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In the actual structural health monitoring system of suspension bridges, only part of suspenders tension can be monitored, but not all the suspenders tension can be obtained. To solve this problem, a method for suspenders tension identification of bridges based on the spatio‐temporal correlation between the girder strain and suspenders tension is proposed. By using actual monitoring data of vehicle loads, a spatio‐temporal correlation model of the girder strain and tension forces of all suspenders is constructed based on the combined application of stacked denoising autoencoder and convolutional neural networks‐long short‐term memory model, so as to realize the preliminary identification of suspenders tension. On this basis, by using the actual monitoring data of suspenders tension and the strain monitoring data obtained through the distributed optical fiber sensors, the delicate identification of tension forces of all suspenders is realized based on the error interpolation of preliminary identification results. The results of the example bridge show that the method in this paper can effectively identify tension forces of all suspenders of the suspension bridge, and identification results are more accurate than the method using only the monitoring data of suspenders. [ABSTRACT FROM AUTHOR]

This paper introduces new contributions for construction procedures designed to enhance the robustness and precision of stress control in active anchorage and short presetressing units for long-span bridges, particularly addressing potential technical risks. The primary focus is on optimizing stress management for bridge stays, suspension cables, and short prestressing units by emphasizing a unified parameter: stress. The contributions of this research encompass (1) the introduction of advanced load cells for stress control in active anchorages and (2) the implementation of a novel synchronized multi-strain gage load cell network for short prestressing units, crucial in situations where prestressing losses can attain significant magnitudes. To validate these advancements, the authors present (3) a practical experience and results obtained from applying these methodologies in monitoring the structural response during the construction of the Tajo Bridge using the cable-stayed cantilever technique. [ABSTRACT FROM AUTHOR]

The First Egongyan Bridge in Chongqing, China was opened to traffic on December 27, 2000. It carries six-lanes of city traffic and two pedestrian paths, one on each side. It is a 600 m span suspension bridge. It was planned that the two pedestrian paths might eventually be converted to transit tracks in the future. However, with the rapid increase in urban traffic, the deck was transformed into an 8-lane bridge instead. Therefore, a new bridge parallel and adjacent to the old bridge was built for the rail transit. For aesthetic reasons, the city decided that the new bridge should also be a suspension bridge, with the same span length and tower height as the first bridge. The First Egongyan Bridge was a true suspension bridge with main cables anchored to ground anchors. However, the new bridge bridge's proximity to the first bridge necessitated the construction of a self-anchored suspension bridge that did away with a second set of ground anchors. This 600 m span happened to be the world's longest span for a self-anchored suspension bridge. [ABSTRACT FROM AUTHOR]

Bridge aerodynamic studies are essential in ensuring the safety and acceptable performance of long-span bridges vulnerable to the effects of cross-winds. Aerodynamic studies were traditionally carried out in wind tunnel facilities, but there are now greater opportunities for using computational fluid dynamics (CFD) modelling. Few three-dimensional (3D) aerodynamic simulations of lightweight vehicles on bridges exist, but limited validation and verification work has been carried out. In the study reported in this paper, 3D CFD models were developed for Queensferry Crossing – a cable-stayed bridge in Scotland – containing wind shields and sample vehicles. The models considered the wind effects from a range of yaw wind angles and subsequently determined the aerodynamic coefficients of vehicles. The models were verified by means of a mesh sensitivity study, a domain sensitivity study and comparisons with wind tunnel tests. The models were then validated using the same modelling process but with a different type of wind shield and again comparing the results with wind tunnel test data for the same configuration. The results showed that CFD modelling can determine aerodynamic coefficients to a level of accuracy similar to that of wind tunnel tests. [ABSTRACT FROM AUTHOR]

Suspenders play a crucial role in transmitting loads from the bridge deck to the main cable in a suspension bridge. They are susceptible to fatigue due to repeated dynamic loads, particularly traffic loads. Traffic Load Models (TLMs), typically created using Monte–Carlo simulation and Weigh-In-Motion (WIM) data, are employed to evaluate this fatigue. However, these models often overlook practical vehicle trajectories and spatio-temporal distribution, which compromises the precision of fatigue assessments. In this study, we introduce a novel 2D Intelligent Driver Model (2D-IDM) that incorporates actual vehicle trajectories, with a particular focus on transverse vehicle movement. This enhancement aims to improve the fidelity of existing TLMs. To provide a clear, qualitative, and quantitative understanding of the effects of fatigue evaluation with or without actual trajectory characteristics, we have structured this paper as a comparative study. We compare our proposed model, denoted as TLM S-3, with two observation-based models (O-1 and O-2) and two simulation-based models (S-1 and S-2). We conducted an experimental case study on a long-span suspension bridge, where the actual traffic load trajectory was obtained using a WIM-Vision integrated system. To calculate fatigue damage considering both longitudinal and transverse directions, we established a multi-scale Finite Element Model (FEM) using solid element types to simulate the bridge girder. This model can generate the stress influence surface of the bridge and has been verified in both static and dynamic aspects. Our detailed comparative analysis demonstrates the consistency of the proposed 2D-IDM with the actual measured traffic load trajectories. This indicates that our approach can enhance the fidelity and precision of fatigue evaluations for bridge suspenders. [ABSTRACT FROM AUTHOR]

The identification of the development of structural defects is an important part of bridge structure damage diagnosis, and cracks are considered the most typical and highly dangerous structural disease. However, existing deep learning-based methods are mostly aimed at the scene of concrete cracks, while they rarely focus on designing network architectures to improve the vision-based model performance from the perspective of unmanned aircraft system (UAS) inspection, which leads to a lack of specificity. Because of this, this study proposes a novel lightweight deep convolutional neural network-based crack pixel-level segmentation network for UAS-based inspection scenes. Firstly, the classical encoder-decoder architecture UNET is utilized as the base model for bridge structural crack identification, and the hourglass-shaped depthwise separable convolution is introduced to replace the traditional convolutional operation in the UNET model to reduce model parameters. Then, a kind of lightweight and efficient channel attention module is used to improve model feature fuzzy ability and segmentation accuracy. We conducted a series of experiments on bridge structural crack detection tasks by utilizing a long-span bridge as the research item. The experimental results show that the constructed method achieves an effective balance between reasoning accuracy and efficiency with the value of 97.62% precision, 97.23% recall, 97.42% accuracy, and 93.25% IOU on the bridge concrete crack datasets, which are significantly higher than those of other state-of-the-art baseline methods. It can be inferred that the application of hourglass-shaped depth-separable volumes can actively reduce basic model parameters. Moreover, the lightweight and efficient attention modules can achieve local cross-channel interaction without dimensionality reduction and improve the network segmentation performance. [ABSTRACT FROM AUTHOR]

To overall investigate the mechanical performance of resilient wheels to suppress the vehicle–bridge (especially LSB) coupled vibration, the coupled dynamic characteristics of metro train–LSB considering nonlinear resilient wheels are studied. Firstly, the mechanical property test of rubber of resilient wheel is designed and conducted, the mechanical characteristics of the nonlinear resilient wheel (NLRW) and linear resilient wheel (LRW) are discussed, and the dynamic model of LRW and NLRW are established. Then, based on train–track–bridge dynamic interaction theory, the coupled dynamic models of metro train–LSB considering LRW and NLRW are established, respectively. Adopting the established model, the dynamic influences of NLRW and LRW on the metro train–LSB coupled system are investigated by long-short wave irregularity excitation. The effects of damping characteristics of LRW and NLRW on the metro train–LSB system are discussed from the time–frequency domain. Results show that the wheel–rail vertical force of NLRW is smaller than that of LRW. The acceleration of the web, axle box, bogie, and car body of the NLRW is smaller than that of the LRW. The main frequency of wheel–rail vertical force under the action of NLRW and LRW is about 4 and 22 Hz. The main frequencies of the rim and web of the NLRW are about 25 Hz, while those of the LRW are about 50 and 25 Hz, respectively. The acceleration of the web of the NLRW is significantly smaller than that of the LRW. The main frequency of acceleration of the LSB is about 10 Hz, and the acceleration of the LSB under the action of NLRW is significantly less than that of the LRW when the frequency is in the range of 22–62 Hz. Vibrations of the metro train and LSB increase with the increase of speed, and the dynamic response of the metro train–LSB system under the action of NLRW is smaller than that of LRW. [ABSTRACT FROM AUTHOR]

Structural health monitoring (SHM) systems are widely deployed to monitor the dynamic behaviors of large civil infrastructures such as bridges and tall buildings. Global Navigation Satellite System- (GNSS-) based technologies are often a key component in such an SHM system considering the unique capability of GNSS in determining real-time displacements. GNSS often integrates with an accelerometer to achieve complementary advantages. However, due to the various error sources in GNSS measurements and accelerometer, accuracies of GNSS and accelerometer fusion results often cannot meet the requirements of SHM. We propose to integrate a multi-antenna GNSS and an accelerometer with an unscented multi-rate Kalman filter (UMRKF-MA) to correct the system misalignment errors between the sensors, aiming to produce a much more accurate real-time displacement measurement technology for monitoring large civil infrastructures. Extensive experiments with datasets gathered using a shaking table have indicated that the proposed method was able to improve the accuracy of real-time displacement measurements by up to about 40–65% compared to some existing approaches, and that a 1 mm level of real-time monitoring of displacements could be achieved with the method. The method has also been applied to process a dataset from a real-world long-span bridge when heavy vehicles passed through the bridge in a loading test and significantly improved results were obtained. [ABSTRACT FROM AUTHOR]

The Gordie Howe International Bridge project is providing a new modern border crossing between Windsor, ON, Canada and Detroit, MI, USA. The centrepiece of the project is a 2.5 km long cable-stayed bridge with 853 m main span over the Detroit River and 220 m tall towers on both sides of the river. In addition to the bridge, the project includes ports of entry on both sides of the border and a new freeway interchange with Interstate-75 in Detroit. The project was procured as a public–private partnership that allowed the proponents to propose either a suspension or cable-stayed bridge, with the ultimate selection creating the longest cable-stayed bridge in North America. The paper outlines the need for the new border crossing and results of the environmental assessment process, as well as describing the project evolution from planning through procurement and into detailed design. The scoping of the bridge design parameters is discussed, including: comprehensive geotechnical investigation; load study to develop project-specific live loading; the approach for durability requirements to achieve a service life of 125 years; special considerations for security; wind engineering; and compliance with both Canadian and US design codes. The paper also discusses the approach to achieving an aesthetically pleasing bridge design. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the flow field characteristics of the road-rail same-story asymmetric bridge deck and the influence of the asymmetric arrangement of the bridge deck on the flow field of the main girders. Numerical simulation tests were conducted on this bridge to analyze the distribution characteristics of the flow field near the main girder, as well as the aerodynamic characteristics of the railway bridge deck and highway bridge deck under different wind speeds and directions. The results indicate that the wind speed has less influence on the flow field distribution and aerodynamic characteristics of the road-rail same-story asymmetric bridge deck, but the incoming flow direction has a significant impact on its flow field characteristics. Compared to the railway bridge deck, during the reattachment position of the airflow, the highway bridge deck moves toward the windward side, and the volume of the separation bubble has been reduced, thus improving the effect on the negative pressure area of the railway bridge deck. The road-rail same-story asymmetric bridge deck has different aerodynamic interference characteristics for different wind speeds and different wind directions. [ABSTRACT FROM AUTHOR]

Aging, corrosive environments, and inadequate maintenance may result in performance deterioration of civil infrastructures, and finite element model updating is a commonly employed structural health monitoring procedure in civil engineering to reflect the current situation and to ensure the safety and serviceability of structures. Using the finite element model updating process to obtain the relationship between the structural responses and updating parameters, this paper proposes a method of using the wavelet neural network (WNN) as the surrogate model combined with the wind-driven optimization (WDO) algorithm to update the structural finite element model. The method was applied to finite element model updating of a continuous beam structure of three equal spans to verify its feasibility, the results show that the WNN can reflect the nonlinear relationship between structural responses and the parameters and has an outstanding simulation performance; the WDO has an excellent ability for optimization and can effectively improve the efficiency of model updating. Finally, the method was applied to update a real bridge model, and the results show that the finite element model update based on WDO and WNN is applicable to the updating of a multi-parameter bridge model, which has practical significance in engineering and high efficiency in finite element model updating. The differences between the updated values and measured values are all within the range of 5%, while the maximum difference was reduced from −10.9% to −3.6%. The proposed finite element model updating method is applicable and practical for multi-parameter bridge model updating and has the advantages of high updating efficiency, reliability, and practical significance. [ABSTRACT FROM AUTHOR]

Structural health monitoring (SHM) has attracted significant attention over the past two decades due to its ability to provide real-time insight into the condition of structures. Despite the development of several SHM systems for long-span bridges, which play a crucial role in the assessment of these structures, studies focusing on short- or middle-span bridges remain scarce. This research paper presents an efficient and practical bridge monitoring and warning system established on a middle-span bridge, a key crossroad bridge located in Shenzhen. The monitoring system consists of sensors and measuring points that collect a substantial amount of data, enabling the close monitoring of various operational indicators to facilitate the early detection of threshold exceedances. Based on this system, the subtle condition of the bridge can be evaluated, and the operational condition of the bridge can be studied through the comparative analysis of the collected data. Over four months of monitoring, data including the strain and creep of the main beam, the strain and settlement of piers and the crack width of the bridge body are observed. Furthermore, the real-time operational status of the bridge is analyzed and evaluated through the combination of the collected data and the structural finite element model. [ABSTRACT FROM AUTHOR]

Because of the large number of components and complex evaluation indexes of long-span bridges, it is necessary to adopt the evaluation method suitable for complex structures. Since the hypothetical membership degree of fuzzy theory and the layer weight of traditional analytic hierarchy process (AHP) may have subjective bias, the evaluation precision may be influenced if it is applied independently in bridge evaluation and thus the fuzzy analytic hierarchy process (FAHP) is more applicable to large-span concrete cable-stayed bridge. The traditional analytic hierarchy process using triangular fuzzy number (FAHP) has the shortcomings of computational errors and limited range, so the improved FAHP is adopted. The improved FAHP method introduces the reliability into the judgment matrix, which can not only solve the existing problems, but also reflect the influence of the fuzziness of the man-made subjective judgment on the result. Based on the detection results for a concrete cable-stayed bridge in Jilin Province, the corresponding hierarchy of index system is established, the trapezoidal function is used to calculate membership degree, and the weight of each index relative to target layer is calculated. Improved FAHP is finally applied to assess the security levels of various parts of this bridge and make comprehensive evaluation on the whole bridge. [ABSTRACT FROM AUTHOR]

The rapid growth of suspension bridges' span makes vortex-induced vibration (VIV) appears more and more frequently, and once it occurs the closure of the bridge results in considerable economic losses. Investigating the dynamic behavior of the bridge experiencing VIV and the vehicles running on it is thus imperative for providing a reliable guidance for the managers to make operation decisions. Nevertheless, most of the existing studies focus on VIV of bridges subjected to smooth winds, but a certain level of turbulence always exists in reality. The effects of turbulence on vortex-induced dynamic response of the bridge and ride comfort of the vehicles are not clear. This study thus develops a coupled vortex-vehicle-bridge system applicable to the multi-mode lock-in regions of a twin-box deck subjected to both vortex-induced forces and buffeting forces in a turbulent flow. The system is then applied to a real long suspension bridge with three types of vehicles subjected to either smooth or turbulent winds. The results from the case study show that the increasing turbulence mitigates vortex-induced responses of both the bridge and the vehicles and reasonably improves the vehicles' ride comfort. However, the buffeting forces induced by turbulent wind component should not be ignored when turbulence intensity becomes high. [ABSTRACT FROM AUTHOR]

This paper proposes a vision monitoring system for multipoint deflection of a large‐span bridge that can well compensate the camera motion–induced errors. The camera network system (CNS) consists of a series of dual‐camera stations that are linked with the cooperative markers. The infrared illumination supplement device is integrated in the camera station and the regular double‐sided prism is selected as the cooperative marker to realize 24‐h continuous monitoring. The feasibility and efficiency of CNS are verified by conducting a field test inside the steel box girders of a suspension bridge with a length of 1038 m. The results show that the proposed camera networking method can well solve the problem of the large‐scale high‐precision monitoring under unstable measuring platform. For the kilometer‐level flexible bridge, CNS can meet submillimeter precision in quasi‐static measurement, and can also provide deflection data similar to the conventional robotic total station and connecting pipe system in long‐term monitoring. The geometric alignment of large‐span bridges with dense multimeasuring points can be automatically monitored and recorded by CNS. The observed deflections of the studied suspension bridge are dominated with the vehicle load and wind load in the short term and are correlated with the temperature change in the long term. The proposed CNS can provide a new option for the bridge deflection monitoring and provide new parameters for bridge safety evaluation. [ABSTRACT FROM AUTHOR]

To measure uncertainties of site-specific extreme loads for a signature bridge, a probabilistic method is developed based on structural health monitoring data in the Bayesian context. Compared with respective design loads, the probability of the predicted extreme load exceeding the design one is used to determine whether the design load is sufficient. The generalized Pareto distribution was first employed to model extreme value information. Then, Bayesian estimation was applied to predict probabilistic distributions of extreme loads, accounting for uncertainties within the prediction process. Finally, the effectiveness of the proposed method was validated through wind speed and temperature measurements from the Nanjing Dashengguan Yangtze River Bridge. The extreme wind speed and four types of thermal loads were predicted based on site-specific monitored loading data by using Bayesian estimation of the generalized Pareto distribution. As a result, the design wind speed and design change in uniform temperature are sufficient for the signature bridge. However, the probability that the predicted extreme vertical girder temperature difference exceeds the design one is 99.96%, and the probabilities subject to the transverse girder temperature difference and tower temperature difference are almost 100%. [ABSTRACT FROM AUTHOR]

Structural Health Monitoring (SHM) is a technique that involves gathering information to ensure that a structure is safe and behaving as expected. Within SHM, vibration-based monitoring is generally seen as one of the more cost-effective types of monitoring. However, vibration-based monitoring has mostly been undertaken on long-span bridges using data collected with a dense network of sensors. Historically, the logistical difficulty of collecting data on short- and medium-span bridges has meant that the usefulness of vibration-based methods on these bridges is largely unknown. Therefore, this study proposes Minimal Information Data-modelling (MID). MID is an approach that utilises low-cost, easily implementable sensors that are potentially feasible for operators to purchase and operate across a network. This approach will be investigated to determine whether MID is a feasible approach for monitoring short- and medium- span bridges. The results from MID were assessed to determine whether they could detect a suitably small shift in frequency, which is indicative of damage. It was determined that the data models could reliably detect frequency shifts as low as 0.01 Hz. This magnitude of frequency shift is similar to the level of frequency shift reported for a range of bridge damage cases found by others and validated with FE models. The accuracy achieved by the data models indicates that MID could potentially be used as a damage detection method. The cost of the equipment used to collect the data was approximately £370, demonstrating that it is feasible to use MID to monitor bridges across an entire network. [ABSTRACT FROM AUTHOR]

It is inevitably to encounter overtaking events as vehicles pass through long-span bridges under crosswinds. The effects of the aerodynamic interference on the dynamic responses of the overtaking vehicles should be taken into account in the analysis of the driving safety of vehicles under crosswinds. The time-varying aerodynamic coefficients of the overtaking vehicles are obtained by scale model wind tunnel tests. A vehicle dynamic model is established for the analysis of the dynamic responses of articulated lorry. Based on the coupling vibration framework of the wind-vehicle-bridge system, an improved dynamic analysis system is constructed to solve the transient aerodynamic responses of the overtaking vehicle. It investigates the effects of the overtaking events on the driving safety of vehicles on bridge deck under crosswinds. The results show that the interference aerodynamic forces produced during the overtaking process have significant influences on the dynamic responses of vehicles. The maximum load transfer ratio and side-slip factor of vehicles in consideration of the effects of overtaking event are much greater than the case taking no account of the interference aerodynamic forces. Although the overtaking event do not play a decisive role in the driving safety of vehicles crossing the bridge, it is necessary to consider the combined adverse effects of the overtaking event and crosswinds on the safety of vehicles. [ABSTRACT FROM AUTHOR]

Damage detection algorithms employing the conventional acceleration measurements and the associated modal features may underperform due to the limited number of sensors used in the monitoring and the smoothing effect of spline functions used to increase the spatial resolution. The effectiveness of such algorithms could be increased if a more accurate estimate of mode shapes were provided. This study presents a hybrid structural health monitoring method for vibration-based damage detection of bridge-type structures. The proposed method is based on the fusion of data from conventional accelerometers and computer vision-based measurements. The most commonly used mode shape-based damage measures, namely, the mode shape curvature method, the modal strain energy method, and the modal flexibility method, are used for damage detection. The accuracy of these parameters used together with the conventional sparse sensor setups and the proposed hybrid approach is investigated in numerical case studies, with damage scenarios simulated on a simply-supported bridge. The simulations involve measuring the acceleration response of the bridge to ambient vibrations and train crossings and then processing the data to determine the modal frequencies and mode shapes. The efficiency and accuracy of the proposed hybrid health monitoring methodology are demonstrated in case studies involving scenarios in which conventional acceleration measurements fail to detect and locate damage. The robustness of the proposed method against various levels of noise is shown as well. In the studies considered, damage as small as 10% decrease in flexural stiffness of the bridge and localized in less than 1% of the span-length of the bridge is reliably detected even with very high levels of measurement noise. Finally, a modified modal flexibility damage parameter is derived and used to alleviate the shortcomings of the modal flexibility damage parameter. [ABSTRACT FROM AUTHOR]

Establishing an online perception mechanism for a driver's front blind area on a full bridge under vertical vortex-induced vibration (VVIV) is essential for ensuring road safety and traffic control on bridge decks under specific conditions. Based on accelerations of vibration monitoring of the main girders, this paper uses a real-time acceleration integration algorithm to obtain real-time displacements of measurement points; realizes the real-time estimation of the dynamic configurations of a main girder through parametric function fitting; and then can perceive the front blind area for vehicles driving on bridges experiencing VVIV in real time. On this basis, taking a long-span suspension bridge suffering from VVIV as an engineering example, the influence of different driving conditions on the front blind area is examined. Then, the applicability of the intelligent perception technology framework of the front blind area is verified. The results indicate that, during VVIV, the driver's front blind area changes periodically and the vehicle model has the most significant impact on the front blind area; in contrast, the vehicle's speed and the times of the vehicle entering the bridge have minimal impact on it. Meanwhile, it is shown that the framework can accurately perceive front blind areas of vehicles driving on the bridge, and identify different vehicle models, speeds and times of vehicle bridge entries in real time. [ABSTRACT FROM AUTHOR]

Currently the importance of bridge inspection and maintenance is widely recognized. It seems reasonable to mention that a gantry is essential for the inspection and maintenance of a long span bridge. Therefore, most long span bridges are equipped with a gantry as a permanent access tool. Honshu Shikoku Bridges compose three highways and one railway between Honshu and Shikoku islands in Japan. Three routes consist of 17 long span bridges with a main span of more than 200 m. Since the bridges had been constructed with accumulating knowledge for construction and maintenance from 1975 to 1999, a gantry had also been improved for gaining better access. Despite the improvement, there were still a certain number of inaccessible elements and components, so further improvement is being made to increase access capability due to growing requirements of arms-length inspection and maintenance. There are 152 gantries in total, consisting of four types of gantries: a suspended gantry, an internal gantry, a tower gantry, and a cable gantry. This article presents the gantries installed in the Honshu-Shikoku Bridges, containing improvement histories for each type of gantry in the construction and several efforts to improve access capability in the maintenance. [ABSTRACT FROM AUTHOR]

Mode shapes are sensitive to the structural condition of bridges but a reasonable estimate of such changes require several accelerometers, which can be resource intensive. This paper obviates this problem through a novel structure health monitoring (SHM) approach for estimating modal parameters of bridges, including damage-induced changes of boundary conditions by using progressively re-deploying sensors along a monitored bridge. This concept of re-deployable sensors and subsequent use of a series of measurements allow extracting data from different bridge segments and also to get an indication of the condition of the bridge through frequency domain decomposition. Data from different segments are combined to estimate the global mode shape of the bridge and its gradient is observed to be indicative of support stiffness change. The concept is successfully tested through a full-scale field trial on a railway bridge in the Republic of Ireland, before and after the rehabilitation of its supports. The results are expected to guide future on-site measurement of damages due to flooding, scour, and other natural hazards, along with the effectiveness of intervention actions like repair and rehabilitation, providing a clear evidence base for practical value of SHM. [ABSTRACT FROM AUTHOR]

This study proposes a simplified analysis method that couples the bridge and train-track subsystem in a weak form to facilitate the dynamic analysis of the train-track-bridge coupled system (TTBS) under earthquakes. The method includes three main steps: (i) performing dynamic analysis of the bridge under seismic conditions to obtain the response of the bridge deck; (ii) interpolating the bridge displacement beneath each wheelset based on the train's velocity, departure time, and the initial positions of the wheelsets; and (iii) assessing the running safety of the train by incorporating the interpolated bridge response as track irregularity into the train-track coupled system. Steps (i) and (iii) can be analyzed separately using finite element and multibody dynamics software, eliminating the need to create a complex TTBS model that is challenging to achieve within a single software platform. Additionally, based on the method's assumptions, the earthquake excitation on the train can be separated into the seismic inertial effect and seismic-induced bridge deformation, enabling a quantitative analysis of the impact of these two types of excitations on train safety. Taking a 10-span simply supported bridge and a long-span cable-stayed bridge as examples, the proposed method's assumptions are verified by comparing its results with those obtained from a complex TTBS model. Furthermore, the impact characteristics of inertial effects and seismic-induced bridge deformation on train safety for these two types of bridges are analyzed. The proposed method offers robust support for seismic design of bridges and facilitates a comprehensive analysis of the mechanisms through which seismic excitations affect train safety. • Proposal and validation of a simplified method for running safety evaluation of train on bridges under earthquake excitation. • Separation of seismic excitation on the train into seismic inertial effect and seismic-induced bridge deformation. • Analysis of impact characteristics of inertial effects and seismic-induced bridge deformation on train running safety. [ABSTRACT FROM AUTHOR]

• A comprehensive analysis is conducted to reveal the mechanism of widespread failure of light poles on an elevated bridge. • Large eddy simulation is performed to model the wind filed and aerodynamic pressures on the light poles. • Nonlinear Finite Element modeling is conducted to analyze the structure responses of the light poles. • The bridge superstructure can significantly enhance the local wind field, leading to increased wind loads (mean & fluctuating) on light poles. • Under enhanced wind loads, significant plastic strains/stresses develop at the bottom of the light poles. Light poles are critical secondary structural components that support the functionality and safety of transportation systems. However, they are tall slender structures vulnerable to wind load. This research attempts to analyze the mechanism of the widespread failure (69 poles failed) of light poles on an elevated highway bridge exposed to Category 4 Hurricane Laura (2020). First, large eddy simulation is performed to simulate the wind field and the aerodynamic pressure on light poles considering and without considering the presence of the bridge superstructure, respectively. Simulation result shows that the presence of the bridge superstructure strengthens the local wind field and the aerodynamic pressures. A nonlinear finite element model is created to simulate the structural responses. Research results indicate that, when considering the presence of the bridge superstructure, stresses at the pole bottom exceed the yielding strength and significant inelastic strains are developed, which is the main cause of the widespread pole failure. The present study can be used to evaluate the current design standard for luminaire pole structures on elevated bridges. [ABSTRACT FROM AUTHOR]

This study develops a novel Horizontal Bidirectional Hybrid Damping System (HBHDS) for mitigating the vibration of long-span bridges. It consists of eddy current dampers (ECDs), metallic yielding dampers (MYDs), fuse-lock device (FLD), and a spherical steel bearing (SSB). The ECD and MYD are connected in series through the FLD along the longitudinal direction to form an integrated passive control system together with the SSB. This system can not only mitigate the vibrations caused by service and seismic loads in the longitudinal direction, but also reduce the bridge seismic response when experiencing an earthquake in the transverse direction. The mechanical model of the HBHDS is introduced, and the method for determining the parameters of the HBHDS is given. To verify the superiority of the proposed HBHDS, a case study is performed on a long-span cable-stayed bridge. The numerical results confirm that the HBHDS has an excellent multi-level vibration control capacity, i.e., it can effectively mitigate structural vibrations caused by moving vehicle as well as earthquakes. • A novel hybrid damping system for mitigating vibration of long-span bridges is proposed. • The method for determining the parameters of the damping system is introduced. • The system is capable of mitigating structural vibrations caused by both the service and seismic loads. [ABSTRACT FROM AUTHOR]

The kilometer scale rail-road suspension bridge is subjected to environmental thermal actions, causing significant temperature-induced effects on the rail track alignment and the rail-track vertical irregularity exceeding the threshold during operation. This paper investigates the temperature distribution and associated responses of a rail-road suspension bridge through a combination of structural health monitoring (SHM), on-site tests, and numerical analysis. Based on the SHM, a strong linear relationship between the ambient temperature and the temperature-induced effects on the girder was observed. It is concluded that the long-term temperature-induced effects can cause an overall temperature variation in the structure with the main factor being the girder deflection. Then, the long-term temperature-induced deflection of the mid-span can reach up to 30 mm/°C. The on-site test results also indicate that the absolute elevation of the rail track has good followability relative to the girder, and dramatic temperature fluctuations can significantly influence rail-track irregularity. Based on measurements of the ambient temperatures and the adoption of a solar radiation model, the time-dependent temperature distribution and the temperature-induced deflections were calculated through a coupled thermo-mechanical method. Moreover, the dramatical variations of ambient temperature were then put into the numerical model to obtain the deflections of girder and chord offset values of the rail track. Results show that the dramatic variations of ambient temperature have exerted significant impacts on the rail-track irregularity on the bridge. These findings can provide an improved recommendation for maintaining rail-track operating performance during operation. • The long-term temperature-induced effects is the main factor for the deflection of the girder. • The absolute elevation of the rail track has good followability relative to the girder. • The ambient temperatures dramatical variation have a impact on the rail track irregularity on suspension bridges. [ABSTRACT FROM AUTHOR]

Bridges and subgrades are the main route forms for expressways. The ideal form for passing through sandy areas remains unclear. This study aims to understand the differences in the influence of expressway bridges and subgrades on the near-surface blown sand environment and movement laws, such as the difference in wind speed and profile around the bridge and subgrade, the difference in wind flow-field characteristics, and the difference in sand transport rate, to provide a scientific basis for the selection of expressway route forms in sandy areas. Therefore, a wind tunnel test was carried out by making models of a highway bridge and subgrade and comparing the environmental effects of wind sand on them. The disturbance in the bridge to near-surface blown sand activities was less than that of the subgrade. The variation ranges of the wind speed of the bridge and its upwind and downwind directions were lower than those of the subgrade. However, the required distance to recover the wind speed downwind of the bridge was greater than that of the subgrade, resulting in the sand transport rate of the bridge being lower than that of the subgrade. The variation in the wind field of the subgrade was more drastic than that of the bridge, but the required distance to recover the wind field downwind of the bridge was greater than that of the subgrade. In the wind speed-weakening area upwind, the wind speed-weakening range and intensity of the bridge were smaller than those of the subgrade. In the wind speed-increasing area on the top of the model, the wind speed-increasing range and intensity of the bridge were smaller than those of the subgrade. In the wind-speed-weakening area downwind, the wind speed weakening range of the bridge was greater than that of the subgrade, and the wind speed-weakening intensity was smaller than that of the subgrade. This investigation has theoretical and practical significance for the selection of expressway route forms in sandy areas. [ABSTRACT FROM AUTHOR]

The in-service sea-crossing bridge handles a large number of vehicles, while considerable wind exists on the superstructure and wave exists on the substructure simultaneously, on a daily basis. Apart from the service loads, the bridges may also encounter extreme natural hazards such as earthquake, hurricane, etc., which might greatly threaten the structural safety. In particular, this article attempts to illuminate the influence of the simultaneous service and extreme loads on the dynamic performance of an in-service sea-crossing bridge along with traversing vehicles. To this end, a general earthquake-wind-wave-vehicle-bridge (EWWVB) simulation platform is established, which systematically integrates the interactions between earthquake, wind, wave, vehicle and bridge. The safety indicators are also implemented in the proposed platform to enable the driving safety evaluations of the vehicles travelling on the bridge during earthquakes. With the proposed simulation platform, an illustrative example is presented in which a number of road vehicles are travelling on an in-service prototype sea-crossing cable-stayed bridge during a sudden earthquake event. The results indicate that the extreme seismic load could become the dominant load affecting the dynamic response of the prototype sea-crossing bridge as well as the vehicles running on it. [ABSTRACT FROM AUTHOR]

Summary: The drive‐by bridge health monitoring is to assess the bridge condition using the acceleration responses measured on the body or axle of instrumented vehicles. The vehicle responses are greatly affected by the road surface roughness that makes the bridge dynamic information blurred. Instead of direct using vehicle responses for the bridge monitoring, the dynamic response of contact point (CP) between the vehicle and bridge is further explored to enhance the drive‐by bridge modal identification. A novel three‐step framework is proposed to extract the components related to the bridge vibration from vehicle responses. The first step is to identify the input forces of two successive vehicles by solving the combined state‐input estimation problem using dual Kalman filter. The CP responses of two contact points are calculated using the input forces and vehicle parameters. In the second step, the subtraction technique is applied to the identified CP responses of the two instrumented vehicles and the effect of the road surface roughness can be significantly reduced. Finally, an automatic singular spectrum analysis technique (auto SSA) is incorporated to decompose the response residual. Then the mono‐component modes related to the bridge response are extracted from the response residual for drive‐by bridge modal identification and/or the nonstationary characteristic identification of vehicle–bridge interaction (VBI) system. Results of numerical and experimental study demonstrate that the method can significantly suppress the vehicle response component and reduce the effect of road surface roughness to enhance the bridge modal identification. [ABSTRACT FROM AUTHOR]

The present article proposes a novel framework for analyzing the dynamic responses of suspended monorail vehicles running over curved bridges under crosswinds. In this model, the curved bridge model is established with the finite element method and vehicles are simulated as a multibody system. Subsequently, a wind model is proposed with the wind tunnel test, spectral representation method, and yaw wind-decomposition method, taking into account the effects of the angle between the wind and vehicle changes when vehicles pass through the curved bridge. Finally, a suspended monorail curved bridge is analyzed to demonstrate the effect of the wind model on the vibration of the system. The results show that wind direction has a great effect on the lateral dynamic response of curved bridges, the lateral force of guiding tire, and the vertical force of running tire. The influence of crosswind on the dynamic response of the vehicle decreases with the increase of running time of vehicle on curved bridges. [ABSTRACT FROM AUTHOR]

High-sided vehicles are particularly vulnerable to high wind conditions and at sites that are regarded as vulnerable, a range of vehicle restrictions are imposed in high winds. These may include vehicle speed reductions or complete restrictions on the movement of different categories of vehicle at different wind gust speeds. This paper builds on earlier work that has been carried out and seeks to develop a simple but conservative method that can be used to specify vehicle restriction strategies. This is based on a collation of a wide range of data for aerodynamic rolling moment coefficients that allows a simple parameterisation to be developed. This is then used in an overturning model to develop a non-dimensional relationship between overturning gust speed and vehicle speed. The parameter used in the non-dimensionalisation is a characteristic wind speed that is a function of vehicle weight and geometry, and effectively specifies the vulnerability of the vehicle to overturning in high winds. Dimensional relationships between overturning gust velocities and vehicle velocities can thus be derived for different vehicle types and used to develop site-specific vehicle restriction methods. [ABSTRACT FROM AUTHOR]

Offshore piled wharves are usually connected to land area by approach bridge. The approach bridge structure isgenerally of high pile beam and plate type, and the superstructure forms the bridge deck system by erecting prestressed T beams. Due to the characteristics of a large weight and long span, the T beams are usually installed by crane ships. Therefore,the construction cost and safety risk are high. For Indonesia Shenhua Guohua Java 7 Power Plant Project, the maritime nonrotating synchronous double hoisting technology was applied to install T-beam. During the hoisting process, the lifting distance was adjusted by the ups and downs boom to control the installation position of T -beam, which effectively reduced the construction safety risks. It is the first application in the industry, and has achieved good economic and social benefits, which provides a reference basis for similar engineering construction. [ABSTRACT FROM AUTHOR]

• A novel modeling methodology of monorail train and large-scale bridge interaction is developed and validated with a field test. • Convergence, accuracy, and computational efficiency of the proposed methodology are all discussed. • Comparison with traditional model illustrates the advantages and significance of the proposed methodology. • Effects of the varying bridge profiles on the vehicle-bridge interaction are elaborately evaluated. High–efficiency solutions for extremely long bridge structures are a challenge in vehicle-bridge interaction modelling. In the present work, a novel modelling methodology for a monorail train and large-scale bridge interaction system is developed based on moving element technology. First, the governing equations for the monorail train subsystem are derived by adopting the Newton-Euler method, and an extremely long bridge is modelled based on an improved component mode synthesis method in which a bridge unit with finite length is updated and moved as the train moves forward. The train and bridge subsystems are coupled together by a nonlinear wheel–track interaction model. Subsequently, the convergence of the proposed method is discussed in detail, and reasonable values of several crucial model parameters are determined. On this basis, the simulation results obtained by the proposed methodology are compared with those of the finite element method (FEM) and field test data, validating the reliability of the proposed methodology and revealing its remarkable advantages. Finally, by applying the proposed methodology, the dynamic performance of the monorail train-bridge system is evaluated under different operating conditions. Results indicate that the proposed methodology can achieve good calculation accuracy for the vehicle-bridge dynamic responses; additionally, its computational efficiency is much higher than that of the FEM. The variation of the bridge section profile has a notable effect on the dynamic performance of the monorail vehicle-bridge system, which becomes more significant with increasing train speed. [ABSTRACT FROM AUTHOR]

The purpose of this study is to explore the application of numerical simulation methods in determining the design wind speed for large-span bridges situated in mountainous terrain. Compared to isolated mountains, the simulation of continuous mountain is more complex and often requires a larger computational domain. This implies that excessively high terrain model resolution can compromise computational resources. However, existing studies lack insights into selecting the optimal size of terrain extent, terrain model resolution, as well as the form of truncation curve. In this study, the impacts of terrain model resolution and size of terrain extent are discussed. In addition, the results from various transitional sections are compared against field measurement data. The results show that the UBTS transitional section form with the terrain resolution of 300 m and a diameter of 30 km of the mountain terrain can yield a reasonable simulation result at the bridge site. Furthermore, the research adopts the Xingkang bridge as a case study to outline the steps of determine the design wind speed for mountain bridges. The findings of this research offer valuable guidance for an appropriate numerical method in the practical engineering applications in determining the design wind speed for bridges in mountainous areas. • The terrain model with a horizontal geometry resolution of 300 m is adequate to get a reasonable result. • The adoption of the terrain model with a diameter of 30 km could yield a reasonable result. • The transitional form of UBTS models shows the best performance compared with the field measurements data. • The process of the determining the design wind speed of mountain bridge is illustrated. [ABSTRACT FROM AUTHOR]

• Novel method for removing damping distortion effect on bridge mode shapes with no prior knowledge of bridge damping. • New formula for recovering mode shapes by normalizing the moving vehicle's response relative to the stationary vehicle's. • The present method is not restricted to single-span bridges, but to other beam-type bridges. • The normalized formula works in the presence of pavement roughness when aided by an accompanying truck. Recovering bridge mode shapes using the response of a moving test vehicle has become a technique of interest. However, the mode shapes recovered tend to be distorted by bridge damping. To remove the distortion effect, a normalized formula that utilizes the responses of a moving and a stationary vehicle is devised for recovering bridge mode shapes with no prior knowledge of bridge damping ratios. Specifically, the moving test vehicle is used to recover the global modal response of the bridge throughout its span length at different instants as the vehicle moves over, and the stationary vehicle to generate a reference response at a fixed location of the bridge for removing the damping effect. In this paper, closed-form solutions are derived for the dynamic responses of the bridge and two test vehicles. The contact response is used in place of the vehicle response to alleviate the vehicle frequency's masking effect on bridge frequencies. The formula for recovering the modal mode shape is derived by normalizing the instantaneous amplitude of the Hilbert transform (HT) for the bridge from the moving test vehicle with respect to that by the stationary vehicle. The following conclusions are drawn: (1) the damping distortion effect on bridge mode shapes can be removed by the normalized formula; (2) the normalized formula is robust with regard to bridge damping, stationary vehicle location, and vehicle speed for beam-type bridges; (3) the mode shapes recovered by the present method are acceptable, even in the presence of pavement roughness, when aided by an accompanying truck. [ABSTRACT FROM AUTHOR]

• Field-measured bridge DLFs under random traffic excitations decrease with increasing load levels. • Specification-level bridge DLF extrapolated using deflection-measured DLFs at low load levels. • Two extrapolation methods proposed using linear regression and bivariate extreme value modeling. • Numerical traffic-bridge coupled analysis and field load tests validate extrapolation methods. • Methodology showcased with field-measured deflections on a long-span continuous girder bridge. Field-measured dynamic load factors (DLFs) are underutilized for bridge health assessment. Bridge practitioners often face confusion when comparing field-measured DLFs to specification design values owing to significant DLF variations across different traffic load levels. However, mathematical relations or methods correlating bridge DLFs and load levels are lacking. To address this challenge, this study proposes practical methods for determining specification-level DLFs using field-deflection measurements during ambient traffic excitations. Deflections from a continuous rigid-frame bridge over six months were measured, and DLFs were computed using hourly maximal total deflections and their corresponding static deflections. Two approaches were developed and validated to extrapolate the specification-level DLF using field-measured DLFs of low load levels. Extrapolated DLFs from both methods illustrated a noticeable downward trend in DLFs relative to load levels. Both methods yielded consistent results, falling within the range of 0.03–0.09, equivalent to the design DLF value of 0.05 for the bridge under study. No significant temporal-dependent changes in extrapolated DLFs were evident, indicating that bridge performance and pavement roughness met design expectations and did not deteriorate significantly. This study provides an alternative data-driven approach that utilizes field-measured DLFs to assess the health condition of bridges. [ABSTRACT FROM AUTHOR]

Bridges are playing a major role in the socio-economic development of any country over the world. Suspension bridges are one of the most sensitive structures to various external influences and loads. Therefore, the need for structural monitoring system, maintenance and deformation prediction for these types of structures is important and vital. Time of observations for the purpose of structural deformation can vary from a few hours, days to several months or even years. This paper investigates the performance of several soft computing techniques for point displacement modeling using GNSS technique during the process of monitoring the structural deformation of suspension highway bridge, taking into consideration the effect of wind, temperature, humidity and traffic loads during the operational and short-term measurements. Due to the availability of a large amount of positions data generated from GNSS data positions for monitoring the deformation of such structure, artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS) should be chosen. One of the main objectives of this paper is to investigate the optimum predictive soft computing model for processing GNSS positions and points displacement prediction. Several mathematical models and two cases of data amount (66.67% and 50% of all available data) for dynamic and kinematic state are applied and compared for prediction of suspension bridge displacement with confidence interval with a probability ρ = 0.95, Δ = ± 2σ. The resulting point displacement values by applying ANNs and ANFIS, which used a confidence interval with a probability of ρ = 0.95, Δ = ± 2σ when using 66.67% of all data, are more accurate and reliable than any other applied methods, and therefore, ANNs and ANFIS can provide a significant improvement of understanding and predicting the structure deformation values where conventional mathematical modeling techniques were not as accurate or capable especially in dynamic prediction of displacements. [ABSTRACT FROM AUTHOR]

A partial cable-stayed composite girder bridge with prestressed concrete flanges and corrugated steel webs (CSWs) is a beneficial new type of bridge structure that provides lower structural weight, reduced structural depth, increased span and lower seismic response. The structural responses and cost of four bridge types (a partial stayed-cable composite bridge with CSWs, a partial stayed-cable concrete bridge, a cable-stayed composite bridge with CSWs and a continuous rigid-frame composite bridge with CSWs) were compared and analysed. The results showed that the structural form and response of the main girder of a partial cable-stayed composite bridge are between those of a continuous rigid-frame composite bridge and a composite cable-stayed bridge. Compared with a concrete cable-stayed bridge of the same span, the self-weight of a partial cable-stayed composite bridge with CSWs is lighter, the main beam is lighter and the overall cost is less. [ABSTRACT FROM AUTHOR]

Due to the designing characteristics of long span and low stiffness, the high-order vortex-induced vibration (VIV) of suspension bridges may occur under a special wind environment. The prototype monitoring data make it feasible to rapidly capture and evaluate the VIV behavior during bridge operation. Based on the multisource load-response data of a long-span suspension bridge in a rare VIV phenomenon, this paper comprehensively evaluated the entire process of the input–output behavior of bridge VIV. The cause of this bridge VIV phenomenon is discussed, and the VIV parameter is estimated. The human comfort of vehicle riding in the VIV phenomenon is evaluated. A fast early-warning method of bridge VIV driven by multisource monitoring data is proposed according to the analysis and evaluation results of the bridge VIV phenomenon. The main results demonstrated that continuous excitation of wind whose direction is almost perpendicular to the longitudinal direction of the bridge are more likely to cause VIV; the Strouhal number of the three-meter-high stiffening box-shape opening-below steel girder is approximately 0.101694 according to the k -means clustering of inversely-calculated results of the monitoring data. The evaluation results and proposed early-warning method support the wind-resistant design, health monitoring, and intelligent maintenance of long-span suspension bridges. [ABSTRACT FROM AUTHOR]

Long-span cable-stayed bridges are subjected to the risk of collision from passing ships. Conducting experimental study on the collision of bridges and vessels is difficult due to high cost and limited space. In this paper, the behavior of a 1 018-m long-span cable-stayed bridge subjected to ship collisions is numerically studied. Finite element models of the entire bridge and ships are established. Four different dead weight tonnages (DWT), namely, 2 700, 12 000, 30 000, and 75 000 t, with impact velocities of 1 m/s to 6 m/s are investigated. The complete collision process under different loading scenarios is simulated, from which the collision force, bridge responses and local damage are obtained. The calculated collision force is significantly affected by the impact velocity and DWT, and exhibits a linear relationship with the impact velocity. Comparison with design codes shows that different codes vary significantly in estimating the collision force and Eurocode provides most accurate results. The effect of the material model on the collision force is also studied. This numerical study provides a reference for the ship collision design of long-span cable-stayed bridges. [ABSTRACT FROM AUTHOR]

In this study, new-type hybrid faring is suggested to improve the aerodynamic performance of the long-span cable-stayed bridge. The proposed fairing is developed by applying the concept of the multibox section to the normal faring. The proposed faring has void regions inside the faring so that wind passes through the gaps in the faring. As a result, the wind flow is changed and the forces to the bridge section are reduced. The efficiency of the proposed faring was verified by a series of wind tunnel test. From the test result, it can be found that aerodynamic performances, such as drag force and flutter resistance, are enhanced. [ABSTRACT FROM AUTHOR]

Summary: From 2010 to 2016, wind speed time history and synchronous acceleration responses along Xihoumen Bridge (XB) girder were recorded by a health‐monitoring system. Based on this dataset, wind speed, wind direction, angle of attack (AoA), turbulence intensity, and turbulence length scale are studied based on 10‐min time intervals. The environmental wind characteristics and synchronous structural effects are decoupled by the control variable method. The probabilistic dependence between wind parameters and structural responses is explored by explicit polynomial regression equations. With wind environment parameters as input, the acceleration responses of the bridge could be rapidly predicted with a certain confidence interval using decoupling and regression modeling (DRM). The proposed DRM can reproduce the buffeting acceleration responses when the bridge is subject to future potential strong typhoon attacks. The key factors affecting the buffeting responses of XB are analyzed and discussed. Generally, the buffeting acceleration responses of XB are significantly affected by wind speed and turbulence intensity rather than by turbulence length scale, which agrees well with previous observations. [ABSTRACT FROM AUTHOR]

In the wind tunnel test of a long-span bridge model, to ensure that the dynamic characteristics of the model can satisfy the test design requirements, it is particularly important to accurately identify the modal parameters of the model. First, the stochastic subspace identification algorithm was used to analyze the modal parameters of the model in the wind tunnel test; then, Grubbs criterion was introduced to effectively eliminate outliers in the damping ratio matrix. Stochastic subspace identification algorithm with Grubbs criterion improved the accuracy of the modal parameter identification and the ability to determine system matrix order and prevented the modal omissions caused by determining the stable condition of the damping ratio in the stability diagram. Finally, Oujiang Bridge was used as an example to verify the stochastic subspace identification algorithm with Grubbs criterion and compare with the results of the finite element method. The example shows that the improved method can be effectively applied to the modal parameter identification of bridges. [ABSTRACT FROM AUTHOR]

Long-span bridges face various threats every day due to their sophisticated operational environments. To investigate the operational state of bridges, a real-time dynamic warning method on the abnormity of cable-stayed bridges is proposed based on deflection measurements. The generalized Pareto distribution (GPD) model and finite-element (FE) calculation are used to determine the basic warning threshold. Considering the complicated components of the monitoring deflection signals (e.g., measurement noise, thermal effect, and vehicle load-induced effect), each signal component should be further modeled and investigated to improve the accuracy and effectiveness of the warning system. Because thermal effects are usually not the signal component of interest that may cover the signal fluctuation induced by abnormity, they should be separated from the raw signals. Then, in view of the variations of operational condition over time, the warning threshold is updated termly according to the operational period by using statistical approaches. Finally, the effectiveness of the proposed warning methodology is validated by analyzing the recorded deflection data from the third Nanjing Yangtze River Bridge. As a result, the proposed dynamic warning method is more effective than the conventional static one and will help bridge management departments identify emergencies in time and take inspection or maintenance decisions to ensure structural safety. [ABSTRACT FROM AUTHOR]

The long-span bridge, characterized by slenderness and flexibility, is particularly sensitive to wind action. Extreme wind events, including typhoons and hurricanes, will threaten the safety and serviceability of long-span bridges. More specifically, long-span bridges usually experience significant vibrations under typhoon events, increasing the risk of serviceability failure and traffic accidents. An efficient way to mitigate the risk of such threats is to predict the typhoon-induced response (TIR). Traditionally, TIR prediction of long-span bridges is usually carried out based on finite-element (FE) simulations. Due to the assumptions in formulating the FE model and establishing the wind load (e.g., boundary conditions, simplified structural elements, stationary aerodynamic wind forces), prediction accuracy is inevitably undermined. In this work, as opposed to traditional FE-based analysis, TIR is predicted in real time from a data-driven perspective. Quantile random forest (QRF) with Bayesian optimization is presented as the data-driven method for probabilistic prediction. A long-span cable-stayed bridge with a main span of 1,088 m is used as a test bed to illustrate the effectiveness of the present method. Other optimization algorithms used with QRF (grid search and random search) and response surface methodology (RSM) are also implemented for comparison purposes. Results indicate that QRF with Bayesian optimization can provide reliable probabilistic estimations allowing for quantification of uncertainty in prediction. It shows superior performance compared with other optimization algorithms and models in terms of accuracy and computational expense. The analysis and predictive framework for TIR are expected to provide insight into data-driven structural wind engineering. [ABSTRACT FROM AUTHOR]

On the basis of the definition and the three-dimensional characteristics of an integrated transfer function, the transfer function identification method based on reasonable technical means considering the three-dimensional effect was proposed. An original method to predict the bridge buffeting responses directly using the integrated transfer function is presented and investigated by means of segmental model vibration tests. Taking a suspension bridge as the background, the integrated transfer function was identified using segmental model vibration tests, and the effect of span-width ratio on it was studied. The buffeting response test of a full-bridge model was carried out in two different wind fields. Further, the identified integrated transfer functions were applied to predict the buffeting responses of the full-bridge model. By comparing the results, it is demonstrated that the method using reasonable segmental model vibration tests to obtain the integrated transfer functions to predict the bridge buffeting responses was highly accurate. The feasibility of the proposed method according to segmental model vibration tests was verified through tests for the first time. The method can effectively improve the deviation of results arise from the inaccurate simulating of turbulent characteristics in the tests, and avoid the many limitations of pressure and force measurement methods. • The influence of the span-width ratio on the buffeting response prediction of bridges is investigated. • An accurate identification method of integrated transfer function via segmental model vibration test is provided. • A prediction method for bridge buffeting responses via segmental model vibration test is proposed. [ABSTRACT FROM AUTHOR]

Large bridges' decks often exhibit different adhesion coefficients in complex environments, which are frequently accompanied by significant crosswind effects. This results in a complex and constantly changing flow field around vehicles, which can severely impact driving safety. In this study, the two-way coupling method is utilized to investigate the transient aerodynamic characteristics and dynamic response of vehicles passing through bridge towers at high speeds in different lanes with varied adhesion coefficients under crosswind conditions. The vehicle speed was 30 m/s, and the crosswind velocity was recorded at 11.33 m/s. The results indicate that the aerodynamic load fluctuates more significantly due to the influence of the bridge tower. In the same lane, the bridge deck with an adhesion coefficient of 0.4 produces a greater lateral displacement and yaw angle. When passing through the bridge tower, a vehicle in lane L1 is suddenly affected by vortex shedding, resulting in a larger lateral displacement and yaw angle compared to vehicles in L2 and L3 lanes. The lateral displacement measures 0.251 m, and the yaw angle measures 0.0205 radians at an adhesion coefficient of 0.4. This also indicates that driving in the L1 lane in a crosswind environment is relatively less safe. • A two-way coupling method is established. • The transient aerodynamic characteristic and dynamic response is investigated. • The high speed vehicle in different lane is considered. • Considering the effects of the adhesion coefficients. [ABSTRACT FROM AUTHOR]