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19 pages, 17780 KiB

Open AccessArticle

Research on a Bridge Hybrid Isolation Control System Based on PID Active Control and Genetic Algorithm Optimization

by Ning Li, Ying Sheng, Wenjie Zheng, Zhenchao Yang, Zhonghai Zhang and Yanmei Li

Appl. Sci. 2024, 14(20), 9512; https://doi.org/10.3390/app14209512 - 18 Oct 2024

Viewed by 492

Abstract

A bridge hybrid isolation system, integrating both active and passive control strategies, is proposed and investigated to enhance seismic performance. The system is modeled as a two-layer structure, with the upper layer subjected to active control via a Proportional–Integral–Derivative (PID) controller, and the [...] Read more.

A bridge hybrid isolation system, integrating both active and passive control strategies, is proposed and investigated to enhance seismic performance. The system is modeled as a two-layer structure, with the upper layer subjected to active control via a Proportional–Integral–Derivative (PID) controller, and the lower layer employing a conventional passive base isolation system. The displacement response of the superstructure is minimized by the control forces generated by the PID controller, which also accounts for the reaction forces transmitted to the lower isolation layer. To optimize the controller’s performance, a genetic algorithm is implemented for real-time tuning of the PID parameters. Numerical simulations, conducted using the Newmark method, are employed to assess the influence of active control on the lower isolation system. The results reveal that, while active control increases the peak displacement of the superstructure to some extent, it significantly prolongs the structural period, thus enhancing the system’s overall seismic resilience and stability. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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15 pages, 7071 KiB

Open AccessArticle

A Study on the Design of a New Three-Dimensional Seismic Isolation Bearing Based on an Improved Genetic Algorithm for Bridge Engineering

by Ying Sheng, Zhenchao Yang, Yu Meng and Bin Jia

Appl. Sci. 2024, 14(20), 9453; https://doi.org/10.3390/app14209453 - 16 Oct 2024

Viewed by 611

Abstract

(1) Background: In most cases, passive isolation control methods are commonly used for the seismic isolation design in bridge engineering. However, passive seismic isolation devices, due to their non-adjustable performance parameters, struggle to achieve effective seismic isolation across a wide frequency range of [...] Read more.

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

(This article belongs to the Special Issue Bridge Structural Analysis)

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18 pages, 7492 KiB

Open AccessArticle

Experimental and Numerical Analysis of an Innovative Combined String–Cable Bridge

by Edmundas Beivydas and Algirdas Juozapaitis

Appl. Sci. 2024, 14(17), 7542; https://doi.org/10.3390/app14177542 - 26 Aug 2024

Viewed by 625

Abstract

Suspension bridges, such as stress-ribbon, are among the simplest structural bridge systems and have the lowest structural height. The flexibility of these elegant bridges poses great challenges for designers to minimize their deformability under asymmetrical operational loads. Due to the small initial sag, [...] Read more.

Suspension bridges, such as stress-ribbon, are among the simplest structural bridge systems and have the lowest structural height. The flexibility of these elegant bridges poses great challenges for designers to minimize their deformability under asymmetrical operational loads. Due to the small initial sag, such load-bearing structures also cause significant tensile forces, which requires them to have large cross-sections and massive anchor foundations. This paper analyzes an innovative suspension steel bridge structure combined with a string and a cable. More attention is paid to asymmetric loading as this is more relevant for suspension structures. The new structure is studied numerically and experimentally. It is established that the string stabilizes the displacements of the bridge under asymmetric loading. The stabilization efficiency is proportional to the value of the pre-tension force of the string. The obtained results reveal the behavior of the structure and enable an evaluation of the accuracy of the numerical results, as well as the applied modeling. In addition, the experimentally obtained results allow the evaluation of more aspects of the behavior of the new bridge, which will be useful in further studies of this type of structures. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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12 pages, 4134 KiB

Open AccessArticle

Characteristics Comparison and Case Study of Traditional Anti-Slip Saddles and Innovative Rolling Saddles in Highway Long-Span Bridges

by Jun Wan, Gang Liu and Zhendong Qian

Appl. Sci. 2024, 14(12), 5290; https://doi.org/10.3390/app14125290 - 19 Jun 2024

Viewed by 629

Abstract

The cable saddle structure is the main support component for long-span bridges to transmit cable force, which is of great significance for the structural force system. Nowadays, the main cable saddle structures used in long-span bridges are mainly traditional anti-slip saddles and innovative [...] Read more.

The cable saddle structure is the main support component for long-span bridges to transmit cable force, which is of great significance for the structural force system. Nowadays, the main cable saddle structures used in long-span bridges are mainly traditional anti-slip saddles and innovative rolling saddles. To clarify the characteristics of the saddles in long-span bridges, the design principles, mechanical properties, and casting process of these two types of saddle structures were researched. A rolling saddle in a bridge project was taken as an example and its mechanical situation in the roller area was investigated. The results showed that the stress concentration phenomenon is prone to occurring in the rolling saddle because of the line contact in the contact area and the rolling saddle is mainly subjected to vertical force. Thus, attention should be paid to the von Mises stress in the contact area between the saddle base and the roller shaft, the lower surfaces of both ends of the roller shaft, and the top surface of the tower, to avoid material damage. Furthermore, the casting process of the anti-slip saddle structure is mature, but also faced with problems due to the welding of thick plates, and urgently needs to be improved and upgraded. The rolling saddle is used with the all-welded casting process, but its technology is relatively immature and the requirements for the roller shaft material performance are strict. The research results can provide a reference for the selection and design of the saddle structure in long-span bridges. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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19 pages, 4926 KiB

Open AccessArticle

Effect of Subsequent Subgrade on Seismic Response of the High-Speed Railway Track–Bridge System

by Biao Wei, Shuaijie Yuan, Lizhong Jiang, Yujie Yu, Binqi Xiao, Jun Chen, Ruimin Zhang, Zhixing Yang and Shuaijun Li

Appl. Sci. 2024, 14(12), 5037; https://doi.org/10.3390/app14125037 - 10 Jun 2024

Cited by 1 | Viewed by 1081

Abstract

As an important part of the boundary conditions on both sides of the high-speed railway track–bridge system, the seismic response of the subgrade structure is different from that of the bridge structure. This difference has become increasingly significant with the widespread adoption of [...] Read more.

As an important part of the boundary conditions on both sides of the high-speed railway track–bridge system, the seismic response of the subgrade structure is different from that of the bridge structure. This difference has become increasingly significant with the widespread adoption of continuous welded rail technology in bridge construction. Therefore, investigating the seismic response of the bridge system, with a specific focus on the longitudinal constraint effects of the subsequent subgrade track structure, is of paramount importance. Utilizing finite element software, two distinct bridge models are developed: one incorporating the subsequent subgrade track structure and another excluding it. Through nonlinear time history analysis under varying seismic intensities, it is demonstrated that the longitudinal constraint of the subsequent subgrade track structure mitigates the longitudinal displacements and internal forces in critical components of the high-speed railway track–bridge system. Concurrently, acknowledging the heightened complexity and cost associated with post-earthquake repairs of the bridge structure compared to subgrade structure, this study uses a risk transfer connecting beam device. This device can redirect seismic damage from bridge structure to subgrade structure, thereby potentially reducing post-seismic repair expenses for the bridge. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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24 pages, 4037 KiB

Open AccessArticle

Shear Lag Effect of Ultra-Wide Box Girder under Influence of Shear Deformation

by Yanfeng Li, Jiyuan Xie, Fengchi Wang and Yuanhui Li

Appl. Sci. 2024, 14(11), 4778; https://doi.org/10.3390/app14114778 - 31 May 2024

Viewed by 573

Abstract

The objective of this study was to determine the reasonable flexural functions of ultra-wide box girders, reveal the mechanism of the shear lag effect, and improve the analysis theory of ultra-wide box girders. Considering a single-box three-chamber thin-walled box girder as an example, [...] Read more.

The objective of this study was to determine the reasonable flexural functions of ultra-wide box girders, reveal the mechanism of the shear lag effect, and improve the analysis theory of ultra-wide box girders. Considering a single-box three-chamber thin-walled box girder as an example, starting from an uneven transfer of shear flow, the flexural displacement function of the curved box girder under the influence of shear deformation of each plate was derived according to the flexural theory of a thin-walled box girder, balance equation of a thin-walled microelement plate, and theory of plane stress. The energy variational method was used to analyze the flexural displacement function, providing a theoretical solution for the shear lag effect of the curved box girder. A displacement correction of the cantilever plate displacement function was performed by comparing the calculation results for the shear lag coefficients. The results indicated that under the shear deformation of each plate, the flexural displacement functions of the wing and web plates of the box girder no longer satisfy the assumption of plane section. The flexural displacement function is a quadratic function of the transverse wing plate, and the web height is the sum of the first- and third-order functions. The theoretical calculation results agree sufficiently well with the experimental results, proving that the flexural displacement function of the box girder under the influence of the shear deformation of each plate is reliable. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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18 pages, 7610 KiB

Open AccessArticle

Investigation of the Mechanical Features of Steel–Concrete Composite Girder Rigid Frame Bridges with V-Shaped Piers during Construction Stages

by Yong Zeng, Tao Yu, Yunchuan Xiao and Weilong Li

Appl. Sci. 2024, 14(8), 3343; https://doi.org/10.3390/app14083343 - 16 Apr 2024

Cited by 2 | Viewed by 1660

Abstract

Steel–concrete composite girder rigid frame bridges with V-shaped piers are a new type of bridge structure. Based on the traditional composite continuous beam bridge, part or all of the vertical piers are changed into V-shaped piers. This special structure makes them have the [...] Read more.

Steel–concrete composite girder rigid frame bridges with V-shaped piers are a new type of bridge structure. Based on the traditional composite continuous beam bridge, part or all of the vertical piers are changed into V-shaped piers. This special structure makes them have the mechanical characteristics of both composite continuous beams and V-shaped piers. In this paper, the finite element model of the first steel–concrete composite continuous beam V-pier rigid frame bridge in China is established by simulation software, the construction process of the bridge is simulated, and the stress and deflection of the bridge in each construction stage are studied. At the same time, the stress of the completed bridge model considering the construction stage is compared with that of the completed bridge model without considering the construction stage. It is found that the stress difference between the two concrete slabs is as high as 2.7 MPa. The results show that the stress state of the bridge is greatly affected by the construction process. This study can provide guidance for the design and construction of such bridges, which is of great significance. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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27 pages, 12488 KiB

Open AccessArticle

Entropy Wavelet-Based Method to Increase Efficiency in Highway Bridge Damage Identification

by Jose M. Machorro-Lopez, Jesus J. Yanez-Borjas, Martin Valtierra-Rodriguez and Juan P. Amezquita-Sanchez

Appl. Sci. 2024, 14(8), 3298; https://doi.org/10.3390/app14083298 - 14 Apr 2024

Cited by 1 | Viewed by 733

Abstract

Highway bridges are crucial civil constructions for the transport infrastructure, which require proper attention from the corresponding institutions of each country and constant financing for their adequate maintenance; this is important because different types of damage can be generated within these structures, caused [...] Read more.

Highway bridges are crucial civil constructions for the transport infrastructure, which require proper attention from the corresponding institutions of each country and constant financing for their adequate maintenance; this is important because different types of damage can be generated within these structures, caused by natural disasters, among other sources, and the heavy loads they transport every day. Therefore, the development of simple, efficient, and low-cost methods is of vital importance, allowing us to identify damage in a timely manner and avoid bridges collapsing. As reported in a previous work, the wavelet energy accumulation method (WEAM) and its corresponding application in the Rio Papaloapan Bridge (RPB) represented an important advance within the field. Despite identifying damage in bridges with precision and at a low cost, there are several aspects to improve in that method. Therefore, in this work, that method was improved, eliminating several steps, and meaningfully reducing the computational burden by implementing an algorithm based on the Shannon entropy, thus giving way to the new entropy wavelet-based method (EWM). This new method was applied directly with regard to the real-life RPB, in both its healthy and damaged conditions. Also, its corresponding numerical model based on the finite element method in its healthy condition and different damage scenarios were carried out. The results indicate that the new EWM retains the advantages of WEAM, and it allows for damage identification to be completed more efficiently, increasing the precision by approximately 0.11%, and significantly reducing the computing time required to obtain results by 5.67 times. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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15 pages, 7729 KiB

Open AccessArticle

Experimental Study on Flexural Resistance of UHPC Wet Joint Precast Reinforced Concrete Bridge Deck Slabs with Variable Cross-Section

by Jiaqi Hu, Yin Gu, Jinhuang Yan, Ying Sun and Xinyi Huang

Appl. Sci. 2024, 14(7), 3028; https://doi.org/10.3390/app14073028 - 4 Apr 2024

Cited by 1 | Viewed by 1202

Abstract

With the convenient and fast requirements for construction in bridge engineering, prefabricated assembly technology is widely applied in engineering construction. Typically, prefabricated bridge decks are connected through cast-in-place wet joints. Wet joints, as the primary load-bearing parts of bridge decks, undergo complex stress [...] Read more.

With the convenient and fast requirements for construction in bridge engineering, prefabricated assembly technology is widely applied in engineering construction. Typically, prefabricated bridge decks are connected through cast-in-place wet joints. Wet joints, as the primary load-bearing parts of bridge decks, undergo complex stress and are prone to cracking and damage. Particularly in the negative bending moment region of bridges, the influence of tensile stress on wet joints is more severe, thus enhancing the mechanical performance and crack resistance of joints becomes crucial. This paper investigates the mechanical behavior of prefabricated reinforced concrete bridge deck panels with variable cross-sections under negative bending moments, focusing on the performance of Ultra High-Performance Concrete (UHPC) wet joints. Full-scale experimental tests were conducted on a 176 m steel truss composite continuous rigid bridge, employing C50 concrete panels with UHPC wet joints. Results show three distinct stages: elastic, crack initiation and propagation, and failure. The maximum failure load reached 822 kN, with a maximum displacement of 21.64 mm. Concrete strains indicate compressive stress near the wet joint and tensile stress near the loading positions. Cracks primarily develop at the wet joint interface and propagate under increasing load, ultimately leading to flexural–shear failure near the variable cross-section of the wet joint. Numerical simulations using ABAQUS/CAE (2020) corroborate experimental findings, closely matching load-displacement curves and identifying damage locations. The study demonstrates that UHPC wet joints significantly enhance crack resistance, meeting design requirements for improved mechanical performance in bridge structures subjected to negative bending moments. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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30 pages, 41188 KiB

Open AccessArticle

Analytical Method of the Shear Lag Effect in Thin-Walled Box Girders Based on the Shear Flow Distribution Law

by Yuan Shi, Shijun Zhou, Gang Wang and Cao Zhou

Appl. Sci. 2024, 14(2), 828; https://doi.org/10.3390/app14020828 - 18 Jan 2024

Viewed by 1207

Abstract

This paper presents an analytical method based on the shear flow distribution law to study the shear lag effect of thin-walled single- and double-cell box girders. The first step in this method is to determine the box girder’s shear flow distribution. Subsequently, a [...] Read more.

This paper presents an analytical method based on the shear flow distribution law to study the shear lag effect of thin-walled single- and double-cell box girders. The first step in this method is to determine the box girder’s shear flow distribution. Subsequently, a series of novel improved longitudinal displacement functions mathematically expressed as cubic parabolas are established. The parabolic origin of these functions is located at the zero point of the shear flow corresponding to each plate; the unknown parameters used to describe the function form can be determined according to the shear flow distribution, the continuity conditions, and the axial force balance condition. Then, the variational energy method is adopted to derive the governing differential equations. The shear lag effect in thin-walled single- and double-cell box girders under several boundary conditions and load cases is studied and analytical expressions for the shear lag coefficient are derived. Finally, results obtained using the proposed method are validated via comparison with numerical results. The results show that the proposed method can provide reasonable predictions for the shear lag effect of single- and double-cell box girders, and that this method is more straightforward and practical. In addition, the shear lag coefficients at different webs are not entirely equal, which is related to the distance from the web to the zero point of the shear flow. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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16 pages, 2916 KiB

Open AccessArticle

Observing Material Properties in Composite Structures from Actual Rotations

by Seyyedbehrad Emadi, Yuan Sun, Jose A. Lozano-Galant and Jose Turmo

Appl. Sci. 2023, 13(20), 11456; https://doi.org/10.3390/app132011456 - 19 Oct 2023

Viewed by 1064

Abstract

The shear deflection effects are traditionally neglected in most structural system identification methods. Unfortunately, this assumption might lead to significant errors in some structures, like deep beams. Although some inverse analysis methods based on the stiffness matrix method, including shear deformation effects, have [...] Read more.

The shear deflection effects are traditionally neglected in most structural system identification methods. Unfortunately, this assumption might lead to significant errors in some structures, like deep beams. Although some inverse analysis methods based on the stiffness matrix method, including shear deformation effects, have been presented in the literature, none of these methods are able to deal with actual rotations in their formulations. Recently, the observability techniques, one of the first methods for the inverse analysis of structures, included the shear effects into the system of equations. In this approach, the effects of the shear rotation are neglected. When actual rotations on-site are used to estimate the mechanical properties in the inverse analysis, it can result in serious errors in the observed properties. This characteristic might be especially problematic in structures such as deep beams where only rotations can be measured. To solve this problem and increase the observability techniques’ applicability, this paper proposes a new approach to include the shear rotations into the inverse analysis by observability techniques. This modification is based on the introduction of a new iterative process. To illustrate the applicability and potential of the proposed method, the inverse analysis of several examples of growing complexity is presented. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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27 pages, 7346 KiB

Open AccessArticle

The Structural Design and Optimization of Top-Stiffened Double-Layer Steel Truss Bridges Based on the Response Surface Method and Particle Swarm Optimization

by Lingbo Wang, Rongjie Xi, Xinjun Guo and Yinping Ma

Appl. Sci. 2023, 13(19), 11033; https://doi.org/10.3390/app131911033 - 7 Oct 2023

Cited by 1 | Viewed by 2734

Abstract

A lightweight design optimization algorithm is proposed to optimize the design parameters of stiffened double-layer steel girder bridges, the aim of which is to improve structural safety and reduce superstructure works. Taking a top-stiffened double-layer steel truss bridge as the reference project, a [...] Read more.

A lightweight design optimization algorithm is proposed to optimize the design parameters of stiffened double-layer steel girder bridges, the aim of which is to improve structural safety and reduce superstructure works. Taking a top-stiffened double-layer steel truss bridge as the reference project, a multiscale mixed-element model of the initial design parameters is established, and its computational accuracy is verified. Considering the structural configuration and loading characteristics of the bridge, the elastic modulus of steel, the deck plate thickness, the stiffening vertical bar height, and the relative distance between the double-layer main girders are selected as the design parameters for optimization. The mid-span vertical deflection, the axial forces in the stiffeners, the bottom plate of the deck, the compressed web tube at the pier top, and the quantity of superstructure works are chosen as the objective functions to be minimized. A lightweight calculation equation reflecting the relationship between the optimization parameters and the objective functions is established using the response surface method (RSM). Subsequently, an improved weighted particle swarm optimization (WPSO) model is employed to perform the multi-objective optimization of the design parameters for the bridge, and the results are compared with those obtained from the multi-objective genetic algorithm NSGA-II. The results show that the RSM accurately fits the numerical relationship between the optimization parameters and the objective response functions. When minimizing the quantity of superstructure works as the primary control objective and minimizing the mid-span vertical deflection and the axial forces in the compressed web tube at the pier top as secondary control objectives, the optimization results achieved by WPSO outperform those obtained by NSGA-II. The optimized results lead to reductions of 11.09%, 3.92%, 7.56%, 4.45%, and 8.38% in the respective objective function values of the structure. This method has important theoretical significance for the optimization of structural design parameters. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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13 pages, 6168 KiB

Open AccessArticle

The Maintenance Effect of Diaphragm-to-Rib Fatigue Cracks in Orthotropic Steel Deck via Steel Plate Reinforcement

by Xihua Dai, Xinmin Zhang, Cheng Meng, Yawei Guo, Yaoyu Zhu and Zhiyuan Yuanzhou

Appl. Sci. 2023, 13(18), 10368; https://doi.org/10.3390/app131810368 - 16 Sep 2023

Viewed by 944

Abstract

To investigate the maintenance effect of diaphragm-to-rib fatigue cracks via steel plate reinforcement, finite element models of different-shaped steel plates were established. Stress intensity factors at the crack tip before and after reinforcement were obtained, and the variations in stresses were studied. Polygonal [...] Read more.

To investigate the maintenance effect of diaphragm-to-rib fatigue cracks via steel plate reinforcement, finite element models of different-shaped steel plates were established. Stress intensity factors at the crack tip before and after reinforcement were obtained, and the variations in stresses were studied. Polygonal steel plate reinforcements were then carried out on a real bridge based on the finite element calculation results. The changes in stress amplitudes and fatigue damage degrees at the crack tip were analyzed via the rain-flow counting method and Miner’s linear damage accumulating theory. The results show that both the polygonal steel plate and the rectangular steel plate could effectively eliminate the stress concentration and restrain the propagation of cracks. The stresses in other parts of the arc notch increased after reinforcement and polygonal steel plates had less influence. After the reinforcement in a real bridge, the cycle number of high stress amplitudes at the crack tip decreased significantly. The fatigue damage degree of the repaired part reduced by 70.1%, which verified the maintenance effect via polygonal steel plate reinforcement on diaphragm-to-rib fatigue cracks. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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16 pages, 6608 KiB

Open AccessArticle

Sensitivity Analysis of Structural Parameters of Unequal-Span Continuous Rigid Frame Bridge with Corrugated Steel Webs

by Maojun Duan, Fei Wang, Yutian Wu, Hao Tao and Danping Zhang

Appl. Sci. 2023, 13(18), 10024; https://doi.org/10.3390/app131810024 - 5 Sep 2023

Cited by 1 | Viewed by 1025

Abstract

To investigate the effect of structural parameters of bridges with unequal spans on the bridge alignment, the finite element model simulating the full-scale bridge was developed, considering the construction process. For ease of finite element modeling and investigation, the section of composite beam [...] Read more.

To investigate the effect of structural parameters of bridges with unequal spans on the bridge alignment, the finite element model simulating the full-scale bridge was developed, considering the construction process. For ease of finite element modeling and investigation, the section of composite beam with corrugated steel web was first converted into the section composed of the same material. For this purpose, an equivalent method of replacing corrugated steel webs with concrete webs was proposed based on theoretical derivation. After equivalent replacement, the influences of material bulk density, internal prestress, pipe friction coefficient, and pipe deviation coefficient on the main beam at the maximum cantilever stage were analyzed, and the influences of external prestress on the main beam after bridge construction were analyzed. The results show that the most sensitive parameter to structural response is bulk density, subsequently the external prestress, internal prestress, pipe friction coefficient, and pipe deviation coefficient. Among them, the bulk density, internal prestress, and external prestress are all sensitive parameters, while pipe friction coefficient and pipe deviation coefficient are non-sensitive parameters. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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22 pages, 8838 KiB

Open AccessArticle

Fatigue Assessment of Cable-Girder Anchorage Zone in a Low Ambient Temperature Environment Based on Extended Finite Element Method

by Huating Chen, Yifan Zhuo, Yubo Jiao and Weigang Bao

Appl. Sci. 2023, 13(17), 9990; https://doi.org/10.3390/app13179990 - 4 Sep 2023

Cited by 2 | Viewed by 1126

Abstract

The fatigue safety of cable-girder anchorage structures in cable-stayed bridges under long-term service has attracted much attention. For bridges located in seasonally cold regions, the effect of low-temperature environments should be considered when evaluating fatigue performance. Using the Heilongjiang Bridge in China as [...] Read more.

The fatigue safety of cable-girder anchorage structures in cable-stayed bridges under long-term service has attracted much attention. For bridges located in seasonally cold regions, the effect of low-temperature environments should be considered when evaluating fatigue performance. Using the Heilongjiang Bridge in China as a case study, a room-temperature fatigue test with a numerical simulation that considers the low-temperature effect on both load effect and fatigue resistance was proposed. A fatigue test with increased testing load amplitude was performed on a 1:3.75 ratio specimen. After 3.2 million loading cycles and using an acoustic emission technique, no fatigue crack was observed in the anchorage structure. The extended finite element method was then adopted to analyze the anchorage zone’s fatigue crack initiation position and propagation path. Finally, based on the fatigue characteristics of bridge steel, the fatigue resistance to the crack propagation of the vulnerable area was evaluated under three different service conditions. The results show that the fatigue performance of the anchorage zone at low temperatures is sufficient. Moreover, this paper provides a more widely applicable and cost-effective approach for the fatigue evaluation of steel bridges. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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21 pages, 7942 KiB

Open AccessArticle

Long-Term Deflection Analysis of Large-Span Continuous Prestressed Concrete Rigid-Frame Bridges Based on a Refined Modeling Approach

by Xu Han, Wanheng Li and Pengfei Li

Appl. Sci. 2023, 13(17), 9727; https://doi.org/10.3390/app13179727 - 28 Aug 2023

Cited by 3 | Viewed by 2225

Abstract

Numerical modeling approaches are favored for performing long-term analyses of continuous prestressed concrete rigid-frame (CPCR) bridges due to the complexity and high cost of experimental testing on such structures. In this study, a refined numerical modeling approach is first presented and validated by [...] Read more.

Numerical modeling approaches are favored for performing long-term analyses of continuous prestressed concrete rigid-frame (CPCR) bridges due to the complexity and high cost of experimental testing on such structures. In this study, a refined numerical modeling approach is first presented and validated by comparing the field monitor data of an existing long-span CPCR bridge in China. Then, long-term deflection analysis—considering box girder cracks, concrete creep, joint damage behavior and prestress—is conducted based on the proposed refined modeling approach. It is found that the time-dependent loss of longitudinal prestress has the most significant influence on the long-term structural stiffness, while joint damage between different segments has limited impact on overall structural performance, especially for large-span bridge cases. The local stress distribution is significantly influenced by typical damage, albeit with a different scope of impact. Therefore, targeted reinforcement has to be performed to achieve satisfactory repair results under different damage conditions. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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14 pages, 7181 KiB

Open AccessArticle

Notch Fatigue Life Research Based on Critical Distance Theory

by Jifa Chen, Hao Ni, Li Huang, Yu Yang and Zhuoyi Chen

Appl. Sci. 2023, 13(17), 9641; https://doi.org/10.3390/app13179641 - 25 Aug 2023

Viewed by 1161

Abstract

Orthotropic anisotropic steel bridge panels are widely used in civil engineering due to their advantages of light deadweight, high ultimate bearing capacity, and wide range of applications. However, their fatigue problem is serious, and the fatigue-resistant design of the steel box girder diaphragm [...] Read more.

Orthotropic anisotropic steel bridge panels are widely used in civil engineering due to their advantages of light deadweight, high ultimate bearing capacity, and wide range of applications. However, their fatigue problem is serious, and the fatigue-resistant design of the steel box girder diaphragm curved cutout is still difficult. In order to effectively predict the fatigue life of this typical fatigue-susceptible detail, a fatigue test of the specimen with curved notched segments of the diaphragm was carried out. ABAQUS 2016 version finite element analysis software was used to establish three kinds of finite element simplified models of the fatigue specimens with curved notches, and the laws of the influence of different notch radii on the fatigue life of the specimens were studied. Through the finite element solution of the three arc notch specimen models with different radii under the tensile load of 50 kN their respective principal stress distributions were obtained. The critical distance theory was introduced to analyze the characteristic stresses in the stress concentration area of the arc notch, and the point method and line method were used to calculate the characteristic stresses. The fatigue life prediction models of three kinds of notched components were established by combining the material fatigue limit and FE-safe life results. The results show that the point method is more conservative than the line method; no matter if the point method or the line method is used, the characteristic stress and the notch radius are inversely proportional to each other, and it is beneficial for the fatigue life of the structure to appropriately increase the notch radius. The fatigue prediction model of steel box girder diaphragms with curved notches based on the critical distance theory is of high accuracy, which is basically consistent with the test results, verifying the feasibility of the critical distance theory in the fatigue life prediction of notched specimens, and providing a reference for the fatigue life assessment of similar steel structures. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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17 pages, 6067 KiB

Open AccessArticle

Analysis of the Temperature Field Effect on the Thermal Stress of the Main Tower of Long-Span Suspension Bridges

by Maojun Duan, Juntian Zhu, Zhong Gu, Zijun Fang and Jiaying Xu

Appl. Sci. 2023, 13(15), 8787; https://doi.org/10.3390/app13158787 - 29 Jul 2023

Cited by 1 | Viewed by 1252

Abstract

To investigate the temperature field variation of the main tower of large-span suspension bridges, the Nanjing Xinshengwei Yangtze River Bridge was selected as the objective of the present study. The finite element model of the main tower was developed, and the analysis of [...] Read more.

To investigate the temperature field variation of the main tower of large-span suspension bridges, the Nanjing Xinshengwei Yangtze River Bridge was selected as the objective of the present study. The finite element model of the main tower was developed, and the analysis of the effect of the temperature field on the structure of the main tower was carried out. The calculation parameters of the temperature field of the main tower were determined, and the influence of the solar radiation temperature of the main tower within 24 h was investigated. Differences in the temperatures inside and outside the wall of the tower column were analyzed, and the thermal stress of the tower wall under the most unfavorable temperature difference was calculated. Results show that under the positive temperature difference, the area of tensile stress is mainly concentrated on the inner wall, the maximum value is located at the corner of the intersection of the tower wall, and the range of tensile stress is mainly diffused along the vertical wall. Under the action of negative temperature difference, the area of tensile stress is mainly concentrated in the outer tower wall, the maximum value is located in the upper part of the western outer tower wall, and the range of tensile stress is mainly diffused along the center of the tower wall to both sides. The maximum tensile stresses in the inner and outer tower wall are 2.8 MPa and 1.3 MPa, respectively, which meets the standard value of 2.85 MPa for the tensile strength of C60 concrete specified in the Chinese national standard. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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21 pages, 18099 KiB

Open AccessArticle

Implications of Arch Warp Altitudes on an Ancient Masonry Bridge under Ground Movements

by Memduh Karalar and Mustafa Yeşil

Appl. Sci. 2023, 13(13), 7395; https://doi.org/10.3390/app13137395 - 22 Jun 2023

Cited by 5 | Viewed by 1252

Abstract

Although only a few of the ancient masonry arch bridges (MABs) are in fairly good condition today, many ancient arch bridges are still in use. Over time, the condition of the masonry bridges declines and the safety requirements change. Therefore, it is important [...] Read more.

Although only a few of the ancient masonry arch bridges (MABs) are in fairly good condition today, many ancient arch bridges are still in use. Over time, the condition of the masonry bridges declines and the safety requirements change. Therefore, it is important to examine these bridges under different influences. The strengthening of MABs is generally not essential. The major cause of damage to MABs is their insufficient width and height, and thus, it is not the safety but the usability that has restricted the life-time of the MABs. Therefore, in this investigation, the effect of the arch height on the static and dynamic behavior of a single-span MAB was investigated. For this aim, the Ancient Tokatlı Bridge, built in Karabük, Türkiye, was selected for investigation under near-fault (NF) and far-fault (FF) ground motions (GMs). To observe the altitude of the arch warp on the ancient MAB, first, the finite element model (FEM) was utilized, using ANSYS and SAP 2000. Furthermore, to constitute the arch warp’s influence on a MAB, the FEM was remodeled considering the different arch warps between 7.0 and 9.0 m. Moreover, GMs were applied to the FEM to investigate the effect of dynamic behavior. Under these GMs, stresses and strains (compression and tensile) were observed and compared with each other. Consequently, at the end of these investigations, it was observed that the maximum motions were reduced, while the height of the one-span MAB was increased under NF and FF GMs, and this was also true for the contrary situations. The compression stresses were not observed to be hazardous at the point of destruction, while the altitude of the one-span MAB increased. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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16 pages, 4481 KiB

Open AccessArticle

Numerical Investigation on Novel Shear Connectors in Prefabricated Composite Beams

by Chengjun Li, Zhixiang Zhou, Huan Wang, Yanmei Gao and Liang Fan

Appl. Sci. 2023, 13(10), 6130; https://doi.org/10.3390/app13106130 - 17 May 2023

Cited by 1 | Viewed by 1313

Abstract

An innovative horizontal-arranged shear stud was proposed for prefabricated composite beams, in response to the engineering demand for accelerated precast decks construction on steel–concrete composite bridges. In order to verify the shear behavior of the studs, a push-out test was performed in which [...] Read more.

An innovative horizontal-arranged shear stud was proposed for prefabricated composite beams, in response to the engineering demand for accelerated precast decks construction on steel–concrete composite bridges. In order to verify the shear behavior of the studs, a push-out test was performed in which two groups of specimens were designed, and each group included three specimens. In addition, a finite element method based on the ABAQUS2020 software was adopted to analyze the influence factors of the prefabricated studs, which reveals the most influential factor, to provide a guide for optimum design. Therefore, 10 models were established, including one finite element model with the same parameters as the push-out test, and 9 models based on an orthogonal testing design. The results showed that, firstly, the prefabricated shear studs had longitudinal shear resistance, the same as conventional shear studs. Secondly, the ultimate load capacity, as well as the ductility of the prefabricated studs, was better than conventional studs. Thirdly, the modeling results were in good agreement with the push-out test results, which indicated the validity of the modeling method. Lastly, by analyzing the calculated results of the nine orthogonal models, it was found that the stud diameter was the most influential factor for the shear capacity, and the shear capacity was directly proportional to the stud diameter, while it was not proportional to the other factors. This study is evidence that the orthogonal testing design has a high efficiency in finite element modeling, which will provide a guide for the optimum design of prefabricated shear studs. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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22 pages, 8598 KiB

Open AccessArticle

Pavement Strategy Optimization of Cable-Stayed Bridges against the Negative Reaction Risks of Auxiliary Piers

by Yunteng Bai, Xiaoming Wang, Xudong Wang, Huan Wang, N. Frederic C. Tchuente and Wentao Wu

Appl. Sci. 2023, 13(8), 4877; https://doi.org/10.3390/app13084877 - 13 Apr 2023

Cited by 2 | Viewed by 1758

Abstract

Because the adjustment of the stay cable tension and girder counterweight is limited at the operation stage it is a difficult problem to control the negative reaction risk of the auxiliary pier (NRRAP) caused by multisource construction uncertainties and traffic growth. This paper [...] Read more.

Because the adjustment of the stay cable tension and girder counterweight is limited at the operation stage it is a difficult problem to control the negative reaction risk of the auxiliary pier (NRRAP) caused by multisource construction uncertainties and traffic growth. This paper proposes a pavement strategy optimization to control the NRRAP by adjusting the pavement thickness. The pavement strategy optimization is formulated as a reliability-constrained, multiobjective optimization problem, which is resolved by the nondominated sorting genetic algorithm (NSGA-II). A sensitivity analysis and a reliability analysis based on the generalized regression neural network (GRNN) surrogate model were performed to illustrate the significance of the uncertainty level in auxiliary pier negative reactions. The Pareto front examines the balance of construction cost, driving comfort and specified reliability threshold. The efficiency and accuracy of the proposed method are validated in a real cable-stayed bridge, and the results exhibit its advantages in controlling the NRRAP. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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Review

Jump to: Research

27 pages, 7316 KiB

Open AccessReview

A Review of the Network Arch Bridge

by Alexandra Denisa Danciu, Ștefan I. Guțiu, Cătălin Moga, Mihai L. Dragomir, Mădălina Ciotlăuș and Vladimir Marusceac

Appl. Sci. 2023, 13(19), 10966; https://doi.org/10.3390/app131910966 - 4 Oct 2023

Cited by 2 | Viewed by 4605

Abstract

The network arch bridge (NAB) is a new structural form of arch bridge that was devised 60 years ago by the Norwegian engineer Per Tveit, who is now prof. dr. docent emeritus at the University of Agder, Norway. The network arch is a [...] Read more.

The network arch bridge (NAB) is a new structural form of arch bridge that was devised 60 years ago by the Norwegian engineer Per Tveit, who is now prof. dr. docent emeritus at the University of Agder, Norway. The network arch is a tied-arch (also known as a bowstring-arch) bridge that combines the benefits of tied-arch bridges and trusses in a single system. While in a classical tied arch, the hangers are vertical, in a network arch, the suspension of the deck to the arch is ensured through a network of inclined hangers that intersect each other at least twice. Thus, the core of the NAB is the hanger arrangement that minimizes the bending moment in the arch to very small values, leading to compression in the arch. Compression with only small bending leads to very slender cross-sections for the elements of the bridge, and deep reductions in terms of materials used and economic and environmental costs. This paper reviews the research into the structural form proposed by Per Tveit and extended by researchers and engineers worldwide. The research methodology included bibliometric literature research, obtained by interrogating the ISI Web of Science (WoS) database and the cited references from the articles on WoS. While the first structural form of a network arch is still in use today and it has proven to be a good idea for spans around 100–120 m, engineers worldwide devised new bridge cross-sections. A brief view of the types of bridge cross-section in use today is given, with details about the bridges chosen as representative. Using analysis of Prof. Tveit’s map, Structurae database and literature review, a database of the network arches around the world was created, emphasizing the development of network arches from the perspectives of continental distribution, opening year, number of structures in different structural forms, and bridge purposes. The structural form was assessed from the perspective of materials used for the arch and the tie, span, purpose and number of lanes, the presence/absence of upper wind-bracings and arch disposition in the vertical plane. In the last part of this review, the newest research into the development of the network arch is discussed. In the past 15 years we have seen an acceleration in network arch development from multiple perspectives: new materials used, such as glulam for the arch or carbon fiber-reinforced plastic for the hangers; span lengths of 250 m and 380 m for large bridge widths; architectural constraints that lead to the outward inclination of the arch, that is pleasing to the eye, but difficult to address from an engineering perspective; the most slender arch bridge in the world, with very slender cross-sections for the arch and the tie. Full article

(This article belongs to the Special Issue Bridge Structural Analysis)

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