Considering frictional slippage at saddle-cable interface in seismic behavior of a suspension bridge

2020 ◽  
pp. 136943322097477
Author(s):  
Canhui Zhao ◽  
Jiahong Duan ◽  
Xianzhi Zeng ◽  
Kailai Deng ◽  
Jia Guo ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Deformation Pattern ◽  
Earthquake Excitation ◽  
Long Span ◽  
Dynamic Analyses ◽  
Nonlinear Dynamic Analyses ◽  
Main Girder ◽  
Nonlinear Numerical Model

Long-span suspension bridges are widely used in deep valleys, which face severe seismic risk. However, the potential saddle-cable frictional slippage under earthquake excitation as well as its influence on the seismic response of the whole suspension bridge has not yet been investigated. To investigate the effect of frictional slippage at the saddle-cable interface, this paper developed a nonlinear numerical model that considers the saddle-cable slippage. Another contrasting model with a non-slipping saddle-cable interface was used for quantitative comparison. Nonlinear dynamic analyses were conducted using these two models. The saddle-cable interfacial response indicated the realization of the frictional slippage at the saddle-cable interface under the maximum considered earthquake. The overall damage patterns, critical sectional performance, main girder drift, and energy dissipation were discussed in detail. Under the design based and maximum considered intensities, the saddle-cable slippage was seldom observed. The visible frictional slippage was encountered only at ultimate safety earthquake, which could be helpful to limit the transferred load, protect the pylon from yielding, and dissipate approximately 14% of the input seismic energy. While the slippage could not evidently affect the overall deformation pattern of the suspension bridge, as well as the response of bearings and central buckles.

Impact Analysis of Tower Number on Automotive Live Load Effect in Suspension Bridge

2014 ◽  
Vol 1020 ◽  
pp. 124-129
Author(s):  
Zhi Gang Qi ◽  
Jun Dong ◽  
Bo Qiang Yao
Keyword(s):  
Mechanical Properties ◽  
Impact Analysis ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Load Effect ◽  
Bridge Programs ◽  
Long Span ◽  
The Difference ◽  
Main Girder ◽  
Bridge Models

As a bridge with a large span, suspension bridge has obvious advantage in the current cross-sea engineering. In order to achieve longer span capacity, long-span multi-tower suspension bridge programs were repeatedly proposed. Due to the increase in the number of tower, the mechanical behavior would be inevitably different with the ordinary two-tower suspension bridge. For better grasp the difference of the mechanical properties, Midas civil 2011 is used to model to analyze. Suspension bridge models whose spans are 1080m with different towers (two, three, four, five, six,) are established to analyze the change in the mechanical properties under the action of vehicle load. The results show that the mechanical properties of multi-tower suspension bridge are quietly different from two-tower suspension bridge and with the increase in the number of bridge tower, the displacements of main girder and main tower have large difference. When the number of tower is more than or equal to four, multi-tower suspension bridges have little difference in the mechanical properties and that means multi-tower effect is not obvious.

Control of Vibrations due to Moving Loads on Suspension Bridges

2006 ◽  
Vol 11 (3) ◽  
pp. 293-318 ◽  
Author(s):  
M. Zribi ◽  
N. B. Almutairi ◽  
M. Abdel-Rohman
Keyword(s):  
Bridge Deck ◽  
Suspension Bridge ◽  
Lyapunov Theory ◽  
Dynamic Responses ◽  
Suspension Bridges ◽  
Control Force ◽  
Moving Loads ◽  
Hydraulic Actuator ◽  
Long Span ◽  
Suspended Cables

The flexibility and low damping of the long span suspended cables in suspension bridges makes them prone to vibrations due to wind and moving loads which affect the dynamic responses of the suspended cables and the bridge deck. This paper investigates the control of vibrations of a suspension bridge due to a vertical load moving on the bridge deck with a constant speed. A vertical cable between the bridge deck and the suspended cables is used to install a hydraulic actuator able to generate an active control force on the bridge deck. Two control schemes are proposed to generate the control force needed to reduce the vertical vibrations in the suspended cables and in the bridge deck. The proposed controllers, whose design is based on Lyapunov theory, guarantee the asymptotic stability of the system. The MATLAB software is used to simulate the performance of the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a velocity feedback controller.

scholarly journals Probabilistic Assessment of the Safety of Main Cables for Long-Span Suspension Bridges considering Corrosion Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Hao Tian ◽  
Jiji Wang ◽  
Sugong Cao ◽  
Yuanli Chen ◽  
Luwei Li
Keyword(s):  
Probability Model ◽  
Steel Wire ◽  
Suspension Bridge ◽  
Element Model ◽  
Traffic Load ◽  
Suspension Bridges ◽  
Accelerated Corrosion ◽  
Long Span ◽  
Accelerated Corrosion Tests ◽  
Main Cables

This paper presents a reliability analysis to assess the safety of corroded main cables of a long-span suspension bridge. A multiscale probability model was established for the resistance of the main cables considering the length effect and the Daniels effect. Corrosion effects were considered in the wire scale by relating the test results from accelerated corrosion tests to the corrosion stages and in the cable scale by adopting a corrosion stage distribution of the main cable section in NCHRP Report 534. The load effects of temperature, wind load, and traffic load were obtained by solving a finite element model with inputs from in-service monitoring data. The so-obtained reliability index of the main cables reduces significantly after operation for over 50 years and falls below the design target value due to corrosion effects on the mechanical properties of the steel wire. Multiple measures should be taken to delay the corrosion effects and ensure the safety of the main cables in the design service life.

scholarly journals A Master Digital Model for Suspension Bridges

2020 ◽  
Vol 10 (21) ◽  
pp. 7666
Author(s):  
Ngoc-Son Dang ◽  
Gi-Tae Rho ◽  
Chang-Su Shim
Keyword(s):  
Suspension Bridge ◽  
Geometrical Model ◽  
Information Modeling ◽  
Digital Model ◽  
Suspension Bridges ◽  
Actual Behavior ◽  
Data Generation ◽  
Element Analysis ◽  
Long Span ◽  
Bridge System

Long-span suspension bridges require accumulated design and construction technologies owing to challenging environmental conditions and complex engineering practices. Building information modeling (BIM) is a technique used to federate essential data on engineering knowledge regarding cable-supported bridges. In this study, a BIM-based master digital model that uses a data-driven design for multiple purposes is proposed. Information requirements and common data environments are defined considering international BIM standards. A digital inventory for a suspension bridge is created using individual algorithm-based models, and an alignment-based algorithm is used to systematize them and generate the entire bridge system. After assembling the geometrical model, metadata and various BIM applications are linked to create the federated master model, from which the mechanical model is derived for further stages. During the construction stage, the advantage of this digital model lies in its capability to perform efficient revisions and updates with respect to varying situations during the erection process. Stability analyses of the bridge system can be performed continuously at each erection step while considering the geometric control simulation. Furthermore, finite element analysis models for any individual structural member can be extracted from the master digital model, which is aimed at estimating the actual behavior of bridge members. In addition, a pilot master digital model was generated and applied to an existing suspension bridge; this model exhibited significant potential in terms of bridge data generation and manipulation.

Fatigue Test on Integral Joint of the Main Truss of the Baling River Bridge

2009 ◽  
Vol 417-418 ◽  
pp. 481-484 ◽  
Author(s):  
Gao Liu ◽  
Wen Ming Wu ◽  
Liang Tang ◽  
Tian Liang Wang
Keyword(s):  
Fatigue Test ◽  
Fatigue Resistance ◽  
Suspension Bridge ◽  
Scale Model ◽  
Fatigue Reliability ◽  
Truss Bridges ◽  
Long Span ◽  
Load Spectra ◽  
Main Girder ◽  
Test Result

The Baling River Bridge is a single-span simply-supported suspension bridge with a main span of 1088 m. The steel stiffening truss is employed as its main girder and comprises the integral joints connecting the chord members. The integral joint is a key structure and determines the safety of the bridge, but it is very complex in detail and has an undefined fatigue resistance. In order to investigate its mechanical behavior and fatigue reliability, a fatigue test was performed on a 1:1.4 scale model of the integral joint of the main truss of the Bridge. With an assumption of the load spectra represented by the standard fatigue vehicle in BS 5400, the test fatigue load was derived accounting for the multiple vehicle effect and the model scale. The test result shows that no cracks were detected in the model when subjected to two million stress range cycles, and the structure has an reliable fatigue resistance satisfying the design requirement. This type of integral joint is an alternative for long-span truss bridges.

Compositive Optimal Control for the Seismic Response of a Long-Span Triple-Tower Suspension Bridge

2018 ◽  
Vol 18 (08) ◽  
pp. 1840009 ◽  
Author(s):  
Hao Wang ◽  
Yifeng Wu ◽  
Ben Sha ◽  
Wenzhi Zheng ◽  
Yuqi Gao
Keyword(s):  
Optimal Control ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Seismic Responses ◽  
Viscous Dampers ◽  
Analytic Hierarchy ◽  
Expansion Joints ◽  
Elastic Links ◽  
Long Span ◽  
Floating System

In the design of super-long-span suspension bridges, the floating system is commonly adopted. However, this system may lead to the excessive earthquake-excited longitudinal displacement (LD) at the end of the main girder, which in return could result in pounding damage at expansion joints. In this paper, Taizhou Bridge, the triple-tower suspension bridge with the longest main span in the world, is taken as an example to demonstrate the effectiveness of three different approaches (elastic links, viscous dampers, and their combination) of mitigating the possible excessive LD. The finite element code ABAQUS is used to build the numerical model of the bridge and calculate the dynamic characteristics as well as the seismic responses. Then, 24 cases with different parameters of elastic links and viscous dampers are investigated and it is observed that the mitigation effect of the 24 cases varies significantly with different parameters. To obtain the optimized mitigation effect for seismic responses, including the LD of the girder, the LD and shear force of all towers, in the 24 cases, the modified analytic hierarchy process (AHP) method is introduced to realize the compositive optimal control of the triple-tower suspension bridge. Results show that the 24th case is the optimal one in which the LD of the girder is reduced significantly while the inner force of towers does not get excessive increase.

Wind Tunnel Studyon Vortex-Induced Vibration Characteristics of Long-Span Suspension Bridges with Single Cable Plane

2014 ◽  
Vol 633-634 ◽  
pp. 1263-1266
Author(s):  
Huang Yu
Keyword(s):  
Wind Tunnel ◽  
Suspension Bridge ◽  
Wind Tunnel Experiment ◽  
Vibration Characteristics ◽  
Torsional Stiffness ◽  
Suspension Bridges ◽  
Vortex Induced Vibration ◽  
Long Span Bridges ◽  
Wind Speeds ◽  
Long Span

For modern long-span bridges, both the optimization of aerodynamic shape and the increase of torsional stiffness according to the result of the wind tunnel experiment could avoid the flutter instability.Vortex-inducedvibration with relatively large amplitude happens easily at low wind speeds. In this paper, based on wind tunnel experiment, by studying on the vortex-induced vibration characteristics of a long-span suspension bridge with single cable plane, aerodynamic measures for easing the vortex-induced vibration are given.

scholarly journals Fragility-Based Improvement of System Seismic Performance for Long-Span Suspension Bridges

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Guanya Lu ◽  
Kehai Wang ◽  
Wenhua Qiu
Keyword(s):  
Seismic Performance ◽  
Fragility Curves ◽  
Suspension Bridge ◽  
System Level ◽  
Suspension Bridges ◽  
Fragility Function ◽  
Long Span ◽  
Damage Indices ◽  
Composite Damage ◽  
Demand Models

In this study, a procedure is developed to evaluate and improve the seismic performance of long-span suspension bridges based on the performance objectives under the fragility function framework. A common type of suspension bridge in China was utilized in the proposed procedure, considering its approach structures according to earthquake damage experience and fortification criteria. Component-level fragility curves were derived by probabilistic seismic demand models (PSDMs) using a set of nonlinear time-history analyses that incorporated the related uncertainties such as earthquake motions and structural properties. In addition, one step that was covered was to pinpoint the capacity limit states of critical components including bearings, pylons, and columns. The stepwise improved seismic designs were proposed in terms of the component fragility results of the as-built design. Results of the comparison of improved designs showed that the retrofit measure of the suspension span should be selected based on two attributes, i.e., displacement and force, and the restraint system of the approach bridges was a key factor affecting the reasonable damage sequence. Necessarily, from the comparison of different system vulnerability models, the mean values of earthquake intensity of system-level fragility function developed by the composite damage state indices were used to assess the overall seismic performance of the suspension bridge. The results showed that compared to the absolutely serial and serial-parallel assumptions, the defined composite damage indices incorporating the thought of component classification and structural relative importance between the main bridge and approach structures were necessary and were able to derive a good indicator of seismic performance assessment, hence validating the point that the different damage states were dominated by the seismic demands of different structures for the retrofitted bridges.

Loading Test Scheme Research on Long-Span Suspension Bridges

2013 ◽  
Vol 785-786 ◽  
pp. 1248-1252
Author(s):  
Xiao Bin Li ◽  
Meng Yan ◽  
Qu Yu ◽  
Xiang Lin Zeng
Keyword(s):  
Field Test ◽  
Dynamic Performance ◽  
Suspension Bridge ◽  
Load Test ◽  
Suspension Bridges ◽  
Test Scheme ◽  
Loading Test ◽  
Linear Effect ◽  
Long Span ◽  
Capacity Loading

In order to get a full understanding the whole bridge's actual stress state and dynamic performance as well as to check whether the bridge structure could meet the requirements of carrying capacity and traffic capacity, loading test has been carried out to the Nanxi Yangtze River Bridge. As the bridge is a long-span suspension bridge, there is a significant geometric non-linear effect which must be considered in the calculation. Besides, a reasonable field test organization scheme is necessary to guarantee the success of the test since there are a variety of working conditions and a large number of loading trucks. Finally, this kind of static and dynamic load test has a high guiding significance to the field test.

The Influence of the Cable Parameters on Vibration Characteristics of a Long-Span Suspension Bridge

2013 ◽  
Vol 694-697 ◽  
pp. 476-480
Author(s):  
Hai Qing Zhu ◽  
Xie Dong Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Optimization Design ◽  
Suspension Bridge ◽  
Element Model ◽  
Suspension Bridges ◽  
Cable System ◽  
Long Span ◽  
Long Span Bridge ◽  
The World ◽  
Set Up

The type of suspension bridge is used all over the world because of its long span. But the cable system which forced the main load is vulnerable to damage and corrosion. In order to discuss the dynamic characteristics of typical long-span suspension bridges, a finite-element model of a typical long-span bridge was set up with ANSYS, and its top ten frequencies and vibration types were calculated. What’s more the dynamic characteristics under the variations such as modulus of elasticity, sectional size of the cable system, initial strain of the cable, as well as the deficiency of suspender cable were discussed. According to the analysis, the researchers got the conclusion that how the cable system impacts the whole bridge and which suspender cable plays the most significant role. Moreover, the results could serve as some valuable references for the optimization design and preservation of long-span suspension bridges.

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