With people living longer,the societal impact of age-related cognitive decline is becoming more pronounced(Crimmins,2015).Thus,it is increasingly important to comprehend the cognitive shifts linked to aging-whether th...With people living longer,the societal impact of age-related cognitive decline is becoming more pronounced(Crimmins,2015).Thus,it is increasingly important to comprehend the cognitive shifts linked to aging-whether they are physiological or pathological.展开更多
The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities,including design,construction,and maintenance of bridges,tunnels,ports and other infrastructures.In this...The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities,including design,construction,and maintenance of bridges,tunnels,ports and other infrastructures.In this paper,a distributed vibration sensing system is proved to be responsive to a single touch over a 1.8-m-long equivalent fiber segment,covering a vibration frequency from 5 Hz to 25 kHz.The sensing fiber was arranged as an S type layout on the bridge to recognize the standing state,windblown disturbance,and walking vibration.Moreover,the knocking and climbing events are recognized fiber laying spinning lines and hanging on the fences,respectively.The demonstration shows an accurate positioning and sensitive vibration monitoring applied on the automated three-dimensional(3D) printed bridge,which is applicable to all kinds of 3D printed facilities as intelligent sensory neuro-networks.展开更多
Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the...Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the approach bridge.For long-span railway bridges,it must also be coordinated with rail expansion joint(REJ),which is necessary to accommodate the expansion and contraction of,and reducing longitudinal stress in,the rails.The main aim of this study is to present analysis of recent developments in the research and application of BEJs in high-speed railway(HSR)long-span bridges in China,and to propose a performance-based integral design method for BEJs used with REJs,from both theoretical and engineering perspectives.Design/methodology/approach–The study first presents a summary on the application and maintenance of BEJs in HSR long-span bridges in China representing an overview of their state of development.Results of a survey of typical BEJ faults were analyzed,and field testing was conducted on a railway cable-stayed bridge in order to obtain information on the major mechanical characteristics of its BEJ under train load.Based on the above,a performance-based integral design method for BEJs with maximum expansion range 1600 mm(±800 mm),was proposed,covering all stages from overall conceptual design to consideration of detailed structural design issues.The performance of the novel BEJ design thus derived was then verified via theoretical analysis under different scenarios,full-scale model testing,and field testing and commissioning.Findings–Two major types of BEJs,deck-type and through-type,are used in HSR long-span bridges in China.Typical BEJ faults were found to mainly include skewness of steel sleepers at the bridge gap,abnormally large longitudinal frictional resistance,and flexural deformation of the scissor mechanisms.These faults influence BEJ functioning,and thus adversely affect track quality and train running performance at the beam end.Due to their simple and integral structure,deck-type BEJs with expansion range 1200 mm(±600 mm)or less have been favored as a solution offering improved operational conditions,and have emerged as a standard design.However,when the expansion range exceeds the above-mentioned value,special design work becomes necessary.Therefore,based on engineering practice,a performance-based integral design method for BEJs used with REJs was proposed,taking into account four major categories of performance requirements,i.e.,mechanical characteristics,train running quality,durability and insulation performance.Overall BEJ design must mainly consider component strength and the overall stiffness of BEJ;the latter factor in particular has a decisive influence on train running performance at the beam end.Detailed BEJ structural design must stress minimization of the frictional resistance of its sliding surface.The static and dynamic performance of the newlydesigned BEJ with expansion range 1600 mm have been confirmed to be satisfactory,via numerical simulation,full-scale model testing,and field testing and commissioning.Originality/value–This research provides a broad overview of the status of BEJs with large expansion range in HSR long-span bridges in China,along with novel insights into their design.展开更多
Main cable displacement-controlled devices(DCDs)are key components for coordinating the vertical deformation of the main cable and main girder in the side span of continuous suspension bridges.To reveal the mechanical...Main cable displacement-controlled devices(DCDs)are key components for coordinating the vertical deformation of the main cable and main girder in the side span of continuous suspension bridges.To reveal the mechanical action mechanisms of DCD on bridge structures,a three-span continuous suspension bridge was taken as the engineering background in this study.The influence of different forms of DCD on the internal force and displacement of the components in the side span of the bridge and the structural dynamic characteristics were explored through numerical simulations.The results showed that the lack of DCD caused the main cable and main girder to have large vertical displacements.The stresses of other components were redistributed,and the safety factor of the suspenders at the side span was greatly reduced.The setting of DCD improved the vertical stiffness of the structure.The rigid DCD had larger internal forces,but its control effect on the internal forces at the side span was slightly better than that of the flexible DCD.Both forms of DCD effectively coordinated the deformation of the main cable and main girder and the stress distribution of components in the side span area.The choice of DCD form depends on the topographic factors of bridge sites and the design requirements of related components at the side span.展开更多
The girder end restraint devices such as bearings and dampers on long span suspension bridge will deteriorate over time.However,it is difficult to achieve the quantitative assessment of the performance of the restrain...The girder end restraint devices such as bearings and dampers on long span suspension bridge will deteriorate over time.However,it is difficult to achieve the quantitative assessment of the performance of the restraint device through existing detection methods in actual inspections,making it difficult to obtain the impact of changes in the performance of the restraint device on the bridge structure.In this paper,a random vehicle load model is firstly established based on the WIM data of Jiangyin Bridge,and the displacement of girder end under the actual traffic flow is simulated by using finite element dynamic time history analysis.On this basis,according to the performance test data of the bearings and dampers,the performance degradation laws of the above two restraint devices are summarized,and the performance degradation process of the two restraint devices and the effects of different restraint parameters on the bridge structure are simulated.The results show that the performance degradation of the damper will significantly reduce the damping force at low speed,resulting in a significant increase in the cumulative displacement of the girder end;in the presence of longitudinal dampers,the increase in the friction coefficient caused by the deterioration of the bearing sliding plate has little effect on the cumulative displacement,but excessive wear of the bearing sliding plate adversely affects the structural dynamic performance.展开更多
The Beipanjiang Bridge sits over 565 meters above the Beipan River Valley nestled between two very steep cliffs,making it the world's highest bridge.Also known as the Duge Bridge or“China's Impossible Enginee...The Beipanjiang Bridge sits over 565 meters above the Beipan River Valley nestled between two very steep cliffs,making it the world's highest bridge.Also known as the Duge Bridge or“China's Impossible Engineering Feat”,the world's highest bridge may not look that impressive at first sight,but it is a testament to Chinese engineering and innovation.展开更多
As Thailand and China mark the 50th anniversary of their diplomatic ties this year,most headlines will naturally focus on trade deals,railways,and strategic partnerships.But tucked behind the golden spires of Bangkok...As Thailand and China mark the 50th anniversary of their diplomatic ties this year,most headlines will naturally focus on trade deals,railways,and strategic partnerships.But tucked behind the golden spires of Bangkok’s Wat Po temple lies a quieter,gentler form of diplomacy—one that happens through kneading hands,respectful bows,and an ancient art passed down across generations.At the Wat Po Thai Traditional Medical School,headmaster Serat Tangtrongchitr sees Thai massage not only as a healing craft,but as a cultural bridge—one that connects people across borders,languages,and belief systems.“We don’t just teach massage,”Serat said,his voice calm but assured.“We teach a way of life.And when people from other cultures learn this with us—Chinese students included—they come to understand not just the techniques,but the heart of Thai culture.”展开更多
Complex bridge structures designed and constructed by humans often necessitate extensive on-site execution,which carries inherent risks.Consequently,a variety of engineering practices are employed to monitor bridge co...Complex bridge structures designed and constructed by humans often necessitate extensive on-site execution,which carries inherent risks.Consequently,a variety of engineering practices are employed to monitor bridge construction.This paper presents a case study of a large-span prestressed concrete(PC)variable-section continuous girder bridge in China,proposing a feedback system for construction monitoring and establishing a finite element(FE)analysis model for the entire bridge.The alignment of the completed bridge adheres to the initial design expectations,with maximum displacement and pre-arch differences from the ideal state measuring 6.39 and 17.7 mm,respectively,which were less than the 20 mm limit required by the specification.Additionally,the stress monitoring showed that the maximum compressive stress was 10.44 MPa,which was 7.5%different from the finite element results,and better predicted the most unfavorable possible location.These results demonstrate that a scientifically rigorous construction monitoring and feedback system can ensure the safety of bridge construction and meet the expected construction standards.The findings presented in this paper provide valuable insights for bridge construction monitoring practices.展开更多
This article discusses the design strategy of complex mountain highway bridges.During the research phase,details were obtained based on prior literature review and analysis of engineering materials from mountainous ar...This article discusses the design strategy of complex mountain highway bridges.During the research phase,details were obtained based on prior literature review and analysis of engineering materials from mountainous area bridges.After analyzing the design characteristics of complex mountainous area road and bridge projects,the principles for the design of bridges on complex mountainous area expressways were proposed.The research on bridge design was carried out from five dimensions:bridge type selection,foundation design,superstructure design,connection part design,and material and technological innovation.Eventually,a relatively complete design system was formed.It is expected that this paper can provide technical references and value for road and bridge projects in China and promote the sustainable development of China’s road traffic system from a macro perspective.展开更多
Much of the research has focused on identifying bridge frequencies for health monitoring,while the bridge damping ratio also serves as an important factor in damage detection.This study presents an enhanced method for...Much of the research has focused on identifying bridge frequencies for health monitoring,while the bridge damping ratio also serves as an important factor in damage detection.This study presents an enhanced method for identifying bridge damping ratios using a two-axle,three-mass test vehicle,relying on wheel responses captured by only two mounted sensors.Damping ratio estimation formulas are derived using both the Hilbert Transform(HT)and Wavelet Transform(WT),with a consistent formulation that confirms accurate estimation is achievable with minimal instrumentation,particularly when addressing the support effect.A comparative analysis of the two signal processing techniques reveals the superior performance of WT in identifying bridge damping ratios.The effectiveness of the proposed procedure and formulas is validated through a detailed parametric study,demonstrating robustness across bridges with varying modal damping ratios and different spans using minimal sensors.Moreover,the present study shows that responses from only the first two spans of a multi-span bridge are sufficient for reliable damping estimation,underscoring the practicality and scalability of the procedure for structural health monitoring applications.展开更多
The effect of seismic directionality is crucial for curved bridges,a subject generally overlooked in seismic vulnerability analysis.This paper focuses on seismic fragility development as a function of seismic incidenc...The effect of seismic directionality is crucial for curved bridges,a subject generally overlooked in seismic vulnerability analysis.This paper focuses on seismic fragility development as a function of seismic incidence directions for a geometrically curved bridge.A series of non-linear time history analyses were carried out for a representative finite element model of the bridge by considering actual ground motions.For reliable seismic demand models,a total of eleven intensity measures(IM)were analyzed based on optimality metrics.To quantify the sensitivity of fragility functions to input incidence directions,fragility surfaces were developed throughout the horizontal plane by considering spectral acceleration at one second(Sa_(1.0))as the optimal IM.Results show that the optimal IM ranking is insignificantly influenced by seismic directionality.However,seismic orientation influences fragility,which intensifies in higher damage states,particularly for piers.For a bridge system,the differences in median demand corresponding to the least and most vulnerable direction for slight,moderate,extensive,and collapse states are about 9.0%,7.31%,10.32%,and 11.60%,respectively.These results imply that while evaluating the vulnerability of curved bridges,the optimality of IM in demand estimation and the impact of seismic directionality should not be disregarded.展开更多
From complicated overpasses that defy(违抗)engineering conventions to suspended“river highways”,China is internationally recognized for its innovative infrastructure.Another example of the nation's fearless appr...From complicated overpasses that defy(违抗)engineering conventions to suspended“river highways”,China is internationally recognized for its innovative infrastructure.Another example of the nation's fearless approach to building and design is the temporary suspension bridge.展开更多
To address local concrete damage in joint areas at the footing of prefabricated assembled self-centering bridge piers(PASPs)in seismic design,a damage transfer configuration(DTC)was proposed,based on the bridge pier s...To address local concrete damage in joint areas at the footing of prefabricated assembled self-centering bridge piers(PASPs)in seismic design,a damage transfer configuration(DTC)was proposed,based on the bridge pier structure configuration and the mechanism of local damage formation.Integrating the DTC into the PASP,numerical models of a previous experimental reference PASP and a PASP with damage transfer configuration(DTPASP)were established using the finite element software ABAQUS with a concrete damage plasticity(CDP)model.The models were then compared with experimental results regarding damage distribution,hysteresis curves,energy dissipation capacity,the joint opening degree,and residual displacement.The findings indicate that the finite element model developed in this study can well reflect the experimental results of the reference PASP.The incorporation of the DTC proved to be beneficial in preserving structural integrity,bearing capacity,and the functionality of the core structure of bridge piers following an earthquake.Meanwhile,this addition did not exert a significant influence on the seismic behavior of the core structure of the bridge pier.展开更多
The detection of surface defects in concrete bridges using deep learning is of significant importance for reducing operational risks,saving maintenance costs,and driving the intelligent transformation of bridge defect...The detection of surface defects in concrete bridges using deep learning is of significant importance for reducing operational risks,saving maintenance costs,and driving the intelligent transformation of bridge defect detection.In contrast to the subjective and inefficient manual visual inspection,deep learning-based algorithms for concrete defect detection exhibit remarkable advantages,emerging as a focal point in recent research.This paper comprehensively analyzes the research progress of deep learning algorithms in the field of surface defect detection in concrete bridges in recent years.It introduces the early detection methods for surface defects in concrete bridges and the development of deep learning.Subsequently,it provides an overview of deep learning-based concrete bridge surface defect detection research from three aspects:image classification,object detection,and semantic segmentation.The paper summarizes the strengths and weaknesses of existing methods and the challenges they face.Additionally,it analyzes and prospects the development trends of surface defect detection in concrete bridges.展开更多
When a coin is tossed to a gravity well,it will spiral instead of falling directly to the center.Inspired by this phenomenon,a gravity well-inspired double friction pendulum system(GW-DFPS)is developed to extend the l...When a coin is tossed to a gravity well,it will spiral instead of falling directly to the center.Inspired by this phenomenon,a gravity well-inspired double friction pendulum system(GW-DFPS)is developed to extend the length of sliding trajectories of bridge superstructures during pulse-like near-fault earthquakes.As a result,a greater amount of energy will be dissipated due to the frictional sliding of the isolators.The GW-DFPS consists of a spherical surface and an outer surface described by a 1/x or logarithmic function to build gravity well.Full-scale isolators were fabricated and their response was characterized considering various parameters such as the friction material of slider,surface roughness of sliding surfaces,and applied vertical loads.Additionally,a finite element model of the isolator was created using the experimental test data.Numerical simulations were performed on a case-study bridge structure isolated using both a conventional DFPS system and the proposed GW-DFPS systems.The experimental results reveal that the proposed isolators exhibit stable response under vertical loads varying from 200 kN to 1000 kN with a negative stiffness response when the isolator slides at the outer sliding surface.The numerical simulations of the selected bridge structure demonstrate that the GW-DFPS significantly extends the sliding trajectory lengths of the superstructure during half of the earthquake pulses,resulting in increased energy dissipation during this interval.The kinetic energies of the bridge isolated by GW-DFPS are consistently lower than those of the bridge isolated by the other two kinds of isolators,resulting lower shear forces on the bridge.展开更多
BIM technology has become an important tool in road and bridge design.Through the application of BIM technology,the entire bridge process can be modeled to form a virtual bridge form.Through the simulation of bridge c...BIM technology has become an important tool in road and bridge design.Through the application of BIM technology,the entire bridge process can be modeled to form a virtual bridge form.Through the simulation of bridge construction materials,construction techniques,and construction processes,a comprehensive analysis can be conducted to achieve visualization of the design and improve the efficiency of bridge design.This article mainly analyzes the advantages of BIM technology in bridge design,explores the application forms in bridge design,and proposes strategies to optimize bridge design,providing a certain reference for the improvement and optimization of bridge design work.展开更多
Aiming at the problems of difficulty in balancing construction efficiency and quality,as well as the high safety risks of working at heights during the construction of main piers for highway bridges,this study takes a...Aiming at the problems of difficulty in balancing construction efficiency and quality,as well as the high safety risks of working at heights during the construction of main piers for highway bridges,this study takes a specific bridge project as an example to introduce the technology of hydraulically sliding formwork for the construction of main piers of highway bridges.An in-depth analysis of the project’s construction process found that this technology can effectively improve construction efficiency,ensure the quality of concrete pouring,and significantly reduce the potential safety hazards of working at heights.It provides a reliable technical solution for constructing the main piers of highway bridges and has important reference significance for similar projects.展开更多
The purpose of this study is to analyze the application of ultrasonic non-destructive testing technology in bridge engineering.During the research phase,based on literature collection and reading,as well as the analys...The purpose of this study is to analyze the application of ultrasonic non-destructive testing technology in bridge engineering.During the research phase,based on literature collection and reading,as well as the analysis of bridge inspection materials,the principle of ultrasonic non-destructive testing technology and its adaptability to bridge engineering are elaborated.Subsequently,starting from the preparation work before inspection until damage assessment,the entire process of ultrasonic non-destructive testing is studied,and finally,a technical system of ultrasonic non-destructive testing for bridge engineering that runs through the entire process is formed.It is hoped that this article can provide technical reference value for relevant units in China,and promote the high-quality development of China’s bridge engineering from a macro perspective.展开更多
Bridge networks are essential components of civil infrastructure,supporting communities by delivering vital services and facilitating economic activities.However,bridges are vulnerable to natural disasters,particularl...Bridge networks are essential components of civil infrastructure,supporting communities by delivering vital services and facilitating economic activities.However,bridges are vulnerable to natural disasters,particularly earthquakes.To develop an effective disaster management strategy,it is critical to identify reliable,robust,and efficient indicators.In this regard,Life-Cycle Cost(LCC)and Resilience(R)serve as key indicators to assist decision-makers in selecting the most effective disaster risk reduction plans.This study proposes an innova-tive LCC-R optimization framework to identify the most optimal retrofit strategies for bridge networks facing hazardous events during their lifespan.The proposed framework employs both single-and multi-objective opti-mization techniques to identify retrofit strategies that maximize the R index while minimizing the LCC for the under-study bridge networks.The considered retrofit strategies include various options such as different mate-rials(steel,CFRP,and GFRP),thicknesses,arrangements,and timing of retrofitting actions.The first step in the proposed framework involves constructing fragility curves by performing a series of nonlinear time-history incre-mental dynamic analyses for each case.In the subsequent step,the seismic resilience surfaces are calculated using the obtained fragility curves and assuming a recovery function.Next,the LCC is evaluated according to the pro-posed formulation for multiple seismic occurrences,which incorporates the effects of complete and incomplete repair actions resulting from previous multiple seismic events.For optimization purposes,the Non-Dominated Sorting Genetic Algorithm II(NSGA-II)evolutionary algorithm efficiently identifies the Pareto front to represent the optimal set of solutions.The study presents the most effective retrofit strategies for an illustrative bridge network,providing a comprehensive discussion and insights into the resulting tactical approaches.The findings underscore that the methodologies employed lead to logical and actionable retrofit strategies,paving the way for enhanced resilience and cost-effectiveness in bridge network management against seismic hazards.展开更多
This investigation examines the shear performance of concrete T-beams reinforced with thin layers of ultra-high performance concrete(UHPC)through an approach that integrates experimental evaluation,numerical simulatio...This investigation examines the shear performance of concrete T-beams reinforced with thin layers of ultra-high performance concrete(UHPC)through an approach that integrates experimental evaluation,numerical simulation,and practical project verification.The research is based on a real bridge,and in accordance with the similarity principle,three reduced-scale T-beams with varying UHPC thicknesses were fabricated and tested to examine their failure modes and shear behaviors.A finite element model was created to enhance understanding of how UHPC reinforces these structures,while also considering the effects of material strength and arrangement.In addition to the laboratory tests,the actual bridge was analyzed to assess the effectiveness of the proposed strengthening technique.Results indicated that concrete T-beams strengthened with 30 mm-thick layers of UHPC had significant improvements,including a 491%increase in shear stiffness,a 23.15%rise in ultimate resistance,and a 155%enhancement in deformability compared to unreinforced T-beams.Furthermore,these improvements continued to increase with the application of thicker UHPC layers.Using 120MPa-grade UHPC with a thickness of 50mmand an A-type arrangement ensured that the dynamic and static performance of the T-beambridge met established code requirements.This research highlights the potential of UHPC thin layers in effectively reinforcing concrete beams for enhanced shear performance.展开更多
基金Clévio Nóbrega’s laboratory is funded by the Cure CSB projectthe Viljem Julijan Association for Children with Rare Diseases(Slovenia)+1 种基金the Algarve Biomedical Center Research Institute(ABC-Ri)funded by CRESC Algarve 2020(Operation Code:ALG-01-0145-FEDER-072586)(to CN)。
文摘With people living longer,the societal impact of age-related cognitive decline is becoming more pronounced(Crimmins,2015).Thus,it is increasingly important to comprehend the cognitive shifts linked to aging-whether they are physiological or pathological.
基金supported by the National Natural Science Foundation of China (No.6210031560)the Natural Science Foundation of Hebei Province (No.A2020202013)the Natural Science Foundation of Tianjin City (No.21JCQNJC00780)。
文摘The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities,including design,construction,and maintenance of bridges,tunnels,ports and other infrastructures.In this paper,a distributed vibration sensing system is proved to be responsive to a single touch over a 1.8-m-long equivalent fiber segment,covering a vibration frequency from 5 Hz to 25 kHz.The sensing fiber was arranged as an S type layout on the bridge to recognize the standing state,windblown disturbance,and walking vibration.Moreover,the knocking and climbing events are recognized fiber laying spinning lines and hanging on the fences,respectively.The demonstration shows an accurate positioning and sensitive vibration monitoring applied on the automated three-dimensional(3D) printed bridge,which is applicable to all kinds of 3D printed facilities as intelligent sensory neuro-networks.
基金National Key R&D Program of China(2022YFB2602900)R&D Fund Project of China Academy of Railway Sciences Corporation Limited(2021YJ084)+2 种基金Project of Science and Technology R&D Program of China Railway(2016G002-K)R&D Fund Project of China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.(2021)R&D Fund Project of China Railway Shanghai Group(2021141).
文摘Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the approach bridge.For long-span railway bridges,it must also be coordinated with rail expansion joint(REJ),which is necessary to accommodate the expansion and contraction of,and reducing longitudinal stress in,the rails.The main aim of this study is to present analysis of recent developments in the research and application of BEJs in high-speed railway(HSR)long-span bridges in China,and to propose a performance-based integral design method for BEJs used with REJs,from both theoretical and engineering perspectives.Design/methodology/approach–The study first presents a summary on the application and maintenance of BEJs in HSR long-span bridges in China representing an overview of their state of development.Results of a survey of typical BEJ faults were analyzed,and field testing was conducted on a railway cable-stayed bridge in order to obtain information on the major mechanical characteristics of its BEJ under train load.Based on the above,a performance-based integral design method for BEJs with maximum expansion range 1600 mm(±800 mm),was proposed,covering all stages from overall conceptual design to consideration of detailed structural design issues.The performance of the novel BEJ design thus derived was then verified via theoretical analysis under different scenarios,full-scale model testing,and field testing and commissioning.Findings–Two major types of BEJs,deck-type and through-type,are used in HSR long-span bridges in China.Typical BEJ faults were found to mainly include skewness of steel sleepers at the bridge gap,abnormally large longitudinal frictional resistance,and flexural deformation of the scissor mechanisms.These faults influence BEJ functioning,and thus adversely affect track quality and train running performance at the beam end.Due to their simple and integral structure,deck-type BEJs with expansion range 1200 mm(±600 mm)or less have been favored as a solution offering improved operational conditions,and have emerged as a standard design.However,when the expansion range exceeds the above-mentioned value,special design work becomes necessary.Therefore,based on engineering practice,a performance-based integral design method for BEJs used with REJs was proposed,taking into account four major categories of performance requirements,i.e.,mechanical characteristics,train running quality,durability and insulation performance.Overall BEJ design must mainly consider component strength and the overall stiffness of BEJ;the latter factor in particular has a decisive influence on train running performance at the beam end.Detailed BEJ structural design must stress minimization of the frictional resistance of its sliding surface.The static and dynamic performance of the newlydesigned BEJ with expansion range 1600 mm have been confirmed to be satisfactory,via numerical simulation,full-scale model testing,and field testing and commissioning.Originality/value–This research provides a broad overview of the status of BEJs with large expansion range in HSR long-span bridges in China,along with novel insights into their design.
基金The National Natural Science Foundation of China(No.52338011)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_0067).
文摘Main cable displacement-controlled devices(DCDs)are key components for coordinating the vertical deformation of the main cable and main girder in the side span of continuous suspension bridges.To reveal the mechanical action mechanisms of DCD on bridge structures,a three-span continuous suspension bridge was taken as the engineering background in this study.The influence of different forms of DCD on the internal force and displacement of the components in the side span of the bridge and the structural dynamic characteristics were explored through numerical simulations.The results showed that the lack of DCD caused the main cable and main girder to have large vertical displacements.The stresses of other components were redistributed,and the safety factor of the suspenders at the side span was greatly reduced.The setting of DCD improved the vertical stiffness of the structure.The rigid DCD had larger internal forces,but its control effect on the internal forces at the side span was slightly better than that of the flexible DCD.Both forms of DCD effectively coordinated the deformation of the main cable and main girder and the stress distribution of components in the side span area.The choice of DCD form depends on the topographic factors of bridge sites and the design requirements of related components at the side span.
基金supported by the National Key Research and Development Program of China(No.2022YFB3706704)the Academician Special Science Research Project of CCCC(No.YSZX-03-2022-01-B).
文摘The girder end restraint devices such as bearings and dampers on long span suspension bridge will deteriorate over time.However,it is difficult to achieve the quantitative assessment of the performance of the restraint device through existing detection methods in actual inspections,making it difficult to obtain the impact of changes in the performance of the restraint device on the bridge structure.In this paper,a random vehicle load model is firstly established based on the WIM data of Jiangyin Bridge,and the displacement of girder end under the actual traffic flow is simulated by using finite element dynamic time history analysis.On this basis,according to the performance test data of the bearings and dampers,the performance degradation laws of the above two restraint devices are summarized,and the performance degradation process of the two restraint devices and the effects of different restraint parameters on the bridge structure are simulated.The results show that the performance degradation of the damper will significantly reduce the damping force at low speed,resulting in a significant increase in the cumulative displacement of the girder end;in the presence of longitudinal dampers,the increase in the friction coefficient caused by the deterioration of the bearing sliding plate has little effect on the cumulative displacement,but excessive wear of the bearing sliding plate adversely affects the structural dynamic performance.
文摘The Beipanjiang Bridge sits over 565 meters above the Beipan River Valley nestled between two very steep cliffs,making it the world's highest bridge.Also known as the Duge Bridge or“China's Impossible Engineering Feat”,the world's highest bridge may not look that impressive at first sight,but it is a testament to Chinese engineering and innovation.
文摘As Thailand and China mark the 50th anniversary of their diplomatic ties this year,most headlines will naturally focus on trade deals,railways,and strategic partnerships.But tucked behind the golden spires of Bangkok’s Wat Po temple lies a quieter,gentler form of diplomacy—one that happens through kneading hands,respectful bows,and an ancient art passed down across generations.At the Wat Po Thai Traditional Medical School,headmaster Serat Tangtrongchitr sees Thai massage not only as a healing craft,but as a cultural bridge—one that connects people across borders,languages,and belief systems.“We don’t just teach massage,”Serat said,his voice calm but assured.“We teach a way of life.And when people from other cultures learn this with us—Chinese students included—they come to understand not just the techniques,but the heart of Thai culture.”
基金The Guangdong Basic and Applied Basic Research Foundation(Grant#2023A1515010535).
文摘Complex bridge structures designed and constructed by humans often necessitate extensive on-site execution,which carries inherent risks.Consequently,a variety of engineering practices are employed to monitor bridge construction.This paper presents a case study of a large-span prestressed concrete(PC)variable-section continuous girder bridge in China,proposing a feedback system for construction monitoring and establishing a finite element(FE)analysis model for the entire bridge.The alignment of the completed bridge adheres to the initial design expectations,with maximum displacement and pre-arch differences from the ideal state measuring 6.39 and 17.7 mm,respectively,which were less than the 20 mm limit required by the specification.Additionally,the stress monitoring showed that the maximum compressive stress was 10.44 MPa,which was 7.5%different from the finite element results,and better predicted the most unfavorable possible location.These results demonstrate that a scientifically rigorous construction monitoring and feedback system can ensure the safety of bridge construction and meet the expected construction standards.The findings presented in this paper provide valuable insights for bridge construction monitoring practices.
文摘This article discusses the design strategy of complex mountain highway bridges.During the research phase,details were obtained based on prior literature review and analysis of engineering materials from mountainous area bridges.After analyzing the design characteristics of complex mountainous area road and bridge projects,the principles for the design of bridges on complex mountainous area expressways were proposed.The research on bridge design was carried out from five dimensions:bridge type selection,foundation design,superstructure design,connection part design,and material and technological innovation.Eventually,a relatively complete design system was formed.It is expected that this paper can provide technical references and value for road and bridge projects in China and promote the sustainable development of China’s road traffic system from a macro perspective.
文摘Much of the research has focused on identifying bridge frequencies for health monitoring,while the bridge damping ratio also serves as an important factor in damage detection.This study presents an enhanced method for identifying bridge damping ratios using a two-axle,three-mass test vehicle,relying on wheel responses captured by only two mounted sensors.Damping ratio estimation formulas are derived using both the Hilbert Transform(HT)and Wavelet Transform(WT),with a consistent formulation that confirms accurate estimation is achievable with minimal instrumentation,particularly when addressing the support effect.A comparative analysis of the two signal processing techniques reveals the superior performance of WT in identifying bridge damping ratios.The effectiveness of the proposed procedure and formulas is validated through a detailed parametric study,demonstrating robustness across bridges with varying modal damping ratios and different spans using minimal sensors.Moreover,the present study shows that responses from only the first two spans of a multi-span bridge are sufficient for reliable damping estimation,underscoring the practicality and scalability of the procedure for structural health monitoring applications.
基金financial support from the Ministry of Education,Culture,Sports,Science and Technology (MEXT),Japan
文摘The effect of seismic directionality is crucial for curved bridges,a subject generally overlooked in seismic vulnerability analysis.This paper focuses on seismic fragility development as a function of seismic incidence directions for a geometrically curved bridge.A series of non-linear time history analyses were carried out for a representative finite element model of the bridge by considering actual ground motions.For reliable seismic demand models,a total of eleven intensity measures(IM)were analyzed based on optimality metrics.To quantify the sensitivity of fragility functions to input incidence directions,fragility surfaces were developed throughout the horizontal plane by considering spectral acceleration at one second(Sa_(1.0))as the optimal IM.Results show that the optimal IM ranking is insignificantly influenced by seismic directionality.However,seismic orientation influences fragility,which intensifies in higher damage states,particularly for piers.For a bridge system,the differences in median demand corresponding to the least and most vulnerable direction for slight,moderate,extensive,and collapse states are about 9.0%,7.31%,10.32%,and 11.60%,respectively.These results imply that while evaluating the vulnerability of curved bridges,the optimality of IM in demand estimation and the impact of seismic directionality should not be disregarded.
文摘From complicated overpasses that defy(违抗)engineering conventions to suspended“river highways”,China is internationally recognized for its innovative infrastructure.Another example of the nation's fearless approach to building and design is the temporary suspension bridge.
基金National Natural Science Foundation of China under Grant Nos.51408359,52278527 and 52478536。
文摘To address local concrete damage in joint areas at the footing of prefabricated assembled self-centering bridge piers(PASPs)in seismic design,a damage transfer configuration(DTC)was proposed,based on the bridge pier structure configuration and the mechanism of local damage formation.Integrating the DTC into the PASP,numerical models of a previous experimental reference PASP and a PASP with damage transfer configuration(DTPASP)were established using the finite element software ABAQUS with a concrete damage plasticity(CDP)model.The models were then compared with experimental results regarding damage distribution,hysteresis curves,energy dissipation capacity,the joint opening degree,and residual displacement.The findings indicate that the finite element model developed in this study can well reflect the experimental results of the reference PASP.The incorporation of the DTC proved to be beneficial in preserving structural integrity,bearing capacity,and the functionality of the core structure of bridge piers following an earthquake.Meanwhile,this addition did not exert a significant influence on the seismic behavior of the core structure of the bridge pier.
基金supported by the Key Research and Development Program of Shaanxi Province-International Science and Technology Cooperation Program Project (No.2020KW-001)the Contract for Xi'an Municipal Science and Technology Plan Project-Xi'an City Strong Foundation Innovation Plan (No.21XJZZ0074)the Key Project of Graduate Student Innovation Fund at Xi'an University of Posts and Telecommunications (No.CXJJZL2023013)。
文摘The detection of surface defects in concrete bridges using deep learning is of significant importance for reducing operational risks,saving maintenance costs,and driving the intelligent transformation of bridge defect detection.In contrast to the subjective and inefficient manual visual inspection,deep learning-based algorithms for concrete defect detection exhibit remarkable advantages,emerging as a focal point in recent research.This paper comprehensively analyzes the research progress of deep learning algorithms in the field of surface defect detection in concrete bridges in recent years.It introduces the early detection methods for surface defects in concrete bridges and the development of deep learning.Subsequently,it provides an overview of deep learning-based concrete bridge surface defect detection research from three aspects:image classification,object detection,and semantic segmentation.The paper summarizes the strengths and weaknesses of existing methods and the challenges they face.Additionally,it analyzes and prospects the development trends of surface defect detection in concrete bridges.
基金financially supported by the National Natural Science Foundation of China(Grants 52178124,52478151).
文摘When a coin is tossed to a gravity well,it will spiral instead of falling directly to the center.Inspired by this phenomenon,a gravity well-inspired double friction pendulum system(GW-DFPS)is developed to extend the length of sliding trajectories of bridge superstructures during pulse-like near-fault earthquakes.As a result,a greater amount of energy will be dissipated due to the frictional sliding of the isolators.The GW-DFPS consists of a spherical surface and an outer surface described by a 1/x or logarithmic function to build gravity well.Full-scale isolators were fabricated and their response was characterized considering various parameters such as the friction material of slider,surface roughness of sliding surfaces,and applied vertical loads.Additionally,a finite element model of the isolator was created using the experimental test data.Numerical simulations were performed on a case-study bridge structure isolated using both a conventional DFPS system and the proposed GW-DFPS systems.The experimental results reveal that the proposed isolators exhibit stable response under vertical loads varying from 200 kN to 1000 kN with a negative stiffness response when the isolator slides at the outer sliding surface.The numerical simulations of the selected bridge structure demonstrate that the GW-DFPS significantly extends the sliding trajectory lengths of the superstructure during half of the earthquake pulses,resulting in increased energy dissipation during this interval.The kinetic energies of the bridge isolated by GW-DFPS are consistently lower than those of the bridge isolated by the other two kinds of isolators,resulting lower shear forces on the bridge.
文摘BIM technology has become an important tool in road and bridge design.Through the application of BIM technology,the entire bridge process can be modeled to form a virtual bridge form.Through the simulation of bridge construction materials,construction techniques,and construction processes,a comprehensive analysis can be conducted to achieve visualization of the design and improve the efficiency of bridge design.This article mainly analyzes the advantages of BIM technology in bridge design,explores the application forms in bridge design,and proposes strategies to optimize bridge design,providing a certain reference for the improvement and optimization of bridge design work.
文摘Aiming at the problems of difficulty in balancing construction efficiency and quality,as well as the high safety risks of working at heights during the construction of main piers for highway bridges,this study takes a specific bridge project as an example to introduce the technology of hydraulically sliding formwork for the construction of main piers of highway bridges.An in-depth analysis of the project’s construction process found that this technology can effectively improve construction efficiency,ensure the quality of concrete pouring,and significantly reduce the potential safety hazards of working at heights.It provides a reliable technical solution for constructing the main piers of highway bridges and has important reference significance for similar projects.
文摘The purpose of this study is to analyze the application of ultrasonic non-destructive testing technology in bridge engineering.During the research phase,based on literature collection and reading,as well as the analysis of bridge inspection materials,the principle of ultrasonic non-destructive testing technology and its adaptability to bridge engineering are elaborated.Subsequently,starting from the preparation work before inspection until damage assessment,the entire process of ultrasonic non-destructive testing is studied,and finally,a technical system of ultrasonic non-destructive testing for bridge engineering that runs through the entire process is formed.It is hoped that this article can provide technical reference value for relevant units in China,and promote the high-quality development of China’s bridge engineering from a macro perspective.
文摘Bridge networks are essential components of civil infrastructure,supporting communities by delivering vital services and facilitating economic activities.However,bridges are vulnerable to natural disasters,particularly earthquakes.To develop an effective disaster management strategy,it is critical to identify reliable,robust,and efficient indicators.In this regard,Life-Cycle Cost(LCC)and Resilience(R)serve as key indicators to assist decision-makers in selecting the most effective disaster risk reduction plans.This study proposes an innova-tive LCC-R optimization framework to identify the most optimal retrofit strategies for bridge networks facing hazardous events during their lifespan.The proposed framework employs both single-and multi-objective opti-mization techniques to identify retrofit strategies that maximize the R index while minimizing the LCC for the under-study bridge networks.The considered retrofit strategies include various options such as different mate-rials(steel,CFRP,and GFRP),thicknesses,arrangements,and timing of retrofitting actions.The first step in the proposed framework involves constructing fragility curves by performing a series of nonlinear time-history incre-mental dynamic analyses for each case.In the subsequent step,the seismic resilience surfaces are calculated using the obtained fragility curves and assuming a recovery function.Next,the LCC is evaluated according to the pro-posed formulation for multiple seismic occurrences,which incorporates the effects of complete and incomplete repair actions resulting from previous multiple seismic events.For optimization purposes,the Non-Dominated Sorting Genetic Algorithm II(NSGA-II)evolutionary algorithm efficiently identifies the Pareto front to represent the optimal set of solutions.The study presents the most effective retrofit strategies for an illustrative bridge network,providing a comprehensive discussion and insights into the resulting tactical approaches.The findings underscore that the methodologies employed lead to logical and actionable retrofit strategies,paving the way for enhanced resilience and cost-effectiveness in bridge network management against seismic hazards.
基金The Science and Technology Project of Guangzhou(Grant#2024A04J9888)the National Natural Science Foundation of China(Grant#52278161)the Guangdong Basic and Applied Basic Research Foundation(Grant#2023A1515010535).
文摘This investigation examines the shear performance of concrete T-beams reinforced with thin layers of ultra-high performance concrete(UHPC)through an approach that integrates experimental evaluation,numerical simulation,and practical project verification.The research is based on a real bridge,and in accordance with the similarity principle,three reduced-scale T-beams with varying UHPC thicknesses were fabricated and tested to examine their failure modes and shear behaviors.A finite element model was created to enhance understanding of how UHPC reinforces these structures,while also considering the effects of material strength and arrangement.In addition to the laboratory tests,the actual bridge was analyzed to assess the effectiveness of the proposed strengthening technique.Results indicated that concrete T-beams strengthened with 30 mm-thick layers of UHPC had significant improvements,including a 491%increase in shear stiffness,a 23.15%rise in ultimate resistance,and a 155%enhancement in deformability compared to unreinforced T-beams.Furthermore,these improvements continued to increase with the application of thicker UHPC layers.Using 120MPa-grade UHPC with a thickness of 50mmand an A-type arrangement ensured that the dynamic and static performance of the T-beambridge met established code requirements.This research highlights the potential of UHPC thin layers in effectively reinforcing concrete beams for enhanced shear performance.
