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.

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.

scholarly journals Preliminary numerical study on seismic response of ordinary long-span suspension bridges crossing active faults

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Hongyu Jia ◽  
Kang Jia ◽  
Caizhi Sun ◽  
Yanqiang Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Fault Plane ◽  
Numerical Study ◽  
Ground Motions ◽  
Active Faults ◽  
Suspension Bridge ◽  
Element Model ◽  
Suspension Bridges ◽  
Finite Element Software ◽  
Long Span

AbstractThe objective of this paper is to expediently expose the seismic performance pertinent to demand and capacity of general long-span suspension bridges crossing active faults. Firstly three dimensional finite element model of the ordinary long-span suspension bridge is established based on the powerful and attractive finite element software ANSYS. Secondly a series of appropriate fault ground motions with different target final permanent displacements (Tectonic displacements or ground offset) in the direction perpendicular to the fault plane are assumed and applied to the employed long-span suspension bridge. And then the Newmark method is utilized to solve the equation of motion of the long-span suspension bridge structure subjected to fault ground motions in the elastic range. Finally some important conclusions are drawn that the final permanent displacements in the direction perpendicular to the fault plane has significant influence on the seismic responses and demands of general long-span suspension bridges crossing active faults. And the resultant conclusions deliver explicitly and directly specifications and guidelines for seismic design of ordinary long-span suspension bridges across fault-rupture zones.

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 Monitoring the dynamic behaviors of the Bosporus Bridge by GPS during Eurasia Marathon

2007 ◽  
Vol 14 (4) ◽  
pp. 513-523 ◽  
Author(s):  
H. Erdoğan ◽  
B. Akpınar ◽  
E. Gülal ◽  
E. Ata
Keyword(s):  
Frequency Domain ◽  
Element Model ◽  
Traffic Load ◽  
Suspension Bridges ◽  
Engineering Structures ◽  
Low Frequencies ◽  
Temperature Changes ◽  
Bridge Responses ◽  
Special Complex ◽  
Short Time

Abstract. Engineering structures, like bridges, dams and towers are designed by considering temperature changes, earthquakes, wind, traffic and pedestrian loads. However, generally, it can not be estimated that these structures may be affected by special, complex and different loads. So it could not be known whether these loads are dangerous for the structure and what the response of the structures would be to these loads. Such a situation occurred on the Bosporus Bridge, which is one of the suspension bridges connecting the Asia and Europe continents, during the Eurasia Marathon on 2 October 2005, in which 75 000 pedestrians participated. Responses of the bridge to loads such as rhythmic running, pedestrian walking, vehicle passing during the marathon were observed by a real-time kinematic (RTK) Global Positioning System (GPS), with a 2.2-centimeter vertical accuracy. Observed responses were discussed in both time domain and frequency domain by using a time series analysis. High (0.1–1 Hz) and low frequencies (0.00036–0.01172 Hz) of observed bridge responses under 12 different loads which occur in different quantities, different types and different time intervals were calculated in the frequency domain. It was seen that the calculated high frequencies are similar, except for the frequencies of rhythmic running, which causes a continuously increasing vibration. Any negative response was not determined, because this rhythmic effect continued only for a short time. Also when the traffic load was effective, explicit changes in the bridge movements were determined. Finally, it was seen that bridge frequencies which were calculated from the observations and the finite element model were harmonious. But the 9th natural frequency value of the bridge under all loads, except rhythmic running could not be determined with observations.

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.

scholarly journals Parametric Study on Responses of a Self-Anchored Suspension Bridge to Sudden Breakage of a Hanger

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Wenliang Qiu ◽  
Meng Jiang ◽  
Cailiang Huang
Keyword(s):  
Suspension Bridge ◽  
Element Model ◽  
Dynamic Responses ◽  
Flexural Stiffness ◽  
Static And Dynamic Analysis ◽  
Main Cable ◽  
Reaction Forces ◽  
Internal Forces ◽  
Torsion Stiffness ◽  
Main Cables

The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

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.

scholarly journals Wind-driven damage localization on a suspension bridge

2016 ◽  
Vol 11 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Marco Domaneschi ◽  
Maria Pina Limongelli ◽  
Luca Martinelli
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Identification ◽  
Structural Response ◽  
Suspension Bridge ◽  
Element Model ◽  
Damage Localization ◽  
Damage Scenarios ◽  
Long Span Bridges ◽  
Long Span

The paper focuses on extending a recently proposed damage localization method, previously devised for structures subjected to a known input, to ambient vibrations induced by an unknown wind excitation. Wind induced vibrations in long-span bridges can be recorded without closing the infrastructure to traffic, providing useful data for health monitoring purposes. One major problem in damage identification of large civil structures is the scarce data recorded on damaged real structures. A detailed finite element model, able to correctly and reliably reproduce the real structure behavior under ambient excitation can be an invaluable tool, enabling the simulation of several different damage scenarios to test the performance of any monitoring system. In this work a calibrated finite element model of an existing long-span suspension bridge is used to simulate the structural response to wind actions. Several damage scenarios are simulated with different location and severity of damage to check the sensitivity of the adopted identification method. The sensitivity to the length and noise disturbances of recorded data are also investigated.

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