaluation of methodologies and findings. Advanced bibliometric tools, such as CiteSpace and VOSviewer, are employed to identify research trends, hotspots, and collaborations in this domain. Additionally, the review highlights the integration of intelligent technologies for mitigating ship collision risks and improving bridge safety management in scour-prone environments. By consolidating existing knowledge, this paper can serve as a critical reference for understanding the compounded effects of scour and other hazards on bridge pile foundations, offering guidance for future research and engineering practices.

1. Introduction

Bridge pile foundations are critical components of bridge structures, ensuring their stability and load-bearing capacity. However, these foundations face significant threats under multi-hazard scenarios, particularly in scouring environments prone to ship collisions and seismic forces. Local scour around bridge pile foundations, as illustrated in Figure 1, significantly reduces the bearing capacity of pile foundations and alters the natural frequency of the superstructure, negatively impacting its dynamic response and stability [1,2,3]. The scouring of riverbeds due to the blocking of the downstream current by the bridge pier is one of the main causes of bridge failure [4,5]. Scour has been identified as a primary cause of structural failure and remains a critical issue in pile foundation design [6,7,8]. Notable cases include the Schoharie Creek Bridge in New York, the Annascaul and Victoria Masonry Bridges in Ireland, the Longshan Bridge in China, the Mississippi Highway 33 Bridge in the United States, and an Italian bridge abutment that collapsed after continuous scour removed its supporting soil [9,10]. Additionally, the combined effects of scour and dynamic forces, such as ship impacts or seismic events, have been shown to amplify the risks of structural failure, as seen in the I-10 Bridge collapse in the United States in 2015 and the Pooley Bridge failure during the Cambria floods [11,12].

Maritime transport, which accounts for approximately 90% of global trade, has experienced rapid growth in recent years, with the global fleet expanding by 3.2% in 2022 to reach 105,493 ships with a total deadweight tonnage of 2.27 billion by early 2023 [13]. This surge in maritime activity has increased the size and number of ships, which has intensified the vulnerability of bridges over navigable waterways to ship collisions. Historical data reveal that ship collisions are a leading cause of bridge failures. Harik reported that 24% of 114 bridge collapses in the United States between 1951 and 1988 were attributed to ship collisions, while Wardhana and Hadipriono found that 12% of U.S. bridge failures between 1989 and 2000 were caused by lateral impacts, with 10 incidents involving ship collisions [7,14]. Further details on bridge failures due to ship collisions and earthquakes under scour are provided in Table 1. Recent events, such as the 2024 collapse of the Lixinsha Bridge in China following a container ship collision and the Francis Scott Key Bridge failure in the United States due to a cargo ship impact, highlight the ongoing risks associated with ship–bridge collisions.

Regions susceptible to seismic activity face compounded challenges when scour-affected foundations are subjected to earthquake forces. Scour exposes pile foundations, significantly reducing lateral strength and transferring earthquake-induced damage from bridge piers to piles, thereby increasing the likelihood of collapse during seismic events [15,16,17,18]. Regions such as California, the New Madrid Seismic Zone, and coastal southern China, which are prone to both seismic activity and flooding, face compounded risks from scour-affected foundations subjected to earthquake forces [19,20].

Table 1. Summary of bridge failures caused by ship collisions and earthquakes under scour.

Authors	Location	Span of Time Period	Amount of Bridge Failures
Harik et al. [14]	Kentucky, US	1951–1988	27
Wardhana and Hadipriono [7]	US	1989–2001	154
Diaz et al. [21]	Colombia	1986–2001	35
Cook et al. [22]	US	2004	52
Lee et al. [23]	US	1980–2012	249
Lin et al. [24]	US	2007	36
Stearns and Padgett [25]	Texas	2008	19
Biezma and Schanack [26]	US	last 200 years	192
Liu et al. [27]	CN	2019	5
Xiong et al. [28]	World	1831–2020	694

Table 1. Summary of bridge failures caused by ship collisions and earthquakes under scour.

Authors	Location	Span of Time Period	Amount of Bridge Failures
Harik et al. [14]	Kentucky, US	1951–1988	27
Wardhana and Hadipriono [7]	US	1989–2001	154
Diaz et al. [21]	Colombia	1986–2001	35
Cook et al. [22]	US	2004	52
Lee et al. [23]	US	1980–2012	249
Lin et al. [24]	US	2007	36
Stearns and Padgett [25]	Texas	2008	19
Biezma and Schanack [26]	US	last 200 years	192
Liu et al. [27]	CN	2019	5
Xiong et al. [28]	World	1831–2020	694

Under multi-hazard scenarios, bridge foundations are more vulnerable than in situations involving a single hazard [29]. Addressing these challenges requires a comprehensive understanding of how bridge pile foundations respond to combined hazards, particularly under scour conditions, where the effects of ship collisions and seismic forces can be significantly exacerbated. Over the past two decades, researchers have conducted extensive experimental studies, developed advanced numerical models, and proposed innovative theoretical frameworks to analyze and mitigate these risks. This review aims to consolidate the current state of knowledge in this interdisciplinary field, providing a thorough examination of experimental research, numerical simulations, and theoretical models related to ship collisions, local scour, and seismic dynamic responses under scour conditions.

The study employs advanced bibliometric tools, such as CiteSpace 6.3R1 and VOSviewer 1.6.20, to visualize research trends and collaborations, offering valuable insights into global progress in this area. By synthesizing findings from the existing literature, this review highlights key challenges and outlines potential future directions for the design of resilient bridge pile foundations capable of withstanding the compounded impacts of scour, ship collisions, and seismic forces. The work is intended to serve as a vital reference for researchers and engineers, contributing to the development of safer and more sustainable practices in offshore and bridge engineering under increasingly complex environmental conditions.

2. Bibliometric Analysis of Research Trends, Collaborations, and Emerging Frontiers

A comprehensive literature review was conducted to compile a dataset of research articles and review papers published between 2007 and 2025, addressing the combined effects of ship collisions, scour, and seismic actions on bridge pile foundations. The Web of Science (WoS), a globally recognized citation database encompassing over 12,000 high-impact journals [30], served as the primary source for the literature retrieval. Search terms included “ship collision”, “scour”, “seismic effects”, and related combinations to ensure thorough coverage of interdisciplinary studies in maritime engineering, geotechnical hazards, and seismic resilience. Records retrieved from WoS were exported and analyzed using CiteSpace, an analytical tool that generated visualizations, including keyword co-occurrence networks, thematic evolution maps, and collaboration clusters. These outputs enabled the identification of research trends, interdisciplinary connections, and knowledge gaps, providing a robust foundation for analyzing ship collision and seismic impacts on bridge structures.

2.1. Bibliometric Study on Pile Foundations Under Ship Collision

The number of relevant papers was quantified on an annual basis, as depicted in Figure 2. As shown, the volume of papers in this field was relatively low in 2007. However, starting from 2008, there has been a gradual increase in the number of publications, reflecting a steady upward trend. This rise coincides with the growing awareness of safety issues and advancements in high-tech solutions, leading to continuous growth in research on scour and ship collisions. This increasing volume of publications indicates a clear shift toward intensified research in this area.

The keyword clustering diagram (Figure 3), generated using VOSviewer, provides a visualization of the associations and groupings of keywords across the literature. Notably, the keywords “ship collisions”, “collision prevention”, “safety and risk”, and “numerical simulation” are most strongly associated, reflecting the current focal points in the research landscape.

Figure 4 illustrates the number of documents published by different countries, offering a clear representation of each country’s contribution to the field. Notably, China has made the most significant contribution to global research on scour and ship collisions. Other nations, including South Korea, the United States, and the United Kingdom, have also made substantial advancements and maintain strong collaborative ties in this domain. The journal co-citation map reveals the citation relationships among academic journals in the field. As seen in Figure 5, ocean engineering leads the discourse on ship collision research and has made significant contributions. Other key journals, such as the Journal of Navigation and Journal of Marine Science and Engineering, also play pivotal roles in advancing the study of ship collisions, reflecting their central importance in this area of research.

The author collaboration clustering diagram (Figure 6) highlights the cooperative relationships among researchers in relevant academic fields, showcasing the frequency and extent of joint publications globally. From the diagram, it is evident that prominent scholars such as Kujala, Amdahl, and Wang have made substantial contributions to the field of ship collisions, as indicated by their frequent collaborations and impactful research outputs.

2.2. Bibliometric Study on Seismic Response of Piles Under Scouring Condition

The temporal distribution of research papers focusing on the seismic response of piles under scour conditions is depicted in Figure 7. The number of relevant publications was notably limited in 2010 but has shown a gradual upward trend since 2015. This growth aligns with increased awareness of structural safety and advancements in technology, particularly in the fields of geotechnical and earthquake engineering. The continuous rise in publications underscores the growing importance of research into the combined effects of seismic forces and scour, marking it as a critical and inevitable direction for future studies.

The evolution of keywords, as presented in Figure 8, illustrates the shifting research focus and emerging trends in this interdisciplinary field. The chart captures the prominence of specific keywords over time, shedding light on how research priorities have developed. Notably, the combination of “seismic dynamic response” and “scour” has consistently been a focal point, reflecting their interconnected nature and critical role as research hotspots. This evolution provides valuable insights into the field’s trajectory and helps identify areas warranting further investigation.

The geographical distribution of publications, shown in Figure 9, highlights the contributions of various countries to research on scour and seismic effects. China has emerged as the leading contributor, producing a significant portion of the global literature in this field. Other countries, such as the United States, Canada, and the United Kingdom, have also made notable advancements and maintained robust collaborative networks. This geographical data emphasize the global nature of the research and underscores the importance of international cooperation in addressing complex multi-hazard scenarios.

The co-citation network of journals, depicted in Figure 10, reveals the scholarly influence and collaboration within the field. Engineering Structures has established itself as a leading journal, making substantial contributions to seismic effects research. Other key journals, including Earthquake Engineering & Structural Dynamics and Soil Dynamics and Earthquake Engineering, have also played significant roles in advancing the understanding of the seismic behavior of structures under scour conditions. This network demonstrates the interdisciplinary nature of the research and the centrality of these journals in disseminating critical findings.

The analysis of research hotspots, institutional affiliations, and author collaborations is illustrated in Figure 11. This visualization highlights the flow relationships between researchers, institutions, and thematic research areas. It reveals the dynamic exchange of ideas and findings across disciplinary boundaries, facilitated by researchers affiliated with multiple institutions. Such collaboration has been instrumental in driving innovation and addressing cutting-edge challenges in the field of seismic responses under scour conditions. This interconnectedness underscores the importance of fostering interdisciplinary approaches and global partnerships to enhance the depth and impact of research.

This bibliometric analysis offers a detailed overview of the research landscape concerning the seismic responses of piles under scour conditions. By examining temporal trends, keyword evolution, geographical contributions, and collaborative networks, the study highlights key research hotspots and significant achievements in this field. Building on this foundation, the paper will further investigate the combined effects of multiple hazards, specifically ship collisions, scour, and seismic dynamic responses, on bridge pile foundations. By integrating existing research findings and methodologies, this review aims to clarify the interacting effects of these hazards and contribute to the advancement of knowledge in marine and bridge engineering.

3. Research Status and Analysis of Pile Foundation Subjected to Ship Collision

3.1. Experimental and Numerical Investigations

With the continuous growth in maritime traffic demands, the number of ships has increased significantly. Compared to other types of accidents, ship–bridge collisions occur more frequently and often result in severe consequences. These collisions can lead to fatalities, substantial economic losses, and environmental pollution, highlighting their critical importance in the maritime transport sector [31].

Due to the high costs and extended implementation cycles of full-scale barge–bridge impact tests, scaled tests are frequently employed by researchers worldwide to investigate the dynamic responses of barges and bridge substructures. Xu et al. [32] conducted pendulum impact tests on four concrete-filled steel tubular pier–pile foundation systems to study their impact behaviors with scour depth effects, as illustrated in Figure 12. The impact performance of the scoured bridge, reinforced with a concrete-filled steel tubular pier and an increased pile section area, was then evaluated. Compared to the pristine bridge, the pile foundation with scour is prone to yield under the same impact condition, especially at deep scour depths. Yao et al. [33] conducted a ball–cylinder collision experiment in a water tank to simulate the response of a bridge pier colliding with a barge. They provided a comprehensive analysis of the simulation results, including impact force, crushing depth of the barge bow, and displacement of the bridge pier. Xie et al. [34] examined the dynamic response of pile-supported wharves buried in saturated sand layers under the combined effects of wave action and ship berthing collisions. Using wave flume experiments and a three-stage pendulum steel ball, they explored pile group effects, such as wave scour around the piles, the propagation of collision energy in the sand layer, and the peak bending moment on the piles, as shown in Figure 13.

Guo et al. [35] conducted pendulum impact tests on ten scaled pier foundation system models with artificially introduced scour conditions. These tests aimed to explore the dynamic performance of scaled pier foundation systems under scour and barge impact conditions, as depicted in Figure 14. Similarly, Kantrales et al. [36] performed scaled pendulum impact tests (at 40% scale) to characterize the force deformation behavior of barges in high-energy collision scenarios. Their study included both rounded and flat-faced impactor tests to evaluate the barge’s force deformation characteristics during barge–bridge collision events.

Huang et al. [37] utilized a large mass horizontal impact test device to conduct multiple cumulative collision tests on a scaled bow model of a 500 DWT ship without a bulbous bow. A refined scaled bow model was subsequently developed using LS-DYNA 17.2 finite element analysis software. By employing the restart function, simulation analyses were conducted on multiple consecutive collisions, revealing a clear relationship between the bow structure collision damage depth and absorbed energy. Chen et al. [38] performed 1:5 scaled barge bow and rigid body lateral impact tests on a double-column pier model to study the dynamic response and damage failure of bridge piers under barge impact. Their results demonstrated that under the same impact energy, the impact speed significantly influenced the permanent crushing depth of the barge bow, while the impact angle had a notable effect on the impact duration and the bridge’s dynamic behavior, thereby increasing the risk of bridge collapse.

Field-scale experiments for ship–bridge collisions are prohibitively expensive and have limited applicability. Consequently, numerical simulations are extensively utilized to study ship–bridge collisions and have become indispensable tools in bridge pile foundation collision research. Guo et al. [39] employed a high-resolution finite element method to investigate the nonlinear dynamic characteristics of a twin-tower cable-stayed bridge. By simulating drop hammer tests, a finite element model of the complex collision system between the twin-tower cable-stayed bridge and a ship was established, enabling nonlinear dynamic analysis.

Wang et al. [40] used OrcaFlex to define a constraint element attached to an impacting ship to simulate ship–bridge interactions, thereby developing a numerical model of the bridge. Similarly, Wang and Morgenthal coupled a simplified mass–spring model with a concrete bridge pier using a link unit to predict the dynamic response of concrete piers under tugboat impacts [41]. Ye et al. [42] developed a physics-based high-fidelity finite element (FE) model to examine the fluid–structure interaction (FSI) behavior of ship–bridge collisions at different collision angles. Using the potential flow solver WADAM, they validated the fluid–structure coupling modeling method implemented in the LS-DYNA code. Their findings indicated that the hydrodynamic effects predicted by the FSI model were consistent with the results obtained from WADAM simulations, as shown in Figure 15.

Wang et al. [43] constructed a finite element model incorporating a 1000-ton bulk carrier, FGAD, and dock to simulate ship collision impacts. They also conducted field tests to verify the effectiveness and reliability of the model. Ma et al. [44] adopted a coarse-graining method and porous media model to establish a CFD-DEM model for analyzing local scouring mechanisms around double piles. Four key mechanisms of local scour during the collision process were identified. Scour is a major cause of bridge failure and must be considered when modeling ship collisions. Wang et al. [45] employed an empirical scour prediction model in conjunction with LS-DYNA to study barge–bridge collisions under the influence of pile foundation scour. Li et al. [46] proposed a model conversion method that integrates Revit 2024 and Midas-Civil 2022 software to enhance the efficiency and accuracy of finite element modeling for complex bridge structures. By developing a secondary development program on the Visual Studio platform, model information is converted, significantly improving the efficiency of finite element modeling for large bridge superstructures. While the vulnerability of such bridges has been investigated in an intact condition under vessel collision, the existing assessment methods fail to capture how scour events that bridge piers often experience during their service life can affect their response to vessel-induced impact loads. Oppong et al. [47] established a comprehensive simulation matrix to account for various combinations of scour depths and barge impact velocities.

3.2. Classic Theories and Standard and Simplified Analytical Methods

Classical collision theories, as summarized in

Table 2. Classical collision theories.

Reference	Calculation Formula	Principle	Peculiarity
Minorsky’s theory [48]	$m_1{u}_1\sin \alpha =(m_1+m_2+d{m}_2)U$	Conservation of momentum, conservation of energy	Established a simple foundational theory for studying ship collisions.
Woisin’s theory [49]	${\mathrm{E}}_{k,v}={\displaystyle \frac{1}{2}}\times 1.05m_1{v}_0^2$	Conservation of energy, impulse theorem	Introduced the concept of ship damage length and considered energy loss.
The principle of energy exchange [50]	$\begin{array}{l}{Y}_{\max }=v_0/l;P_{\max }=k{Y}_{\max }\\ {\alpha }_{\max }=v_0\lambda ;t_{\max }={\displaystyle \frac{\pi }{2\lambda }}\end{array}$	Energy conservation law	Simplified the system using a spring–mass model to simulate the impact response.
Heins–Derucher Theory [51]	$E=E_d+E_m+E_1+E_{f-d}$	Energy conservation law	Analyzed collision duration and multiple parameters related to ship–bridge impacts.

, provide an essential framework for analyzing the dynamic interactions during ship–bridge collisions. These theories are primarily grounded in principles such as momentum conservation, energy conservation, and the impulse theorem. They have significantly contributed to the understanding of collision mechanisms and the structural responses of impacted elements.

Globally, various standards have been developed for calculating ship collision forces. These standards include the following:

(1)

US AASHTO standard formula [52]:

$$p_t=0.98{\left(DWT\right)}^{{\displaystyle \frac{1}{2}}}\left({\displaystyle \frac{v}{8}}\right)$$

(1)

where P_t is the equivalent frontal impact force; DWT is the ship’s mass; and v is the ship’s speed.

(2)

European standard formula [53,54]:

$$P=0.024{\left(V{D}_{\max }\right)}^{{\displaystyle \frac{2}{3}}}$$

(2)

where P is the impact force; V is the ship’s velocity; and D_max is the full load displacement.

(3)

China’s general code for highway bridges and culverts [55]:

$$P={\displaystyle \frac{WV}{gT}}$$

(3)

where P is the impact force; W is the floating object’s weight; V is water velocity; g is gravitational acceleration; and T is the collision duration.

Bridge pile capacity is a vital criterion used to assure the durability and stability of a bridge pile foundation. In fact, reliably predicting pile capacity plays a significant role in supporting data-driven decisions for the design, construction, and quality assurance of bridge piles [56]. Simplified analytical methods are widely adopted for ship–bridge collision analysis due to their efficiency and reliability. While high-resolution finite element analyses (FEAs) with millions of degrees of freedom offer detailed insights, they are computationally expensive. Simplified methods provide an alternative for reducing computational costs while maintaining acceptable accuracy. For instance, Consolazio and Davidson developed simplified finite element models to study barge–bridge collisions [57,58]. Their approach involved modeling the barge as a point mass with spring elements calibrated for force deformation relationships, while piers were represented with fiber cross-sections. The results of these models, including impact forces and structural responses, were validated against high-resolution FEA.

Sha et al. [59] utilized empirical equations derived from dense numerical simulations to estimate pier impact loads. A nonlinear single-degree-of-freedom model was proposed for dynamic response calculations. Similarly, Zhang et al. [60] established a simplified collision intensity model based on the deformation characteristics of double-layer sidewall structures, demonstrating consistency with experimental results through an “energy absorption-deformation” approach. Further advancements include that by Liu et al. [61], who investigated pile vertical vibration under scour conditions. Using an equivalent scour depth for circular piles, they validated their findings against the existing literature, emphasizing the influence of scour depth and pile aspect ratios on vertical impedance. In ship–ship collisions, the problem is often divided into internal mechanics and external dynamics [62,63]. Internal mechanics focus on local deformation and structural damage, which can be analyzed using nonlinear FEA programs like LS-DYNA 17.2 or ABAQUS 6.14. External dynamics account for the ship’s rigid body motion and hydrodynamic effects, enhancing the understanding of collision scenarios [64].

Considering the short-duration high-intensity impact loads typical of ship collisions, both local and global structural responses must be evaluated. Fu et al. [65] demonstrated that ship impacts could induce bending or shear damage in bridge components. Fan et al. [66] proposed a single-degree-of-freedom interaction model to evaluate the dynamic demands on bridge structures. By deriving a nonlinear static relationship between impact force and bow indentation, they analyzed the effects of pier height. Song et al. [67] developed a simplified impact load model, enabling predictions of bridge dynamic responses under ship impacts. By decoupling ship–bridge interactions and assuming bridge rigidity, the model provided a practical framework for assessing collision scenarios. These simplified analytical approaches continue to evolve, offering practical solutions for complex ship–bridge collision challenges.

3.3. Collision Prevention Strategies and Technological Innovations

To mitigate the risks of ship–bridge collisions, effective collision prevention has become a key research focus to enhance the safety of both bridges and ships. In China, bridge collision prevention devices are primarily categorized into two types based on their placement, namely direct collision prevention and indirect collision prevention. These devices can be further classified into high-strength rigid structures, composite material structures, combined structures, and flexible guiding structures [43,68,69,70].

Dai et al. [71], building on the concept of cofferdam-type collision protection facilities, proposed a steel pipe pile cofferdam collision protection device filled with expanded clay energy-absorbing materials [72]. Fang et al. [73] introduced a large composite bumper system designed for bridge piers to resist ship collisions. This system significantly extends the collision impact duration and reduces the peak collision force to a non-damaging level, demonstrating excellent energy dissipation performance. Additionally, Wang et al. [74] applied a constant resistance device to the non-navigation span area of the HeYang Port Bridge. This device effectively intercepts yawing ships, ensuring the safety of both the bridge’s non-navigation span and approaching ships.

The integration of artificial intelligence (AI) into the water conservancy industry has offered unique advantages. AI technology enhances human resource utilization, especially in environments that are inaccessible due to harsh conditions. With efficient computational assistance, the reliability and safety of tools and equipment can be ensured, while accuracy and work efficiency are significantly improved. In the realm of ship–bridge collision avoidance, various intelligent algorithms have been proposed to tackle complex decision-making challenges. As summarized in

Table 3. Summary of intelligent algorithms for ship–bridge collision avoidance measures.

Reference	Research Method	Representative Formula	Peculiarity
Xie et al. [76]	Global Multi-directional A* Algorithm	$g\left(n\right)=g\left(n-1\right)+kr+{\displaystyle {\sum }_{i-1}^r{P}_{total}}\left(i\right)$	APF is expressed in scalar mode instead of vector mode
Yu et al. [77]	Bayesian Network Risk Model	$E\left(O_{ijk}|D,B_c\right)={\displaystyle \frac{N_{ijk}+1}{N_{ij}+n}}$	The combination of BN and ER
Liang et al. [78]	Minimum Course Change Algorithm (MCA)	$\arctan \left({\displaystyle \frac{R}{d}}\right)+\vartheta \le {\psi }^{\prime }=\psi +\Delta \psi \le \psi +\Delta {\psi }_{\max }$	Autonomous route planning
Wang et al. [79]	Multiple USVs	$u_m=u_{Dm}\oplus u_{Tm}$	Improved genetic algorithm
Szlapczynski and Szlapczynska [80]	AIS, CAS, DSS Application	$lat{e}_{-}manoeuvr{e}_{-}variable={\displaystyle \frac{t_{LM}-TD{V}_{sf}}{t_{DDV}-TD{V}_{sf}}}$	Multiple combination variables and detection methods
Liu et al. [81]	Multi-stage, Multi-objective CADM Optimization Method	$\begin{array}{l}{f}_{loss}=V•t_r+Rs•rad\left(\Delta c\right)-\\ \left[2Rs•\tan \left({\displaystyle \frac{\Delta c}{2}}\right)+V•t_r+Rs•rad\left(\Delta c\right)\right]•\cos \left(\Delta c\right)\end{array}$	Multi-ship cooperative anti-collision decision-making mechanism
Xue and Qian [82]	Mean-shift Intelligent Optimization Algorithm	$\begin{array}{l}f=w_1{\displaystyle \frac{1}{1+DCPA}}+w_{2}v{x}_2\sin x_1+w_3(x_1-30)\\ +w_4{f}_4+w_5{\displaystyle \frac{1}{1+TCPA}}\end{array}$	Adaptive brainstorm optimization

, these methods include innovative approaches such as the global multi-directional A* algorithm, Bayesian network risk models, and multi-objective CADM optimization methods, among others. Each algorithm demonstrates unique strengths, such as improved route planning, adaptive optimization, and multi-ship cooperative mechanisms. These advancements highlight the potential of AI to address intricate safety concerns, enabling effective personnel deployment, cost savings, and optimized talent utilization [75].

The application of digital technologies has facilitated rapid predictions in ship–bridge collision prevention. Digital systems on model ships can collect vast streams of big data, including information on ship maneuvering, dynamics, operational conditions, and nearby traffic. Leveraging these data, a data-driven ship maneuvering system identification model can be constructed to predict ship movement. This model functions similarly to a digital twin by simulating ship dynamics, as shown in Figure 16. The big data stream and movement predictions assist in the early detection of collision-related scenarios and grounding risks. Each key scenario, along with the corresponding ship maneuvering commands, enables early damage assessment by considering real-world ship dynamics under actual operating conditions [83,84,85].

4. Research Status and Analysis of Seismic Dynamic Responses Under Scour Conditions

Structural deterioration is induced by multiple mechanisms due to progressive degradation, such as aging, corrosion, and scour, as well as sudden events, such as earthquakes, tsunamis, and hurricanes [86]. In complex marine environments, structural foundations are often subjected to seismic forces. Scour, the erosion of soil around foundations caused by water flow, significantly impacts the dynamic impedance of the pile–soil system [87,88,89,90]. Earthquake-induced soil liquefaction remains a significant contributor to foundation damage and the loss of bridge functionality [91]. The pile–soil interaction mechanism experiences unfavorable changes due to earthquake excitation in seismically active regions [92]. These changes in impedance influence the seismic response of structures, necessitating detailed investigations [93].

4.1. Experimental and Numerical Investigations

Earthquakes pose significant threats to the stability and integrity of structures, making seismic analysis and design an indispensable aspect of civil engineering. Past earthquake experiences highlight the importance of considering the effects of soil–pile–structure interactions in the seismic design of structures [94]. In coastal areas, the presence of scour around pile foundations often results in substantial residual deformations after strong seismic events. These deformations may lead to functional failure or collapse of the support structure. To address this issue, Wang et al. [95] investigated the seismic performance of scour-affected pile groups exhibiting pile uplift behavior. By applying cyclic lateral loads near the pier tops, sufficient bending moments were induced in the foundation, significantly enhancing the pile–soil interaction and reducing structural damage. However, Wang et al. [96] limited his analysis to elastic responses, highlighting the need for further exploration of non-elastic or plastic seismic responses in scour-affected pile foundations. Subsequent studies involving static tests on reinforced concrete pile group foundations embedded in medium dense sand revealed critical insights into vertical displacement, lateral displacement, cap rotation, and ductile seismic behavior under scour conditions.

Dynamic testing methods such as centrifuge and 1 g shake table tests have also been used to better understand the seismic behavior of foundations under scour conditions. Zhu et al. [97] conducted centrifuge tests on single piles, showing that the presence of scour holes nearly doubled the bending moments along the piles. He et al. [98] conducted pseudo-static tests on reinforced concrete pile groups to investigate their nonlinear seismic behavior under local scour conditions, addressing knowledge gaps related to both global and localized scour effects. The results indicate that local scour significantly reduces the lateral load-bearing capacity and seismic performance of pile foundations (Figure 17).

Past research on the seismic performance of bridges has extensively utilized field and laboratory tests [99,100,101,102,103], as well as numerical analyses [104,105,106,107,108]. These studies have predominantly examined the effects of liquefaction or scour in isolation. However, bridges are often located in regions where scour caused by flooding can coexist with a seismic-induced liquefaction of saturated sands [109].

To accurately assess the seismic performance of pile foundation bridges affected by scour, an appropriate simulation of soil–pile–structure interactions is crucial. Several analytical approaches have been developed for this purpose, including finite element methods, finite difference methods [110], dynamic p-y methods, and simplified two-step methods [99,111,112]. Shang et al. [113] compared the results of soil–pile–structure integrated analyses using the substructure-based method (SBM) with shake table test data, proposing a two-step approach to estimate the seismic response of pile-supported structures under scour conditions.

Further research by Wang et al. [109] utilized a foundation–structure coupling finite element model, validated through experimental data, to incorporate the effects of scour and liquefaction. This study conducted fragility analyses using seismic wave inputs and introduced a vulnerability-based sensitivity analysis method. Yuan et al. [114] advanced this field by performing centrifuge shake table tests and developing a two-dimensional finite element model using OpenSees (Figure 18). This model enabled the evaluation of the seismic response of single-pile foundations supporting offshore wind turbines under both local and general scour conditions. Similarly, Wu et al. [115] developed a finite element model of a representative bridge using OpenSees to analyze scour depth risks under flood events with varying return periods and investigate the effects of flood-induced scour on pile–soil interaction (PSI) mechanisms. The results demonstrated that scour significantly impacts seismic vulnerability functions at both the component level (e.g., pile groups, thin-walled piers) and system level (global structural integrity), reinforcing the critical role of time-dependent hydraulic structural coupling in multi-hazard resilience assessments of complex bridge systems. Wu et al. [116] developed an analytical framework for the dynamic impedance of pile groups, accounting for secondary seismic wave effects from pile–soil interactions and dynamic water pressure generated by pile–water interactions. This framework offers a comprehensive approach for analyzing pile–pile interactions in complex marine environments and represents a significant contribution to understanding the dynamic behavior of pile foundations under seismic excitation.

4.2. Seismic Vulnerability and Resilience Assessment

The seismic life cycle cost (SLCC) assessment of civil structural and infrastructure systems remains an essential tool for prolonged service life performance prediction, both in terms of structural vulnerability and economic consequences [117]. As a primary component of bridge resilience, fragility assessment under disasters allows for the precise calculation of the probability of a structure exceeding a certain limit state. To evaluate the susceptibility of bridges to floods and formulate resilient mitigation strategies, the utilization of fragility curves constitutes a reliable and established methodology [118]. Seismic vulnerability analysis remains a cost-effective tool for evaluating bridge performance [119]. Key components of such analyses include selecting optimal seismic intensity measures and establishing probabilistic seismic demand models. However, for pile-supported bridges under varying scour conditions, the influence of scour depth on seismic performance and scour resistance requires further investigation. To address this, Zhou et al. [120] utilized OpenSees to create and analyze foundation–structure–bridge coupled models under five different scour scenarios, incorporating uncertainties in structural and soil parameters (Figure 19). This research culminated in the development of a probabilistic seismic demand model specifically tailored to scour-affected pile group bridges. The proposed model offers a robust framework for evaluating group pile effects under seismic excitation and assessing the vulnerability of scour-influenced bridge systems. Based on the nonlinear Winkler foundation approach, Zhou et al. [121] proposed an efficient finite element model for pile groups that accurately captures both the global and local structural responses of pile group foundations.

For coastal highway bridges facing multi-hazard conditions during long-term service, the resilience-based assessment plays a critical role in decision-making processes for their operation, maintenance, and management. Zhou et al. [122] pioneered the development of a resilience loss rate index to quantify the impact of scour depth variations on seismic resilience under different ground motion intensities. This framework incorporates soil–pile interactions, uncertainties in structural and geotechnical parameters, and seismic excitation characteristics. Finite element models of benchmark bridges were established for each scenario. For the studied bridge, it was concluded that scour effects significantly increase the fundamental structural period, thereby reducing curvature demands on pile columns. Consequently, under fixed corrosion levels, both seismic vulnerability and resilience loss of the bridge exhibit a decreasing trend as scour depth intensifies.

Although some studies have effectively conducted analytical fragility analyses of CSBs for individual earthquake hazards, analytical approaches for evaluating the fragility, resilience, and economic loss of CSBs in combined scour earthquake hazard scenarios remain notably scarce. Wu et al. [123] developed numerical models incorporating epistemic uncertainties in loads, structural properties, and soil conditions under varying scour depths using the Latin Hypercube Sampling (LHS) method. Subsequently, a comparative evaluation of resilience and economic losses was conducted by integrating damage probabilities with corresponding uncertain functional recovery functions. Finally, based on the concept of critical traffic capacity surfaces, a rapid bridge traffic capacity assessment method was proposed, specifically tailored to seismic vulnerability analysis considering scour erosion around pile foundations. This method introduces innovative load models, analytical approaches, performance metrics, and assessment techniques, which significantly differ from traditional CSB (cable-stayed bridge) seismic performance evaluation frameworks. The developed approach facilitates the investigation of seismic impact–scour compound hazard effects on the performance of cable-stayed bridges.

5. Discussion and Conclusions

Current research on the dynamic response of bridge pile foundations under multi-hazard coupling effects faces notable challenges. The interaction mechanisms among scour, seismic activity, and ship collisions are not yet fully elucidated, as most studies tend to focus on individual hazards. A cohesive theoretical framework to address the spatiotemporal coupling of soil stiffness degradation, changes in pile foundation dynamic properties, and external dynamic loads is lacking. The nonlinear effects of hazard sequences on cumulative structural damage require rigorous quantification. Additionally, the dynamic evolution of scour processes is often oversimplified in existing models, and the bidirectional coupling between scour parameter variability, such as scour pit morphology, and structural dynamic responses poses significant challenges. This leads to discrepancies between numerical simulations and field conditions. Experimental data for extreme multi-hazard scenarios are scarce, as current tests rely on idealized assumptions, such as uniform soil profiles or simplified collision models, limiting their applicability to high-fidelity model validation. Furthermore, the integration of intelligent technologies, including machine learning and digital twins, into the engineering workflow for scour risk prediction, seismic resilience, and collision mitigation remains underdeveloped, hindering comprehensive, workflow-oriented solutions.

To address these limitations, future research should prioritize advancing theoretical frameworks and integrating intelligent technologies to enhance multi-hazard resilience. A hybrid modeling approach combining high-fidelity numerical methods, such as coupled discrete element method–finite element method–fluid dynamics simulations, with large-scale physical experiments, including shaking table tests and centrifuge modeling, is essential to quantify interactions among unsaturated soil properties, material fatigue, and fluid–structure coupling. Such efforts should aim to develop life cycle models for scour–seismic impact interactions. Experimental studies should focus on generating robust datasets for extreme multi-hazard scenarios, incorporating realistic soil heterogeneity and dynamic loading conditions to validate advanced numerical models. Technologically embedded sensor networks, unmanned aerial vehicle inspections, and digital twin platforms should be leveraged with machine learning algorithms, such as long short-term memory networks and transfer learning, enabling the real-time prediction of scour evolution and pile performance degradation. Innovative structural solutions, including adaptive pile designs with adjustable-stiffness bearings and energy-dissipating devices like metallic dampers or composite material layers, require development and validation through scaled-prototype hybrid testing. Cross-disciplinary approaches integrating computational fluid dynamics, Bayesian updating, and big data analytics should establish tiered scour risk early-warning systems. International standards for multi-hazard testing protocols are needed to accelerate the adoption of intelligent monitoring and resilience-focused design guidelines.

This review underscores the need to update bridge design codes to incorporate advancements in multi-hazard engineering, as current standards often fail to account for the coupled effects of scour, seismic loads, and ship collisions. International collaboration, including shared datasets and harmonized methodologies, is essential to address the global challenges posed by multi-hazard scenarios. The adoption of intelligent monitoring systems, such as digital twins and predictive analytics, offers a pathway for real-time structural health assessment and proactive maintenance. Practical engineering solutions, including adaptive foundation systems and energy-dissipating technologies, should be prioritized to enhance bridge resilience. By integrating innovative research methodologies with robust design and monitoring strategies, the field of bridge engineering can develop sustainable infrastructure capable of withstanding increasingly complex environmental conditions.