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Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Integral abutment bridges (IABs) have been widely applied in bridge engineering because of their excellent seismic performance, long service life, and low maintenance cost. The superstructure and substructure of an IAB are integrally connected to reduce the possibility of collapse or girders falling during an earthquake. The soil behind the abutment can provide a damping effect to reduce the deformation of the structure under a seismic load. Girders have not been considered in some of the existing published experimental tests on integral abutment–reinforced-concrete (RC) pile (IAP)–soil systems, which may not accurately represent real conditions. A pseudo-static low-cycle test on a girder–integral abutment–RC pile (GIAP)–soil system was conducted for an IAB in China. The experiment's results for the GIAP specimen were compared with those of the IAP specimen, including the failure mode, hysteretic curve, energy dissipation capacity, skeleton curve, stiffness degradation, and displacement ductility. The test results indicate that the failure modes of both specimens were different. For the IAP specimen, the pile cracked at a displacement of +2 mm, while the abutment did not crack during the test. For the GIAP specimen, the pile cracked at a displacement of −8 mm, and the abutment cracked at a displacement of 50 mm. The failure mode of the specimen changed from severe damage to the pile top under a small displacement to damage to both the abutment and pile top under a large displacement. Compared with the IAP specimen, the initial stiffness under positive horizontal displacement (39.2%), residual force accumulation (22.6%), residual deformation (12.6%), range of the elastoplastic stage in the skeleton curve, and stiffness degradation of the GIAP specimen were smaller; however, the initial stiffness under negative horizontal displacement (112.6%), displacement ductility coefficient (67.2%), average equivalent viscous damping ratio (30.8%), yield load (20.4%), ultimate load (7.8%), and range of the elastic stage in the skeleton curve of the GIAP specimen were larger. In summary, the seismic performance of the GIAP–soil system was better than that of the IAP–soil system. Therefore, to accurately reflect the seismic performance of GIAP–soil systems in IABs, it is suggested to consider the influence of the girder. [ABSTRACT FROM AUTHOR]

The field load test is a direct and effective method for evaluating the performance of bridge structures. However, existing bridge field static load tests are costly and inefficient; moreover, they obstruct traffic and cause unavoidable damage to the bridge structure. As an alternative the the static load test, a random model update method based on bridge dynamic load tests and the Bayesian inference is proposed in this paper. The bridge static load test results were predicted with a high accuracy. To speed up the Bayesian method to infer the posterior probability density of the updated parameters, the Gaussian process was used in place of the finite element model, and the Bayesian inference used the Markov chain Monte Carlo method based on the delayed rejection adaptive Metropolis algorithm. First, the parameters to be modified for the bridge structure analysis model were determined based on the global sensitivity analysis method. Second, a uniform design sampling method was used to establish the Gaussian process optimization model to update the random model of the bridge structure. Finally, a reinforced concrete truss arch bridge was used to verify the correctness of the static load results of the bridge predicted by the random model update method based on dynamic load testing and Bayesian inference. The research results reveal that the prediction results of the bridge static load test based on the dynamic load test and Bayesian inference method agree with the actual test results. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

(1) Background: In most cases, passive isolation control methods are commonly used for the seismic isolation design in bridge engineering. However, passive seismic isolation devices, due to their non-adjustable performance parameters, struggle to achieve effective seismic isolation across a wide frequency range of 0 Hz to 20 Hz in response to random and varying seismic loads. (2) Methods: The sensitivity of the design parameters of the seismic isolation bearing was analyzed using the optimization center gradient method, and an improved genetic algorithm was employed to quickly optimize and obtain the optimal design parameters. (3) Results: The effectiveness of the three-dimensional seismic isolation bearing was validated through experiments. (4) Conclusions: The multi-factor sensitivity analysis approach used in this study for designing novel isolation bearings is applicable not only to seismic design in bridges but also serves as a reference for parameter design in isolation bearings requiring medium to high precision in seismic performance. [ABSTRACT FROM AUTHOR]

The degradation of bridge structural performance arises from the combined influence of various factors. Performance assessment and reliable prediction of bridge performance degradation through effective utilizing of detection information updates is a challenging problem. In this paper, the concept of performance indicators is redefined, employing to delineate bridge performance degradation. A bridge performance degradation model (the error ≤8%) is formulated, considering the multiple-variable Bayesian dynamic linear method (MBDLM) and revealing the coupling mechanisms among factors influencing bridge performance degradation. On this basis, the prediction performance of the model is quantitatively evaluated by three metrics: mean squared error, predictive mean squared error and mean absolute percentage error. A methodology is presented for the assessment, prediction, and maintenance reinforcement of in-service bridge structural performance degradation. This approach holds promise for future applications in safety assessments and the decision-making process for preventive maintenance of operational bridges. [ABSTRACT FROM AUTHOR]

The plastic hinge region length is the critical parameter to determine the deformation capacity of a reinforced concrete (RC) column. The foregoing researches showed that many factores should be included to accurately access the length of plastic hinge, which could be found in the existing formulas. However, the effect of the tension shift of longitudinal rebar was not paid enough attention in these publications. In order to consider the tension shift effect, a novel model of the plastic hinge length was established based upon the equivalent principle of plastic rotation. The quasi-static tests of seven RC columns were carried out to quantify the undetermined parameters in the proposed formula. To eveluate the rationallity of the suggested model, several existing formulas were applied to calculate the plastic hinge length of the tested columns. The comparison between test and calculation shows that the proposed model can predict more accurately the hinge length of 30 columns in the literature with less discreteness than the existing formulas. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Existing reinforced concrete (RC) bridges are subjected to environmental erosion and vehicle loads. It is becoming an urgent problem to evaluate the safety condition of bridge structures combining inspection data with artificial intelligence methods. This paper proposes a data-driven capacity assessment framework for existing RC bridges. The load capacity limit state (LCLS) and serviceability limit state (SLS) prediction model are established based on the proposed information fusion machine learning model. The genetic algorithm (GA) optimized support vector machine (SVM) learner is established to capture the relationship between the feature variables and the LSLS or SLS. Forty-five samples are obtained by static and dynamic simulation of the ANSYS models. Five-dimensional parameters are adopted as the key input parameters of the model, including the maximum dynamic deflection, crack opening ratio, and crack normal damage ratio at midspan, 1/4 span, and 3/4 span. The Shapley additive explanations method is proposed to conduct parameters sensitivity analysis. The results show that the GA-SVM regression algorithm in LCLS and SLS reduction factor prediction is better than the artificial neural network (ANN) model. The crack opening ratio is the most critical parameter that can considerably affect the outcomes of the LCLS and SLS prediction. [ABSTRACT FROM AUTHOR]

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The objective of this study is to examine the dynamic response behavior of a long-span cable-stayed bridge with ultra-high piles subjected to near-fault ground motions, comprehensively considering deep-water, sedimentation, local site, and wave-passage effects. Firstly, a 3D finite element (FE) model of the long-span cable-stayed bridge with ultra-high piles (Approximately 105 m) and a tower height of 216.4 m was established using Midas software. The deep-water, sedimentation, local site, and wave-passage effects were synthetically considered in this FE model. The FE model incorporates the sag effect of the stayed cable and the pile-soil interaction, enabling a detailed seismic analysis. Secondly, the examined near-fault ground motions with long-period velocity pulses were selected from the PEER database according to the design acceleration response spectrum with a fortification intensity of VIII degrees. Finally, nonlinear time history analyses of the selected long-span cable-stayed bridge, subjected to spatial near-fault ground motions including local site effect and wave-passage effect, were conducted, and the responses of critical design sections and points in structures were examined and evaluated. The results demonstrate that long-period velocity pulses can significantly affect the structural responses, while deep-water and sedimentation effects do not have a significant impact on the dynamic responses of long-span cable-stayed bridges. For the local site effect, the softer the soil at the support site and the greater the difference in soil conditions at the support, the larger the structural response. Regarding the wave effect, the structural response will increase or decrease depending on the magnitude of the wave speed and the span length between towers.

Abstract Fabricated ballastless track has witnessed increasingly wide application in large-span bridges of municipal railways. The current ballastless track standard is applicable to bridges with a main span of 200 m to 400 m. For the main span is longer than 400 m, it is necessary to ensure the travelling safety and comfort on the fabricated tracks. In this study, static and dynamic analysis models of train-track-bridge are established to explore the influence of complex ambient temperature changes and concrete shrinkage and creep on bridge deformation, followed by the analysis of the deformation coordination between long-span bridge and fabricated ballastless tracks, thereby revealing the dynamic response of the train-track-bridge system under the complex influence of temperature. The results show that when a train runs at a speed of 160 km/h, the existing ballastless track design standard is still applicable to a bridge span of 688 m. Compared with CRTS type III track, the adoption of the novel prefabricated ballastless track on long-span urban bridges provides higher safety and greater comfort, with comprehensive power performance improved by more than 10%. This design comprehensively takes into account the deformation coordination and dynamic performance of the rail bridge, providing a basis for the design and application of fabricated ballastless tracks on long-span bridges of urban railways.

Abstract The real juncture between corrugated steel webs (CSWs) and flanges follows a multi-segmented line, distinct from that of flat steel webs. Classic methods may yield significant deviations in predicting the elastic global shear buckling capacity of CSWs of various scales due to their failure to consider real boundary constraints. Therefore, a universally applicable formula for calculating the elastic critical global shear buckling stress of CSWs, which accounts for real boundary conditions, is proposed. This formula is pertinent to both large-scale engineering CSWs and small-scale testing CSWs. This study commenced with a comprehensive reassessment of the elastic global shear buckling calculation method. Subsequently, the influence of geometric parameter ratios on the elastic critical global buckling stress was examined. The primary parameter was identified and employed to improve the global buckling coefficient. The proposed calculation method was validated using different corrugation configurations, including 1000-type, 1200-type, 1600-type, 1800-type, and 2000-type CSWs, as well as other CSWs used in experimental settings. These results were compared with those obtained from other reference methods. Findings indicate that the accuracy of the classic theoretical method is affected by variations in both boundary conditions and geometric dimensions due to the constraint effect of real boundary conditions. Under the real boundary conditions, the elastic critical global shear buckling stress of CSWs with simply supported boundary conditions is close to that of CSWs with consolidated boundary conditions. The ratio of web height to corrugation depth primarily affects the elastic global shear buckling capacity, which decreases as the ratio increases. The Easley formula can be modified based on the web height to corrugation depth ratio. Comparisons of numerous numerical and theoretical results reveal that the proposed calculation method exhibits commendable computational precision. In comparison to alternative formulas, the proposed method demonstrates enhanced consistency for calculating CSWs with varying geometric dimensions and boundary conditions, thereby demonstrating its favorable applicability. These conclusions provide valuable reference for the shear design of CSWs.

Abstract The full life-cycle state monitoring of bridge structures is an effective way to ensure traffic safety and is also an important trend in the development of modern transportation. The accuracy, traceability, and reliability of sensor data are the foundation for the Bridge Health Monitoring (BHM) system to achieve its various functions. However, commonly seen uncertainties in measurement results of the monitoring system such as error, linearity, and repeatability often need to be calibrated to ensure accuracy and reliability of the data. Therefore, the calibration of these basic uncertain elements has been brought to our research focus. In this study, we first comb the monitoring parameters and characteristics of different sensor systems to help select suitable bridge structure monitoring sensors and adopt appropriate calibration and traceability strategies. Then, in combination with the research on traditional sensor calibration techniques and new sensor calibration technology, we present the key factors to be considered in the sensor calibration process and the challenges faced by the current technologies. Finally, suggestions are made for the research trend on the calibration of bridge monitoring sensors, aiming to provide reference for both theoretical and practical studies on bridge sensor calibration in the future.

Abstract Fire is a sporadic disaster of concrete bridges, with diverse fire environments and complex damage mechanisms. Accurately evaluating the damage situation of concrete bridges after a fire is exceedingly challenging. This study formulates a damage analysis and assessment method based on the step-by-step and progressively deepening working principle. The method relies on fire scene numerical reconstruction and encompasses key technical aspects, including bridge detection and analysis during the fire incident, fire scene numerical reconstruction, and subsequent bridge damage assessment. Building upon these principles, the study utilizes results from the detection and analysis of the concrete T-girder bridge during a fire incident to establish Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) models for the numerical reconstruction of the fire scene. These models enable the calculation of varying temperature distributions and the evolution of the bridge under fire. Compared with the parameters obtained through the ISO834 method, the numerical reconstruction approaches not only enhances the accuracy of replicating the bridge combustion process but also enables the extraction of temperature field distribution patterns within the bridge fire space and its concrete components.

Abstract The increasing frequency of extreme weather events, such as hurricanes and rising sea levels due to climate change, presents significant challenges to coastal infrastructure. With 42% of bridges in the United States exceeding 50 years of age, which surpasses their intended service life, there is a pressing need to assess their structural integrity, especially in coastal regions. This study focuses on evaluating the structural performance of bearing pads in coastal bridges under hurricane-induced wave loadings. Utilizing a combination of physics-based models (PBM), nonlinear modal time history analysis, and numerical validation, the research examines the hysteresis response of eight distinct bearing pad configurations. The findings indicate that reinforced circular bearing pads exhibit significantly greater shear displacements compared to plain elastomeric pads, underscoring the critical influence of shape factors on shear response. Fragility functions developed in the study illustrate the probability of shear failure, with reinforced circular pads showing a 28% higher likelihood of exceedance compared to rectangular plain pads. These results highlight the necessity for advanced design methodologies specifically for bearing pads to enhance the resilience of coastal infrastructure against severe hydrodynamic forces induced by hurricanes.

Abstract Carbon fiber reinforced polymers (CFRP) are recognized for their exceptional strength-to-weight ratio. They offer a viable and effective solution for strengthening and retrofitting masonry bridges, helping to extend their service life, improve structural performance, and meet modern safety and load requirements. Wrapping of CFRP around masonry elements can enhance their confinement and ductility. This flexibility plays a crucial role in preventing sudden brittle failure, allowing for controlled deformation, which is essential for blast resistance. Additionally, CFRP materials possess the ability to flex and absorb energy, which proves beneficial in containing and redistributing forces generated during an explosion, consequently reducing the risk of catastrophic failure. This study employed the coupled Eulerian–Lagrangian (CEL) technique available in the finite element software Abaqus/Explicit to simulate the blast loads. Various detonation scenarios were considered, taking into account factors such as location and their impacts on bridge structures. A detailed micro-model was developed using finite element software and accurate geometric data acquired from FARO laser scanning of the case study. The properties of masonry units and backfill were characterized using the Johnson-Holmquist II damage model and Mohr–Coulomb criteria. The Jones-Wilkins-Lee equation of state (EOS) was applied to replicate the behavior of trinitrotoluene (TNT). In accordance with the JH-II model, the researchers formulated a VUMAT code. The study examined the distinct damage mechanisms and overall structural responses of bridges. By evaluating the blast resistance of individual bridge models, the most critical scenarios were pinpointed. Carbon Fiber Reinforced Polymer (CFRP) was then utilized as a method to fortify bridges against blast loads. A comparison was made between the damage propagation before and after the reinforcement.

Abstract The approximation of complex engineering problems and mathematical regressions serves as the authentic inspiration behind the artificial intelligence metamodeling methods. Among these methods, polynomial chaos expansion, along with artificial neural networks, has emerged at the forefront and become the most practical technique. Previous studies have highlighted their robust capabilities in solving complex problems and their wide utilization across numerous applications, particularly in structural analysis, optimization design problems, and predictive models of uncertainty outcomes. The aim of this article is to present a methodology that introduces their implementation of for structural engineering, primarily focusing on reinforced concrete bridges. The proposed approach consists of demonstrating the applicability of the polynomial chaos to evaluate the dynamic behavior of two-span reinforced concrete bridges through a predictive model of natural vibration properties for eigenvalues modal analysis. Subsequently, response spectral method is conducted according to the Moroccan guide for bridge seismic design and the prescription of the EUROCODE 8 within the context of reliability assessment using Monte Carlo simulation. The efficacy of the proposed approach is illustrated by a comparison between the predicted vibration properties and the resulting values obtained through finite element modal analysis and artificial neural networks. The polynomial chaos process is based on a collected dataset of multiple reinforced concrete bridges sourced from technical studies offices and the Regional Administration of the East, affiliated with the Moroccan Ministry of Equipment and Water. Finally, this work contributes to the field by enhancing predictive modeling and reliability evaluation for bridge engineering using artificial intelligence metamodels.

Abstract In order to assess the damage condition of bridge components for a large-span rigid bridge in a soft clay site in a mountainous area in China southwest, a finite element model of a large-span rigid bridge is established based on the OpenSees software, and the joint probability density distribution function of the ground motion strength and seismic demand and the marginal distribution function of the ground motion are introduced into the kernel density function. As a basis to get the method of calculating the fragility of the bridge members, and the method is verified for its feasibility, on this basis, the damage condition of the bridge components are analyzed, and finally the damage condition of the bridge system are analyzed by the first-order bounds method and the improved PCM method (IPCM). The results showed that: (1) Kernel density method (KDE) can effectively calculate the damage probability of each component, for example, under ground motions with PGA equal to 0.2 g, the probability of slight damage of the 1# pier is 29%, that of the intermediate consolidation pier (2# pier ~ 4# pier) is about 90%; the probability of slight damage of the 1# bearing is 48%, and that of the 2# bearing is 87%. (2) Reasonable value of the expansion joints can effectively reduce the probability of main beam collision. In this investigation, the value is taken as 0.18 m ~ 0.24 m. (3) The bridge system is more likely to be damaged than a single component in the system, and the damage probability of a single component cannot be used as a criterion for the bridge system in the actual working condition. Comparing the first-order boundary law with the IPCM method, the IPCM method has higher accuracy.

Abstract A novel prefabricated segmental guardrail is proposed to facilitate connections between guardrails and between guardrails and bridge decks by casting ultrahigh-performance concrete (UHPC) joints in situ. Through finite element crash simulation analysis of three types of vehicles and crash tests of real vehicles, the prefabricated segmental guardrail with a UHPC connection was systematically evaluated in terms of its energy-absorbing capacity, vehicular acceleration, post-impact trajectory of the impacting vehicle, and behaviour of the guardrail upon impact. During the evaluation process, performance comparisons of the prefabricated segmental guardrails are made with the monolithic concrete guardrails. The results indicate that the performance of the prefabricated segmental guardrail with a UHPC connection was superior to that of the conventional concrete monolithic guardrails: it exhibited a higher level of crash performance, the occupants of the impacting vehicle were better protected, and the impacting vehicle exhibited better post-collision stability. Finally, the convenience of the prefabricated segmental guardrails with UHPC connections was proven in practical engineering applications.

Abstract The time-dependent effects in steel-concrete composite beam bridges can intensify track irregularities, subsequently leading to amplified train-bridge coupling vibrations. This phenomenon may increase the stress amplitudes in the bridge steel, thereby impacting the fatigue performance of the composite structures. This paper employs multiple rigid body dynamics to construct a high-speed train model and utilizes the finite element method to develop a steel-concrete composite beam element model that accounts for time-dependent effects, interfacial slip, and shear hysteresis. This approach enables the computational analysis of the train-bridge coupling system, facilitating an investigation into the influence of concrete’s time-dependent effects on the fatigue performance of railway steel-concrete composite bridges. Focusing on a 40-m simply supported composite bridge, the train-bridge coupling dynamic responses were computed for each operational year within a decade of the completion of construction. Applying the P-M linear fatigue damage accumulation theory, statistical analysis of stress history data across various operational periods was conducted to quantify the fatigue damage induced by a single eight-car high-speed train on the lower flange of the mid-span steel beam and the beam-end studs. The findings reveal that the beam-end studs sustain greater damage than the mid-span steel beam. Moreover, the detrimental impact of time-dependent effects diminishes with the increase of operational years. Notably, compared to the initial year, the fatigue damage to the lower flange of the mid-span steel beam by an eight-car train in the tenth year has surged by 39.3%. Conversely, the damage to the beam-end studs has decreased by 47.5%.

Abstract To improve the energy dissipation and self-resetting ability of bridge structures under strong earthquakes, a new buckling-restrained SMA bar-based friction damper (SFD) is proposed. The damper is composed of buckling-restrained super-elastic SMA bars, friction pads, and a steel frame. The buckling-restrained SMA bars provide self-reset capability, while the friction pads provide additional energy dissipation capacity. Firstly, the configuration, working mechanism, and restoring force model of the SMA bar-based friction damper are introduced. Secondly, a specimen of the damper is made, and the pseudo-static test is carried out. Finally, the experimental results are analyzed based on the Abaqus finite element model. The results indicate that the damper has better self-resetting ability and energy dissipation capacity.

Abstract Although building information modelling (BIM) has been widely used in the building industry, its usage in infrastructure projects such as bridges has been very challenging. Extended Reality (XR) that simulates a construction project is still considered a new technology in the Architecture, Engineering, and Construction (AEC) industry. This paper investigates the viability of integrating both BIM and XR technologies into transportation infrastructure projects. A fully integrated workflow for introducing different XR, Augmented Reality (AR), and Virtual Reality (VR), and BIM technologies using different software for a case study of El-Merghani bridge, a reinforced concrete girder type bridge, was developed. The models for the bridge included GIS integration and geometric road design according to AASHTO, documentation, shop drawings and quantification were developed for the bridge. A hypothetical time schedule was generated in Oracle Primavera P6 elevating the BIM model to 4-D and developing VR and AR virtual experiences with the capability to investigate, visualize, and present the model in a virtual environment, at a high level of immersion. Additionally, the associated risk reduction for the considered XR technology was assessed using Monte Carlo simulation. The workflow and the detailed 3D models developed for the bridge along with the highly immersive VR and AR experiences have provided an interactive platform for engineers and different stakeholders to monitor the project during the design and construction phases. The risk analysis showed that significant cost savings can be achieved with the utilization of VR and AR technology in bridges construction.

Abstract In order to study the effect of the velocity pulse on the dynamic response of the train-bridge system of the high-speed railway simple supported beam bridge, the velocity pulse is simulated by the trigonometric function method and superimposed with the far-field earthquake without pulse to synthesize the pulse with different pulse types, pulse periods and pulse peaks. A 10 $$\times$$ × 32m typical high-speed railway simple supported beam bridge is considered an case illustrating study. Then, the dynamic response of train-track-bridge coupling system is calculated by train-track-bridge seismic analysis software TTBSAS. Afterwards, the influence of pulse near-field earthquakes parameters and vertical components on dynamic response of train-bridge system and the safety of the train on the bridge are discussed in detail.The new derailment evaluation index is adopted to evaluate driving safety under earthquakes. The train safety control of simply supported beam bridge under the action of near-field earthquake is studied. The results show that the impact of pulse ground motion on the dynamic response of the train-track-bridge coupling system is significantly higher than that of no-pulse ground motion, especially the impact on the bridge and rail subsystem is more significant than that of train subsystem. Under the excitation of ground motion intensity of 0.05g $$\sim$$ ∼ 0.15g, the safe speed threshold of pulse near-field ground motion is smaller than that of far-field ground motion. When the ground motion intensity is 0.20g $$\sim$$ ∼ 0.30g, the safe speed threshold of pulse near-field ground motion and far field ground motion is 200km/h. So, the pulse near-field earthquake poses a greater threat to the safety of the train on the bridge than the far-field earthquake. Therefore, the influence of pulse near-field earthquakes should be considered in the seismic design. The research results of this paper can provide theoretitcal support for the design of a high-speed railway bridge in the near-field area.

In order to study the difference of dynamic response between large diameter variable section single pile and pile group foundations in seismic subsidence soil with different thicknesses under ground motion, based on the Xiang’an Bridge of Xiamen Second East Channel, a shaking table model test was conducted to study the difference of dynamic response of soil subsidence, horizontal displacement of pile top, acceleration of pile body and bending moment between single pile and pile group foundation when the thickness of seismic subsidence soil layer is 30, 40, and 50 cm. The results show that with the increase of the thickness of seismic subsidence layer, the seismic subsidence, horizontal displacement of pile top, acceleration and bending moment of single pile and pile group foundations increase gradually, and the acceleration and bending moment change abruptly at variable section. In the seismic subsidence layer with the same thickness, the seismic subsidence of soil around pile group foundation is larger than that of single pile, but the acceleration of pile group foundation, horizontal displacement of pile top and bending moment of pile body are smaller than those of single pile. It is suggested that in the design of pile foundation in seismic subsidence site, the difference of dynamic response between variable section single pile and pile group should be mainly considered to ensure the seismic performance of pile foundation.

Abstract Breakwaters play an important role in in mitigating wave-induced damage to marine structures. However, conventional submerged breakwaters often exhibit limited wave dissipation capabilities, while floating breakwaters may lack adequate safety performance. Therefore, this study introduces a novel combined breakwater design aimed at addressing the shortcomings of both traditional types. The proposed breakwater integrates a floating structure with a trapezoidal submerged breakwater via an anchor chain connection. To evaluate its efficacy, numerical simulations of wave interactions with structures were conducted using the OpenFOAM computational fluid dynamics (CFD) software in a two-dimensional (2D) numerical flume. Dynamic mesh technology was employed to simulate the motion of the floating body, and the resulting wave loads on a box girder bridge deck positioned behind the breakwater were analyzed to assess the combined breakwater’s protective capabilities and influencing factors. Analysis of wave heights and loads on the bridge deck revealed that the combined breakwater outperformed traditional submerged breakwaters in terms of wave dissipation. Furthermore, it was observed that the protective efficacy of the combined breakwater was more sensitive to variations in the size of the floating body compared to the submerged structure, and more responsive to changes in wave period than wave height. Leveraging the ability of the floating body to attenuate waves near the surface and the enhanced impact resistance provided by the combined floating and submerged structures, the proposed breakwater offers a promising approach to improving wave attenuation performance and enhancing safety for coastal infrastructure.

Abstract Sea-crossing bridges are subject to long-term simultaneous wave and current loadings throughout thier life cycle. The wave-current interaction makes the hydrodynamic load calculation difficult and challenging, especially in simulating the noncollinear wave-current interactions between waves and currents due to potential disturbances such as wall reflections within the observational zone. Therefore, in this study, a numerical flume was built based on the Reynolds time-average (RANS) equation and k-ε turbulence model using the computational fluid dynamics (CFD) software Flow-3D to investigate noncollinear wave-current interaction numerical simulation methods. The collinear wave-current interactions were then numerically simulated using the inflow boundary and mass source wave generation method, and the developed numerical flume was validated with experimental results based on a large-scale wave-current flume. Furthermore, a three-dimensional numerical simulation of complex noncollinear wave-current interactions was developed. The developed rectangular numerical basin based on the collinear wave-current flume was validated with theoretical results regarding wavelength variations in a noncollinear wave-current interaction field. Finally, the effective observation zone of orthogonal wave-current interactions was explored. This study is important for advancing bridge hydrodynamic research into noncollinear wave-current interactions.

The approximation of complex engineering problems and mathematical regressions serves as the authentic inspiration behind the artificial intelligence metamodeling methods. Among these methods, polynomial chaos expansion, along with artificial neural networks, has emerged at the forefront and become the most practical technique. Previous studies have highlighted their robust capabilities in solving complex problems and their wide utilization across numerous applications, particularly in structural analysis, optimization design problems, and predictive models of uncertainty outcomes. The aim of this article is to present a methodology that introduces their implementation of for structural engineering, primarily focusing on reinforced concrete bridges. The proposed approach consists of demonstrating the applicability of the polynomial chaos to evaluate the dynamic behavior of two-span reinforced concrete bridges through a predictive model of natural vibration properties for eigenvalues modal analysis. Subsequently, response spectral method is conducted according to the Moroccan guide for bridge seismic design and the prescription of the EUROCODE 8 within the context of reliability assessment using Monte Carlo simulation. The efficacy of the proposed approach is illustrated by a comparison between the predicted vibration properties and the resulting values obtained through finite element modal analysis and artificial neural networks. The polynomial chaos process is based on a collected dataset of multiple reinforced concrete bridges sourced from technical studies offices and the Regional Administration of the East, affiliated with the Moroccan Ministry of Equipment and Water. Finally, this work contributes to the field by enhancing predictive modeling and reliability evaluation for bridge engineering using artificial intelligence metamodels. [ABSTRACT FROM AUTHOR]

Deformation monitoring of bridges applying remote sensing satellite radar measurements Deformations of the Earth's surface can be measured from space using remote sensing radar interferometry (InSAR). This paper demonstrates the use of these data for deformation monitoring on the Schottwienbrücke‐S6 Semmering motorway. The European Space Agency (ESA) recently began providing free research satellite data from the Sentinel‐1 mission. The approach uses historically recorded natural reflection points as well as corner reflectors artificially attached to the structure. These are measured coordinately and analyzed using remote sensing methods. Thermal displacements of the structure are compensated to increase accuracy. A new model predicts the temperature of the structure based on network weather data. This means that the deformation measurements from the satellites can be analyzed and thermally compensated without sensors on the building, and the deviations can be more than halved. The recorded and processed annual measurements from 2022 onwards show a standard deviation of 1.7 to 3.0 mm compared to the reference system (Liquid Leveling System). Good agreement with the long‐term settlement behavior of the bridge was also found for natural reflection points. Satellites can also be used to simultaneously record different structures at 6‐day intervals up to 2016. Due to the time‐delayed processing, they are currently well suited for long‐term deformation monitoring of long‐span bridges. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Southeast University / Dongnan Daxue Xuebao is the property of Journal of Southeast University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The bridge influence line can effectively reflect its overall structural stiffness, and it has been used in the studies of safety assessment, model updating, and the dynamic weighing of bridges. To accurately obtain the influence line of a bridge, an Empirical and Variational Mixed Modal Decomposition (E-VMD) method is used to remove the dynamic component from the vehicle-induced deflection response of a bridge, which requires the preset fundamental frequency of the structure to be used as the cutoff frequency for the intrinsic modal decomposition operation. However, the true fundamental frequency is often obtained from the picker, and the testing process requires the interruption of traffic to carry out the mode decomposition. To realize the rapid testing of the influence lines of bridges, a new method of indirectly identifying the operational modal frequency and deflection influence lines of bridge structures from the axle dynamic response is proposed as an example of cable-stayed bridge structures. Based on the energy method, an analytical solution of the first-order frequency of vertical bending is obtained for a short-tower cable-stayed bridge, which can be used as the initial base frequency to roughly measure the deflection influence line of the cable-stayed bridge. The residual difference between the deflection response and the roughly measured influence line under the excitation of the vehicle is operated by Fast Fourier Transform, from which the operational fundamental frequency identification of the bridge is realized. Using the operational fundamental frequency as the cutoff frequency and comparing the influence-line identification equations, the empirical variational mixed modal decomposition, and the Tikhonov regularization to establish a more accurate identification of the deflection influence line, the deflection influence line is finally identified. The accuracy and practicality of the proposed method are verified by real cable-stayed bridge engineering cases. The results show that the relative error between the recognized bridge fundamental frequency and the measured fundamental frequency is 0.32%, and the relative error of the recognized deflection influence line is 0.83%. The identification value of the deflection influence line has a certain precision. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shenzhen University Science & Engineering is the property of Editorial Department of Journal of Shenzhen University Science & Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Suspension bridges are the most common type of bridge used to cross the ocean. The cable clamps in suspension bridges clamp the main cables by bolt preload, but the elastic interaction of the bolts reduces the preload, which is detrimental to the force in suspension bridges. However, research on the factors influencing the elastic interaction of cable clamp bolts in suspension bridges is currently limited. This paper aims to explore the law of influence of external factors on the elastic interaction of bolts through a combined approach of theoretical analysis, full-scale experiment, and finite element simulation. The results indicate that the average preload loss was reduced by about 27% when the elastic modulus was increased by about 110%. The average preload loss was reduced by about 45% when the bolt center distance was increased by 75%. The number of bolts has a small effect on the elastic interaction, which can be ignored. When the preload of bolt installation was increased by 133%, the average preload loss was reduced by approximately 125%, which was almost a linear relationship. Tightening the bolt from the center bolt creates greater elastic interaction. The conclusions can provide suggestions for reducing the elastic interaction of bolts in the design and construction of suspension bridge cable clamps. [ABSTRACT FROM AUTHOR]

The threat of rockfall impacting bridges in mountainous areas poses a great risk to the safety of passing trains. This study delves into the dynamics of rockfall impact and its implications on the interaction between train vehicles and bridges. Leveraging LS-DYNA, this study first captured the force–time history of rockfall impact on bridge structures. Subsequently, there was a comparison with the impact forces generated at various speeds with those predicted by established formulas, validating the accuracy of simulations. Employing BANSYS software, the dynamic responses of both bridge structures and the vehicle–bridge coupling system to falling rocks were analyzed. The investigation encompassed parameters such as impact speed, position, and train location. The findings reveal that escalating impact speeds correlate with increased average and maximum impact forces from falling rocks. Notably, the average impact force does not linearly correspond with rock speed and often exceeds values calculated by conventional formulas. Impact position minimally affects maximum impact force, yet alterations in position prolong impact duration, consequently reducing average impact force. Rockfall-induced impacts precipitate notable spikes in train lateral acceleration, lateral wheelset force, wheel unloading rate, and derailment coefficient, albeit with a comparatively lesser impact on vertical acceleration. Increasing impact speed and altering position intensifies the vehicle’s response, particularly when the train is in close proximity to the impact site. [ABSTRACT FROM AUTHOR]

Based on a damaged continuous rigid-frame bridge in Shaanxi Province, this study deduced the crack damage simulation algorithm and the vehicle-bridge coupling numerical algorithm. Then, it established a finite element analysis model using ANSYS APDL. The Newmark-β iterative method was used to study the dynamic response of different speeds, vehicle weights, and damage degrees before and after the structural damage. In the analysis of the influence of different speeds, the results showed that the dynamic stress responses of key sections of the undamaged bridge reached the maximum when the speed was 80 km/h, indicating that the undamaged bridge was sensitive to a speed of 80 km/h. The peak response of the damaged bridge was 90 km/h. In addition, the displacement peaks and the stress peaks rose and fell together. The analysis of different vehicle weights and damage degrees showed that with the increase in them, the displacement and impact coefficients of each section increased significantly. It can be concluded that the dynamic performance of the in-service bridge decreases continuously with the aggravation of the damage. Therefore, the influence of vehicle-bridge coupling should be emphasized in maintenance, and the frequent cracking area at the midspan should be strengthened in time to prevent further damage. [ABSTRACT FROM AUTHOR]

To reveal the influence of steel fiber content on the axial compressive properties of ultra-high performance concrete (UHPC), UHPC axial compression tests were conducted with steel fiber content as the control variable and constitutive simulations were conducted. The research show that the stress-strain curve of UHPC under compression consists of an ascending segment and a descending segment. After adding steel fibers, the descending section of the stress-strain curve of UHPC under compression becomes slower. With the increase of steel fiber content, the compressive elastic modulus, peak stress, and peak strain of UHPC all show a decreasing trend. Assuming that the UHPC compression damage area follows a Weibull random distribution, a damage variable is constructed, and a damage correction factor is introduced. A new UHPC compression damage model considering different steel fiber contents is established, and the development law of damage variables is analyzed. The reliability of the new model is verified using UHPC axial compression test data. The research results provide reference for the study of axial compressive properties and constitutive simulation of UHPC under different steel fiber contents. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper focuses on the analysis of the stress state of a large-span frame pier-continuous box girder bridge with pier crossbeams anchored by pier crossbeams on the main pier of the Guangfo-Zhao Expressway. The bridge is constructed by the cantilever method, and a refined finite element model of the entire bridge is established using the finite element software Midas/FEA to analyze the stress state of the frame pier during the cantilever construction process. It is found that under the possible combined action of an unbalanced load during construction, the torsional resistance of the frame pier crossbeam does not meet the requirements of the design code. In order to eliminate the torsion of the frame piers, counterweights were used to monitor the frame piers during the construction of the box girders. In this paper, the theoretical calculation formula of the inclination angle of the end section of the frame pier crossbeam with the change of unbalanced bending moment, the calculation formula of the relationship between the horizontal displacement of the frame pier and the unbalanced bending moment, and the calculation formula corresponding to the relationship with the water tank counterweight are derived using the structural mechanics method. Two monitoring methods for the frame pier are proposed. In the construction monitoring of the bridge, the numerical fitting formula obtained by finite element numerical analysis calculation is compared with the calculated formula obtained by substituting the design parameters of the frame pier into the theoretical formula. The basic constants in both formulas are basically equal, verifying the correctness of the monitoring calculation formula proposed in this paper for the torsional resistance of the frame pier crossbeam. The applicability of the two monitoring methods is also compared and analyzed. This paper takes the main pier of Chaoyang overpass's mainline bridge as the engineering background, which adopts the framework pier with a large-span prestressed concrete continuous box girder bridge. It analyzes the torsional state of the beam of the framework pier during the bridge construction process and conducts research on the construction monitoring of the framework pier crossbeam, providing valuable references for the construction monitoring of framework pier crossbeams in the construction of large-span framework pier continuous bridges in the future. The research results of this paper can provide assistance for the construction monitoring of similar projects. This paper's innovation primarily resides in employing structural mechanics methods to compute the torsion of frame piers. On this basis, a simplified beam torsion calculation formula is proposed to strengthen its practical application in construction monitoring. The findings of this paper can help in the construction monitoring of similar projects. [ABSTRACT FROM AUTHOR]

To investigate the anchorage loss mechanism of externally prestressed CFRP tendons in concrete beams, this study introduces a novel theoretical calculation system (TCS) developed through both the finite element method (FEM) and experimental validation. Firstly, the FEM and the proposed TCS were employed based on the mechanism of anchorage loss to compute the deformation of each part of the prestressed tendon–main beam connection system, ensuring result accuracy through mutual validation. Subsequently, field tests, designed according to FEM guidelines, measured the anchorage loss in externally prestressed CFRP tendons, with long-term monitoring included. Finally, experimental data were then used to refine the TCS. The results indicate that deformation at the connecting screw and the front end of the steel reaction frame constitutes approximately 95% of the total deformation, with theoretical calculations aligning closely with the FEM results. The field tests revealed that the anchorage loss of a 12 m long CFRP tendon under 950 MPa prestress accounted for about 35% of the total prestress loss. The discrepancy in deformation compared with the theoretical results was due to a gap of approximately 0.4 mm between the two threaded connections, which can be minimized by improving construction techniques. After correction, the calculation error was reduced to about 5%. Control variable studies confirmed that anchorage loss is influenced by the prestress level, the dimensions of the steel reaction frame front end, the connecting screw length, and the number of thread gaps. This study provides a comprehensive approach for accurately predicting and mitigating anchorage loss in externally prestressed CFRP tendons, with significant implications for future engineering applications. [ABSTRACT FROM AUTHOR]

Steel truss–arch composite bridge systems are widely used in bridge engineering to provide sufficient space for double lanes. However, a lack of research exists on their mechanical performance throughout their lifespan, resulting in uncertainties regarding bearing capacity and the risk of bridge failure. This paper conducts a numerical study of the structural mechanical performance of a flexible arch composite bridge with steel truss beams throughout its lifespan to determine the critical components and their mechanical behavior. Critical vehicle loads are used to assess the bridge's mechanical performance. The results show that the mechanical performance of the bridge changes significantly when the temporary piers and the bridge deck pavement are removed, substantially influencing the effects of the vehicle loads on the service life. The compressive axial force of the diagonal bar significantly increases to 33,101 kN near the supports during the two construction stages, and the axial force in the upper chord of the midspan increases by 4.1 times under a critical load. Moreover, the suspender tensions and maximum vertical displacement are probably larger than the limit of this bridge system in the service stage, and this is caused by the insufficient longitudinal bending stiffness of truss beams. Therefore, monitoring and inspection of critical members are necessary during the removal of temporary piers and bridge deck paving, and an appropriate design in steel truss beams is required to improve the life cycle assessment of this bridge system. [ABSTRACT FROM AUTHOR]

To explore the problem of additional shrinkage cracking caused by long water vapor balance of large specimens, a new in-situ micromechanical test method was proposed to study the micro creep and shrinkage of cement paste. Combined with digital image correlation (DIC) observation, uniaxial-biaxial compression creep and shrinkage tests were carried out on thin cement blocks in environmental scanning electron microscope (ESEM) and climate chamber (CC). The test results show that compared with the traditional test method, the new test framework significantly shortens the drying time by at least 200 times, thus effectively reducing the risk of cracking. There is a high linear correlation between the free drying shrinkage of cement paste and the mass loss when the relative humidity(RH) is higher than 60%. In the relative humidity of 50% ~ 60%, the cavitation of water influences the drying shrinkage. Compared with the ambient air-drying conditions in the climate chamber, the drying conditions in the environmental scanning electron microscope have lower air pressure, which causes forced convection flow and leads to a significant increase in the drying rate. However, under the equilibrium state of relative humidity of 20% RH, the shrinkage deformation of the two is basically the same. The rapid drying specimens have larger pores than the slow drying specimens, and the pores of the unloaded specimens are larger than those of the loaded specimens. In the uniaxial compression test, the change of drying creep with drying shrinkage shows a bilinear trend. In the biaxial compression test, the drying creep shows a linear relationship. The Poisson's ratio of drying creep is negative in both compression tests. When the Poisson's ratio is between - 0. 1 to 0, the creep properties obtained by CC test are basically consistent with the results of ESEM method. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)