Failure tests were conducted on two concrete-filled steel tubular(CFST)truss arch bridges with a span of approximately 12 m to investigate the influence of initial geometric defects on the in-plane bearing capacity of...Failure tests were conducted on two concrete-filled steel tubular(CFST)truss arch bridges with a span of approximately 12 m to investigate the influence of initial geometric defects on the in-plane bearing capacity of CFST truss arch bridges.The effects of antisymmetric defect on the ultimate bearing capacity,failure mode,structural response,and steel–concrete confinement effect of CFST truss arch bridges under quarter-point loading were analyzed.On this basis,numerical simulations were conducted to investigate the in-plane bearing capacity of CFST truss arch bridges further under different scenarios.The initial defect formof the archwas obtained by using theoretical deduction,and the theoretical basis for the weakening of the ultimate bearing capacity of the arch bridge caused by geometric defects was clarified.Results indicate that the antisymmetric defect does not change the four-hinge failure mode of the model arch under quarter-point loading but increases the local cracking area and crack density of the concrete inside the pipe.The sine geometric defect with an amplitude of L/250 resulted in a 44.4%decrease in the yield load of the single hinge of the model arch,a 10.5%decrease in the failure load of the four hinges,and a 40.9%increase in themaximum vertical deformation during failure.At the initial stage of loading,the steel pipe and the concrete inside the pipe were subjected to relatively independent forces.After reaching 67%of the ultimate load,the catenary arch ribs began to produce a steel pipe concrete constraint effect.The initial geometric defects resulted in a decrease in the load when the constraint effect occurred.The antisymmetric defects with the same amplitude have a greater impact on the in-plane bearing capacity of the CFST arch bridge than the initial geometric defects with symmetry.The linear deviation at L/4 caused by constructionmust be controlled to be less than L/600 to ensure that the internal bearing capacity of the CFST arch bridge reaches 95%of the design bearing capacity.The structural deformation caused by geometric initial defects increases linearly with the increase in defect amplitude.The bearing capacity is weakened because the structural deflection and bending moment are amplified by initial defects.展开更多
In order to study the mechanical performance of a new type of cable-stayed beam-arch combination bridge, the results of field static and dynamic load tests are comparatively analyzed with numerical results based on th...In order to study the mechanical performance of a new type of cable-stayed beam-arch combination bridge, the results of field static and dynamic load tests are comparatively analyzed with numerical results based on the Jingyi bridge straddling the Daxi River in Yixing. First, the test scheme, tasks, the corresponding measure method, as well as the relevant codes are described. Secondly, two sets of three- dimensional finite element models are established. One is Ansys which uses the solid element and the other is Midas which adopts the beam element. Finally, the experimental and analytical results are comparatively analyzed, and they show an agreement with each other. The results show that the bridge possesses adequate load-carrying capacity under all static load cases, but the capacity of dissipating external input energy is insufficient due to the relatively smaller damping ratio. The study results can provide a reference for further study and optimization of this type of bridge. Calibrated finite-element models that reflect the real conditions can be used as a baseline for future maintenance of the bridge.展开更多
By taking Youxi Village which was the typical village with wooden arched bridges in East Fujian for example, it had discussed landforms, geology, soil, climate and vegetation in natural environment which could be perc...By taking Youxi Village which was the typical village with wooden arched bridges in East Fujian for example, it had discussed landforms, geology, soil, climate and vegetation in natural environment which could be perceived and village's cultural and historical background. Based on relevant research results in academic field, it had studied the relationship between wooden arched bridges and villages' environment in East Fujian, and further analyzed the relation of wooden arched bridges as traditional architectural heritages with village's living condition and history. On this basis, it had analyzed imaginability of natural environment of Youxi Village from the aspects of village's site and stream's trend, and imaginability of cultural environment by taking Wenming Bridge, Liren Bridge and Zhangkeng Bridge for example. It was considered that wooden arched bridge was the consolidation of natural environment and had been the recognizable image at villages of East Fujian, manifesting heavy cultural characteristic.展开更多
Theoretical study on and safeguarding of cultural landscape heritage has been put on the agenda of heritage protection in Zhejiang and Fujian provinces.The safeguarding of timber-framed arch bridge heritage in the pas...Theoretical study on and safeguarding of cultural landscape heritage has been put on the agenda of heritage protection in Zhejiang and Fujian provinces.The safeguarding of timber-framed arch bridge heritage in the past 5 decades could be classified into 3 stages,and heritage protection in all 3 stages was closely related to original meaning of "landscape",which proved that timber-framed arch bridge heritage had profound inside information,and the safeguarding of timber-framed arch bridge from the perspective of cultural landscape heritage was worth further study.Safeguarding of timber-framed arch bridge cultural landscape heritage focused on integrated conservation,but not protection of individual bridges.Integrated conservation of world heritage is to maintain and restore the integrated environment landscape of the heritage,thus protection of timber-framed arch bridge heritage is not only to explore its architectural craftsmanship,but also to lay a foundation for the dynamic succession of such craftsmanship as intangible cultural heritage.Value of the existing timber-framed arch bridges as historic building heritage was discussed,and it was proposed that ultimate objectives of the safeguarding could be realized step by step from 3 layers.展开更多
Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete ...Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube(CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a(77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail(CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load.Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.展开更多
In the 1990s, several major earthquakes occurred throughout the world, with a common observation that near fault ground motion （NFGM） characteristics had a distinct impact on causing damage to civil engineering stru...In the 1990s, several major earthquakes occurred throughout the world, with a common observation that near fault ground motion （NFGM） characteristics had a distinct impact on causing damage to civil engineering structures that could not be predicted by using far field ground motions. Since then, seismic responses of structures under NFGMs have been extensively examined, with most of the studies focusing on structures with relatively short fundamental periods, where the traveling wave effect does not need to be considered. However, for long span bridges, especially arch bridges, the traveling wave （only time delay considered） effect may be very distinct and is therefore important. In this paper, the results from a case study on the seismic response of a steel arch bridge under selected NFGMs is presented by considering the traveling wave effect with variable apparent velocities. The effects of fling step and long period pulses of NFGMs on the seismic responses of the arch bridge are also discussed.展开更多
Arch bridges provide significant technical and economic benefits under suitable conditions.In particular,concrete-filled steel tubular(CFST)arch bridges and steel-reinforced concrete(SRC)arch bridges are two types of ...Arch bridges provide significant technical and economic benefits under suitable conditions.In particular,concrete-filled steel tubular(CFST)arch bridges and steel-reinforced concrete(SRC)arch bridges are two types of arch bridges that have gained great economic competitiveness and span growth potential due to advancements in construction technology,engineering materials,and construction equipment over the past 30 years.Under the leadership of the author,two record-breaking arch bridges—that is,the Pingnan Third Bridge(a CFST arch bridge),with a span of 560 m,and the Tian’e Longtan Bridge(an SRC arch bridge),with a span of 600 m—have been built in the past five years,embodying great technological breakthroughs in the construction of these two types of arch bridges.This paper takes these two arch bridges as examples to systematically summarize the latest technological innovations and practices in the construction of CFST arch bridges and SRC arch bridges in China.The technological innovations of CFST arch bridges include cable-stayed fastening-hanging cantilevered assembly methods,new in-tube concrete materials,in-tube concrete pouring techniques,a novel thrust abutment foundation for nonrocky terrain,and measures to reduce the quantity of temporary facilities.The technological innovations of SRC arch bridges involve arch skeleton stiffness selection,the development of encasing concrete materials,encasing concrete pouring,arch rib stress mitigation,and longitudinal reinforcement optimization.To conclude,future research focuses and development directions for these two types of arch bridges are proposed.展开更多
Cantilever casting concrete arch bridge using form traveller has a broad application prospect.However,it is difficult to obtain reasonable initial cable force in construction stage.In this study,stress balance and inf...Cantilever casting concrete arch bridge using form traveller has a broad application prospect.However,it is difficult to obtain reasonable initial cable force in construction stage.In this study,stress balance and influence matrix methods were developed to determine the initial cable force of cantilever casting concrete arch bridge.The stress balance equation and influence matrix of arch rib critical section were established,and the buckle cable force range was determined by the allowable stress of arch rib critical section.Then a group of buckle cable forces were selected and substituted into the stress balance equation,and the reasonable initial buckle cable force was determined through iteration.Based on the principle of force balance,the initial anchor cable force was determined.In an engineering application example,it is shown that the stress balance and influence matrix methods for the determination of initial cable force are feasible and reliable.The initial cable forces of arch rib segments only need to be adjusted once in the corresponding construction process,which improves the working efficiency and reduces the construction risk.It is found that the methods have great advantages for determining initial cable force in cantilever casting construction process of concrete arch bridge.展开更多
X-style arch bridge on high-speed railways(HSR)is one kind of complicated long-span structure,and the track-bridge interaction is essential to ensure the safety and smoothness of HSR.Taking an X-style steel-box arch b...X-style arch bridge on high-speed railways(HSR)is one kind of complicated long-span structure,and the track-bridge interaction is essential to ensure the safety and smoothness of HSR.Taking an X-style steel-box arch bridge with a main span of450 m on HSR under construction for example,a new integrative mechanic model of rail-stringer-cross beam-suspenderpier-foundation coupling system was established,adopting the nonlinear spring element simulating the longitudinal resistance between track and bridge.The transmission law of continuous welded rail(CWR)on the X-style arch bridge was researched,and comparative study was carried out to discuss the influence of several sensitive factors,such as the temperature load case,the longitudinal resistance model,the scheme of longitudinal restraint conditions,the introverted inclination of arch rib,the stiffness of pier and abutment and the location of the rail expansion device.Calculating results indicate that the longitudinal resistance has a significant impact upon the longitudinal forces of CWR on this kind of bridge,while the arch rib’s inclination has little effect.Besides,temperature variation of arch ribs and suspenders should be taken into account in the calculation.Selecting the restraint system without longitudinally-fixed bearing and setting the rail expansion devices on both ends are more reasonable.展开更多
This paper attempts to explore potential benefits of form in a deck-type reinforced concrete（RC） arch bridge in connection with its overall seismic behavior and performance. Through a detailed three-dimensional fini...This paper attempts to explore potential benefits of form in a deck-type reinforced concrete（RC） arch bridge in connection with its overall seismic behavior and performance. Through a detailed three-dimensional finite element modeling and analysis of an actual existing deck-type RC arch bridge, some useful quantitative information have been derived that may serve for a better understanding of the seismic behavior of such arch bridges. A series of the nonlinear dynamic analyses has been carried out under the action of seven different time histories of ground motion scaled to the AASHTO 2012 response spectrum. The concept of demand to capacity ratios has been employed to provide an initial estimation of the seismic performance of the bridge members. As a consequence of the structural form, a particular type of irregularity is introduced due to variable heights of columns transferring the deck loads to the main arch. Hence, a particular attention has been paid to the internal force/moment distributions within the short, medium, and long columns as well as along the main arch. A study of the effects of the vertical component of ground motion has demonstrated the need for the inclusion of these effects in the analysis of such bridges.展开更多
This paper presents the first of a series of case studies on the seismic design of long span bridges （cable-stayed bridges, suspension bridges and arch bridges） under a cooperative research project on seismic behavi...This paper presents the first of a series of case studies on the seismic design of long span bridges （cable-stayed bridges, suspension bridges and arch bridges） under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that （1） the selected near field ground motions cause larger responses to key components （critical sections） of the bridge （such as arch rib ends） with a maximum increase of more than twice those caused by the site specific ground motions; （2） piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and （3） large vertical components of near field ground motions may not significantly affect the bridge＇s internal forces provided that their peak acceleration spectra ordinates only appear at periods of less than 0.2s. However, they may have more influence on the longitudinal displacements of sliding bearings due to their large displacement spectra ordinates at the fundamental period of the bridge.展开更多
A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate...A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders is investigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.展开更多
In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube （CFST） arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has bee...In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube （CFST） arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has been increasing rapidly, which is rare in the history of bridge development. The large-scale construction of expressways and high-speed railways demands the development of long-span arch bridges, and advances in design and construction techniques have made it possible to construct such bridges. In the present study, the current status, development, and major innovative technologies of CFST arch bridges and concrete arch bridges with a CFST skeleton in China are elaborated. This paper covers the key con- struction technologies of CFST arch bridges, such as the design, manufacture, and installation of steel tube arch trusses, the preparation and pouring of in-tube concrete, and the construction of the world＇s longest CFST arch bridge-the First Hejiang Yangtze River Bridge. The main construction technologies of rein- forced concrete arch bridges are also presented, which include cable-stayed fastening-hanging cantilever assembly, adjusting the load by means of stay cables, surrounding the concrete for arch rib pouring, and so forth. In addition, the construction of two CFST skeleton concrete arch bridges-the Guangxi Yongning Yong River Bridge and the Yunnan-Guangxi Railway Nanpan River Bridge--is discussed. CFST arch bridges in China have already gained a world-leading position; with the continuous innovation of key technologies, China will become the new leader in promoting the development of arch bridges.展开更多
A review of the current status and progress of steel arch bridges in China is presented in this paper. The existing steel arch bridges in China were analyzed in terms of steel material, span, structure type, main arch...A review of the current status and progress of steel arch bridges in China is presented in this paper. The existing steel arch bridges in China were analyzed in terms of steel material, span, structure type, main arch rib form and construction method. The comparison with CFST arch bridges and RC arch bridges is also conducted. It is shown that steel arch bridge has gain rapid development in China since 2000, characterized by long main spans. As for the span, most of the steel arch bridges have a span less than 250 m, while when the span exceeds 350 m, steel arch bridges are strongly competitive against CFST or RC arch bridges. Over 80% of the bridges are through and half-through bridge types, and the arch ribs are hingeless structures. The rise-to-span ratios of the arches are mainly between 1：4 and 1： 5. Most of the arches use solid box ribs, and a small portion of arches use truss ribs in which box sections are mostly adopted for the truss members. The cantilever method and scaffolding method are the two main construction methods used, but some other construction methods have also been developed.展开更多
Beipanjiang Bridge is a long-span concrete arch bridges with stiffened skeleton(CABSS)in China.It has a fixed end arch with the span of 445 m and the rise of 100 m.To evaluate the rationality of the construction seque...Beipanjiang Bridge is a long-span concrete arch bridges with stiffened skeleton(CABSS)in China.It has a fixed end arch with the span of 445 m and the rise of 100 m.To evaluate the rationality of the construction sequence and the time-dependent behavior of CABSS,an experimental study of a model bridge was explored.But the measured displacement and stress ratios of arch rib between prototype and model bridge did not subject to linear similarity relation when the time-dependent behavior was considered.So,the three-dimensional finite element models were established,and verified by the measured data.Then,the displacements and stresses of the prototype and model were compared with each other,when the elastic analysis or coupling of temperature and shrinkage,creep effect was considered.Furthermore,a parametric study was studied.The results showed that when the temperature,shrinkage and creep effect of concrete are considered,the finite element analysis results of prototype and model agree well with the measured results.The displacement and stress ratios of prototype and model bridge in construction and bridge completed stage do not present the geometric similarity ratio 7.5 and 1.0,respectively.They are also much influenced by concrete predicting model and variation of temperature.展开更多
To numerically evaluate the reinforcement effect on dynamic characteristics of a concrete-filled steel tube arch bridge with vibration problems,a 12-degree-of-freedom sprung-mass dynamic vehicle model and a 3D finite ...To numerically evaluate the reinforcement effect on dynamic characteristics of a concrete-filled steel tube arch bridge with vibration problems,a 12-degree-of-freedom sprung-mass dynamic vehicle model and a 3D finite element bridge model were established.Then,the coupled equations of vehicle-bridge interaction were derived and a computer program was developed using the FORTRAN language.This program can accurately simulate vehicle-bridge coupled vibration considering the bumping effect and road surface irregularity during motion of the vehicle.The simulated results were compared with those of relevant literatures to verify the correctness of the self-developed program.Then,three reinforcement schemes for the bridge(Addition of longitudinal beams,Reinforcement of bridge decks,and Replacement of suspenders)were proposed and numerically simulated,and the vibration reduction effects of the three schemes were evaluated based on the numerical results to find effective ones.It is confirmed that the reinforcement scheme of Addition of longitudinal beams shows the most significant vibration reduction effect.It is recommended in the engineering practice that the combination of the reinforcement schemes of Addition of longitudinal beams and Replacement of bridge deck can be used to solve the excessive vibration problem.展开更多
A huge number of old arch bridges located in rural regions are at the peak of maintenance.The health monitoring technology of the long-span bridge is hardly applicable to the small-span bridge,owing to the absence of ...A huge number of old arch bridges located in rural regions are at the peak of maintenance.The health monitoring technology of the long-span bridge is hardly applicable to the small-span bridge,owing to the absence of technical resources and sufficient funds in rural regions.There is an urgent need for an economical,fast,and accurate damage identification solution.The authors proposed a damage identification system of an old arch bridge implemented with amachine learning algorithm,which took the vehicle-induced response as the excitation.A damage index was defined based on wavelet packet theory,and a machine learning sample database collecting the denoised response was constructed.Through comparing three machine learning algorithms:Back-Propagation Neural Network(BPNN),Support Vector Machine(SVM),and Random Forest(R.F.),the R.F.damage identification model were found to have a better recognition ability.Finally,the Particle Swarm Optimization(PSO)algorithm was used to optimize the number of subtrees and split features of the R.F.model.The PSO optimized R.F.model was capable of the identification of different damage levels of old arch bridges with sensitive damage index.The proposed framework is practical and promising for the old bridge’s structural damage identification in rural regions.展开更多
This design is about Chongqing Wanzhou district KanKan river crossing test evaluation and reinforcement renovation. The bridge is an open spandrel stone arch bridge. After years of operating, defects arise from differ...This design is about Chongqing Wanzhou district KanKan river crossing test evaluation and reinforcement renovation. The bridge is an open spandrel stone arch bridge. After years of operating, defects arise from different parts. To verify whether the bridge meets the bearing capacity of highway grade I standard, this design firstly evaluates the bridge through the apparent diseases. Then it uses Midas/Civil to calculate the bearing capacity of lateral control section for Zhou Jiaba arch foot, L/4 and arch section. Using Midas/Civil control section load calculation, load test plan is made. In the end, by increasing cross-section method, the bridge reinforcement maintenance plan is made;that is increasing abdominal 26 cm concrete layer in the main arch ring of arch so that the bridge meets grade I highway capacity requirements.展开更多
A well⁃preserved ancient stone arch bridge dating back to the Ming Dynasty(1368-1644)has been uncovered in Songxi County,East China's Fujian Province,amid China's ongoing fourth national cultural relic census,...A well⁃preserved ancient stone arch bridge dating back to the Ming Dynasty(1368-1644)has been uncovered in Songxi County,East China's Fujian Province,amid China's ongoing fourth national cultural relic census,China News Service reported.The discovery was made during an on⁃site in⁃spection in Songxi,according to He Lixing.展开更多
On the basis of investigating wooden arch gallery bridges in China,perspectives of researchers studying wooden arch gallery bridges in northeast Fujian Province were reviewed,and the innovativeness of researches from ...On the basis of investigating wooden arch gallery bridges in China,perspectives of researchers studying wooden arch gallery bridges in northeast Fujian Province were reviewed,and the innovativeness of researches from the perspectives of cultural geography and significance of wooden arch gallery bridge for the locals’behaviors was proposed.Youxi Village in Qinyang Town,Shouning County,known as the Village of Gallery Bridge,was taken for example to analyze physical,spiritual and social properties of its wooden arch gallery bridge spaces.Wooden arch gallery bridge is an effective boundary point of settlement space,constituting natural ecological spaces and man-made physical spaces of rural settlements.And as a type of building space,wooden arch gallery bridge expands settlement spaces,contributes to settlement cultures,and enriches spiritual connotations of regional cultures.In northeast Fujian,wooden arch gallery bridge is an important social space for the locals’daily life by carrying on living,production and spiritual functions.展开更多
基金National Natural Science Foundation of China(Grant No.52408314)Science and Technology Project of Sichuan Provincial TransportationDepartment(GrantNo.2023-ZL-03)Science and Technology Project of Guizhou Provincial Transportation Department(Grant No.2024-122-018).
文摘Failure tests were conducted on two concrete-filled steel tubular(CFST)truss arch bridges with a span of approximately 12 m to investigate the influence of initial geometric defects on the in-plane bearing capacity of CFST truss arch bridges.The effects of antisymmetric defect on the ultimate bearing capacity,failure mode,structural response,and steel–concrete confinement effect of CFST truss arch bridges under quarter-point loading were analyzed.On this basis,numerical simulations were conducted to investigate the in-plane bearing capacity of CFST truss arch bridges further under different scenarios.The initial defect formof the archwas obtained by using theoretical deduction,and the theoretical basis for the weakening of the ultimate bearing capacity of the arch bridge caused by geometric defects was clarified.Results indicate that the antisymmetric defect does not change the four-hinge failure mode of the model arch under quarter-point loading but increases the local cracking area and crack density of the concrete inside the pipe.The sine geometric defect with an amplitude of L/250 resulted in a 44.4%decrease in the yield load of the single hinge of the model arch,a 10.5%decrease in the failure load of the four hinges,and a 40.9%increase in themaximum vertical deformation during failure.At the initial stage of loading,the steel pipe and the concrete inside the pipe were subjected to relatively independent forces.After reaching 67%of the ultimate load,the catenary arch ribs began to produce a steel pipe concrete constraint effect.The initial geometric defects resulted in a decrease in the load when the constraint effect occurred.The antisymmetric defects with the same amplitude have a greater impact on the in-plane bearing capacity of the CFST arch bridge than the initial geometric defects with symmetry.The linear deviation at L/4 caused by constructionmust be controlled to be less than L/600 to ensure that the internal bearing capacity of the CFST arch bridge reaches 95%of the design bearing capacity.The structural deformation caused by geometric initial defects increases linearly with the increase in defect amplitude.The bearing capacity is weakened because the structural deflection and bending moment are amplified by initial defects.
文摘In order to study the mechanical performance of a new type of cable-stayed beam-arch combination bridge, the results of field static and dynamic load tests are comparatively analyzed with numerical results based on the Jingyi bridge straddling the Daxi River in Yixing. First, the test scheme, tasks, the corresponding measure method, as well as the relevant codes are described. Secondly, two sets of three- dimensional finite element models are established. One is Ansys which uses the solid element and the other is Midas which adopts the beam element. Finally, the experimental and analytical results are comparatively analyzed, and they show an agreement with each other. The results show that the bridge possesses adequate load-carrying capacity under all static load cases, but the capacity of dissipating external input energy is insufficient due to the relatively smaller damping ratio. The study results can provide a reference for further study and optimization of this type of bridge. Calibrated finite-element models that reflect the real conditions can be used as a baseline for future maintenance of the bridge.
基金Supported by the subject of " Professor Cultivation Engineering" of Ningde Teachers College of 2010 (2010J002)the special subject of " Cultural Research of East Fujian" in 2011 (2011HW05)A Class Subject of Fujian Department Education (JA11300S)~~
文摘By taking Youxi Village which was the typical village with wooden arched bridges in East Fujian for example, it had discussed landforms, geology, soil, climate and vegetation in natural environment which could be perceived and village's cultural and historical background. Based on relevant research results in academic field, it had studied the relationship between wooden arched bridges and villages' environment in East Fujian, and further analyzed the relation of wooden arched bridges as traditional architectural heritages with village's living condition and history. On this basis, it had analyzed imaginability of natural environment of Youxi Village from the aspects of village's site and stream's trend, and imaginability of cultural environment by taking Wenming Bridge, Liren Bridge and Zhangkeng Bridge for example. It was considered that wooden arched bridge was the consolidation of natural environment and had been the recognizable image at villages of East Fujian, manifesting heavy cultural characteristic.
文摘Theoretical study on and safeguarding of cultural landscape heritage has been put on the agenda of heritage protection in Zhejiang and Fujian provinces.The safeguarding of timber-framed arch bridge heritage in the past 5 decades could be classified into 3 stages,and heritage protection in all 3 stages was closely related to original meaning of "landscape",which proved that timber-framed arch bridge heritage had profound inside information,and the safeguarding of timber-framed arch bridge from the perspective of cultural landscape heritage was worth further study.Safeguarding of timber-framed arch bridge cultural landscape heritage focused on integrated conservation,but not protection of individual bridges.Integrated conservation of world heritage is to maintain and restore the integrated environment landscape of the heritage,thus protection of timber-framed arch bridge heritage is not only to explore its architectural craftsmanship,but also to lay a foundation for the dynamic succession of such craftsmanship as intangible cultural heritage.Value of the existing timber-framed arch bridges as historic building heritage was discussed,and it was proposed that ultimate objectives of the safeguarding could be realized step by step from 3 layers.
基金Project(51378503)supported by the National Natural Science Foundation of ChinaProject(2014M552158)supported by China Postdoctoral Science Foundation
文摘Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube(CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a(77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail(CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load.Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.
基金Federal Highway Administration(FHWA) Under Grant No.DTFH41-98900094
文摘In the 1990s, several major earthquakes occurred throughout the world, with a common observation that near fault ground motion （NFGM） characteristics had a distinct impact on causing damage to civil engineering structures that could not be predicted by using far field ground motions. Since then, seismic responses of structures under NFGMs have been extensively examined, with most of the studies focusing on structures with relatively short fundamental periods, where the traveling wave effect does not need to be considered. However, for long span bridges, especially arch bridges, the traveling wave （only time delay considered） effect may be very distinct and is therefore important. In this paper, the results from a case study on the seismic response of a steel arch bridge under selected NFGMs is presented by considering the traveling wave effect with variable apparent velocities. The effects of fling step and long period pulses of NFGMs on the seismic responses of the arch bridge are also discussed.
基金financially supported by the Guangxi Key Research and Development Plan Program(AB22036007).
文摘Arch bridges provide significant technical and economic benefits under suitable conditions.In particular,concrete-filled steel tubular(CFST)arch bridges and steel-reinforced concrete(SRC)arch bridges are two types of arch bridges that have gained great economic competitiveness and span growth potential due to advancements in construction technology,engineering materials,and construction equipment over the past 30 years.Under the leadership of the author,two record-breaking arch bridges—that is,the Pingnan Third Bridge(a CFST arch bridge),with a span of 560 m,and the Tian’e Longtan Bridge(an SRC arch bridge),with a span of 600 m—have been built in the past five years,embodying great technological breakthroughs in the construction of these two types of arch bridges.This paper takes these two arch bridges as examples to systematically summarize the latest technological innovations and practices in the construction of CFST arch bridges and SRC arch bridges in China.The technological innovations of CFST arch bridges include cable-stayed fastening-hanging cantilevered assembly methods,new in-tube concrete materials,in-tube concrete pouring techniques,a novel thrust abutment foundation for nonrocky terrain,and measures to reduce the quantity of temporary facilities.The technological innovations of SRC arch bridges involve arch skeleton stiffness selection,the development of encasing concrete materials,encasing concrete pouring,arch rib stress mitigation,and longitudinal reinforcement optimization.To conclude,future research focuses and development directions for these two types of arch bridges are proposed.
基金Projects(51478049,51778068)supported by the National Natural Science Foundation of ChinaProject(14JJ2075,2019JJ40301)supported by the Hunan Natural Science Foundation of China+1 种基金Project(17A010)supported by the Scientific Research Fund of Hunan Provincial Education Department of ChinaProject(2017GK4034)supported by the Major Technological Achievements Transformation Program of Hunan Strategic Emerging Industries of China
文摘Cantilever casting concrete arch bridge using form traveller has a broad application prospect.However,it is difficult to obtain reasonable initial cable force in construction stage.In this study,stress balance and influence matrix methods were developed to determine the initial cable force of cantilever casting concrete arch bridge.The stress balance equation and influence matrix of arch rib critical section were established,and the buckle cable force range was determined by the allowable stress of arch rib critical section.Then a group of buckle cable forces were selected and substituted into the stress balance equation,and the reasonable initial buckle cable force was determined through iteration.Based on the principle of force balance,the initial anchor cable force was determined.In an engineering application example,it is shown that the stress balance and influence matrix methods for the determination of initial cable force are feasible and reliable.The initial cable forces of arch rib segments only need to be adjusted once in the corresponding construction process,which improves the working efficiency and reduces the construction risk.It is found that the methods have great advantages for determining initial cable force in cantilever casting construction process of concrete arch bridge.
基金Projects(51378503,51178471) supported by the National Natural Science Foundation of China
文摘X-style arch bridge on high-speed railways(HSR)is one kind of complicated long-span structure,and the track-bridge interaction is essential to ensure the safety and smoothness of HSR.Taking an X-style steel-box arch bridge with a main span of450 m on HSR under construction for example,a new integrative mechanic model of rail-stringer-cross beam-suspenderpier-foundation coupling system was established,adopting the nonlinear spring element simulating the longitudinal resistance between track and bridge.The transmission law of continuous welded rail(CWR)on the X-style arch bridge was researched,and comparative study was carried out to discuss the influence of several sensitive factors,such as the temperature load case,the longitudinal resistance model,the scheme of longitudinal restraint conditions,the introverted inclination of arch rib,the stiffness of pier and abutment and the location of the rail expansion device.Calculating results indicate that the longitudinal resistance has a significant impact upon the longitudinal forces of CWR on this kind of bridge,while the arch rib’s inclination has little effect.Besides,temperature variation of arch ribs and suspenders should be taken into account in the calculation.Selecting the restraint system without longitudinally-fixed bearing and setting the rail expansion devices on both ends are more reasonable.
文摘This paper attempts to explore potential benefits of form in a deck-type reinforced concrete（RC） arch bridge in connection with its overall seismic behavior and performance. Through a detailed three-dimensional finite element modeling and analysis of an actual existing deck-type RC arch bridge, some useful quantitative information have been derived that may serve for a better understanding of the seismic behavior of such arch bridges. A series of the nonlinear dynamic analyses has been carried out under the action of seven different time histories of ground motion scaled to the AASHTO 2012 response spectrum. The concept of demand to capacity ratios has been employed to provide an initial estimation of the seismic performance of the bridge members. As a consequence of the structural form, a particular type of irregularity is introduced due to variable heights of columns transferring the deck loads to the main arch. Hence, a particular attention has been paid to the internal force/moment distributions within the short, medium, and long columns as well as along the main arch. A study of the effects of the vertical component of ground motion has demonstrated the need for the inclusion of these effects in the analysis of such bridges.
文摘This paper presents the first of a series of case studies on the seismic design of long span bridges （cable-stayed bridges, suspension bridges and arch bridges） under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that （1） the selected near field ground motions cause larger responses to key components （critical sections） of the bridge （such as arch rib ends） with a maximum increase of more than twice those caused by the site specific ground motions; （2） piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and （3） large vertical components of near field ground motions may not significantly affect the bridge＇s internal forces provided that their peak acceleration spectra ordinates only appear at periods of less than 0.2s. However, they may have more influence on the longitudinal displacements of sliding bearings due to their large displacement spectra ordinates at the fundamental period of the bridge.
文摘A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders is investigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.
文摘In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube （CFST） arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has been increasing rapidly, which is rare in the history of bridge development. The large-scale construction of expressways and high-speed railways demands the development of long-span arch bridges, and advances in design and construction techniques have made it possible to construct such bridges. In the present study, the current status, development, and major innovative technologies of CFST arch bridges and concrete arch bridges with a CFST skeleton in China are elaborated. This paper covers the key con- struction technologies of CFST arch bridges, such as the design, manufacture, and installation of steel tube arch trusses, the preparation and pouring of in-tube concrete, and the construction of the world＇s longest CFST arch bridge-the First Hejiang Yangtze River Bridge. The main construction technologies of rein- forced concrete arch bridges are also presented, which include cable-stayed fastening-hanging cantilever assembly, adjusting the load by means of stay cables, surrounding the concrete for arch rib pouring, and so forth. In addition, the construction of two CFST skeleton concrete arch bridges-the Guangxi Yongning Yong River Bridge and the Yunnan-Guangxi Railway Nanpan River Bridge--is discussed. CFST arch bridges in China have already gained a world-leading position; with the continuous innovation of key technologies, China will become the new leader in promoting the development of arch bridges.
文摘A review of the current status and progress of steel arch bridges in China is presented in this paper. The existing steel arch bridges in China were analyzed in terms of steel material, span, structure type, main arch rib form and construction method. The comparison with CFST arch bridges and RC arch bridges is also conducted. It is shown that steel arch bridge has gain rapid development in China since 2000, characterized by long main spans. As for the span, most of the steel arch bridges have a span less than 250 m, while when the span exceeds 350 m, steel arch bridges are strongly competitive against CFST or RC arch bridges. Over 80% of the bridges are through and half-through bridge types, and the arch ribs are hingeless structures. The rise-to-span ratios of the arches are mainly between 1：4 and 1： 5. Most of the arches use solid box ribs, and a small portion of arches use truss ribs in which box sections are mostly adopted for the truss members. The cantilever method and scaffolding method are the two main construction methods used, but some other construction methods have also been developed.
基金Projects(20-JKKJ-17,18-JKKJ-05)supported by the Shanxi Communications Holding Group Co.,Ltd.,ChinaProject(41907239)supported by the National Natural Science Foundation of China+1 种基金Project(2020M670698)supported by the China Postdoctoral Science FoundationProject(2019L0295)supported by the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China。
文摘Beipanjiang Bridge is a long-span concrete arch bridges with stiffened skeleton(CABSS)in China.It has a fixed end arch with the span of 445 m and the rise of 100 m.To evaluate the rationality of the construction sequence and the time-dependent behavior of CABSS,an experimental study of a model bridge was explored.But the measured displacement and stress ratios of arch rib between prototype and model bridge did not subject to linear similarity relation when the time-dependent behavior was considered.So,the three-dimensional finite element models were established,and verified by the measured data.Then,the displacements and stresses of the prototype and model were compared with each other,when the elastic analysis or coupling of temperature and shrinkage,creep effect was considered.Furthermore,a parametric study was studied.The results showed that when the temperature,shrinkage and creep effect of concrete are considered,the finite element analysis results of prototype and model agree well with the measured results.The displacement and stress ratios of prototype and model bridge in construction and bridge completed stage do not present the geometric similarity ratio 7.5 and 1.0,respectively.They are also much influenced by concrete predicting model and variation of temperature.
基金This work is supported by the Natural Science Foundation Projects of Liaoning Province(2019-ZD-0145).
文摘To numerically evaluate the reinforcement effect on dynamic characteristics of a concrete-filled steel tube arch bridge with vibration problems,a 12-degree-of-freedom sprung-mass dynamic vehicle model and a 3D finite element bridge model were established.Then,the coupled equations of vehicle-bridge interaction were derived and a computer program was developed using the FORTRAN language.This program can accurately simulate vehicle-bridge coupled vibration considering the bumping effect and road surface irregularity during motion of the vehicle.The simulated results were compared with those of relevant literatures to verify the correctness of the self-developed program.Then,three reinforcement schemes for the bridge(Addition of longitudinal beams,Reinforcement of bridge decks,and Replacement of suspenders)were proposed and numerically simulated,and the vibration reduction effects of the three schemes were evaluated based on the numerical results to find effective ones.It is confirmed that the reinforcement scheme of Addition of longitudinal beams shows the most significant vibration reduction effect.It is recommended in the engineering practice that the combination of the reinforcement schemes of Addition of longitudinal beams and Replacement of bridge deck can be used to solve the excessive vibration problem.
基金supported by the Elite Scholar Program of Northwest A&F University (Grant No.Z111022001)the Research Fund of Department of Transport of Shannxi Province (Grant No.22-23K)the Student Innovation and Entrepreneurship Training Program of China (Project Nos.S202110712555 and S202110712534).
文摘A huge number of old arch bridges located in rural regions are at the peak of maintenance.The health monitoring technology of the long-span bridge is hardly applicable to the small-span bridge,owing to the absence of technical resources and sufficient funds in rural regions.There is an urgent need for an economical,fast,and accurate damage identification solution.The authors proposed a damage identification system of an old arch bridge implemented with amachine learning algorithm,which took the vehicle-induced response as the excitation.A damage index was defined based on wavelet packet theory,and a machine learning sample database collecting the denoised response was constructed.Through comparing three machine learning algorithms:Back-Propagation Neural Network(BPNN),Support Vector Machine(SVM),and Random Forest(R.F.),the R.F.damage identification model were found to have a better recognition ability.Finally,the Particle Swarm Optimization(PSO)algorithm was used to optimize the number of subtrees and split features of the R.F.model.The PSO optimized R.F.model was capable of the identification of different damage levels of old arch bridges with sensitive damage index.The proposed framework is practical and promising for the old bridge’s structural damage identification in rural regions.
文摘This design is about Chongqing Wanzhou district KanKan river crossing test evaluation and reinforcement renovation. The bridge is an open spandrel stone arch bridge. After years of operating, defects arise from different parts. To verify whether the bridge meets the bearing capacity of highway grade I standard, this design firstly evaluates the bridge through the apparent diseases. Then it uses Midas/Civil to calculate the bearing capacity of lateral control section for Zhou Jiaba arch foot, L/4 and arch section. Using Midas/Civil control section load calculation, load test plan is made. In the end, by increasing cross-section method, the bridge reinforcement maintenance plan is made;that is increasing abdominal 26 cm concrete layer in the main arch ring of arch so that the bridge meets grade I highway capacity requirements.
文摘A well⁃preserved ancient stone arch bridge dating back to the Ming Dynasty(1368-1644)has been uncovered in Songxi County,East China's Fujian Province,amid China's ongoing fourth national cultural relic census,China News Service reported.The discovery was made during an on⁃site in⁃spection in Songxi,according to He Lixing.
基金Sponsored by social science research program of Fujian Provincial Department of Education(JA11300S)Special program of "East Fujian Culture Research"(2011HW05)Key project of Ningde Normal University(2010J002)
文摘On the basis of investigating wooden arch gallery bridges in China,perspectives of researchers studying wooden arch gallery bridges in northeast Fujian Province were reviewed,and the innovativeness of researches from the perspectives of cultural geography and significance of wooden arch gallery bridge for the locals’behaviors was proposed.Youxi Village in Qinyang Town,Shouning County,known as the Village of Gallery Bridge,was taken for example to analyze physical,spiritual and social properties of its wooden arch gallery bridge spaces.Wooden arch gallery bridge is an effective boundary point of settlement space,constituting natural ecological spaces and man-made physical spaces of rural settlements.And as a type of building space,wooden arch gallery bridge expands settlement spaces,contributes to settlement cultures,and enriches spiritual connotations of regional cultures.In northeast Fujian,wooden arch gallery bridge is an important social space for the locals’daily life by carrying on living,production and spiritual functions.
