• Title, Summary, Keyword: cable stiffness

Search Result 184, Processing Time 0.05 seconds

Study of structural parameters on the aerodynamic stability of three-tower suspension bridge

  • Zhang, Xin-Jun
    • Wind and Structures
    • /
    • v.13 no.5
    • /
    • pp.471-485
    • /
    • 2010
  • In comparison with the common two-tower suspension bridge, due to the lack of effective longitudinal restraint of the center tower, the three-tower suspension bridge becomes a structural system with greater flexibility, and more susceptible to the wind action. By taking a three-tower suspension bridge-the Taizhou Bridge over the Yangtze River with two main spans of 1080 m as example, effects of structural parameters including the cable sag to span ratio, the side to main span ratio, the deck's dead load, the deck's bearing system, longitudinal structural form of the center tower and the cable system on the aerodynamic stability of the bridge are investigated numerically by 3D nonlinear aerodynamic stability analysis, the favorable structural system of three-tower suspension bridge with good wind stability is discussed. The results show that good aerodynamic stability can be obtained for three-tower suspension bridge as the cable sag to span ratio is assumed ranging from 1/10 to 1/11, the central buckle are provided between main cables and the deck at midpoint of main spans, the longitudinal bending stiffness of the center tower is strengthened, and the spatial cable system or double cable system is employed.

System identification of the suspension tower of Runyang Bridge based on ambient vibration tests

  • Li, Zhijun;Feng, Dongming;Feng, Maria Q.;Xu, Xiuli
    • Smart Structures and Systems
    • /
    • v.19 no.5
    • /
    • pp.523-538
    • /
    • 2017
  • A series of field vibration tests are conducted on the Runyang Suspension Bridge during both the construction and operational stages. The purpose of this study is devoted to the analysis of the dynamic characteristics of the suspension tower. After the tower was erected, an array of accelerometers was deployed to study the evolution of its modal parameters during the construction process. Dynamic tests were first performed under the freestanding tower condition and then under the tower-cable condition after the superstructure was installed. Based on the identified modal parameters, the effect of the pile-soil-structure interaction on dynamic characteristics of the suspension tower is investigated. Moreover, the stiffness of the pile foundation is successfully identified using a probabilistic finite model updating method. Furthermore, challenges of identifying the dynamic properties of the tower from the coupled responses of the tower-cable system are discussed in detail. It's found that compared with the identified results from the freestanding tower, the longitudinal and torsional natural frequencies of the tower in the tower-cable system have changed significantly, while the lateral mode frequencies change slightly. The identified modal results from measurements by the structural health monitoring system further confirmed that the vibrations of the bridge subsystems (i.e., the tower, the suspended deck and the main cable) are strongly coupled with one another.

A Study on the Axial Stiffness Prediction of Stand Using Analysis of Variance (분산분석을 이용한 스트랜드의 축강성 예측에 관한 연구)

  • Park, Yong-Dae;Yang, Won-Ho;Heo, Seong-Pil;Seong, Gi-Deuk
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.25 no.1
    • /
    • pp.127-134
    • /
    • 2001
  • Wire ropes are widely used in cable car, suspension bridge and elevator, etc. and composed of single or multi-layer strands. It is difficult to find out the characteristics of a strand or wire rope because of complicated geometry and contact condition. In this study, the axial stiffness is evaluated using finite element method and reliable finite element analysis model is presented, taking into consideration the convergence on the length. The axial stiffness predictive equation of a strand is developed using analysis of variance, which can be applicable for characterizing the relationship between load and displacement when the strand configuration is determined.

Distribution of Natural Frequency of 2-DOF Approximate Model of Stay Cable to Reduction of Area (단면감소에 따른 사장케이블의 2-자유도 근사모델의 고유진동수 분포)

  • Joe, Yang-Hee;Lee, Hyun-Chol
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.18 no.6
    • /
    • pp.147-154
    • /
    • 2014
  • The cable damages of the bridge structures induce very important impact on the structural safety, which implies the close monitoring of the cable damage is required to secure sustained safety of the bridges. Most usual available maintenance techniques are based on the monitoring the change of the natural frequency of the structures by damages. However, existing method are based on vibration method to calculate lateral vibration and system identification can calculate the axial stiffness using sensitivity equation by trial error method. But the frequency study by the longitudinal movement need because of the sag effect in system identification. This study proposes a new method to investigate the damage magnitudes and status. The method improves the accuracies in the magnitudes and status of damages by adopting the natural frequency of longitudinal movement. The study results have been validated by comparing them with the approximate solution of FEM. Thus, the relationship of cable damage and frequency appear with relation that the severe damage has the little frequency. If we know the real frequency we can estimate the cable damage severity using this relationship. This method can be possible the efficient management of the cable damage.

Static and free vibration analysis of shallow sagging inclined cables

  • Li, Zhi-Jiang;Li, Peng;He, Zeng;Cao, Ping
    • Structural Engineering and Mechanics
    • /
    • v.45 no.2
    • /
    • pp.145-157
    • /
    • 2013
  • Based on link-model, we conducted a static analysis and computation of a three-span suspended cable structure in the present paper, and obtained the static configuration and tension distribution of the cable. Using the link and beam model based on finite element method, we analyzed the vibration modal of three-span suspended cable structure, and compared with the results obtained from ANSYS using link and beam element. The vibration modals of shallow sagging inclined cables calculated from proposed method agrees well with ANSYS results, which validates the proposed method. As a result, the influence of bend stiffness on in-plane natural frequencies is much greater than that on out-of-plane natural frequencies of inclined cables.

A Study on the Bending and Torsional Behaviors of Cable-Stayed Bridges under a Concentrated Moving Load (집중 이동하중을 받는 사장교의 휨 및 비틈 거동에 관한 연구)

  • Chang, Sung Pil;Yhim, Sung Soon;Chu, Seok Beom
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.9 no.3
    • /
    • pp.1-12
    • /
    • 1989
  • The nonlinearity of a cable-stayed bridge results from the large displacement of main girder due to a long span, the catenary action of cables and the flexural stiffness reduced by large axial forces. The dynamic behaviour of a cable-stayed bridge plays an important role in determining its safety. Especially, when the eccentrically moving load is applied to a cable-stayed bridge, the torsional vibration and vertical vibration are coupled and moreover the variation of cable tensions shows important dynamic characteristics. This dissertation presents a theoretical study and a finite element procedure for analysis of a cable-stayed bridge under a eccentrically moving load. Attention is focused on the dynamic behaviours such as dynamic increments of cable tensions and nodal displacements, with the variety of velocities and eccentricities of moving load. It is found that a moving load with eccentricity can have significant effects upon the responses; the torsion of bridge deck and the increments of cable tensions, according to the present results in this study.

  • PDF

Stiffness of hybrid systems with and without pre-stressing

  • Miljanovic, Sladana;Zlatar, Muhamed
    • Coupled systems mechanics
    • /
    • v.9 no.2
    • /
    • pp.147-161
    • /
    • 2020
  • Constructive merging of "basic" systems of different behavior creates hybrid systems. In doing so, the structural elements are grouped according to the behavior in carrying the load into a geometric order that provides sufficient load and structure functionality and optimization of the material consumption. Applicable in all materializations and logical geometric forms is a transparent system suitable for the optimization of load-bearing structures. Research by individual authors gave insight into suitable system constellations from the aspect of load capacity and the approximatemethod of estimating the participation of partialstiffnesswithin the rigidity ofthe hybrid system. The obtained terms will continue to be the basisfor our own research of the influence of variable parameters on the behavior of hybrid systemsformed of glued laminated girder and cable of different geometric shapes. Previous research has shown that by applying the strut-type hybrid systems can increase the load capacity and reduce the deformability ofthe free girder.The implemented parametric analysis pointsto the basic parameterin the behavior of these systems-the rigidity ofindividual elements and the overallstiffnessofthe system.The basic idea ofpre-stressing is that, in the load system or individual load-bearing element, prior to application of the exploitation load, artificially challenge the forcesthatshould optimize the finalsystembehaviorin the overall load. Pre-stressing is possible only if the supporting system orsystem's element possesssufficientstrength orstiffness, orreaction to the imposed forces of pre-stressing. In this paper will be presented own research of the relationship of partial stiffness of strut-type hybrid systemsofdifferentgeometric forms.Conducted parametric analysisofhybridsystemswithandwithoutpre-stressing, and on the example of the glulam-steel strut-type hybrid system under realistic conditions of change in the moisture content ofthe wooden girder,resulted in accurate expressions and diagramssuitable for application in practice.

Probabilistic Structural Safety Assessment Considering the Initial Shape and Non-linearity of Steel Cable-Stayed Bridges (강사장교의 초기형상과 비선형성을 고려한 확률론적 구조안전성 평가)

  • Bang, Myung-Seok;Han, Sung-Ho;Lee, Woo-Sang;Lee, Chin-Ok
    • Journal of the Korean Society of Safety
    • /
    • v.25 no.3
    • /
    • pp.91-99
    • /
    • 2010
  • In this study, the advanced numerical algorithm is developed which can performed the static and dynamic stochastic finite element analysis by considering the effect of uncertainties included in the member stiffness of steel cable-stayed bridges and seismic load. After conducting the linear and nonlinear initial shape analysis, the advanced numerical algorithm is the assessment tool which can performed structural the response analysis considering the static linearity and non-linearity of before or after induced intial tensile force, and examined the reliability assessment more efficiently. The verification of the developed numerical algorithm is evaluated by analyzing the regression analysis and coefficient of correlation using the direct monte carlo simulation. Also, the dynamic response characteristic and coefficient of variation of the steel cable-stayed bridge is calculated by considering the uncertainty of random variables using the developed numerical algorithm. In addition, the quantitative structural safety of the steel cable-stayed bridges is evaluated by conducting the reliability assessment based upon the dynamic stochastic finite element analysis result.

Development of Video Transmission Device for Monitoring of a Cable-Based Retractable Roof (케이블-기반 개폐식 지붕의 모니터링을 위한 영상 전송 장치 개발)

  • Ahn, Soohong;Shon, Sudeok;Lee, Seungjae;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
    • /
    • v.19 no.4
    • /
    • pp.103-110
    • /
    • 2019
  • The cable-based retractable membrane roof makes it impossible to maintain its shape and stiffness during driving process, unlike the hard-type retractable roof. Consequently, monitoring using a relatively simple wireless video transmission device is required. However, since video data has a bigger transmission rating than other monitoring data in terms of the structure velocity or acceleration, there is a need to develop transmission device that is easy to install and entails low maintenance cost. This paper studies on a real-time video transmission system for monitoring the cable-based retractable membrane roof while driving. A video transfer software, using the mobile network, is designed and the embedded system is constructed. Ultimately, the data transmission server is tested. Connecting a trolley to the system allows testing of the validity and efficiency of the developed system through the video data transmitted in the driving process. Result of the test shows that the developed system enables multi-device data transfer with monitoring via the mobile network.

A STUDY ON NUMERICAL SIMULATION OF TOWED LOW-TENSION CABLE WITH NONUNIFORM CHARACTERISTICS (불균일 단면을 갖는 저장력 예인케이블에 관한 수치해석적 연구)

  • Jung, Dong-Ho;Park, Han-Il
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • /
    • pp.161-166
    • /
    • 2002
  • Low-tension cables have been increasingly used in recent years due to deep-sea developments and the advent of synthetic cables. In the case of low-tension cables, large displacements may happen due to relatively small restoring forces of tension and thus the effects of fluid and geometric non-linearities become predominant. In this study, three-dimensional (3-D) dynamic behavior of a towed low-tension cable with non-uniform characteristics is numerically analyzed by considering fluid and geometric non-linearities and bending stiffness. A Fortran program is developed by employing a finite difference method. In the algorithm, an implicit time integration and Newton-Raphson iteration are adopted. For the calculation of huge size of matrices, block tri-diagonal matrix method is applied, which is much faster than the well-known Gauss-Jordan method in two point boundary value problems. Some case studies are carried out and the results of numerical simulations are compared with a in-house program of WHOI Cable with good agreements.

  • PDF