scholarly journals Variational Mode Decomposition Based Time-Varying Force Identification of Stay Cables

2021 ◽  
Vol 11 (3) ◽  
pp. 1254
Author(s):  
Shitong Hou ◽  
Bin Dong ◽  
Jianhua Fan ◽  
Gang Wu ◽  
Haochen Wang ◽  
...  
Keyword(s):  
Good Effect ◽  
Time Varying ◽  
Variational Mode Decomposition ◽  
Stay Cable ◽  
Cable Tension ◽  
Force Identification ◽  
Stay Cables ◽  
Mode Decomposition ◽  
Cable Force ◽  
Cable Stayed Bridges

Stay cables are important structural members of cable-stayed bridges, which play a significant role in the health monitoring and assessment of cable-stayed bridges. The in-service cable force, which varies from the effects of vehicle load, wind load and other environmental factors, may cause fatigue damage in stay cables. Traditional force identification methods can only calculate the time-average cable force instead of the instantaneous force. A novel method has been proposed in this paper for identifying time-varying cable tension based on the variational mode decomposition (VMD) method. This recent method decomposes signals and adaptively estimates instantaneous frequency combined with the Hilbert–Huang transform method. In the proposed study, the time-varying modal frequencies were identified from stay cable acceleration data, and then the time-varying cable tension was identified by the relationship between cable tension and identified fundamental frequency. Scaled and full-scale models of stay cables were implemented successively to illustrate the validity of the proposed method. The results showed that the variational mode decomposition (VMD) method has a good effect on identifying the time-varying cable forces, even the sudden changes in cable force. According to the cable force identification results, the maximum error was 8.4%, which meets the actual application of time-varying cable force measurements. An on-site test was also implemented to monitor the cable force during a construction period, and the results showed that the proposed method can provide accurate real-time results for evaluation and decision-making.

Measuring Methods of Cable Tension in Cable-Stayed Bridges

2011 ◽  
Vol 295-297 ◽  
pp. 1230-1235
Author(s):  
Jiang Bo Sun ◽  
Zuo Zhou Zhao ◽  
Hong Hua Zhao
Keyword(s):  
Natural Vibration ◽  
String Model ◽  
Beam Model ◽  
Stay Cable ◽  
Fem Model ◽  
Cable Tension ◽  
Cable Stayed Bridge ◽  
Stay Cables ◽  
Beam Bending ◽  
Cable Stayed Bridges

This paper presents several methods usually used for measuring cable tension in cable-stayed bridges, especially frequency vibration method. Taken two different length stay-cables under given tension forces in a real cable-stayed bridge as an example, different modeling methods in finite element methods (FEM) were used to solve their natural vibration frequencies. The results by FEM were compared with those from other available theoretical predicting method. It was found that FEM based on tightening string model is more suitable for a long stay-cable. For a short stay-cable under given tension force, beam bending stiffness can be ignored in predicting its first five natural frequencies using a hinged beam model in FEM. While the predicted lower frequency using clamped beam FEM model is more accurate and reasonable.

scholarly journals Optimization of Cable Force Adjustment in Cable-Stayed Bridge considering the Number of Stay Cable Adjustment

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Han-Hao Zhang ◽  
Nan-Nan Sun ◽  
Pei-Zhi Wang ◽  
Man-Hui Liu ◽  
Yuan Li
Keyword(s):  
Sensitivity Analysis ◽  
Calculation Method ◽  
Maintenance Phase ◽  
Optimization Method ◽  
Stay Cable ◽  
Stay Cables ◽  
Design Variables ◽  
Optimization Calculation ◽  
Cable Force ◽  
Cable Stayed Bridges

Modern cable-stayed bridges are spatial, multicable systems. The cable force needs to be adjusted during the construction phase and maintenance phase. The existing calculation methods of cable force adjustment mainly considered the rationality of structural force, but only few research studies have been conducted on how to reduce the number of stay cables which need to be adjusted. This study aims to propose an optimization calculation method including the optimization module with the sensitivity analysis and updating design variable module (UDVM), which are used for cable force adjustment in cable-stayed bridges. Based on the finite difference method, the sensitivity analysis is adopted in the optimization module, which can capture the response of structures as design variables vary; the particle swarm optimization method is adopted for structural optimization. The proposed method can dramatically reduce the number of stay cables which need to be adjusted and ensure the main girder stresses remain in a reasonable state during stay cable adjustment progress by UDVM. Moreover, the proposed method can continuously update the objective function, constraint conditions, and design variables. Finally, this proposed optimization calculation method is applied to two different cable-stayed bridges to validate the reliability and feasibility of the method.

scholarly journals Serviceability Assessment Method of Stay Cables with Vibration Control Using First-Passage Probability

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Seunghoo Jeong ◽  
Young-Joo Lee ◽  
Sung-Han Sim
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Principal Component ◽  
Assessment Method ◽  
Stay Cable ◽  
First Passage ◽  
Long Span Bridges ◽  
Long Span ◽  
Stay Cables ◽  
Cable Stayed Bridges

As the construction of long-span bridges such as cable-stayed bridges increases worldwide, maintaining bridge serviceability and operability has become an important issue in civil engineering. The stay cable is a principal component of cable-stayed bridges and is generally lightly damped and intrinsically vulnerable to vibration. Excessive vibrations in stay cables can potentially cause long-term fatigue accumulation and serviceability issues. Previous studies have mainly focused on the mitigation of cable vibration within an acceptable operational level, while little attention has been paid to the quantitative assessment of serviceability enhancement provided by vibration control. This study accordingly proposed and evaluated a serviceability assessment method for stay cables equipped with vibration control. Cable serviceability failure was defined according to the range of acceptable cable responses provided in most bridge design codes. The cable serviceability failure probability was then determined by means of the first-passage problem using VanMarcke’s approximation. The proposed approach effectively allows the probability of serviceability failure to be calculated depending on the properties of any installed vibration control method. To demonstrate the proposed method, the stay cables of the Second Jindo Bridge in South Korea were evaluated and the analysis results accurately reflected cable behavior during a known wind event and show that the appropriate selection of vibration control method and properties can effectively reduce the probability of serviceability failure.

A Combined Method for Time-Varying Parameter Identification Based on Variational Mode Decomposition and Generalized Morse Wavelet

2020 ◽  
Vol 20 (07) ◽  
pp. 2050077
Author(s):  
Chao Wang ◽  
Jing Zhang ◽  
Hong Pin Zhu
Keyword(s):  
Parameter Identification ◽  
Structural Response ◽  
Time Varying ◽  
Variational Mode Decomposition ◽  
Combined Method ◽  
Moving Vehicle ◽  
Mode Decomposition ◽  
Time Varying Parameter ◽  
Time Varying Systems ◽  
And Performance

Time-varying parameter identification is essential for structural health monitoring and performance evaluation. In this paper, a combined method based on the variational mode decomposition and generalized Morse wavelet is proposed to identify the structural time-varying parameters. Based on the sparse property of structural response signals in wavelet domain, a fast iterative shrinkage-thresholding algorithm is adopted to reduce the noise. Then the de-noised signal is decomposed into multi- modes by the variational mode decomposition, and the generalized Morse wavelet is performed to identify the instantaneous frequency. To validate the proposed method, a numerical example including different frequency variations is studied. Experimental validations of a moving vehicle across a bridge and a time-varying cable system considering two patterns of cable tension variations in the laboratory are carried out to investigate the capability of the proposed approach. It is confirmed that the proposed approach can effectively perform the signal decomposition, while identifying the instantaneous frequencies of the time-varying systems accurately.

scholarly journals Time-varying system identification using variational mode decomposition

2018 ◽  
Vol 25 (6) ◽  
pp. e2175 ◽  
Author(s):  
Pinghe Ni ◽  
Jun Li ◽  
Hong Hao ◽  
Yong Xia ◽  
Xiangyu Wang ◽  
...  
Keyword(s):  
System Identification ◽  
Time Varying ◽  
Variational Mode Decomposition ◽  
Mode Decomposition

Deviation saddles for cables bridges: development and qualification ofstay cable technology

2019 ◽  
Author(s):  
Julien-Erdem Erdogan ◽  
Ivica Zivanovic ◽  
Matthieu Guesdon
Keyword(s):  
Corrosion Protection ◽  
High Performance ◽  
Cost Effective ◽  
Stay Cable ◽  
Stay Cables ◽  
Accurate Definition ◽  
High Performance Fiber ◽  
Definition Of ◽  
Bridge Aesthetics ◽  
Cable Stayed Bridges

<p>Deviation saddles for cables are regularly used in projects such as cable stayed bridges, suspended bridges or extradossed bridges. The choice of a deviation saddle may be imposed to improve the bridge aesthetics with a slender pylon and to simplify the construction with a solid pylon section. Saddles are a proper anchorage and must be designed such as to ensure a safe transfer of vertical forces and of differential forces of stay cables into the pylon structure.</p><p>For parallel strand cables, since grouted stay cable tends to disappear from commonly accepted design and technologies, due to corrosion protection and fatigue issues, the most widely used concept of saddle is made of a battery of individual tubes, placed inside a guide pipe poured of concrete.</p><p>The most recent saddle system developed consists in allowing the passage of the strands through the saddle without individual tubes. Strands go directly through concrete recesses within the Ultra High Performance Fiber Concrete (UHPFC) matrix. Recesses are made thanks to reusable rubber bars removed after poured concrete is hardened. Thanks to an optimized cross section of the recesses, individual holes maximize the friction between the concrete and specially sheathed strands with local application of a cohesive sheathing (Cohestrand®), which allow strands to transfer important asymmetrical loads to the saddle without sliding. Meanwhile, a continuous corrosion protection is ensured by the strand sheathing from one deck anchorage to the other.</p><p>This make the use of saddle a cost-effective and durable mean to deviate and anchor parallel strand cables, that suits Owners needing simple but robust design for stay cable or extradossed bridges. Such saddle bridge design is nowadays clearly described in the 7<span>th</span> edition of the PTI recommendations, that specifies the qualification process of saddle technologies, especially in regards to the accurate definition of a minimum friction coefficient.</p>

scholarly journals The use of Classical Rolling Pendulum Bearings (CRPB) for vibration control of stay-cables

2018 ◽  
Vol 148 ◽  
pp. 02002
Author(s):  
Georgia Papastergiou ◽  
Ioannis Raftoyiannis
Keyword(s):  
Suspension Bridges ◽  
Geometrical Parameters ◽  
Structural Elements ◽  
Stay Cable ◽  
Stay Cables ◽  
Taut String ◽  
Integral Differential Equations ◽  
Cable Vibrations ◽  
Cable Stayed Bridges

Cables are efficient structural elements that are used in cable-stayed bridges, suspension bridges and other cable structures. A significant problem which arose from the praxis is the cables’ rain-wind induced vibrations as these cables are subjected to environmental excitations. Rain-wind induced stay-cable vibrations may occur at different cable eigenfrequencies. Large amplitude Rain-Wind-Induced-Vibrations (RWIV) of stay cables are a challenging problem in the design of cable-stayed bridges. Several methods, including aerodynamic or structural means, have been investigated in order to control the vibrations of bridge’s stay-cables. The present research focuses on the effectiveness of a movable anchorage system with a Classical Rolling Pendulum Bearing (CRPB) device. An analytical model of cable-damper system is developed based on the taut string representation of the cable. The gathered integral-differential equations are solved through the use of the Lagrange transformation. . Finally, a case study with realistic geometrical parameters is also presented to establish the validity of the proposed system.

Stay Cable Tension Estimation of Cable-Stayed Bridges Using Genetic Algorithm and Particle Swarm Optimization

2017 ◽  
Vol 22 (10) ◽  
pp. 05017008 ◽  
Author(s):  
Seyed Ehsan Haji Agha Mohammad Zarbaf ◽  
Mehdi Norouzi ◽  
Randall J. Allemang ◽  
Victor J. Hunt ◽  
Arthur Helmicki
Keyword(s):  
Genetic Algorithm ◽  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Stay Cable ◽  
Swarm Optimization ◽  
Cable Tension ◽  
Cable Stayed Bridges

Structural optimization of two-girder composite cable-stayed bridges under dead and live loads

2020 ◽  
Vol 47 (8) ◽  
pp. 939-953
Author(s):  
C.A.N. Santos ◽  
A.A. El Damatty ◽  
M.S. Pfeil ◽  
R.C. Battista
Keyword(s):  
Structural Optimization ◽  
Concrete Slab ◽  
Slab Thickness ◽  
Optimization Approach ◽  
Stay Cable ◽  
Algorithm Optimization ◽  
Stay Cables ◽  
Design Variables ◽  
Live Loads ◽  
Cable Stayed Bridges

A large number of variables are involved in the optimization of cable-stayed bridges, which makes the optimization impractical when many load cases are considered. To reduce the number of variables to be optimized, a discrete phases approach for structural optimization is developed in this study. The approach couples the finite element method with the genetic algorithm optimization approach. The design variables are divided into two categories: (i) main variables: number of stay cables, I-girder inertia, concrete slab thickness, and tower dimensions; and (ii) secondary variables: I-girder dimensions, stay-cable areas, and pre-tensioning forces. Two design objectives are tested: (i) lightest deck mass; and (ii) lowest material cost. Three load cases are considered: (i) dead and truck plus lane live loads; (ii) dead and lane live loads; and (iii) dead load. The results show the importance of considering the truck loads in structural optimization and the efficacy of the phases approach for different objectives.

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