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.

scholarly journals STATIC ANALYSIS AND SIMPLIFIED DESIGN OF SUSPENSION BRIDGES HAVING VARIOUS RIGIDITY OF CABLES

2010 ◽  
Vol 16 (3) ◽  
pp. 363-371 ◽  
Author(s):  
Tatjana Grigorjeva ◽  
Algirdas Juozapaitis ◽  
Zenonas Kamaitis
Keyword(s):  
Static Loading ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Design Procedures ◽  
Suspension Systems ◽  
Main Cable ◽  
Composite Section ◽  
Internal Forces ◽  
Standard Section ◽  
Main Cables

Increased deformability can be considered as the basic disadvantage of suspension bridges. One of the ways to increase the rigidity of a suspension bridge is to transfer a part of stiffening girder rigidity to a suspension main cable. To give the suspension bridge more stable appearance, the authors propose to use the cables of varying bending stiffness. The main cables can be made of standard section shapes or have a composite section. The object of this work was to study a method for analyzing and determining the internal forces in the main cables and stiffening girder under static loading to provide recommendations for designing suspension bridges with stiffened cables. Simple formulas are presented for determining displacements, internal forces and stresses in the main cable and stiffening girder. Finite element modeling was performed. The final part of the paper discusses design procedures for such suspension systems. An example of a pedestrian suspension bridge is appended. Santrauka Esminis kabamuju tiltu trūkumas ‐ didelis ju deformatyvumas. Deformatyvumui sumažinti autoriai siūlo dali standumo sijos lenkiamojo standžio perduoti kabamajam lynui. Baigtinio lenkiamojo standumo lynai gali būti daromi iš standartiniu valcuotuju profiliuočiu arba sudetinio skerspjūvio. Šio darbo tikslas ‐ pateikti supaprastinta metodika kabamojo tilto standaus lyno ir standumo sijos elgsenos analizei atlikti bei rekomendacijas tokiems statiškai apkrautiems tiltams projektuoti. Pateiktos paprastos formules lyno ir sijos poslinkiams, iražoms ir itempiams apskaičiuoti. Atliktas kabamosios tilto siste‐mos modeliavimas baigtiniais elementais. Aptartos tokiu kabamuju tiltu projektavimo procedūros. Pateiktas pesčiuju via‐duko kabamuju konstrukciju projektavimo pavyzdys.

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.

Analysis on the Dynamic Responses of the Broken Conductors in Transmission Lines

2011 ◽  
Vol 50-51 ◽  
pp. 511-515 ◽  
Author(s):  
Feng Li Yang ◽  
Jing Bo Yang
Keyword(s):  
Transmission Lines ◽  
Element Model ◽  
Dynamic Responses ◽  
Impact Loads ◽  
Safe Operation ◽  
Rayleigh Damping ◽  
Fea Model ◽  
Insulator Element ◽  
Reaction Forces ◽  
Short Time

Impact loads from the broken conductors are common for transmission lines, which can bring threaten to the safe operation of the transmission lines. Dynamic analysis of the conductors in transmission lines under broken load was carried out. A finite element model of seven span conductors in transmission line was established in general software ANSYS. The insulator and the phase spacer were considered in the FEA model. The broken load case can be realized by the birth-death element method in ANSYS. Stiffness of the broken conductor or insulator element was changed to be a near zero value in a very short time. Effect of the damping property of the conductors was considered by the Rayleigh damping method. Dynamic responses of displacements at the broken points and the reaction forces of the insulators were obtained. Dynamic responses for the broken conductors with different damping ratios and bundle numbers were compared.

scholarly journals Wind-Induced Vibration Response of an Inspection Vehicle for Main Cables Based on Computer Simulation

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Lu Zhang ◽  
Shaohua Wang ◽  
Peng Guo ◽  
Qunsheng Wang
Keyword(s):  
Finite Element ◽  
Wind Speed ◽  
Ride Comfort ◽  
Suspension Bridge ◽  
Vibration Response ◽  
Fe Model ◽  
Main Cable ◽  
Main Cables ◽  
Wind Induced Vibration ◽  
Wind Induced Vibration Response

This paper presents a simulation approach based on the finite element method (FEM) to analyze the wind-induced vibration response of an inspection vehicle for main cables. First, two finite element (FE) models of a suspension bridge and a main cable-inspection vehicle coupled system are established using MIDAS Civil software and ANSYS software, respectively. Second, the mean wind speed distribution characteristics at a bridge site are analyzed, and the wind field is simulated based on the spectral representation method (SRM). Third, a modal analysis and a wind-induced vibration response transient analysis of the suspension bridge FE model are completed. Fourth, the vibration characteristics of the inspection vehicle are analyzed by applying fluctuating wind conditions and main cable vibration displacements in the main cable-inspection vehicle coupled FE model. Finally, based on the ISO2631-1-1997 standard, a vehicle ride comfort evaluation is performed. The results of the suspension bridge FE modal analysis are in good accordance with those of the experimental modal test. The effects of the working height, number of nonworking compressing wheels, and number of nonworking driving wheels during driving are discussed. When the average wind speed is less than 13.3 m/s, the maximum total weighted root mean square acceleration (av) is 0.1646 m/s2 and the vehicle ride comfort level is classified as “not uncomfortable.” This approach provides a foundation for the design and application of inspection vehicles.

scholarly journals Mechanical Properties and Structural Optimization of Continuous Welded Rail on Super-Long-Span Suspension Bridges for High-Speed Railway

2021 ◽  
Vol 12 (1) ◽  
pp. 305
Author(s):  
Guanyuan Zhao ◽  
Xiaopei Cai ◽  
Wanli Liu ◽  
Tielin Wang ◽  
Tao Wang
Keyword(s):  
High Speed ◽  
Suspension Bridge ◽  
Element Model ◽  
Correction Method ◽  
Driving Safety ◽  
Suspension Bridges ◽  
High Speed Railway ◽  
Static And Dynamic Analysis ◽  
Bending Load ◽  
Continuous Welded Rail

In order to ensure driving safety and comfort, it is necessary to figure out the complex interaction between continuous welded rail (CWR) and suspension bridges for high-speed railway. A spatial finite element model for a 1092 m main span suspension bridge was established based on the bridge-track interaction theory. A specific correction method was put forward to keep the rail in a zero-stress state when just laid. Three rail expansion joint (REJ) layout schemes were proposed according to practical engineering experience. Both static and dynamic analysis methods were used to evaluate the feasibility of these schemes. The results show that the REJ should be laid at the position with a distance away from the primary beam end, and the beam with more substantial integral stiffness should be preferentially selected. For the recommended scheme, the REJ expansion reaches more than 380 mm under expansion load. The factors affecting the REJ expansion from major to minor are temperature, earthquake, rail fracture, braking, and bending load. The superposition effect of the above factors is suggested to be considered in the selection of REJ range.

Effects of Sudden Breakage of Hangers on Suspension Bridge

2013 ◽  
Vol 811 ◽  
pp. 234-239
Author(s):  
Wen Liang Qiu ◽  
Meng Jiang ◽  
Zhe Zhang
Keyword(s):  
Finite Element ◽  
Nonlinear Dynamic ◽  
Traffic Accident ◽  
Nonlinear Dynamic Analysis ◽  
Suspension Bridge ◽  
Element Model ◽  
Initial Value ◽  
3D Finite Element ◽  
Critical Elements ◽  
Main Cable

Hangers are the critical elements supporting stiffening girder in suspension bridge. The hangers probably break suddenly in service for the reasons of corrosion, fatigue or traffic accident. Because the hangers are anchored to the main cable, the sudden breakage of hanger causes strong vibration of main cable, and the vibration may damage some of the elements of the bridge. Using nonlinear dynamic analysis methods and adopting 3D finite element model, the responses of a suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of hanger has significant effects on tensions of the hangers adjacent to the broken hanger, the maximum tension of hanger produced by breakage of a hanger exceeds 2.2 times of its initial value, and the tensions of other hangers far away from the broken hanger are affected little. The breakage of a single hanger causes very large torsion moments of girder and reactions of bearings, but it has little effects on the tensions of main cable and moments of tower.

Experimental study on torsional behavior of spatial main cable for a self-anchored suspension bridge

2019 ◽  
Vol 22 (14) ◽  
pp. 3086-3099 ◽  
Author(s):  
Chuanxi Li ◽  
You Li ◽  
Jun He
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Finite Element Model ◽  
Twist Angle ◽  
Suspension Bridge ◽  
Element Model ◽  
Torsional Angle ◽  
Positive Direction ◽  
Main Cable ◽  
Torsional Behavior

In order to understand the torsional behavior of the spatial main cable between two saddles for a self-anchored suspension bridge during the transition process from construction state to completed state, a scaled model (1:15) was prepared and tested. First, the cable anchorage system and cable measurement device were designed. Then, a series of model tests under the conditions of different preloading angles and different tensioning forces for hangers were carried out. Finally, the regularity of the torsional properties was revealed on the basis of the measured twist angle of the main cable. The experimental study shows that the transverse pre-deflected angle of the cable clamp has a decisive influence on the torsional angle of the main cable sections near the cable clamp, but for the main cable sections far from the pre-deflected cable clamp, this influence can almost be negligible. The torsional angle changes linearly within adjacent cable clamps. When inclined angle of the hanger is larger than the pre-deflected angle of the cable clamp, the cable clamp will cause the main cable section to twist in the positive direction, otherwise, the result is reverse. With the increase in the hanger force, the direction of hanger force passes through the cross-sectional center of the main cable, resulting in an unchanged twisting angle. In addition, a three-dimensional finite element model of the test specimen was established and used to analyze the influence of pre-deflected angle of a cable clamp on the torsion angle of the main cable, the same results can be found in finite element analyses in comparison with the test results. Therefore, a reasonable pre-deflected angle of cable clamp can be determined by the finite element model in the primary design state before the construction stage.

Influence of Central Buckle on Dynamic Behavior of Long-Span Suspension Bridge with Deck-Truss Composite Stiffening Girder

2013 ◽  
Vol 838-841 ◽  
pp. 1096-1101 ◽  
Author(s):  
Feng Jiang Qin ◽  
Jin Di ◽  
Jie Dai ◽  
Guang Ling Li
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Great Influence ◽  
Suspension Bridge ◽  
Element Model ◽  
Vibration Modes ◽  
Element Analysis ◽  
Long Span ◽  
Main Cable ◽  
Central Buckle

A 3-D finite element model for Yueyang Dongting Lake bridge was established with a large scale general finite element analysis software, and the subspace iteration method was adopted to analyze the natural vibration characteristics of the bridge, meanwhile, the influences of settings different types of central buckles at the mid-span of the main spans between the main cables and girder on the dynamic behaviors of the long-span suspension bridge with deck-truss composite stiffening girder were studied. The results show that compared with only setting short hanger cable at mid-span, the the whole rigidity of suspension bridge is raised and the natural frequencies increase by the setting central buckle, but various types of vibration modes are affected in different extents; among all of these vibration modes, the antisymmetric vibration and Longitudinal floating of stiffening girder are most obviously affected. The stiffness of central buckle has a great influence on the vibration of main cable, while compared with only setting short hanger cable, the vibration of main cable increases 7.32% while setting the rigid central buckle. The conclusions of this paper provide theoretical basis for the using of central buckle in long-span suspension bridge.

scholarly journals A Novel Shape Finding Method for the Main Cable of Suspension Bridge Using Nonlinear Finite Element Approach

2021 ◽  
Vol 11 (10) ◽  
pp. 4644
Author(s):  
Weiliang Zhu ◽  
Yaojun Ge ◽  
Genshen Fang ◽  
Jinxin Cao
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Suspension Bridge ◽  
Nonlinear Finite Element ◽  
Finite Element Approach ◽  
Main Cable ◽  
Element Approach ◽  
Lagrangian Coordinate ◽  
Main Cables ◽  
Finding Method

The determination of the final cable shape under the self-weight of the suspension bridge enables its safe construction and operation. Most existing studies solve the cable shape segment-by-segment in the Lagrangian coordinate system. This paper develops a novel shape finding method for the main cable of suspension bridge using nonlinear finite element approach with Eulerian description. The governing differential equations for a three-dimensional spatial main cable is developed before a one-dimensional linear shape function is introduced to solve the cable shape utilizing the Newton iteration method. The proposed method can be readily reduced to solve the two-dimensional parallel cable shape. Two iteration layers are required for the proposed method. The shape finding process has no need for the information of the cable material or cross section using the present technique. The commonly used segmental catenary method is compared with the present method using three cases study, i.e., a 1666-m-main-span earth-anchored suspension bridge with 2D parallel and 3D spatial main cables as well as a 300-m-main-span self-anchored suspension bridge with 3D spatial main cables. Numerical studies and iteration results show that the proposed shape finding technique is sufficiently accurate and operationally convenient to achieve the target configuration of the main cable.

Vibration of Double Cable Suspension Bridge under Vehicle Load

2011 ◽  
Vol 50-51 ◽  
pp. 328-332
Author(s):  
Nan Hong Ding ◽  
Li Xia Lin ◽  
Wei Hua Liao
Keyword(s):  
Dynamic Performance ◽  
Suspension Bridge ◽  
Longitudinal Axis ◽  
Dynamic Responses ◽  
Coupling Vibration ◽  
Shape Coefficient ◽  
Main Cable ◽  
Vehicle Loading ◽  
Impact Coefficient ◽  
Mass Spring

A single moving mass-spring-damper model is adopted to simulate the vehicle model. The equation of vehicle-bridge coupling vibration is derived, using D'Alembert principle and the conditions of displacement compatibility. The dynamic responses of a double cable suspension bridge to the vehicle moving at different speeds are analyzed, considering the geometric nonlinearity and the bridge carriageway irregularity factor, under two types of vehicle loading conditions, namely moving along the center and the eccentric longitudinal axis. Then the influence of vehicle velocity and bridge carriageway irregularity on impact coefficient of double cable suspension bridge is discussed. Single cable suspension bridge can be taken as a special case of double cable suspension bridge, after the main cable shape coefficient is introduced. The dynamic responses of double cable suspension bridge and single cable suspension bridge are compared to reveal the character of vehicle vibration of double cable suspension bridge. The study of the dynamic responses character of double cable suspension bridge has a positive significance on structural form selection of such type bridge during designing, dynamic performance evaluation and vibration control.

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