Search Results (83)

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

This article presents a probabilistic methodology for assessing corrosion initiation in reinforced concrete structures exposed to chloride ingress. The approach addresses key limitations of conventional analytical models by accounting for non-diffusive barriers and incorporating a rigorous statistical treatment of censored data to mitigate biases introduced by limited simulation durations. A combination of analytical solutions for diffusion from opposite sides with time-dependent boundary conditions is also proposed and validated. The probabilistic study includes the depassivation assessment of a hollow pier section. The blocking effect caused by rebars is statistically characterised through correction factors derived from finite element simulations. These factors are used to adjust analytical solutions, which are computationally inexpensive. Results show that neglecting the rebar blocking effect can overestimate the mean corrosion initiation time by up to 42%, while the use of censored data reduces bias in lifetime estimates. The observed frequency of censored events reached up to 20% when simulations were truncated at 100 years. The corrected analytical models closely match the finite element results, statistically validating their application. The case study indicates premature corrosion initiation (less than 10 years to achieve target reliability), underscoring the need to better reconcile the desired levels of reliability with realistic input parameters for depassivation. 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

In recent years, the serious damage and even collapse accidents of bridge under vehicle-to-pier collision occurred frequently and have attracted growing attention world widely. Numerous studies have been conducted to examine the structural resistance of bridge piers against vehicle-with-pier collisions. Nevertheless, most of those studies employed a deterministic approach without incorporating the inherent uncertainty in structural and loading parameters. This study proposes a probabilistic approach to investigate the vulnerability of reinforced concrete (RC) piers under collisions with trucks and tractors. To do this, a dynamic mass-spring numerical model was developed to simulate the pier–vehicle collision process, which was further validated through simulating experimental data. A total of four parameters, including concrete strength, pier diameter, stirrup yield strength, and stirrup spacing, were considered and regarded as uncertainty parameters with their probability distributions determined according to the available studies. The Monte Carlo simulation method was used to generate 1000 samples for each of the uncertainty parameters and these random samples were coupled in the simplified numerical model. Through probabilistic analysis, the collapse vulnerability of RC piers was estimated. The results revealed that a tractor with a higher mass can result in higher failure probabilities than a truck. The uncertainty of the pier diameter and concrete strength have a great impact on the vulnerability of RC piers under different damage states. Full article

Reinforced Concrete (RC) barriers are used for different purposes in the highway inventory. An important purpose is the use of concrete barriers to act as railing that protects bridge piers against vehicular collision force (VCF). Therefore, these barriers are designed to absorb the collision energy and/or redirect the vehicle away from the parts being protected. Accurate estimation of the capacity of RC barriers during crash events is an important consideration in their design and placement. The American Association of State Highway and Transportation Officials (AASHTO) considers yield line analysis (YLA) with the V-shape failure pattern to predict the barrier capacity. AASHTO’s analysis method involves some assumptions that are intended to simplify the analysis process. Some of these assumptions have been shown to underestimate the actual barrier capacity and might disqualify many existing RC barriers from acting as intervening structures due to structural inadequacy. Many researchers have proposed alternative failure patterns and methodologies in an attempt to better predict the capacity of RC barriers. This research shows that AASHTO’s YLA, with the current V-shape failure pattern, can be improved and still predict the barrier capacity when some of the simplifying assumptions are eliminated. Also, the research presents an alternative innovative truss analogy model to predict the capacity of RC barriers. The results of the improved YLA and the proposed truss model are validated by finite element analysis (FEA) using Abaqus. The results of this research will help structural engineers in the highway industry to initially design new barriers for the intended capacity as well as estimate the capacity of existing ones. Full article

The construction of highway bridges using continuous precast prestressed concrete girders provides an economical solution by minimizing formwork requirements and accelerating construction. Different ways can be used to integrate bridge continuity and enable the development of negative bending moments at piers. Continuous bridge connections enhance structural integrity by reducing deflections and distributing loads more efficiently. Research has led to the development of various continuity details, categorized into partial and full integration, to improve performance under diverse loading conditions. This review summarizes studies on both partial and fully integrated continuous bridges, highlighting improvements in connection resilience and the incorporation of advanced construction technologies. While extended deck reinforcement presents an economical solution for partial continuity, it has limitations, especially in longer spans. However, full integration provides additional benefits, such as further reduced deflections and bending moments, contributing to improved overall structural performance. Positive-moment connections using bent bars have shown enhanced performance in achieving continuity, though skewed bridge configurations may reduce the effectiveness of continuity. Ultra-High-Performance Concrete (UHPC) has been identified as a superior material for joint connections, providing greater load capacity, durability, and seismic resistance. Additionally, mechanical splices, such as threaded rod systems, have proven effective in achieving continuity across various load types. The seismic performance of precast prestressed concrete girders relies on robust joint connections, particularly at column–foundation and column–cap points, where reinforcements such as steel plates, fiber-reinforced shells, and unbonded post-tensioning are important for shear and compression transfer. Full article

Numerous catastrophic events, including fire, vehicle collisions, and air blasts, have highlighted the significance of examining bridge performance under multi-hazard scenarios. While these hazards cause extensive damage, the loss of life, and drastically impact economies, limited attention has been devoted to study the behavior of bridge structural elements under such extreme demand combinations. Hence, comprehensive research to understand the resiliency of bridges and their response to combinations of fire, vehicular impact, and air blast is warranted so that effective retrofitting techniques can be developed and design recommendations be made. To address this research gap, present investigations utilized previously validated finite element (FE) models in LS-DYNA to study the structural behavior of two-, three-, and four-column piers under post-fire medium truck collision and subsequent air blast. The response of multi-column piers was quantified and evaluated based on damage propagation, failure patterns, and permanent deformation sets. The effectiveness of selected retrofitting techniques that employed carbon-fiber-reinforced polymers (CFRPs) to mitigate damage was investigated. Study findings enhance current understanding, provide valuable insights, and can ultimately be used to ensure safety and improve the structural integrity of bridge piers under coupled vehicle collision and air blast following fire exposure. Full article

To systematically study the mechanical behavior of a steel fiber-reinforced concrete (SFRC) pier under bending–torsion coupling, three pier specimens with a clear height of 1200 mm, a diameter of 300 mm, and an SFRC height of 300 mm in the plastic hinge region were designed and fabricated. Quasi-static tests were carried out to observe the damage patterns and failure modes of the specimens. On this basis, multiple finite element models were established using the ABAQUS 2018 software to study the influence of the torsion–bending ratio and SFRC height on the seismic performance of the pier. The results show that the bending–torsion coupling effect leads to a decrease in the bending and torsion capacities of the pier. The presence of torque causes the plastic hinge position to move up and the plastic hinge area to expand. Adding SFRC at the bottom of the pier can effectively improve the bearing capacity of the pier under earthquake action. The optimal height of SFRC is half of the clear height of the pier under the common torsion–bending ratio, which can not only improve the seismic performance of the structure but also avoid material waste. Full article

Coastal reinforced concrete (RC) bridge piers are often subjected to seawater splash and tidal action, leading to bottom corrosion of the steel reinforcement and thereby producing the corrosion–induced cracks of concrete. The increased risk of vehicle collisions to piers poses significant threats to bridge and traffic disruption, potentially causing severe pier damage or even bridge collapse. Many studies have investigated the dynamic responses of bridge piers to vehicle collisions, but no study of the effect of the corrosion degradation of piers on vehicle collision response and damage has been reported yet. This study numerically investigates the influence of bottom chloride-induced corrosion on the truck collision response and damage of coastal RC bridge piers by using LS-DYNA. The results reveal that localized damage occurs in the impact zone for both intact and corroded piers. For the corroded pier, punching shear failure becomes the dominant failure mode and the pier is more vulnerable to collapse at lower truck velocities. Corrosion degradation influences the dynamic response, increasing the lateral displacement of the pier while reducing the impact force, particularly during the engine and cargo impact stages of truck collisions. The impulses in 500 ms collision time show reductions of 1.1% and 4.3% for piers with 45-year and 90-year corrosion, respectively. Notably, the lateral displacement at the bottom corrosion zone shows no oscillations due to the punching shear failure. Full article

The main task of the operation of engineering structures is to ensure the stability of structures with aggressive external influences, which have a complex probabilistic nature. The reliable functioning of bridge structures requires the development and application of modern systems for inspection and assessment of the technical condition of the structure to take timely measures to ensure the safe operation of the structure in changing operating conditions. With the rapid development of AI, modern approaches are increasingly adopted, offering distinct advantages compared to classical methods. The article aims to develop an AI-based model for quantifying the technical condition of bridge structural components based on data obtained from the survey. To achieve this goal, the authors analyzed existing approaches to the inspection and assessment of bridges and studied the experience of using AI in bridge assessment. Based on the Polish Principles of Bridge Technical Condition Assessment, three datasets were formed to quantify the condition of the bridge components made from reinforced concrete: bridge deck, span structures, and piers and abutments. This study created and compared the performance of five AI-based models: XGBoost, Decision Trees, Random Forest, Support Vector Regression, and Artificial Neural Networks (ANNs). The initial comparison revealed relatively low performance across all models, with the ANN model showing a slight advantage. Subsequently, nine ANN models were optimized to achieve higher performance levels. The performance of models was conducted based on a comparison of mean absolute percentage error (MAPE) and R² metrics. The ANN model with ReLU activation functions for hidden layers and the RMSprop optimizer achieves optimal performance at 100 epochs (MAPE = 3.5%; R² = 0.994). The practical implementation of such a model can considerably reduce uncertainties stemming from subjective expert judgments and enhance the accuracy of assessments. Full article

Compared to conventional reinforced concrete (RC) piers, self-centering rocking piers exhibit better seismic resilience and sustain minor damage. However, their construction typically relies on prefabrication. Moving large, prefabricated components can be challenging in mountainous areas with limited transportation access. Therefore, using concrete-filled steel tube (CFST) piers is a practical alternative. The steel tube both serves as a construction permanent formwork and enhances the compressive performance of concrete through confinement effects. To apply CFST self-centering rocking piers in mountainous regions with high seismic intensity, a fast construction system was designed and a 1:4 scale specimen was developed for testing. Lateral cyclic loading tests revealed that the specimen exhibited good deformation and self-centering capabilities, with a residual drift ratio of only 0.17% at a drift ratio of 7.7%. Most of the horizontal displacement was contributed through a rocking gap opening, resulting in minimal damage to the pier itself. The damage was concentrated primarily in the energy-dissipating rebars, while the prestress strands remained elastic, though prestress loss was observed. Full article

Concrete-filled steel tubes (CFTs) offer significant structural advantages in terms of stiffness, strength, and ductility. The concrete core enhances the stiffness and compressive strength of columns, whereas the steel tube serves as a reinforcement to resist tension and bending by confining the concrete. Moreover, CFT columns offer exceptional resistance, such as high strength, ductility, and energy absorption capacity. This study presents experiments focused on prefabricated bridge piers featuring multiple CFT columns. Commercial circular steel tubes were utilized to streamline fabrication efforts, with bracings employed to enhance structural performance by connecting the CFT columns. Component tests were conducted for different connection details to prevent premature failure owing to cyclic loading. A full-scale modular pier was designed to explore its cyclic behavior using the bracing connection details derived from the component test. The plastification location in a modular pier can be designed using the connection details, as validated experimentally. The results of this study indicate that CFT columns, as the main component of the bridge pier, can be protected by designing connection details to induce stress concentration in the braces, thereby achieving ductile behavior. Full article

The rock-socketed pier anchored by inclined anchors (RPIA) is a new type of foundation developed by combining a rock-socketed pier and inclined anchors. Current research on RPIA is relatively limited, and the impact of design parameters on its bearing performance remains unclear. To investigate the uplift-bearing performance of RPIA, a finite-element model that considers the nonlinear properties of materials and multidirectional interactions was developed and verified. Based on this model, numerical simulations were performed on twenty-five RPIA that were designed using the L25 orthogonal array proposed by the Taguchi method, and the uplift load–displacement curve for each RPIA was obtained. Based on the interpretation of the elastic limit, uplift resistance, initial stiffness, and the ductility index for each simulated RPIA, the sensitivity of each factor was examined by analyzing the signal-to-noise ratio and variance. The results indicated that rock strength and pier diameter were the main factors determining the uplift performance of the RPIAs, while the angle of inclined anchors is the most influential factor affecting the ductility of RPIA. The primary role of the inclined anchor is to reduce the extraction of the pier after failure of the side resistance between the pier and rock mass, thus significantly enhancing the ductility of the uplift-loaded RPIA. The addition of reinforcements around the connection joints of the pier and anchors may prevent concrete failure and to fully execute the role of inclined anchors. Full article

The bio-inspired honeycomb column thin-walled structure (BHTS) is inspired by the biological structure of beetle elytra and designed as a lightweight buffer interlayer to prevent damage to the reinforced concrete bridge pier (RCBP) under the overload impact from vehicle impact. According to the prototype structure of the pier, a batch of scale models with a scaling factor of 1:10 was produced. The BHTS buffer interlayer was installed on the reinforced concrete (RC) column specimen to carry out the steel ball impact test. Then, the modified numerical model was subjected to the low-energy input impact test of the steel ball without energy loss during the falling process at the equivalent height of 1.0–3.5 m, and the dynamic response characteristics of the RC column were analyzed. By comparing the impact force and impact duration, maximum displacement, and residual displacement in the impact model, the BHTS buffer interlayer’s protective effect on RC columns under lower energy lateral impact was evaluated. Later, a high-energy input lateral impact test of a steel ball falling at an equivalent height of 20.0 m was carried out. According to the material damage, dynamic response, and energy absorption characteristics in the impact model, the failure process of the RC columns was analyzed. The results showed that BHTS absorbed 82.33% of the impact kinetic energy and reduced 77.27% of the impact force, 86.51% of the inertia force, and 64.86% of the base shear force under the failure mode of a 20 m impact condition. It can transform the shear failure of the RC column into bending failure and play an effective protective role for the RC column. This study can provide useful references for collision prevention design in practical engineering. Full article