Search Results (443)

The resilience concept is well established in engineering, but the quantitative studies of vessel impact resilience for bridge structures remain limited. This paper presents an integrated framework for assessing vessel impact resilience under combined rebar corrosion and vessel collision effects. First, a corroded reinforced concrete bridge is considered for nonlinear static analysis to quantify initial corrosion damage and for nonlinear dynamic analysis to evaluate post-impact function loss. Then, recovery for each damage state is modeled by using both negative exponential and triangular recovery functions to estimate restoration times and to obtain a vessel impact resilience index. The results show that increasing corrosion severity markedly reduces resilience capacity. Furthermore, resilience indices obtained from the negative exponential function generally exceed those from the triangular function, and this improvement becomes more significant at lower resilience levels. Resilience indices calculated by using negative exponential and triangular recovery functions show negligible differences when the concrete bridge is in the uncorroded initial state and the vessel impact velocity is below 1.5 m/s. However, as reinforcement corrosion increases, the maximum discrepancy between these two recovery functions also increases, reaching a value of 67% at a corrosion level of 15.0%. From the numerical results obtained from a case study, it is important to select an appropriate recovery model when assessing vessel impact resilience. For rapid initial restoration followed by slower long-term recovery, the negative exponential model yields greater resilience gains compared to the triangular model. The proposed method thus provides an effective tool for engineers and decision makers to evaluate and improve the vessel impact resilience of aging bridges under the combined corrosion and impact effects. This proposes a quantitative metric for resilience-based condition assessment and maintenance planning. Full article

Variations in damper configuration strategies have a direct impact on the seismic damage patterns of long-span deck-type concrete-filled steel tube (CFST) arch bridges. This study developed an analysis and evaluation framework to identify the damage category, state, and progression sequence of structural components. The framework aims to investigate the influence of viscous dampers on the seismic response and damage patterns of long-span deck-type CFST arch bridges under near-fault pulse-like ground motions. The effects of different viscous damper configuration strategies and design parameters on seismic responses of long-span deck-type CFST arch bridges were systematically investigated, and the preferred configuration and parameter set were identified. The influence of preferred viscous damper configurations on seismic damage patterns of long-span deck-type CFST arch bridges was systematically analyzed through the established analysis and evaluation frameworks. The results indicate that a relatively optimal reduction in bridge response can be achieved when viscous dampers are simultaneously installed at both the abutments and the approach piers. Minimum seismic responses were attained at a damping exponent α = 0.2 and damping coefficient C = 6000 kN/(m/s), demonstrating stability in mitigating vibration effects on arch rings and bearings. In the absence of damper implementation, the lower chord arch foot section is most likely to experience in-plane bending failure. The piers, influenced by the coupling effect between the spandrel construction and the main arch ring, are more susceptible to damage as their height decreases. Additionally, the end bearings are more prone to failure compared to the central-span bearings. Implementation of the preferred damper configuration strategy maintains essentially consistent sequences in seismic-induced damage patterns of the bridge, but the peak ground motion intensity causing damage to the main arch and spandrel structure is significantly increased. This strategy enhances the damage-initiation peak ground acceleration (PGA) for critical sections of the main arch, while concurrently reducing transverse and longitudinal bending moments in pier column sections. The proposed integrated analysis and evaluation framework has been validated for its applicability in capturing the seismic damage patterns of long-span deck-type CFST arch bridges. Full article

Tall-pier girder bridges with fluid viscous dampers (FVDs) are widely used in earthquake-prone mountainous areas. However, the influence of higher-order modes and near-field earthquakes on tall piers has rarely been studied. Based on an asymmetric tall-pier girder bridge, a finite element model is established, and the parameters of FVDs are optimized using SAP2000. The higher-order mode effects on tall piers are explored by proportionally reducing the pier heights. The pulse effects of near-field earthquakes on FVD mitigation and higher-order modes are analyzed. The optimal FVDs can coordinate the force distribution among tall piers, effectively reducing displacement responses and internal forces. Due to higher-order modes, the internal force envelopes of tall piers exhibit concave-convex distributions. As pier heights decrease, the internal force envelopes gradually become linear, implying reduced higher-order mode effects. Long-period pulse-like motions produce the maximum seismic responses because the slender tall-pier bridge is sensitive to high spectral accelerations in medium-to-long periods. The higher-order modes are more easily excited by near-field motions with large spectral values in the high-frequency range. Overall, FVDs can simultaneously reduce the seismic responses of tall piers and diminish the influence of higher-order modes. Full article

This study develops a novel transverse steel damper (TSD) to enhance the seismic performance of tall-pier girder bridges, featuring superior lateral strength and energy dissipation capacity. The TSD’s design and arrangement are presented, with its hysteretic behavior simulated in ABAQUS. Key parameters (yield strength: 3000 kN; initial gap: 100 mm; post-yield stiffness ratio: 15%) are optimized through seismic analysis under near-fault ground motions, incorporating pulse characteristic investigations. The optimized TSD effectively reduces bearing displacements and results in smaller pier top displacements and internal forces compared to the bridge with fixed bearings. Due to the higher-order mode effects, there is no direct correlation between top displacements and bottom internal forces. As pier height decreases, the S-shaped shear force and bending moment envelopes gradually become linear, reflecting the reduced influence of these modes. Medium- to long-period pulse-like motions amplify seismic responses due to resonance (pulse period ≈ fundamental period) or susceptibility to large low-frequency spectral values. Higher-order mode effects on bending moments and shear forces intensify under prominent high-frequency components. However, the main velocity pulse typically masks the influence of high-order modes by the overwhelming seismic responses due to large spectral values at medium to long periods. Full article

This study addresses the water basin effect in the underwater sand layer of steel pipe pile cofferdams by integrating the concept from building foundation pits to cofferdam foundation pit analysis. A theoretical derivation is presented for the deformation evolution of steel pipe piles and bottom seals within the cofferdam pit. The cofferdam construction dewatering process is divided into four stages: riverbed excavation for bottom sealing, dewatering to the second support, dewatering to the third support, and dewatering to final bottom sealing. The steel pipe piles are modeled as single-span or multi-span cantilever continuous beam structures. Using the superposition principle, deformation evolution equations for these statically indeterminate structures across the four stages are derived. The bottom seal is simplified to a single-span end-fixed beam, and its deflection curve equation under uniform load and end-fixed additional load is obtained via the same principle. A case study based on the 6# pier steel pipe pile cofferdam of Xi’an Metro Line 10 Jingwei Bridge rail-road project employs FLAC3D for hydrological–mechanical coupling analysis of the entire dewatering process to validate the water basin effect. Results reveal a unique water basin effect in cofferdam foundation pits. Consistent horizontal deformation patterns of steel pipe piles occur across all working conditions, with maximum horizontal displacement (20.72 mm) observed at 14 m below the pile top during main pier construction completion. Close agreements are found among theoretical, numerical, and monitored deformation results for both steel pipe piles and bottom seals. Proper utilization of the formed water basin effect can effectively enhance cofferdam stability. These findings offer insights for similar engineering applications. Full article

To address the inefficiencies and limited spatial resolution of traditional single-point monitoring techniques, this study proposes a multi-scale analysis method that integrates the Multi-Scale Model-to-Model Cloud Comparison (M3C2) algorithm with least-squares plane fitting. This approach employs the M3C2 algorithm for qualitative full-field deformation detection and utilizes least-squares plane fitting for quantitative feature extraction. When applied to the approach span of a cross-river bridge in Hubei Province, China, this method leverages dense point clouds (greater than 500 points per square meter) acquired using a Leica RTC360 scanner. Data preprocessing incorporates curvature-adaptive cascade denoising, achieving over 98% noise removal while retaining more than 95% of structural features, along with octree-based simplification. By extracting multi-level slice features from bridge decks and piers, this method enables the simultaneous analysis of global trends and local deformations. The results revealed significant deformation, with an average settlement of 8.2 mm in the left deck area. The bridge deck exhibited a deformation trend characterized by left and higher right in the vertical direction, while the bridge piers displayed noticeable tilting, particularly with the maximum offset of the rear pier columns reaching 182.2 mm, which exceeded the deformation of the front pier. The bridge deck’s micro-settlement error was ±1.2 mm, and the pier inclination error was ±2.8 mm, meeting the Chinese Highway Bridge Maintenance Code (JTG H11-2004) and the American Association of State Highway and Transportation Officials (AASHTO) standards, and the multi-scale algorithm achieved engineering-level accuracy. Utilizing point cloud densities >500 pt/m², the M3C2 algorithm achieved a spatial resolution of 0.5 mm, enabling sub-millimeter full-field analysis for complex scenarios. This method significantly enhances bridge safety monitoring precision, enhances the precision of intelligent systems monitoring, and supports the development of targeted systems as pile foundation reinforcement efforts and as improvements to foundations. Full article

Accurate visual inspection of underwater infrastructure, such as bridge piers and retaining walls, is often hindered by severe image degradation due to light attenuation and scattering. This paper introduces an unsupervised enhancement framework tailored for restoring underwater images containing structural cracks. The method combines a physical modeling of underwater light transmission with a deep image translation architecture that operates without requiring paired training samples. To address the loss of fine structural details, this paper incorporates a multi-scale feature integration module and a region-focused discriminator that jointly guide the enhancement process. Moreover, a physics-guided loss formulation is designed to promote optical consistency and texture fidelity during training. The proposed approach is validated on a real-world dataset collected from submerged structures under varying turbidity and illumination levels. Both objective evaluations and visual results show substantial improvements over baseline models, with better preservation of crack boundaries and overall visual quality. This work provides a robust solution for preprocessing underwater imagery in structural inspection tasks. Full article

Through laboratory experiments in an S-shaped channel, this study analyzes how the flow Froude number, the ratio of ice-to-flow rate, pier spacing-diameter ratio, and bed material median grain size influence scour depth around side-by-side double piers under ice-jammed flow conditions. Unlike the development of a scour hole around a bridge pier in a straight channel, where the scour depth increases with the flow Froude number under ice-covered conditions, this study reveals that in an S-shaped channel, scour depth increases with the flow Froude number near the convex bank pier and decreases near the concave bank counterpart. Irrespective of ice conditions, a higher ratio of pier spacing-diameter correlates with augmented scour depth at the convex bank and diminished scour at the concave bank. As the ice-to-flow rate ratio increases, the ice jam thickness in the S-shaped channel also increases, leading to a significant decrease in the flow area and resulting in deeper scour holes around the piers. Equations have been developed to calculate the maximum scour depth around side-by-side double piers positioned in an S-shaped channel with ice-jammed flow. Full article

With the continuous development of maglev transportation technology, medium–low-speed maglev trains have been widely implemented in many countries. However, due to the limitations of existing specifications, the stiffness limit values of the large-span main girders used in medium–low-speed maglev trains have not been unified. To address this issue, this study takes a specific bridge on a dedicated maglev line as an example and uses self-developed software to model the vehicle–bridge dynamic system. The natural vibration characteristics and vehicle–bridge coupling vibration response of the bridge are calculated and analyzed. Based on this, the influence of pier top stiffness on the dynamic characteristics of a typical medium–low-speed maglev train–bridge system under different working conditions is investigated, with a focus on the lateral line stiffness at the pier top. The results show that vehicle speed has no significant effect on the lateral displacement of the main girder, the lateral displacement of the pier top, the lateral acceleration of the pier top, and the transverse and longitudinal angles of the beam end, and no obvious regularity is observed. However, in the double-track operating condition, the vertical deflection of the main girder is significantly higher than that in the single-track operating condition. As the lateral linear stiffness at the pier top increases, the fundamental frequency of the bridge’s lateral bending vibration gradually increases, while the fundamental frequency of longitudinal floating gradually decreases. The lateral displacements, including those of the main girder, pier top, and beam ends, all decrease, whereas the lateral and vertical vibration accelerations of the main girder and the train are less affected by the lateral stiffness at the pier top. Full article

In response to the growing demand for improved operational efficiency in road and bridge networks, constructing parallel bridges in complex river sections has become a crucial strategy. This study focuses on a parallel bridge construction project in the Jinan section of the lower Yellow River, conducting physical model tests to investigate the unique aspects of the impacts of different pier shapes and spans on the flow characteristics of sediment-laden rivers under real-world engineering scenarios. The experimental results demonstrate that the hydraulic physical model of this river section that was constructed is reliable, with a relative error of <20% in sediment deposition, in the simulation of sediment erosion and deposition, flow velocity patterns, water levels, and riverbed morphological changes during parallel bridge construction in bridge-clustered river sections. The newly constructed bridges have a limited influence on the overall regime of this river section, with their impacts on both banks remaining within controllable limits, and the river flow remains largely stable. In areas with denser pier arrangements, the phenomenon of backwater upstream of the bridges is more pronounced, and under characteristic flood conditions, the newly built bridges amplify the water level differences between the upstream and downstream sections near the bridge sites. The ranges of influence of the water level drop downstream of the bridges increase, particularly in the main flow areas. Flow velocities generally increase in the main channel, while significant fluctuations are observed in the floodplain areas. Flood process experiments reveal that the slope at the junction between the main channel and the floodplain becomes gentler, with noticeable scouring occurring in the main channel. After flood events, the river tends to evolve toward a U-shaped channel, posing certain safety risks to the piers located at the junction of the floodplains and the main channel. This research methodology can serve as a reference for studying flow characteristics in similar parallel bridge construction projects in river sections, and the findings hold significant implications for practical engineering. Full article

Single-column hybrid-reinforced self-centering segmental assembled bridges (SHR-SCSAB) exhibit vertical stiffness discontinuities, significantly impacting the refinement of their seismic design methodology. In this study, we investigate SHR-SCSAB by employing the finite strip method to calculate the maximum transverse bearing capability of segmental assembled piers, and the corresponding horizontal displacement at the pier top. By leveraging the mechanical properties of hybrid reinforcement materials, we further derive an analytical expression for the equivalent elastic stiffness of SHR-SCSAB as an integrated system. OpenSees software was used to establish a finite element model of the SHR-SCSAB, and the agreement between numerical simulations and analytical solutions validates the accuracy of the derived equivalent elastic stiffness expression. Additionally, this study evaluates the seismic performance of single-column SHR-SCSAB and examines the influence of key parameters on its behavior. The results demonstrate that hybrid reinforcement effectively addresses the low energy dissipation capacity inherent in self-centering bridges while preserving their advantage of minimal residual displacement. These findings significantly advance the refinement of seismic design methods for SHR-SCSAB. Full article

This study investigates the underlying causes of pier displacement and cracking in a highway link bridge. The initial geological assessment ruled out slope instability as a contributing factor to pier movement. Subsequently, a comprehensive analysis, integrating in situ soil investigation and finite element modeling, was conducted to evaluate the influence of additional fill loads on the piers. The findings reveal that the additional filled soil loads were the primary driver of pier tilting and lateral displacement, leading to a significant risk of cracking, particularly in the mid-section of the piers. Following the removal of the filled soil, visual inspection of the piers confirmed the development of circumferential cracks on the columns of Pier 7, with the crack distribution closely aligning with the high-risk zones predicted by the finite element analysis. To address the observed damage and residual displacement, a reinforcement strategy combining column strengthening and alignment correction was proposed and validated through load-bearing capacity calculations. This study not only provides a scientific basis for analyzing the causes of accidents and bridge reinforcement but, more importantly, it provides a systematic method for analyzing the impact of additional filled soil loads on bridge piers, offering guidance for accident analysis and risk assessment in similar engineering projects. Full article

Double-column self-centering segmentally assembled bridges (SC-SABs) present greater design complexity compared to single-column systems, primarily due to vertical stiffness discontinuities at segmental spandrel abutments, which critically affect the refinement of their seismic design methods. To address these challenges, this study conducts a systematic investigation into the mechanical behavior and seismic performance of double-column SC-SAB. First, leveraging fundamental mechanical principles and stress-strain relationships, the coupling mechanism between the two columns is analytically established. An analytical expression for the elastic stiffness of a double-column SC-SAB, when simplified to an equivalent single-column system, is derived. This establishes the equivalent stiffness conditions for reducing a double-column system to a single-column model, and the overall equivalent stiffness of the double-column system is formulated. To validate the theoretical framework, a finite element model of the double-column SC-SAB is developed using OpenSees (1.0.0.1 version). An equivalent single-column model is constructed based on the derived stiffness equivalence conditions. By comparing the peak displacement and bearing capacity between the double-column and equivalent single-column models, the accuracy and feasibility of the simplification approach are confirmed. The numerical results further validate the derived overall equivalent stiffness, providing a robust theoretical foundation for simplified engineering applications. Additionally, pushover analysis and hysteretic response analysis are performed to systematically evaluate the influence of key design parameters on the seismic performance of double-column SC-SAB. The results demonstrate that the prestressed twin-column system exhibits excellent self-centering capability, effectively controlling residual displacements, aligning with seismic resilience goals. This research advances the seismic design methodology for SC-SAB by resolving critical challenges in stiffness equivalence and joint behavior quantification. The findings of this study can be utilized to derive equivalent damping ratios and equivalent periods. Based on the displacement response spectrum, the pier-top displacement and maximum force can be determined, thereby enabling a displacement-based seismic design approach. This research holds significant theoretical and practical value for advancing seismic design methodologies for self-centering segmental bridge piers and enhancing the seismic safety of bridge structures. Full article

In recent years, frequent vehicle–bridge pier collision accidents have posed a serious threat to people’s economic and life security. In order to avert the impairment of reinforced concrete bridge piers (RCBPs) under the impact of vehicles, three kinds of Mg–Al alloy AlSi10Mg anti-collision structures designed by selective laser melting (SLM) printing were tested by the numerical simulation method in this study: an ultra-high performance concrete (UHPC) anti-collision structure, a bio-inspired honeycomb column thin-walled structure (BHTS) buffer interlayer, and a UHPC–BHTS composite structure were used to reduce the damage degree of RCBPs caused by vehicle impact. In accordance with the prototype configuration of the pier, a scaled model with a scale ratio of 1:10 was fabricated. Three anti-collision structures were installed on the reinforced concrete (RC) column specimens for the steel ball impact test. The impact simulation under low-energy and high-energy input was carried out successively, and the protective effect of the three anti-collision devices on the RC column was comprehensively evaluated. The outcomes demonstrate that the BHTS buffer interlayer and the UHPC–BHTS composite structure are capable of converting the shear failure of RC columns into bending failure, thereby exerting an efficacious role in safeguarding RC columns. The damage was evaluated under all impact conditions of BHTS and UHPC–BHTS composite structures, and the RC column only suffered slight damage, while the RC column without protective measures and the RC column with the UHPC anti-collision structure alone showed serious damage and collapse behavior. This approach can offer a valuable reference for anti-collision design within analogous projects. Full article

Bridges are assets in every society, and their deterioration can have severe economic, social, and environmental consequences. Therefore, implementing effective asset management strategies is crucial to ensure bridge infrastructure’s long-term performance and safety. Roadmaps can serve as valuable tools for bridge asset managers, helping bridge engineers make informed decisions that enhance bridge safety while maintaining controlled life cycle costs. Although some bridge asset management roadmaps exist, such as the one published by the United States Federal Highway Administration (FHWA), there is a lack of structured research roadmaps that are both region-specific and adaptable as guiding frameworks for similar studies. For instance, the FHWA roadmap cannot be universally applied across diverse regional contexts. This study addresses this critical gap by developing a research roadmap tailored to Idaho, USA. The roadmap was developed using a three-phase methodological approach: (1) a comprehensive analysis of past and ongoing Department of Transportation (DOT)-funded research projects over the last five years, (2) a nationwide survey of DOT funding and research practices, and (3) a detailed assessment of Idaho Transportation Department (ITD) deficiently rated bridge inventory, including individual element condition states. In the first phase, three filtering stages were implemented to identify the top 25 state projects. A literature review was conducted for each project to provide ITD’s Technical Advisory Committee (TAC) members with insights into research undertaken by various state DOTs. Moreover, in the second phase, approximately six questionnaires were designed and distributed to other state DOTs. These questionnaires primarily covered topics related to bridge research priorities and funding allocation. In the final phase, a condition state analysis was conducted using data-driven methods. Key findings from this three-phase methodological approach highlight that ultra-high-performance concrete (UHPC), bridge deck preservation, and maintenance strategies are high-priority research areas across many DOTs. Furthermore, according to the DOT responses, funding is most commonly allocated to projects related to superstructure and deck elements. Finally, ITD found that the most deficient elements in Idaho bridges are reinforced concrete abutments, reinforced concrete pile caps and footings, reinforced concrete pier walls, and movable bearing systems. These findings were integrated with insights from ITD’s TAC to generate a prioritized list of 23 high-impact research topics aligned with Idaho’s specific needs and priorities. From this list, the top six topics were selected for further investigation. By adopting this strategic approach, ITD aims to enhance the efficiency and effectiveness of its bridge-related research efforts, ultimately contributing to safer and more resilient transportation infrastructure. This paper could be a helpful resource for other DOTs seeking a systematic approach to addressing their bridge research needs. Full article