Highway Bridges Research Articles

Vibration Measurement and Numerical Simulation of the Effect of Non-Structural Elements on Dynamic Properties of Large-Span Structures

Non-structural elements have been demonstrated to be essential for the dynamic performance of large-span structures. However, how to quantify their effect has not yet been fully understood. In this study, the contribution of non-structural elements to dynamic properties of large-span structures is systematically investigated via both field measurement and numerical simulation methods. Modal testing of an indoor stadium and an elevated highway bridge was conducted during different construction phases, and the corresponding modal characteristics were identified. Results show that the traditional capacity-based models are incapable of reflecting the actual dynamic characteristics of in-service structures since neglecting the effect of non-structural elements would result in remarkable discrepancies in modal properties. A general modeling framework incorporating the contribution of slab/deck pavement, infill walls (or crash barriers), and joints/connections for large-span structures is developed to quantitatively consider the effect of non-structural elements based on the principle of equivalence of stiffness and mass to the actual structure. The effectiveness of the method is validated by vibration measurement results.

Reliability-Centric Maintenance Planning for Bridge Infrastructure: A Novel Method Based on Improved Electric Fish Optimization

Bridge infrastructure provides an important effect on contemporary transportation networks, and its upkeep is significant for ensuring public safety and reducing economic impacts. Nevertheless, the aging and degradation of bridge structures present considerable challenges for asset managers, who must navigate the necessity of maintenance against constrained financial resources. Conventional maintenance approaches typically emphasize reactive repairs, which can result in elevated lifecycle expenses and risk structural integrity. This paper introduces an innovative framework aimed at optimizing bridge maintenance expenditures while maintaining structural safety. The proposed methodology incorporates a reliability-based deterioration model, an intervention effect model, a financial model, and an optimization model empowered by an Improved Electric Fish Optimization (IEFO) algorithm. The framework is demonstrated through a case study of a reinforced bridge framework designed according to the standards of Canadian highway bridge design. The findings illustrate that the proposed methodology can substantially lower lifecycle costs by investigating the most economical maintenance strategies, including minor repairs that can postpone the necessity for expensive major interventions. The optimal scenario identified by the IEFO algorithm yielded lower equivalent uniform annual costs in comparison with the traditional scenario focused solely on major repairs. This research advances the field of data-driven maintenance planning for bridge infrastructure, empowering asset managers to make well-informed decisions that effectively balance cost and safety considerations.

Optimal replicator dynamic controller for semi active control of long span cable stayed bridge with considering special variability of seismic excitations

Cable-stayed bridges are lifeline infrastructures. However, due to their design and structural characteristics, they are sensitive to the vibrations. Thus, vibration control in these structures is essential. Semi-active control systems have gained significant attention due to their high performance and adaptability. However, the implementation of these systems has always faced serious challenges particularly when it comes to developing appropriate control algorithms because semi active devices have complex and non-linear characteristics. Inspired by evolutionary game theory, the author utilizes the replicator dynamic controller concept to optimize the performance of MR dampers to improve the vibration reduction of cable-stayed bridges. Two key parameters in the proposed control methodologies using replicator dynamics are the total population (total available resources or the sum of actuator forces) and the growth rate. Instead of using the sensitivity analysis that has been done in previous studies for vibration reduction of highway bridges using a replicator controller, the author used an evolutionary algorithm named the nondominated sorting genetic algorithm (NSGA-II) to create an optimal replicator dynamic controller for more effective vibration reduction. The proposed methodology is evaluated through its numerical application to a second-generation benchmark example based on the Bill Emerson Memorial Bridge, which considers a more realistic behavior of the cable-stayed bridge by accounting for multiple support excitations. The study indicates that the optimal replicator dynamic controller improves the vibration reduction performance of MR dampers. Specifically, deck displacement is reduced by 46 % compared to passive control system and shear forces at the tower base are reduced by 33 % compared to active control systems for the El Centro earthquake. The results indicate that the proposed Replicator Dynamic Controller optimized through NSGA-II provides a robust and effective solution for improving seismic resilience of cable-stayed bridges.

Numerical Simulations of Abutment PRB Structures with Post-Tensioned Unbonded Prestressing Tendons for Highway Bridges under Horizontal Seismic Loads

Numerical Simulations of Abutment PRB Structures with Post-Tensioned Unbonded Prestressing Tendons for Highway Bridges under Horizontal Seismic Loads

Wireless Channel Propagation Model for Inland Waterway Bridge Scenario

Intelligent shipping is a crucial part of the transportation system, while inland river intelligent shipping is a major safeguard of intelligent transportation. Compared with the studies of mobile fading channels in land-based environments, less current research has focused on channel measurements and modeling for inland waterway bridge environments. In this paper, a segmenting radio channel model is proposed for inland highway and railway combined bridges. The ship's path under the bridge was divided into three phases, and the attenuation of signal strength was modelled separately for each. Hence, it shows ship-to-ship wireless channels in different areas and path loss on inland navigation bridges. A segmented model, instead of a basic path loss model, can accurately forecast path loss and provide a practical approach in ship-to-ship wireless channel transmission scenarios over bridges. Consequently, the channel measurements and modeling in the typical inland waterway are of great significance for establishing a reliable inland navigation broadband radio communication system.

Fatigue performance of repair-welded and HFMI-treated transverse stiffeners

AbstractLarge portions of infrastructure buildings, for example, highway and railway bridges, are steel constructions and reach the end of their service life due to an increase of traffic volume. Repair welding can restore the current welded constructional detail with a similar fatigue strength. However, due to the increase of fatigue loading (traffic), an increase of fatigue strength is needed in such bridge structures. For this reason, the combination of repair welding and high-frequency mechanical impact (HFMI) treatment was investigated in this study in order to quantify the increase of fatigue life by combining both methods. For this, transverse stiffeners made of steel grade S355J2 + N were subjected to fatigue loading until a pre-determined crack depth was reached. The cracks were detected by non-destructive testing methods. Weld repair was realized by removing the material containing the crack and re-welded by a gas metal arc welding (GMAW) process, following that post weld treated was applied by HFMI-treatment and the specimens were subjected to fatigue loading again. Hardness profiles, weld geometries, and residual stress states were investigated for both the original and the repaired condition. In the repaired condition without additional HFMI treatment, a similar fatigue life than in the original condition is observed for the specimens. The repair-welded and HFMI-treated specimens reach a significant higher fatigue life compared to the repaired ones in the as-welded condition.

Reliability and partial factor‐based assessment of a highway bridge supported by nondestructive testing

AbstractThe preservation of the degrading transport infrastructure is vital, as replacing it is impossible in view of limited budgets and environmental impacts. One component in overcoming this challenge is the evaluation of the reliability and the calculation of the remaining service life of existing structures. These structural reliability reassessments allow for the identification and utilization of load‐bearing capacity reserves. The consideration of actual structural characteristics and environmental conditions, various of which can be gathered by means of numerous measurement and inspection techniques, has the potential for more realistic computation results and therefore more economic decisions about the operation as well as maintenance activities. This article attempts to shed light on the potential of nondestructive testing (NDT) methods for updating the input variables in the ultimate limit states during a recalculation. The approach of the NDT‐supported reliability reassessment is demonstrated using a prestressed concrete bridge emphasizing the bending proof in transversal direction. As a result, the semi‐probabilistic, probabilistic and NDT‐based reassessment results are compared and the effects of NDT‐supported structural analysis on the calculated reliability are highlighted.

Blown sand environment characteristics and bridge sand hazard mechanisms of expressways in the South Tibet Valley.

South Tibet expressways are built in the Yalu Tsangpo valley along the route to high-altitude and cold-temperature valleys, which are the main environmental characteristics of the region. Given that the blown sand environment and its potential harm are unclear, targeted prevention and control are not conducive, but its absence would result in severe wind-sand hazards on these expressways. In this research, the blown sand environment of the South Tibet Valley and the mechanism of sand damage to expressway bridges were studied via field observations, wind tunnel experiments and numerical simulations. The sand-moving wind is mainly west wind. The sand-moving wind frequency, sand drift potential, and maximum possible sand transport quantity are high in winter and spring (November-April) and low in summer and autumn (May-October). The sand drift direction is in the east direction. Expressway bridges have a considerable impact on the near-surface blown sand environment, forming a zone for increasing the wind speed between the top of the slope shoulder of the windward side of the bridge to the center of the bridge abutment, forming a zone for weakening the wind speed between the - 3H distances of the upwind direction to the bottom of the slope middle of the windward side of the bridge, further forming a zone for weakening the wind speed centered in the slope shoulder of the leeward side of the bridge. The wind speed within a distance of 40H downwind direction of the bridge generally did not recover. The wind-sand flow is partially blocked when it passes through the bridge and accumulates near the bridge, which cause harm. The impact of the bridge on the blown sand environment in the downwind is greater than that in the upwind. The results of this study can provide a reference for preventing and controlling wind-sand hazards on South Tibet expressways.

Experimental and numerical investigations on the tensile response of pin-loaded carbon fibre reinforced polymer straps

Carbon fibre reinforced polymer (CFRP) pin-loaded looped straps are increasingly being used in a range of structural load-bearing applications, notably for bridge hanger cables in network arch rail and highway bridges. The static performance of such CFRP straps is investigated through experimental and numerical analyses. Finite element (FE) models based on both one-eighth and half pin-strap assembly geometries were modelled. The resulting strains, stresses, and applied loads were compared against experimental data obtained using Digital Image Correlation, Distributed Fibre Optic Sensing (DFOS), and Fibre Bragg Grating (FBG) Sensing. The FE models effectively captured local strain distributions around the vertex area, close to the pin ends of the straps, as well as in the mid-shaft region, and aligned reasonably with experimental observations. The half FE model accurately predicted the overall strain distribution when compared to DFOS data; however, higher strain magnitudes (by 0.45–10.2 %) and larger strain reductions were observed in some locations. Regarding failure loads, the FE models agreed well with Schürmann's analytical solution and the maximum stress criterion, exhibiting less than 2.5 % deviations from the experimental data. Furthermore, the predicted onset of strap failure (by delamination) in the half model agreed with experimental values, with a maximum variance of 9.2 %.

System fragility analysis of highway bridge using multi-output Gaussian process regression surrogate model

This study presents a multi-output Gaussian process regression (GPR) surrogate model for seismic-fragility analysis of bridge structural systems. Multi-output GPR can model the correlations among multiple outputs, accuracy and stability are achieved with fewer training data, which reduces the computational cost of fragility analysis. Furthermore, the explainability of the constructed surrogate model is implemented by adopting an automatic relevance-determination (ARD) kernel in the GPR. The estimated hyperparameters can provide the contribution of the uncertainty of each input parameter to the outputs. The fragility analysis using the multi-output GPR surrogate model was verified by applying it to a seismic isolation highway bridge with multiple spans and a curved geometry. The effectiveness of the multi-output GPR was demonstrated by the construction of an accurate and stable surrogate model with 46 inputs and 28 outputs. The relative contributions of the uncertainties to the structural properties and input earthquake loads could also be understood. The fragility curves, at both the component and system levels, were appropriately obtained using a sufficient number of samples in a Monte Carlo calculation. Furthermore, the failure modes were evaluated, identifying which structural components contributed to the system failure. This enabled discussions on structural system failures from the viewpoint of the structural dynamic characteristics of the bridge and earthquake-load properties.

Підвищення колієстійкастосування армуючих синтетичнихості та довговічності асфальтобетонних покривів на автомобільних дорогах і автодорожніх мостах з допомогою з матеріалів ADFORS GLASGRID

Introduction. One of the most common defects in the asphalt concrete pavements of highways and highway bridges that arise during their operation is the formation of ruts. The problem of increasing the rut resistance and durability of asphalt concrete pavements of highways, city streets and roads, at intersections, in front of traffic light intersections, at public transport stops and on the right lanes of bridges and overpasses is very relevant all over the world. One of the effective means of solving this problem is to increase the rut resistance and durability of asphalt concrete pavements by reinforcing them with Adfors GlasGrid® reinforcing synthetic materials.

Впровадження автоматизованих систем моніторингу мостових споруд в Україні: Світовий досвід та національні перспективи

ntroduction. Highway bridges are an important element of the transport infrastructure of any country, and Ukraine is no exception. Their safe operation is critical to ensure the sustainable functioning of logistics systems and economic development of regions. However, due to constant loads, the impact of natural factors and insufficient funding for maintenance, a significant number of bridges in Ukraine are in poor technical condition. Accordingly, it is necessary to take measures to diagnose the condition of bridges in a timely manner and prevent possible accidents. In this context, automated condition monitoring systems (ACMS) are an effective tool for ensuring the smooth operation of such structures. Problem Statement. There are more than 16 thousand bridges on public roads of national importance in Ukraine, more than half of which do not meet modern standards for dimensions and load capacity. The problem is particularly acute for bridges that have been in operation for more than 40 years, as they are more prone to accidents. Due to the lack of systematic monitoring and control of the technical condition of such structures, there is a threat of their destruction. In the world practice, automated monitoring systems are actively used to prevent such situations. In Ukraine, the need to implement such systems is becoming increasingly relevant in the face of increased requirements for infrastructure security.

Evaluating Driver Response to Bridge Deck Warning Systems During Winter Weather Conditions

Warning signs are often deployed at bridge overpasses during winter to warn motorists of potentially icy surface conditions on the bridge, although the effectiveness of these signs is questionable. One potential improvement to the standard signage methods is the bridge deck warning system (BDWS), which activates a flashing warning sign border or beacon when conditions warrant based on real-time weather and bridge surface data. However, BDWSs have not been broadly implemented in the United States, and consequently, their effectiveness as a safety countermeasure is not well established. To address this knowledge gap, a series of winter field evaluations were performed along three freeway bridge overpasses in Michigan to assess the effectiveness of various BDWS strategies as a speed reduction countermeasure for motorists approaching a potentially icy bridge. The results showed that a BDWS with a flashing light emitting diode (LED) border reduced motorist speeds when encountering a bridge during winter weather conditions compared with the standard “Bridge Ices Before Road” warning sign. The speed reduction effect was consistent between passenger cars and heavy trucks, but was somewhat stronger at night compared with daytime. Greater speed reductions were observed when the BDWS sign was combined with a dynamic speed feedback sign (DSFS) that displayed a “Slow Down” or “Icy Road” message to approaching motorists, with the strongest effects observed when the DSFS message was pulsed between high and low brightness intensities. BDWSs that included only a flashing overhead beacon did not have a significant effect on speeds compared with the standard warning sign.

An index-based multi-hazard risk assessment method for prioritisation of existing bridge portfolios

In recent years, several catastrophic collapses of existing bridges have highlighted the need for rapid risk analysis methods aimed at supporting infrastructure managers in the prioritisation of detailed assessments and, if any, risk mitigation actions. A large percentage of existing road bridges were built between the 1960s and 1980s, having thus already reached or even exceeded their design lifetime. Several studies have also shown that bridges often collapse due to either natural or human-related events, such as floods, collisions or overloading that, in addition to earthquakes, should be duly considered in risk assessment. This calls for multi-hazard approaches that provide an integrated perspective of the risk of bridge portfolios, to identify critical structures to support decision-makers. This study proposes a multi-hazard risk-based prioritisation methodology for application to a large number of bridges under limited level of knowledge. Specifically, the risk level is quantified through indices, accounting for uncertainties, that are used for comparative purposes among bridges. The methodology is applied to a highway bridge portfolio located in northern Italy, producing a risk-based ranking that is critically discussed. Analysis results are then compared with the outcome of the current Italian guidelines for safety assessment and maintenance of existing bridges.

Time-Dependent Reliability-Based Methodology for Assessing Fracture Toughness Requirements for Highway Bridges

Time-Dependent Reliability-Based Methodology for Assessing Fracture Toughness Requirements for Highway Bridges

Generalized system restoration models of ductility bridges for seismic resilience analysis

System restoration models are usually adopted for seismic resilience analysis of bridges. However, no analytical process can be found in the existing literature to develop the restoration models for bridges. This paper proposed a new Monte Carlo-based method to derive the generalized system restoration models for ductility highway bridges. In the proposed method, a large number of random samples for ductility bridges were generated by considering uncertainty of structural parameters. The IDA was adopted for producing the damaged bridge samples at different damage states. The repair time of each bridge sample was estimated to generate the actual restoration curve. The Monte Carlo simulations were then adopted to estimate the expected mean functionality curves, which were used to derive the generalized system restoration models by using mathematical functions. Finally, seismic resilience analysis based on the derived generalized system restoration models was conducted and compared with the traditional method to illustrate the effectiveness of the proposed method. It is concluded that the proposed Monte Carlo-based method is an efficient and reliable method for developing the restoration models for ductility highway bridges.

Fatigue and Ultimate Strength Evaluation of GFRP-Reinforced, Laterally-Restrained, Full-Depth Precast Deck Panels with Developed UHPFRC-Filled Transverse Closure Strips

A depth precast deck panel (FDDP) is one element of the prefabricated bridge element and systems (PBES) that allows for quick un-shored assembly of the bridge deck on-site as part of the accelerated bridge construction (ABC) technology. This paper investigates the structural response of full-depth precast deck panels (FDDPs) constructed with new construction materials and connection details. FDDP is cast with normal strength concrete (NSC) and reinforced with high modulus (HM) glass fiber reinforced polymer (GFRP) ribbed bars. The panel-to-girder V-shape connections use the shear pockets to accommodate the clustering of the shear connectors. A novel transverse connection between panels has been developed, featuring three distinct female-to-female joint configurations, each with 175-mm projected GFRP bars extending from the FDDP into the closure strip, complemented by a female vertical shear key and filled with cementitious materials. The ultra-high performance fiber reinforced concrete (UHPFRC) was selectively used to joint-fill the 200-mm transverse joint between adjacent precast panels and the shear pockets connecting the panels to the supporting girders to ensure full shear interaction. Two actual-size FDDP specimens for each type of the three developed joints were erected to perform fatigue tests under the footprint of the Canadian Highway Bridge Design Code (CHBDC) truck wheel loading. The FDDP had a 200-mm thickness, 2500-mm width, and 2400-mm length in traffic direction; the rest was over braced steel twin girders. Two types of fatigue test were performed: incremental variable amplitude fatigue (VAF) loading and constant amplitude fatigue (CAF) loading, followed by monotonically loading the slab ultimate-to-collapse. It was observed that fatigue test results showed that the ultimate capacity of the slab under VAF loading or after 4 million cycles of CAF exceeded the factored design wheel load specified in the CHBDC. Also, the punching shear failure mode was dominant in all the tested FDDP specimens.

Behaviour of large-diameter high-strength bolted shear connections for prefabricated composite beams

This paper presents an experimental investigation into the structural behaviour of a new proposed shear connection incorporating high-strength large-diameter steel bolts in conjunction with steel fibre reinforced concrete blocks. A detailed account of fourteen large-scale push-out tests is provided with the aim of examining and quantifying the full deformational characteristics of these shear connections. The results include the load-slippage responses, shear resistances, and failure modes for the various specimens. It is shown that the proposed connection configuration is suitable for prefabricated composite beams in highway bridges and can be detailed to provide high stiffness over 1500 kN/mm, large shear resistance exceeding 1000 kN, and slippage at failure greater than 6.0 mm. The proposed connection can also be easily assembled on site and provides significant resistance against pull-out forces. Based on the experimental results, complementary design procedures are proposed to enable a prediction of the shear resistance of the connections. A simplified load-slippage relationship for the shear connections is also suggested and shown to represent closely the full deformation characteristics. Overall, the proposed shear connection configuration is shown to offer considerable stiffness, resistance, and ductility, and can be readily installed on site for joining steel beams and precast slabs in combination with high performance in-situ concrete. This connection form contributes to an enabling construction technology for promoting effective prefabrication of composite bridge structures.

Shaking Table Tests and Numerical Study on the Seismic Performance of Arc-Shaped Shear Keys in Highway Continuous-Girder Bridges

Typical forms of seismic damage to laminated-rubber-bearing girder bridges in the transverse direction are falling beams, girder displacement, and bearing damage. However, the damage to piers and foundations is generally lighter. This is mainly due to slippage of the bearings. Therefore, we propose a new type of arc-shaped shear key to improve the lateral seismic performance. A 1/12-scale highway continuous-girder bridge isolated by different shear keys was tested utilizing a 4 m × 4 m shaking table with six DOFs. The seismic responses of the bridge were analyzed in terms of phenomenon, displacement, strain, and acceleration. The main girder and pier exhibited different seismic responses because the bridge had different stops. A numerical simulation based on FEM showed that the established finite element model can well reproduce the displacement time history of the main girder and the cap girder. By analyzing the finite element model, the relative displacement of the bearing under different seismic waves was obtained. A comparison between the measured and FEM responses showed that the arc-shaped shear key can well limit the displacement of the main girder and the bearing. In addition, it does not significantly amplify the seismic response of the substructure. The arc-shaped shear key dissipates more energy while limiting the displacement of the main girder, and the comprehensive seismic performance is better than that of the rubber pad shear key.

Seismic damage assessment of bonded versus unbonded laminated rubber bearings: A deep learning perspective

Laminated Rubber Bearings (LRBs), widely employed in highway bridges worldwide, are vulnerable to shear failure, squeezing or displacing during seismic events, potentially compromising bridge safety. Establishing a reliable approach for assessing the damage of LRBs is crucial for evaluating the seismic performance of bridges and preventing serious damage. To address this concern, this paper proposes a novel approach for LRBs seismic damage assessment based on computer vision (CV) technique. First, quasi-static loading tests are conducted on both bonded and unbonded LRBs to effectively enhance the understanding of their nonlinear properties. Subsequently, a large number of bearing samples are investigated to develop a comprehensive image database for a CV-based damage assessment model. A deep convolutional network (CNN) is designed to segment damage pixels, which are then combined with damage indicators to quantify the impact of various influencing factors on seismic damage using the interpretable machine learning technique, Shapley value. The results demonstrate that the CNN model achieves high-precision pixel segmentation and accurate predictions of seismic damage to LRBs, with RMSE consistently below 0.009 and R2 exceeding 95 %. The primary factor influencing LRB damage is the type of constraint, which interacts with loading characteristics and geometric dimensions to produce various coupled effects. This high-precision CV-based approach shows significant potential for estimating seismic damage states of critical bridge components and building seismic protection.