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Sample records for cable stayed bridges

  1. Modeling of cable vibration effects of cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The analysis of dynamic responses of cable-stayed bridges subjected to wind and earthquake loads generallyconsiders only the motions of the bridge deck and pylons. The influence of the stay cable vibration on the responses of the bridgeis either ignored or considered by approximate procedures. The transverse vibration of the stay cables, which can be significant insome cases, are usually neglected in previous research. In the present study, a new three-node cable element has been developed tomodel the transverse motions of the cables. The interactions between the cable behavior and the other parts of the bridgesuperstructure are considered by the concept of dynamic stiffness. The nonlinear effect of the cable caused by its self-weight isincluded in the formulation. Numerical examples are presented to demonstrate the accuracy and efficiency of the proposed model.The impact of cable vibration behavior on the dynamic characteristics of cable-stayed bridges is discussed.

  2. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m...... in the Strömsund Bridge (from 1955) to 890 m in the Tatara Bridge (from 1999)....

  3. Technology for long cable erection of a thousand-meter scale cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    Rao Huarong; Deng Huibin

    2009-01-01

    In the background of the construction of Sutong Yangtze River Bridge (short as Sutong Bridge), the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced. Some key construction techniques, such as outspreading cable on deck, installing cable at pylon, pulling and fixing cable at the attachment with decks and cable PE sheath protection are discussed.

  4. Parametrically excited oscillation of stay cable and its control in cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    孙炳楠; 汪至刚; 高赞明; 倪一清

    2003-01-01

    This paper presents a nonlinear dynamic model for simulation and analysis of a kind of parametrically excited vibration of stay cable caused by support motion in cable-stayed bridges. The sag, inclination angle of the stay cable are considered in the model, based on which, the oscillation mechanism and dynamic response characteristics of this kind of vibration are analyzed through numerical calculation. It is noted that parametrically excited oscillation of a stay cable with certain sag, inclination angle and initial static tension force may occur in cable-stayed bridges due to deck vibration under the condition that the natural frequency of a cable approaches to about half of the first model frequency of the bridge deck system. A new vibration control system installed on the cable anchorage is proposed as a possible damping system to suppress the cable parametric oscillation. The numerical calculation results showed that with the use of this damping system, the cable oscillation due to the vibration of the deck and/or towers will be considerably reduced.

  5. Static and Dynamic Characteristics of a Long-Span Cable-Stayed Bridge with CFRP Cables

    Directory of Open Access Journals (Sweden)

    Xu Xie

    2014-06-01

    Full Text Available In this study, the scope of CFRP cables in cable-stayed bridges is studied by establishing a numerical model of a 1400-m span of the same. The mechanical properties and characteristics of CFRP stay cables and of a cable-stayed bridge with CFRP cables are here subjected to comprehensive analysis. The anomalies in the damping properties of free vibration, nonlinear parametric vibration and wind fluctuating vibration between steel cables and CFRP cables are determined. The structural stiffness, wind resistance and traffic vibration of the cable-stayed bridge with CFRP cables are also analyzed. It was found that the static performances of a cable-stayed bridge with CFRP cables and steel cables are basically the same. The natural frequencies of CFRP cables do not coincide with the major natural frequencies of the cable-stayed bridge, so the likelihood of CFRP cable-bridge coupling vibration is minuscule. For CFRP cables, the response amplitudes of both parametric vibration and wind fluctuating vibration are smaller than those of steel cables. It can be concluded from the research that the use of CFRP cables does not change the dynamic characteristics of the vehicle-bridge coupling vibration. Therefore, they can be used in long-span cable-stayed bridges with an excellent mechanical performance.

  6. Seismic Passive Control of Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    Hosam-Eddin M. Ali

    1995-01-01

    Full Text Available A three-dimensional modeling procedure is proposed for cable-stayed bridges with rubber, steel, and lead energy dissipation devices. The passive control technique is investigated by considering the response of bridge models with and without energy dissipation devices. The impact of various design parameters on the seismic response of current and future bridge designs is studied. Appropriate locations and properties of the passive devices can achieve better performance for cable-stayed bridges by balancing the significant reduction in earthquake-induced forces against tolerable displacements. Proper design of passive systems can help provide solutions for retro-fitting some existing bridges.

  7. Aerodynamic stability of cable-stayed-suspension hybrid bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan

    2005-01-01

    Three-dimensional nonlinear aerodynamic stability analysis was applied to study the aerodynamic stability of a cable-stayed-suspension (CSS) hybrid bridge with main span of 1400 meters, and the effects of some design parameters (such as the cable sag, length of suspension portion, cable plane arrangement, subsidiary piers in side spans, the deck form, etc.) on the aerodynamic stability of the bridge are analytically investigated. The key design parameters, which significantly influence the aerodynamic stability of CSS hybrid bridges, are pointed out, and based on the wind stability the favorable structural system of CSS hybrid bridges is discussed.

  8. A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    B. Asgari

    2014-01-01

    Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  9. A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

    Science.gov (United States)

    Asgari, B; Osman, S A; Adnan, A

    2014-01-01

    Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  10. Aerodynamic stability of cable-stayed bridges under erection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan; XIANG Hai-fan

    2005-01-01

    In this work, nonlinear multimode aerodynamic analysis of the Jingsha Bridge under erection over the Yangtze River is conducted, and the evolutions of structural dynamic characteristics and the aerodynamic stability with erection are numerically generated. Instead of the simplified method, nonlinear multimode aerodynamic analysis is suggested to predict the aerodynamic stability of cable-stayed bridges under erection. The analysis showed that the aerodynamic stability maximizes at the relatively early stages, and decreases as the erection proceeds. The removal of the temporary piers in side spans and linking of the main girder to the anchor piers have important influence on the dynamic characteristics and aerodynamic stability of cable-stayed bridges under erection.

  11. Optimal Damping of Stays in Cable-Stayed Bridges for In-Plane Vibrations

    DEFF Research Database (Denmark)

    Jensen, C.N.; Nielsen, S.R.K.; Sørensen, John Dalsgaard

    2002-01-01

    Significant vibrations have been reported in stays of recently constructed cable stayed bridges. The vibrations appear as in-plane vibrations that may be caused by rain–wind- induced aeroelastic interaction or by resonance excitation of the cables from the motion of the pylons. The stays of moder...

  12. Research on Construction Monitoring Techniques for Cable Replacement of the Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Dai Pu

    2013-09-01

    Full Text Available Due to various reasons, some cable-stayed bridges require the replacement of part or all stay cables after operating for a period of time. In this study, based on some engineering practices of stay cable replacement, the condition of bridge structure before replacement is analyzed with Finite Element Analysis method for plane member system. The theoretical calculations, cable force measurement, replacement methods and process monitoring for cable replacement are introduced to find out the key technical problems. From the specified bridge monitoring practices, we suggest monitoring cable tension and the main beam alignment during the process of cable replacement, to make sure the cable-stayed bridge reaches its design conditions.

  13. Probabilistic FE analysis of a cable stayed composite bridge

    NARCIS (Netherlands)

    Boer, A. de; Waarts, P.H.

    1999-01-01

    This paper describes the design of a new cable stayed composite bridge near Kampen in the Netherlands. In the design process, the safety of bridges is insured by means of partial safety factors for both strength and load parameters. As a result it is generally accepted that the structure as a whole

  14. Nonlinear Analysis of Cable Vibration of a Multispan Cable-Stayed Bridge under Transverse Excitation

    OpenAIRE

    Kun Lin; Dujian Zou; Minghai Wei

    2014-01-01

    The nonlinear vibrations of cable in a multispan cable-stayed bridge subjected to transverse excitation are investigated. The MECS (multielements cable system) model, where multielements per cable stay are used, is built up and used to analyze the model properties of the multispan cable-stayed bridges. Then, a simplified two-degrees-of-freedom (2-DOFs) model, where the tower or the deck is reduced to a beam, is proposed to analyze the nonlinear dynamic behaviors of the beam and cable. The res...

  15. Nonlinear Dynamic Reliability of Coupled Stay Cables and Bridge Tower

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Nonlinear vibration can cause serious problems in long span cable-stayed bridges. When the internal resonance threshold is reached between the excitation frequency and natural frequency,large amplitudes occur in the cable. Based on the current situation of lacking corresponding constraint criteria, a model was presented for analyzing the dynamic reliability of coupling oscillation between the cable and tower in a cable-stayed bridge. First of all, in the case of cable sag, the d'Alembert principle is applied to studying the nonlinear dynamic behavior of the structure, and resonance failure interval of parametric oscillation is calculated accordingly. Then the dynamic reliability model is set up using the JC method. An application of this model has been developed for the preliminary design of one cable-stayed bridge located on Hai River in Tianjin, and time histories analysis as well as reliability indexes have been obtained. When frequency ratio between the cable and tower is approaching 1∶2, the reliability index is 0.98, indicating high failure probability. And this is consistent with theoretical derivation and experimental results in reference. This model, which is capable of computing the reliability index of resonance failure, provides theoretical basis for the establishment of corresponding rule.

  16. Damage Detection for Long-Span Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhao Ling; Li Aiqun; Miao Changqing; Wang Yonglan

    2006-01-01

    Based on the updated finite-element model of a cable-stayed bridge, this study investigates the technique of identifying damage existing in cable or girder by means of numerical simulation. The modal analysis is performed to identify the changes in modal frequencies and curvatures caused by damage, and the static analysis is executed to detect the influence of damage on cable force. The results indicate a relatively significant decrease in frequencies of lower vertical bending modes due to the damage in cable and little change of frequencies due to damage in girder. Different sensitivities to the location of damaged cable are observed from the frequency changes of different bending modes, which can be used to initially locate the damaged cable. The damage in either cable or girder can be further localized by the most significant change in curvature of girder. The damage occurred in a cable produces a remarkable change in force of nearby cables, whereas the damage in girder brings little change of cable forces. In addition, a pragmatic approach for localizing the damage in girder or cable is proposed based on a comprehensive utilization of the changes in frequency of vertical bending modes, modal curvature of girder, and force in cables.

  17. Field application of a cable NDT system for cable-stayed bridge using MFL sensors integrated

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Won; Choi, Jun Sung; Park, Seung Hee [Sungkyunkwan University, Seoul (Korea, Republic of); Lee, Eun Chan [Korea Maintance Co., Ltd., Seoul (Korea, Republic of)

    2014-02-15

    In this study, an automated cable non-destructive testing(NDT) system was developed to monitor the steel cables that are a core component of cable-stayed bridges. The magnetic flux leakage(MFL) method, which is suitable for ferromagnetic continuum structures and has been verified in previous studies, was applied to the cable inspection. A multi-channel MFL sensor head was fabricated using hall sensors and permanent magnets. A wheel-based cable climbing robot was fabricated to improve the accessibility to the cables, and operating software was developed to monitor the MFL-based NDT research and control the climbing robot. Remote data transmission and robot control were realized by applying wireless LAN communication. Finally, the developed element techniques were integrated into an MFL-based cable NDT system, and the field applicability of this system was verified through a field test at Seohae Bridge, which is a typical cable-stayed bridge currently in operation.

  18. Thermal Effect of the Cable-Stayed Bridge Tower

    Institute of Scientific and Technical Information of China (English)

    Zhang Hai-long; Li Jun; Liu Chang-guo; Jiang Tian-hua; Wei jun

    2003-01-01

    This paper studies the thermal effect of the cable-stayed bridge tower based on full time accurate measurement and finite element analysis on Xiantao Hanjiang River Highway Bridge. The measured results and the displacement variation of top tower show that the tower rotates periodically when it is exposed in sunshine. But the tower column will not decline when there is no sunshine. In spite of in winter or in summer, the period when the tower column changed smallest is from 0∶00 am to 5∶00 am. The time period when the tower column has maximum deviation lags behind the time when the tower column has maximum temperature difference, and this phenomenon is obvious in winter. The conclusions also have directive value in predicting the tower deformations and their directions in construction control of cable-stayed bridge, and in verifying the finite element program.

  19. Nonlinear Analysis of Cable Vibration of a Multispan Cable-Stayed Bridge under Transverse Excitation

    Directory of Open Access Journals (Sweden)

    Kun Lin

    2014-01-01

    Full Text Available The nonlinear vibrations of cable in a multispan cable-stayed bridge subjected to transverse excitation are investigated. The MECS (multielements cable system model, where multielements per cable stay are used, is built up and used to analyze the model properties of the multispan cable-stayed bridges. Then, a simplified two-degrees-of-freedom (2-DOFs model, where the tower or the deck is reduced to a beam, is proposed to analyze the nonlinear dynamic behaviors of the beam and cable. The results of MECS model analysis show that the main tower in the multispan cable-stayed bridge is prone to the transverse vibration, and the local vibration of cables only has a little impact on the frequency values of the global modes. The results of simplified model analysis show that the energy can be transformed between the modes of the beam and cable when the nature frequencies of them are very close. On the other hand, with the transverse excitation changing, the cable can exhibit richer quasi-periodic or chaotic motions due to the nonlinear terms caused by the coupled mode between the beam and cable.

  20. A simplified fragility analysis of fan type cable stayed bridges

    Institute of Scientific and Technical Information of China (English)

    R. A. Khan; T. K. Datta; S. Ahmad

    2005-01-01

    A simplified fragility analysis of fan type cable stayed bridges using Probabilistic Risk Analysis (PRA)procedure is presented for determining their failure probability under random ground motion. Seismic input to the bridge support is considered to be a risk consistent response spectrum which is obtained from a separate analysis. For the response analysis, the bridge deck is modeled as a beam supported on springs at different points. The stiffnesses of the springs are determined by a separate 2D static analysis of cable-tower-deck system. The analysis provides a coupled stiffness matrix for the spring system. A continuum method of analysis using dynamic stiffness is used to determine the dynamic properties of the bridges .The response of the bridge deck is obtained by the response spectrum method of analysis as applied to multidegree of freedom system which duly takes into account the quasi - static component of bridge deck vibration. The fragility analysis includes uncertainties arising due to the variation in ground motion, material property, modeling, method of analysis,ductility factor and damage concentration effect. Probability of failure of the bridge deck is determined by the First Order Second Moment (FOSM) method of reliability. A three span double plane symmetrical fan type cable stayed bridge of total span 689 m, is used as an illustrative example. The fragility curves for the bridge deck failure are obtained under a number of parametric variations. Some of the important conclusions of the study indicate that (i) not only vertical component but also the horizontal component of ground motion has considerable effect on the probability of failure; (ii) ground motion with no time lag between support excitations provides a smaller probability of failure as compared to ground motion with very large time lag between support excitation; and (iii) probability of failure may considerably increase for soft soil condition.

  1. Study on vulnerability assessment of cable-stayed bridges

    Science.gov (United States)

    Chang, C. C.; Yan, D.

    2006-03-01

    A structure is vulnerable if any small damage will trigger disproportionately large consequences, even leads to a cascade of failure events and progressive collapse. The structural vulnerability performance depends upon the properties, locations of damaged components and the way they are connected to the rest of the structure. In this paper, progressive failure analysis method is utilized for the vulnerability study of cable-stayed bridges. The goal of it is to identify various failure scenarios initiated from the sudden damage of some bridge components. Based on the analysis results, assuming that the behaviors of damaged components can be modeled using plastic hinges, the hybrid element model is introduced to derived the modified stiffness matrix considering both of the effects of bending moments and shear forces. Furthermore, the vulnerability index in terms of the nodal stiffness degradation can be analytically quantified, which could be regarded as an index to determine the bridge failure consequences, so that the vulnerability distribution graph for the whole bridge can be sketched to evaluate the bridge performances from vulnerability viewpoints. This quantitative approach is applicable for structural evaluation under unforeseen attack and illustrated on a typical long-span cable-stayed bridge.

  2. Application study on the first cable-stayed bridge with CFRP cables in China

    Directory of Open Access Journals (Sweden)

    Kuihua Mei

    2015-08-01

    Full Text Available In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

  3. Study on longitudinal wind load calculation method of cables for cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    Pei Minshan; Zhang Xigang; Zhu Bin; Hou Bin; Liu Changpeng

    2009-01-01

    Along with the expanding of span of cable-stayed bridge, wind load becomes a more and more important controlling factor for bridge the design. A very large proportion of the wind load acting on cables has exceeded that acting on deck. There was not any detailed prescript in Chinese code for calculation of longitudinal wind load on cables due to lack of theoretical research and experiment, and conservative simplified calculation was adopted during design, which leads to conservative and uneconomical design of structures. To resolve this problem, cable force experiment was carried out during the design of Sutong Bridge. By comparing with international research results, the calculation formula of longitudinal wind drag coefficient for cables was advanced to fill the blank of bridge wind resistant code of China, and has already been adopted in the Highway Bridge Wind Resistant Design Code (JTG/T D60-01-2004) with great significance for bridge engineering.

  4. Closure technique for the hybrid girder cable stayed bridge of Edong Bridge

    Institute of Scientific and Technical Information of China (English)

    Liu Minghu; Tan Hao; Xu GuoPing; Zhao Canhui

    2012-01-01

    Based on Edong Yangtze River Bridge, which is the second longest hybrid girder cable stayed bridge with 926 m long main span, the influencing factors and crucial techniques of the main span closure method for long span hybrid girder cable stayed bridge are studied. After theoretical analysis, numerical evaluation and practical test, the loading assistant closure method is employed in Edong Yangtze River Bridge. The loading assistant closure method, with better thermal adaptability and less influence on bridge line and the forced status, can meet the requirements of the unstressed state control method. Based on the mentioned advantages, the loading assistant closure method is applicable to long span hybrid girder cable stayed bridges. The conclusion can provide a reference for the further design of the similar brid~es.

  5. Preliminary design and parametric study of 1400 m partially earth-anchored cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The preliminary design and parametric study of 1400 m partially earth-anchored cable-stayed bridge are described. Static per-formance of this new type of bridge is discussed. Compared with fully self-anchored cable-stayed bridge, its advantages in fin-ished state are summarized. Based on numerical calculation, effects of several structural parameters on static performance are presented.

  6. Aerostatic Stability of Long-Span Cable-Stayed Bridges: Parametric Study

    Institute of Scientific and Technical Information of China (English)

    程进; 江见鲸; 肖汝诚; 项海帆

    2003-01-01

    The increasing span of cable-stayed bridges has focused more attention on the aerostatic stability of the design and construction of such bridges. This paper presents a new method to analyze the nonlinear aerostatic stability of cable-stayed bridges including all three components of the wind load and the geometric nonlinearity. The analysis was used to investigate the effects of the wind angle of incidence, the wind load of individual bridge elements, the sagging of cable elements, the changes of tower height and the changes of side span length on the aerostatic stability of cable-stayed bridges. The results show that the wind angle of incidence and the wind loads on the cables have an important effect on the aerostatic stability of cable-stayed bridges.

  7. Research development of digital maintenance and management system for long-span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    REN Yuan; HUANG Qiao; SUN Yong-ming

    2009-01-01

    Digital cable-stayed bridge maintenance and management system (DCBMS) was developed for the need of maintenance and management of long-span cable-stayed bridges. In this paper, the major functions and theoretical application of eight modules were systematically stated with the background of Harbin Songhua River cable-stayed bridge, which include data management module, inspection and measurement module, assessment module, finite element analysis module, disease diagnosis and prediction module, maintenance module, query module and help module. By analyzing and calculating the data from manual inspection database, basic database and health monitoring subsystem, DCBMS can accomplish the functions like life prediction, disease diagnosis, comprehensive assessment, maintenance and management of bridges. Therefore, the maintenance and management of long-span cable-stayed bridges can be made digital, professional and scientific. By running this system, a real-time and specific technical guidance can be provided for the maintainers and managers of longspan cable-stayed bridges.

  8. NONLINEAR TRANSIENT RESPONSE OF STAY CABLE WITH VISCOELASTICITY DAMPER IN CABLE-STAYED BRIDGE

    Institute of Scientific and Technical Information of China (English)

    陈水生; 孙炳楠; 冯义卿

    2004-01-01

    Taking the bending stiffness,static sag,and geometric non-linearity into consideration,the space nonlinear vibration partial differential equations were derived.The partical differential equations were discretized in space by finite center difference approximation,then the nonlinear ordinal differential equations were obtained.A hybrid method involving the combination of the Newmark method and the pseudo-force strategy was proposed to analyze the nonlinear transient response of the inclined cable-dampers system subjected to arbitrary dynamic loading.As an example,two typical stay cables were calculated by the present method.The results reveal both the validity and the deficiency of the viscoelasticity damper for vibration control of stay cables.The efficiency and accuracy of the proposed method is also verified by comparing the results with those obtained by using Runge-Kutta direct integration technique.A new time history analysis method is provided for the research on the stay cable vibration control.

  9. Case Study on 4000 m-span Cable-stayed Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Haijun Wang

    2014-04-01

    Full Text Available This study describes the case studies for a cable-stayed suspension bridges proposed over the Tsugaru Strait, Japan. Center Bridge is designed as a compound bridge of suspension bridges and cable-stayed bridges with 4000 m super-long-span. Case studies about the effects of cable-stayed bridge length, the design of sub-cable, height and stiffness of main tower, type of foundation and length of side span on displacement were carried out. With appropriate design of above parameters, the compound bridge can reduce horizontal displacement of main tower and vertical deflection in the central portion and enhance resistance to partial loading. The study reports the results based on these case studies.

  10. Dynamic responses of cable-stayed bridges to vehicular loading including the effects of the local vibration of cables

    Institute of Scientific and Technical Information of China (English)

    He ZHANG; Xu XIE

    2011-01-01

    Stay cables,the primary load carrying components of cable-stayed bridges (CSBs),are characterised by high flexibility which increases with the span of the bridge.This makes stay cables vulnerable to local vibrations which may have significant effects on the dynamic responses of long-span CSBs.Hence,it is essential to account for these effects in the assessment of the dynamics CSBs.In this paper,the dynamic responses of CSBs under vehicular loads are studied using the finite element method (FEM),while the local vibration of stay cables is analyzed using the substructure method.A case study of a cable-stayed steel bridge with a center span of 448 m demonstrates that stay cables undergo large displacements in the primary mode of the whole bridge although,in general,a cable's local vibrations are not obvious.The road surface roughness has significant effects on the interaction force between the deck and vehicle but little effect on the global response of the bridge.Load impact factors of the main girder and tower are small,and the impact factors of the tension of cables are larger than those of the displacements of girders and towers.

  11. Performances of super-long span prestressed cable-stayed bridge with CFRP cables and RPC girder

    Institute of Scientific and Technical Information of China (English)

    Fang Zhi; Fan Fenghong; Ren Liang

    2013-01-01

    To discuss the applicability of advanced composite carbon fiber reinforced polymer (CFRP) and ultra-high performance concrete reactive powder concrete (RPC) in super-long span cable-stayed bridges , taking a 1 008 m cable-stayed bridge with steel girders and steel cables as an example,a new cable-stayed bridge in the same span with RPC girders and CFRP cables was designed,in which the cable’s cross section was determined by the principle of equivalent cable capacity and the girder’s cross section was determined in virtual of its stiffness, shear capacity and local stability. Based on the methods of finite element analysis,the comparative analysis of these two cable-stayed bridge schemes about static performances,dynamic performances,stability and wind resis-tance behavior were carried out. The results showed that it was feasible to form a highly efficient,durable concrete cable-stayed bridge with RPC girders and CFRP cables and made its applicable span range expand to 1 000 m long around.

  12. Application of Gliding Scaffold System In Cable-Stayed Bridge Construction

    Institute of Scientific and Technical Information of China (English)

    YU Bao-chu; ZHANG Zhe; Chang Fu-ping

    2005-01-01

    Gonghe bridge is a double level cable-stayed concrete bridge with a single-cable-plane of single cable tower. Its span is 114+120 m and a whole length of 236 m. The gliding scaffold equipment is used for the first time in the long span cable-stayed bridge construction to reduce the construction time limit. In the process of construction, to make sure a safe connection among concrete objects with different ages, the single-supporting and single-suspension system is adopted before the concrete pouring. While the double-supporting and single-suspension system is applied after concrete pouring. These construction systems with gliding scaffold equipment are first introduced in long span cable-stayed bridge and presented in detail[1]. The practice shows that these gliding scaffold systems have many advantages over the traditional ones.

  13. Compressive sampling based approach for identification of moving loads distribution on cable-stayed bridges

    Science.gov (United States)

    Bao, Yuequan; Li, Hui; Zhang, Fujian; Ou, Jinping

    2013-04-01

    A moving loads distribution identification method for cable-stayed bridges based on compressive sampling (CS) technique is proposed. CS is a technique for obtaining sparse signal representations to underdetermined linear measurement equations. In this paper, CS is employed to localize moving loads of cable-stayed bridges by limit cable force measurements. First, a vehicle-bridge model for cable-stayed bridges is presented. Then the relationship between the cable force and moving loads is constructed based on the influence lines. With the hypothesis of sparsity distribution of vehicles on bridge deck (which is practical for long-span bridges), the moving loads are identified by minimizing the `l2-norm of the difference between the observed and simulated cable forces caused by moving vehicles penalized by the `l1-norm' of the moving load vector. The resultant minimization problem is convex and can be solved efficiently. A numerical example of a real cable-stayed bridge is carried out to verify the proposed method. The robustness and accuracy of the identification approach with limit cable force measurement for multi-vehicle spatial localization are validated.

  14. Limit span of self-anchored cable-stayed suspension cooperation system bridge based on strength

    Institute of Scientific and Technical Information of China (English)

    Zhe ZHANG; Huili WANG; Sifeng QIN; Xiaomeng GE

    2009-01-01

    The limit span of self-anchored cable-stayed suspension bridge is deduced. The relations among the geometrical parameters, loads and material characteristics are also analyzed. Based on the material strength and commonly used materials, the limit spans of self-anchored cable-stayed suspension bridges with concrete girder or steel girder under vertical static load are discussed in detail.The corresponding upper limit spans and the effect of the factors on the span are given. The results indicate that increasing rise-span ratio, height-span ratio and cable-stayed segment length or reducing the second dead load could increase the cooperation system span.

  15. Investigation of Tension Forces in A Stay Cable System of A Road Bridge Using Vibration Methods

    Directory of Open Access Journals (Sweden)

    Hawryszków Paweł

    2015-01-01

    Full Text Available In the article author presents method of investigation of tension forces in stay cable systems using dynamical methods. Research was carried out during stay cable system installation on WN-24 viaduct near Poznań, that is way it was possible to compare tension forces indicated directly by devices using for tensioning of cable-stayed bridges with results achieved indirectly by means of dynamical methods. Discussion of results was presented. Advantages of dynamical methods and possible fields of application was described. This method, which has been rarely used before, may occur interesting alternative in diagnostics of bridges in comparison to traditional methods.

  16. Research of 1770 MPa galvanized steel wire for stay cable of domestic bridges

    Institute of Scientific and Technical Information of China (English)

    Ding Feng; Sang Chunming; Zhou Daiyi; Bai Bingdong

    2009-01-01

    This paper focuses on introducing the manufacture technology of 1 770 MPa galvanized steel wires for stay cables applied to domestic bridges. During the development practices of high strength galvanized wire for stay cables used in Sutong Bridge, Baosteel has established three key technologies based on research of manufacture technology and technical innovation. The three key technologies are: "Double Tensioning + limiter die" process, "dominant process + fine adjustment" in integrated optimization technology and "three-level control" in hot dip galvanization. With these key technologies, Baosteet has produced 1 770 MPa galvanized wires for stay cable, which has high tensile strength, low relaxation and good torsion performances.

  17. Aerodynamic problems of cable-stayed bridges spanning over one thousand meters

    Institute of Scientific and Technical Information of China (English)

    Chen Airong; Ma Rujin; Wang Dalei

    2009-01-01

    Tbe elongating of cable-stayed bridge brings a series of aerodynamic problems. First of all, geometric nonlin-ear effect of extreme long cable is much more significant for cable-stayed bridge spanning over one thousand meters. Lat-eral static wind load will generate additional displacement of long cables, which causes the decrease of supporting rigidi-ty of the whole bridge and the change of dynamic properties. Wind load, being the controlling load in the design of ca-hie-stayed bridge, is a critical problem and needs to be solved. Meanwhile, research on suitable system between pylon and deck indicates fixed-fixed connection system is an effective way for improvement performance of cable-stayed bridges under longitudinal wind load. In order to obtain aerodynamic parameters of cable-stayed bridge spanning over one thou-sand meters, identification method for flutter derivatives of full bridge aero-elastic model is developed in this paper. Furthermore, vortex induced vibration and Reynolds number effect are detailed discussed.

  18. Comparison of various procedures for progressive collapse analysis of cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    Jian-guo CAI; Yi-xiang XU; Li-ping ZHUANG; Jian FENG; Jin ZHANG

    2012-01-01

    Alternate path (AP) method is the most widely used method for the progressive collapse analysis,and its application in frame structures has been well proved.However,the application of AP method for other structures,especially for cable-stayed structures,should be further developed.The four analytical procedures,i.e.,linear static,nonlinear static,linear dynamic,and nonlinear dynamic were firstly improved by taking into account the initial state.Then a cable-stayed structure was studied using the four improved methods.Furthermore,the losses of both one cable and two cables were discussed.The results show that for static and dynamic analyses of the cable-stayed bridges,there is large difference between the results obtained from simulations starting with either a deformed or a nondeformed configuration at the time of cable loss.The static results are conservative in the vicinity of the ruptured cable,but the dynamic effect of the cable loss in the area farther away from the loss-cable cannot be considered.Moreover,the dynamic amplification factor of 2.0 is found to be a good estimate for static analysis procedures,since linear static and linear dynamic procedures yield approximately the same maximum vertical deflection.The results of the comprehensive evaluation of the cable failure show that the tread of the progressive failure of the cable-stayed bridges decreases when the location of the failed cables is closer to the pylon.

  19. Summarizing the Methods of Determination of Rational Completion Status of Cable-Stayed Bridges

    Institute of Scientific and Technical Information of China (English)

    Yang Jun; Shen Chengwu; Sheng Jun

    2006-01-01

    Cable-stayed bridge is a high-order hyperstatic structure. The size of cable force affects the stress of the structure greatly. The key problem to determine the rational completion status of cable-stayed bridges is how to control cable force on completion status. Surrounding this problem, domestic and foreign experts and scholars have done a lot of favorable work and obtained much achievement. On the basis of comprehensive reading domestic and foreign relative documentation, the author of this article classifies rationally the current researching achievement, comments and compares advantages and disadvantages of each method and lists two synthetic methods' detail steps and puts forward the researching emphasis of the field will deflect to synthesis several methods to determine the rational completion status of cable-stayed bridges.

  20. Seismic performance evaluation for super-long span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    Ye Aijun; Wu Shouchang

    2009-01-01

    Based on the capacity/demand (C/D) analysis of bridge components, and life cycle and performance based seismic design principles, a practical approach is developed for the seismic performance evaluation of super-long span cable-stayed bridges. According to the approach, the seismic performance evaluation of the Sutong Bridge, which is a cable-stayed bridge with a main span of 1 088 m, is completed, and the practicality of the approach is validated. The earthquake resistance level for super-long span cable-stayed bridges is discussed, including the earthquake level, its corresponding structural performance and check indices. And a set of formula for capacity/demand ratio calculation of bridge components is proposed.

  1. Study of the aerostatic and aerodynamic stability of super long-span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    Zhang Xinjun; Sun Hailing

    2014-01-01

    With the increase of span length,the bridge tends to be more flexible,and the wind stability be-comes an important problem for the design and construction of super long-span cable-stayed bridges. By taking a super long-span cable-stayed bridge with a main span of 1 400 m as example,the aerostatic and aerodynamic stability of the bridge are investigated by three-dimensional nonlinear aerostatic and aerodynamic stability analy-sis,and the results are compared with those of a suspension bridge with a main span of 1 385 m,and from the aspect of wind stability,the feasibility of using cable-stayed bridge in super long-span bridge with a main span above 1 000 m is discussed. In addition,the influences of design parameters including the depth and width of the girder,the tower structure,the tower height-to-span ratio,the side-to-main span ratio,the auxiliary piers in the side span and the anchorage system of stay cables,etc on the aerostatic and aerodynamic stability of su-per long-span cable-stayed bridges are investigated numerically;the key design parameters are pointed out,and also their reasonable values are proposed.

  2. Damage identification of a large-span concrete cable-stayed bridge based on genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHU Jinsong; XIAO Rucheng

    2007-01-01

    The global stability of a structure, the stiffness of its main girder and concrete tower, and the variation of the forces of its stay cables are key issues to the safety assessment of an in-service cable-stayed bridge. The efficiency and ratio- nality of local elaborate non-damage-identification could be enhanced by the primary damage identification of cable- stayed bridges on the basis of periodic detection of the cable force and strain monitor in key sections of the main girder. The genetic algorithms of damage identification for cable- stayed bridges were investigated in this paper on the basis of the monitor data of the cable force and strain in a key section of the main girder. A damage detection program for complex civil structure was generated to implement the identification of damage location and extent. The deterioration of the struc- ture was calculated according to the variation of monitor data. It is demonstrated that the results of damage identification from the parametric finite element method are accurate. The method had been verified using a long-span concrete cable- stayed bridge in Ningbo, which has been in use for the past four years.

  3. Multiobjective Optimal Control of Longitudinal Seismic Response of a Multitower Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Geng Fangfang

    2016-01-01

    Full Text Available The dynamic behavior of a multitower cable-stayed bridge with the application of partially longitudinal constraint system using viscous fluid dampers under real earthquake ground motions is presented. The study is based on the dynamic finite element model of the Jiashao Bridge, a six-tower cable-stayed bridge in China. The prime aim of the study is to investigate the effectiveness of viscous fluid dampers on the longitudinal seismic responses of the bridge and put forth a multiobjective optimization design method to determine the optimized parameters of the viscous fluid dampers. The results of the investigations show that the control objective of the multitower cable-stayed bridge with the partially longitudinal constraint system is to yield maximum reductions in the base forces of bridge towers longitudinally restricted with the bridge deck, with slight increases in the base forces of bridge towers longitudinally unrestricted with the bridge deck. To this end, a multiobjective optimization design method that uses a nondominating sort genetic algorithm II (NSGA-II is used to optimize parameters of the viscous fluid dampers. The effectiveness of the proposed optimization design method is demonstrated for the multitower cable-stayed bridge with the partially longitudinal constraint system, which reveals that a design engineer can choose a set of proper parameters of the viscous fluid dampers from Pareto optimal fronts that can satisfy the desired performance requirements.

  4. A new monitoring method of cable tension of cable-stayed bridge-fiber Bragg grating method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-she; DU Yan-liang; NING Chen-xiao

    2005-01-01

    A new on-line monitoring method based on fiber Bragg grating (FBG) for cable tension of cable-stayed bridge was introduced. The major structure of sensing head using in the test of cable tension is elastic annular. The FBG is attached inflexibility to the exterior surface of annulus and form straight-through sensing head. Sensing headis installed between the anchor device and stow-board of funiculus holes of the cable-stayed bridge. Accompany with the change of the outside pressure, the Bragg center reflective wavelength of optical fiber grating changed correspondingly. According to this characteristic, through demodulating the△λ, the value of the cable tension can be determined. The experiment results and the theory indicate that the test system has simple structure, good stability and linear,wide response capacity, and has no special request for tester, The measurement method for the test of ca ble tension is practical and effective.

  5. Study on Fatigue Behavior of Anchorage of Cable and Girder of Long Span Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A full scale model test is done and a FEM model is established toinvestigate the fatigue behavior of the Nancha cable-stayed bridge of the Nanjing Second Yangtz River Bridge, a long span steel bridge with a main span of 628 m. The results of test and FEM are analyzed and compared. It is shown that they are in good agreement. It is verified that the fatigue characteristic of the anchorage structure of cable and girder of the bridge satisfies the requirements specified by Chinese, British and American codes.

  6. Lateral Vibrations of a Cable-Stayed Bridge under Crowd Excitation

    Directory of Open Access Journals (Sweden)

    Lijun Ouyang

    2015-01-01

    Full Text Available A cable-stayed bridge model under crowd excitation is established in this paper by considering the geometric nonlinear property of the cables. Lateral vibrations of the model are investigated by employing the center manifold theory, and the first-order approximation solution of the periodic vibration of the bridge is derived by using the energy method. Numerical simulations are carried out to verify the validity of our analytical expressions. Our research shows that the existence of the cables can reduce the amplitude and frequency of the bridge, especially for the large amplitude case. This might explain why measured data of a cable-stayed bridge (T-bridge in Japan vibrating under crowd excitation are much less than the theoretical results reported in previous studies in which the cable-stayed bridge is viewed as a single-degree-of-freedom system. Our analysis results suggest that the structure types of footbridges should not be easily ignored in the study of pedestrian-footbridge interaction.

  7. A Proposal for 4000m-span Cable-stayed Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Haijun Wang

    2013-06-01

    Full Text Available This study proposed a compound bridge of suspension bridges and cable-stayed bridges with 4000 m super-long-span over the Tsugaru Strait, Japan. Near to the main towers, cable-stayed bridges and prestressed concrete decks are proposed. It is helpful to enhance rigidity and endure the great axial compression force. In the center of the span, suspension bridges and steel box decks are stiffened by trusses, it can reduce self-weigh and the space between girders, thus contribute to aero-elastic stability. RCFT main tower, RC shell pier and RCFT jacket foundation can enhance rigidity and reduce self-weigh. As a result, the live-dead load ratio of proposal is 0.05 and it is equivalent to 2500m-span suspension bridge.

  8. GPS Dynamic Monitoring Experiment and Result Analysis of Long-Span Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    For the sake of timely appraising the working condition of the bridge, measuring the dynamic characteristics of the bridge structure is very important and necessary. A GPS dynamic monitoring test was carried out in the Wuhan Baishazhou Bridge, which is one of the longest span cable-stayed bridges having been built in China. This paper introduces the experimental implementing scheme and data processing method. The vibration characteristics of the middle span of cable-stayed bridge are availably obtained by use of the spectral analytic approach. The measuring results are very identical to the theoretical designed values. The research demonstrates that, with GPS receiver of the high sampling rate and suitable data processing method, the vibration characteristics of the bridge structure can be determined with high accuracy.

  9. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    Directory of Open Access Journals (Sweden)

    Paolo Lonetti

    2016-10-01

    Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes

  10. GPS for structural health monitoring: A case study on the Basarab overpass cable-stayed bridge

    NARCIS (Netherlands)

    Lepadatu, L.; Tiberius, C.C.J.M.

    2014-01-01

    The Basarab cable-stayed bridge is a newly built structure in Bucharest, Romania, which was inaugurated in June 2011. Before the oficial opening, in order to assure its qualification for trafic, it had to pass several loading tests with convoys of trucks and trams. For this, besides a priori evaluat

  11. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...

  12. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    OpenAIRE

    Paolo Lonetti; Arturo Pascuzzo

    2016-01-01

    A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displace...

  13. Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

    Directory of Open Access Journals (Sweden)

    Wang Hui-Li

    2013-01-01

    Full Text Available Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

  14. Simple Program to Investigate Hysteresis Damping Effect of Cross-Ties on Cables Vibration of Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    Panagis G. Papadopoulos

    2012-01-01

    Full Text Available A short computer program, fully documented, is presented, for the step-by-step dynamic analysis of isolated cables or couples of parallel cables of a cable-stayed bridge, connected to each other and possibly with the deck of the bridge, by very thin pretensioned wires (cross-ties and subjected to variation of their axial forces due to traffic or to successive pulses of a wind drag force. A simplified SDOF model, approximating the fundamental vibration mode, is adopted for every individual cable. The geometric nonlinearity of the cables is taken into account by their geometric stiffness, whereas the material nonlinearities of the cross-ties include compressive loosening, tensile yielding, and hysteresis stress-strain loops. Seven numerical experiments are performed. Based on them, it is observed that if two interconnected parallel cables have different dynamic characteristics, for example different lengths, thus different masses, weights, and geometric stiffnesses, too, or if one of them has a small additional mass, then a single pretensioned very thin wire, connecting them to each other and possibly with the deck of the bridge, proves effective in suppressing, by its hysteresis damping, the vibrations of the cables.

  15. Impact Coefficient Analysis of Long-Span Railway Cable-Stayed Bridge Based on Coupled Vehicle-Bridge Vibration

    Directory of Open Access Journals (Sweden)

    Yongle Li

    2015-01-01

    Full Text Available Compared with medium and small span bridges, very limited attention has been paid on the research of the impact coefficient of long-span railway bridges. To estimate the impact effects of long-span railway bridges subjected to moving vehicles, a real long-span railway cable-stayed bridge is regarded as the research object in this study, and a coupled model of vehicle-bridge system is established. The track irregularities are taken as the system excitation and the dynamic responses of the vehicle-bridge system are calculated. The impact effects on main girder, stayed cable, bearings, and bridge tower are discussed at various vehicle speeds. The results show that different components of the long-span railway cable-stayed bridge have different impact coefficients. Even for each part, the impact coefficient is also different at different local positions. It reveals that the impact coefficients in the actual situation may have significant differences with the related code clauses in the present design codes.

  16. Integrated system of structural health monitoring and intelligent management for a cable-stayed bridge.

    Science.gov (United States)

    Chen, Bin; Wang, Xu; Sun, Dezhang; Xie, Xu

    2014-01-01

    It is essential to construct structural health monitoring systems for large important bridges. Zhijiang Bridge is a cable-stayed bridge that was built recently over the Hangzhou Qiantang River (the largest river in Zhejiang Province). The length of Zhijiang Bridge is 478 m, which comprises an arched twin-tower space and a twin-cable plane structure. As an example, the present study describes the integrated system of structural health monitoring and intelligent management for Zhijiang Bridge, which comprises an information acquisition system, data management system, evaluation and decision-making system, and application service system. The monitoring components include the working environment of the bridge and various factors that affect bridge safety, such as the stress and strain of the main bridge structure, vibration, cable force, temperature, and wind speed. In addition, the integrated system includes a forecasting and decision-making module for real-time online evaluation, which provides warnings and makes decisions based on the monitoring information. From this, the monitoring information, evaluation results, maintenance decisions, and warning information can be input simultaneously into the bridge monitoring center and traffic emergency center to share the monitoring data, thereby facilitating evaluations and decision making using the system.

  17. Impact Coefficient Analysis of Long-Span Railway Cable-Stayed Bridge Based on Coupled Vehicle-Bridge Vibration

    OpenAIRE

    Yongle Li; Shifu Dong; Yulong Bao; Kejian Chen; Shizhong Qiang

    2015-01-01

    Compared with medium and small span bridges, very limited attention has been paid on the research of the impact coefficient of long-span railway bridges. To estimate the impact effects of long-span railway bridges subjected to moving vehicles, a real long-span railway cable-stayed bridge is regarded as the research object in this study, and a coupled model of vehicle-bridge system is established. The track irregularities are taken as the system excitation and the dynamic responses of the vehi...

  18. Estimation of load redistribution on a cable-stayed bridge using a combination of sensing techniques

    Science.gov (United States)

    Zonta, Daniele; Esposito, Paolo; Molignoni, Marco; Pozzi, Matteo; Zandonini, Riccardo; Wang, Ming; Zhao, Yang; Inaudi, Daniele; Posenato, Daniele; Glisic, Branko

    2012-04-01

    The motivation of this work is the installation of a monitoring system on a new cable-stayed bridge spanning the Adige River 10 km north of the town of Trento. This is a statically indeterminate structure, having a composite steel-concrete deck of length 260 m overall, supported by 12 stay cables, 6 per deck side. These are full locked steel cables of diameters 116 mm and 128 mm, designed for operational loads varying from 5000 to 8000 kN. The structural redundancy suggests that plastic load redistribution among the cables can be expected in the long term. To monitor such load redistribution, the owner decided to install a monitoring system to measure cable stress; the precision specified was of the order of few MPa. However no cable release or any form of on-site calibration involving tension change was allowed. The solution found was a combination of built-on-site electromagnetic and fiber-optic elongation gauges, these appropriately distributed on both the cables and the anchorages. We discuss how the set of gauges allows tension and elongation measurement with the appropriate precision, and compare the initial monitoring results with the tension estimates made using a non-destructive vibration test.

  19. Cross spectral energy method for damage assessment of the cable-stayed bridge under operational conditions

    Institute of Scientific and Technical Information of China (English)

    Yang Hezhen; Li Huajun

    2008-01-01

    The new cross spectral energy method (CSEM) is proposed for maintaining cable-stayed bridge safety by the measurable output-only vibration response.Damage assessment of real structures is limited by a series of problems such as unknown ambient excitation forces, errors introduced by system identification,incomplete dynamic measurements, etc.Thus the methodology based on cross spectral energy of each substructure member is derived to meet these challenges.The novel damage index does not require any modal or parameter identification technology.It can be calculated directly from vibration test data.In order to evaluate the efficiency of the presented methodology, a three dimensional (3D) actual cable-stayed bridge model with one or more damaged positions under operational conditions was studied.In order to testify the reliability of damage detection method, the response data was polluted by the random noise.It is proved that the proposed method can successfully localize all damage cases even in noisy data.With the help of examples, the CSEM can potentially be applied as a nondestructive evaluation technique (NDT) for on-line health monitoring of cable-stayed bridges with minimum disruption of its operations.

  20. Theoretical and experimental study on shear lag effect of partially cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    WU Gao-feng; XU Hong

    2005-01-01

    In order to resolve the traffic congestion problem, many cable-stayed bridges are designed with a large width to span ratio. This results in significant shear lag effect to cause nonuniform stress distribution along the flanges of the beam of bridge.This paper reports study on the shear lag effect of the Lanzhou Xiaoxihu Yellow River Bridge. A 3D finite element model of the bridge was developed and finite element analysis (FEA) was done to obtain the theoretical results. To evaluate the theoretical results, a scaled model was made to conduct static test in laboratory. The experiment results accorded with the results obtained by FEA. It is proved that FEA is an effective method to predict shear lag effect of bridges of this type.

  1. Numerical and Experimental Study of Free Vibration Characteristics of a Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    Zi Jianmin; Wang Yuanhan; Zhu Hongping

    2006-01-01

    The main aim of this study is to understand the dynamic behavior of a cable-stayed bridge,using both numerical and experimental analysis. A three-dimensionai finite element model for the bridge was developed for the free vibration analysis and the ambient vibration properties of the bridge were determined through field testing. The experimental and numerical results of natural frequencies and the associated mode shapes were compared, and the high accuracy between them shows that the 3D model is capable of approximately representing the dynamic behavior of the bridge and the use of ambient vibration survives in future testing of the bridge. These dynamic characteristics can be used as the basis for updating the finite element model and also for global damage detection.

  2. Instrumentation for durability monitoring of a long-span cable-stayed bridge

    Science.gov (United States)

    Hua, X. G.; Ni, Y. Q.; Zhou, H. F.; Ko, J. M.

    2005-05-01

    This paper outlines the design of an instrumentation system for durability monitoring of the world's longest cable-stayed bridge: the Sutong Bridge with a central span of 1088 m. As part of the Structural Health Monitoring And Safety Evaluation System (SHMASES) for the Sutong Bridge, the durability monitoring system is designed to monitor the corrosion in reinforced concrete structures. The sensors for durability monitoring include two categories. The first category refers to the sensors to monitor the causes leading to corrosion, such as temperature and relative humidity. The second category is electrode assemblies which are used to monitor the end results of corrosion. Data from the sensory system are then periodically collected using a portable or remotely computerized data acquisition system. The collected data from this system will provide useful information on maintenance and repair of concrete structures, and are envisaged to be incorporated into the reliability-based safety evaluation system developed for the Sutong Bridge

  3. APPLICATION OF ULTRA-HIGH PERFORMANCE CONCRETE TO PEDESTRIAN CABLE-STAYED BRIDGES

    Directory of Open Access Journals (Sweden)

    CHI-DONG LEE

    2013-06-01

    Full Text Available The use of ultra-high performance concrete (UHPC, which enables reducing the cross sectional dimension of the structures due to its high strength, is expected in the construction of the super-long span bridges. Unlike conventional concrete, UHPC experiences less variation of material properties such as creep and drying shrinkage and can reduce uncertainties in predicting time-dependent behavior over the long term. This study describes UHPC’s material characteristics and benefits when applied to super-long span bridges. A UHPC girder pedestrian cable-stayed bridge was designed and successfully constructed. The UHPC reduced the deflections in both the short and long term. The cost analysis demonstrates a highly competitive price for UHPC. This study indicates that UHPC has a strong potential for application in the super-long span bridges.

  4. RESEARCH ON THE ASEISMIC BEHAVIOR OF LONG-SPAN CABLE-STAYED BRIDGE WITH DAMPING EFFECT

    Directory of Open Access Journals (Sweden)

    Wu Fangwen

    2016-07-01

    Full Text Available The main beam of a cable-stayed bridge with a floating system may have a larger longitudinal displacement subject to earthquake effect. Thus, seismic control and isolation are crucial to bridge safety. This paper takes Huai’an Bridge, which has elastic coupling devices and viscous dampers set at the joint of the tower and the beam, as the research background. Its finite element model is established, and the elastic stiffness of elastic coupling devices and damper parameters are analyzed. Viscous damper and elastic coupling devices are simulated using Maxwell model and spring elements, and their damping effects are analyzed and compared through structural dynamic time-history analysis. Results show that viscous damper and elastic coupling device furnished at the joint of tower and beam of a cable-stayed bridge tower beam can effectively reduce the longitudinal displacement of the key part of the construction subject to earthquake effect, perfect the internal force distribution, and improve the aseismic performance. Between the two, viscous damper has better damping effects.

  5. Semi-active control of a cable-stayed bridge under multiple-support excitations

    Institute of Scientific and Technical Information of China (English)

    代泽兵; 黄金枝; 王红霞

    2004-01-01

    This paper presents a semi-active strategy for seismic protection of a benchmark cable-stayed bridge with consideration of multiple-support excitations. In this control strategy, Magnetorheological (MR) dampers are proposed as control devices, a LQG-clipped-optimal control algorithm is employed. An active control strategy, shown in previous researches to perform well at controlling the benchmark bridge when uniform earthquake motion was assumed, is also used in this study to control this benchmark bridge with consideration of multiple-support excitations. The performance of active control system is compared to that of the presented semi-active control strategy. Because the MR fluid damper is a controllable energy- dissipation device that cannot add mechanical energy to the structural system, the proposed control strategy is fail-safe in that bounded-input, bounded-output stability of the controlled structure is guaranteed. The numerical results demonstrated that the performance of the presented control design is nearly the same as that of the active control system; and that the MR dampers can effectively be used to control seismically excited cable-stayed bridges with multiple-support excitations.

  6. Real-time condition assessment of the Bill Emerson cable-stayed bridge using artificial neural networks

    Science.gov (United States)

    Wang, Wenjian; Chen, Genda; Hartnagel, Bryan A.

    2007-04-01

    The Bill Emerson Cable-stayed Bridge is a newly built 1206 meter long structure crossing the Mississippi River. Due to its criticality and proximity to the New Madrid Seismic Zone, a seismic monitoring system consisting of 84 accelerometers was established for the bridge and its adjacent area. This paper is focused on a three-step artificial neural network strategy that was developed to identify the stiff of the bridge structure using the field measured dynamic response time histories without performing any eigenvalue analysis. The first step is to develop and train an emulator neural network for accurate prediction of the responses of the Bill Emerson Cable-stayed Bridge model, which represents the healthy state of the structure. A finite element model of the cable-stayed bridge was established, which represents the as-built bridge and was calibrated with the measured earthquake data from the seismic monitoring system. The second step is to establish and train a parameter evaluator neural network for relating the stiff reduction in the model bridge to the response prediction error by the emulator neural network. The third and last step is to identify the location and degree of stiff reduction in the Bill Emerson Cable-stayed Bridge.

  7. Energy harvesting from electrospun piezoelectric nanofibers for structural health monitoring of a cable-stayed bridge

    Science.gov (United States)

    Maruccio, Claudio; Quaranta, Giuseppe; De Lorenzis, Laura; Monti, Giorgio

    2016-08-01

    Wireless monitoring could greatly impact the fields of structural health assessment and infrastructure asset management. A common problem to be tackled in wireless networks is the electric power supply, which is typically provided by batteries replaced periodically. A promising remedy for this issue would be to harvest ambient energy. Within this framework, the present paper proposes to harvest ambient-induced vibrations of bridge structures using a new class of piezoelectric textiles. The considered case study is an existing cable-stayed bridge located in Italy along a high-speed road that connects Rome and Naples, for which a recent monitoring campaign has allowed to record the dynamic responses of deck and cables. Vibration measurements have been first elaborated to provide a comprehensive dynamic assessment of this infrastructure. In order to enhance the electric energy that can be converted from ambient vibrations, the considered energy harvester exploits a power generator built using arrays of electrospun piezoelectric nanofibers. A finite element analysis is performed to demonstrate that such power generator is able to provide higher energy levels from recorded dynamic loading time histories than a standard piezoelectric energy harvester. Its feasibility for bridge health monitoring applications is finally discussed.

  8. Study of Nonlinear Seismic Response and TMD Primary Control of the Cable-Stayed Bridge Section of the Third Macao-Taipa Bridge

    Institute of Scientific and Technical Information of China (English)

    Long Xiaohong; Li Li

    2004-01-01

    The practical design of the cable-stayed bridge of the 3rd Macao-Taipa bridge is investigated by the finite element analysis program ANSYS, and 3-D elements BEAM188 and BEAM4 are adopted to create a dynamic calculation model. In order to analyze the material nonlinear seismic response of the cable-stayed bridge, the nonlinear behaviors of the ductile plastic hinges of the bridge towers are taken into account by employing the nonlinear rotational spring element COMBIN40. To simulate a major earthquake, three earthquake records were chosen using a wave-choosing program and input into the bridge structure along longitudinal and transversal directions. Comparisons of the linear and nonlinear seismic responses of the cable-stayed bridge are performed. In addition, a study of TMD primary control is carried out using element MASS21 and element COMBIN14, and it is indicated that the effects of mitigation monitoring are evident.

  9. Investigation of Influence Factors of Wind-Induced Buffeting Response of a Six-Tower Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Zhi-Qiang Zhang

    2016-01-01

    Full Text Available This paper presents an investigation of the wind-induced buffeting responses of the Jiashao Bridge, the longest multispan cable-stayed bridge in the world. A three-dimensional finite element model for the Jiashao Bridge is established using the commercial software package ANSYS and a 3D fluctuating wind field is simulated for both bridge deck and towers. A time-domain procedure for analyzing buffeting responses of the bridge is implemented in ANSYS with the aeroelastic effect included. The characteristics of buffeting responses of the six-tower cable-stayed bridge are studied in some detail, focusing on the effects including the difference in the longitudinal stiffness between the side towers and central towers, partially longitudinal constraints between the bridge deck and part of bridge towers, self-excited aerodynamic forces, and the rigid hinge installed in the middle of the bridge deck. The analytical results can provide valuable references for wind-resistant design of multispan cable-stayed bridges in the future.

  10. Static behaviors of long-span cable-stayed bridge; Chodai shachokyo no seiteki kyodo ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Xu [Saitama Univ., Saitama (Japan). Graduate School; Yamaguchi, H.; Ito, M. [Saitama Univ., Urawa (Japan). Faculty of Engineering

    1996-04-21

    In this study, incremental equation of cable-stayed bridge is formulated by finite element method taking the geometrical nonlinear analysis into account. Then, as an example of designing a bridge with 1500m span, setting up the initial tension, analysis of in-plane behavior caused by live loads as well as analysis of the behavior against wind caused by out-of-plane wind load that are necessary for designing a bridge with 1500m span are carried out. The main results obtained through the study are as follows. As for the cable stayed bridge with 1500m center super long-span having supplementary supporting points between the side arms, the geometrical non-linearity caused by the in-plane design live loads is not remarkable. The effects of wind which acts on girders on analysis of the behaviors against wind are different depending on the aerodynamic performance of the girder and in the case of high wind speed, strong effects on the behavior against wind of the in-plane and screws generate. As the changing of tension of the cable makes influences on the force of in-plane cross section and on displacement of the girder, if the wind speed is very high, the analysis results of the behaviors against wind of in-plane and screws of the cable-stayed bridge may be different depending on in what manner the wind load on the cable to be treated. 16 refs., 16 figs., 1 tab.

  11. Nonlinear Stability Analysis of a Composite Girder Cable-Stayed Bridge with Three Pylons during Construction

    Directory of Open Access Journals (Sweden)

    Xiaoguang Deng

    2015-01-01

    Full Text Available Based on the nonlinear stability analysis method, the 3D nonlinear finite element model of a composite girder cable-stayed bridge with three pylons is established to research the effect of factors including geometric nonlinearity, material nonlinearity, static wind load, and unbalanced construction load on the structural stability during construction. Besides, the structural nonlinear stability in different construction schemes and the determination of temporary pier position are also studied. The nonlinear stability safety factors are calculated to demonstrate the rationality and safety of construction schemes. The results show that the nonlinear stability safety factors of this bridge during construction meet the design requirement and the minimum value occurs in the maximum double cantilever stage. Besides, the nonlinear stability of the structure in the side of edge-pylon meets the design requirement in the two construction schemes. Furthermore, the temporary pier can improve the structure stability, effectively, and the actual position is reasonable. In addition, the local buckling of steel girder occurs earlier than overall instability under load in some cable tension stages. Finally, static wind load and the unbalanced construction load should be considered in the stability analysis for the adverse impact.

  12. Optimization of Dead Load State in Earth-Anchored Cable-Stayed Bridges

    Institute of Scientific and Technical Information of China (English)

    Bin Sun∗; Rucheng Xiao

    2015-01-01

    In order to determine the reasonable completed dead load state in earth⁃anchored cable⁃stayed bridges, a practical method is proposed. The method is based on the rigidly supported continuous beam method and the feasible zone method, emphasizing on the mutual effect between the self⁃anchored structural parts and the earth⁃anchored ones. Three cable⁃stayed bridge models are designed with the main spans of 1 400 m, including a partially earth⁃anchored cable⁃stayed bridge, a cable⁃stayed⁃suspension bridge and a fully self⁃anchored cable⁃stayed bridge, in which the C50 concrete and Q345 steel are adopted. The partially earth⁃anchored cable⁃stayed bridge and the cable⁃stayed⁃suspension bridge secure lower compressive force in the girder than the fully self⁃anchored cable⁃stayed bridge by 25 percent at least. The same is for the material consumption of the whole bridge. Furthermore, the anchor volume is more than 20% lower in the partially earth⁃anchored cable⁃stayed bridge than that in the cable⁃stayed⁃suspension bridge. Consequently, the practical span of cable⁃stayed bridges can be accordingly extended.

  13. Position-Controlled Data Acquisition Embedded System for Magnetic NDE of Bridge Stay Cables

    Directory of Open Access Journals (Sweden)

    Rouven Christen

    2010-12-01

    Full Text Available This work presents a custom-tailored sensing and data acquisition embedded system, designed to be integrated in a new magnetic NDE inspection device under development at Empa, a device intended for routine testing of large diameter bridge stay cables. The data acquisition (DAQ system fulfills the speed and resolution requirements of the application and is able to continuously capture and store up to 2 GB of data at a sampling rate of 27 kS/s, with 12-bit resolution. This paper describes the DAQ system in detail, including both hardware and software implementation, as well as the key design challenges nd the techniques employed to meet the specifications. Experimental results showing the performance of the system are also presented.

  14. Reduction of seismic response long-span PC cable-stayed bridge by passive dampers; Damper ni yoru saidai PC shachokyo no jishinji oto no teigen

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, T.; Yamanobe, S.; Niihara, Y. [Kajima Corp., Tokyo (Japan)

    1994-10-31

    It is important in designing a PC cable-stayed bridge to properly estimate the seismic response of the bridge for reduction of the response. In this paper, an improvement of the seismic resistance of PC cable-stayed bridges when dampers are installed between the deck and piers and lateral vibration of the deck is restricted is investigated using a time history response model. PC cable-stayed bridges with a span length of 400 m, particularly two types of bridges of harp and semi-harp are investigated and the following is found by analyzing the case where there are installed hysteresis type dampers (with 1 cm yield displacement and secondary rigidity assumed to be 1/10 times that of initial rigidity, the initial rigidity being parametrically changed.) or viscous type dampers (a damping factor is changed.) The result shows that the dampers can reduce the seismic response of a PC cable-stayed bridge and that a semi-harp configuration of stay cables where stay cable members are substantially vertically arranged is more effective than a harp configuration for the seismic performance of PC cable-stayed bridges. The damper partly bear inertial force of the bridge upon earthquake whereby tension of the stay cable members is reduced and bending moment of the deck is reduced. There is existing an optimum characteristic value of the damper concerning the bending moment of the piers. 5 refs., 7 figs., 2 tabs.

  15. Inspection method of cable-stayed bridge using magnetic flux leakage detection: principle, sensor design, and signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Fengyu; Wang, Xingsong [Southeast University, Nanjing (China); Wu, Hongtao [Nanjing University of Aeronautics and Astronautics, Nanjing (China)

    2012-03-15

    A nondestructive testing technique based on magnetic flux leakage is presented to inspect automatically the stay cables with large diameters of a cable-stayed bridge. Using the proposed inspection method, an online nondestructive testing (NDT) modular sensor is developed. The wreath-like sensor is composed of several sensor units that embrace the cable at equal angles. Each sensor unit consists of two permanent magnets and a hall sensor to detect the magnetic flux density. The modular sensor can be installed conveniently on cables with various diameters by increasing the number of sensor units and adjusting the relative distances between adjacent sensor units. Results of the experiments performed on a man-made cable with faults prove that the proposed sensor can inspect the status signals of the inner wires of the cables. To filter the interfering signals, three processing algorithms are discussed, including the moving average method, improved detrending algorithm, and signal processing based on a digital filter. Results show that the developed NDT sensor carried by a cable inspection robot can move along the cable and monitor the state of the stay cables.

  16. Full-scale measurements and system identification on Sutong cable-stayed bridge during Typhoon Fung-Wong.

    Science.gov (United States)

    Wang, Hao; Tao, Tianyou; Guo, Tong; Li, Jian; Li, Aiqun

    2014-01-01

    The structural health monitoring system (SHMS) provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB) in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT) combined with the random decrement technique (RDT). The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

  17. Full-Scale Measurements and System Identification on Sutong Cable-Stayed Bridge during Typhoon Fung-Wong

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available The structural health monitoring system (SHMS provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT combined with the random decrement technique (RDT. The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

  18. Experimental Study on Shear Lag Effect of Partial Cable-Stayed Bridge and Elasto-Plastic Seismic Analysis

    Institute of Scientific and Technical Information of China (English)

    WU Gao-feng; XU Hong; CHEN Xing-chong

    2005-01-01

    The project of Xiaoxihu Yellow River Bridge in Lanzhou is chosen as partial cable-stayed bridge. To get the shear lag effect and anti-earthquake performance of the actual bridge under various loading conditions, organic glass scaled model was adopted to have an experiment and a theory research at one time. The experiment result is the basically same as the theory calculation which proves the FEA method can well calculate shear lag effect and dynamical performance. As a result, because the bridge is located in a seismic area of 8 degree, an elasto-plastic seismic checking is performed by customized FEA program in this paper.

  19. Long-term monitoring of a cable stayed bridge using a SCADA system

    Science.gov (United States)

    Torbol, Marco; Kim, Sehwan; Shinozuka, Masanobu

    2012-04-01

    DuraMote is a MEMS-based remote sensing system, which is developed for the NIST TIP project, Next Generation SCADA for Prevention and Mitigation of Water System Infrastructure Disaster. It is designed for supervisory control and data acquisition (SCADA) of pipe ruptures in water distribution systems. In this project, a method is developed to detect the pipe ruptures by analyzing the acceleration data gathered by DuraMote which consists of two primary components; the first, "Gopher" contains the accelerometers and are attached to the water pipe surface noninvasively, and the second, "Roocas" is placed above ground supplying the power to, and retrieving the data from the multiple Gophers, and then transmit the data through Wi-Fi to a base station. The relays support the Wi-Fi network to facilitate the transmission. A large scale bridge provides an ideal test-bet to validate the performance of such a complex monitoring system as DuraMote for its accuracy, reliability, robustness, and user friendliness. This is because a large bridge is most of the time subjected to susceptible level of ambient vibration due to passing loads, wind, etc. DuraMote can record the acceleration time history arising from the vibration making it possible to estimate the frequency values of various bridge vibration modes. These estimated frequency values are then compared with the values computed from analytical model of the bridge for the verification of the accuracy of DuraMote. It is noted that such a verification method cannot be used practically by deploying DuraMote on a water distribution network since the dynamic behavior of a pipe network, either above or underground, is too complex to model analytically for this purpose, and in addition, the network generally lacks conveniently recordable ambient vibration. In this experiment, the performance of DuraMote system was tested being installed on the Hwamyung Bridge, a 500 m long RC cable stayed bridge in Korea for long term monitoring. In

  20. Exploring damping characteristics of composite tower of cable-stayed bridges

    Indian Academy of Sciences (India)

    SHEHATA E ABDEL RAHEEM

    2016-03-01

    The damping characterization is important in making accurate predictions of the seismic response of the hybrid structures dominated by different damping mechanisms. Different damping characteristics arise from the construction of the tower with different materials: steel for the upper part; reinforced concrete for the lower main part and interaction with supporting soil. The process of modeling damping matrices and experimental verification is challenging because damping cannot be determined via static tests as mass and stiffness can be. The assumption of classical damping is not appropriate if the system to be analyzed consists of two or more parts with significantly different levels of damping. The dynamic response of structures is critically determined by the damping mechanisms, and its value is very important for the design and analysis of vibrating structures. An analytical approach that is capable of evaluating the equivalent modal damping ratio from structural components is desirable for improving seismic design. Two approaches are considered to define and investigate dynamic characteristics of a composite tower of cable-stayed bridges: The first approach makes use of a simplified approximation of two lumped masses to investigate the structure irregularity effects including damping of different material, mass ratio, frequency ratio on dynamic characteristics and modal damping. The second approach employs a detailed numerical step-by-step integration procedure.

  1. Impact of cross-tie design on the in-plane stiffness and local mode formation of cable networks on cable-stayed bridges

    Science.gov (United States)

    Ahmad, Javaid; Cheng, Shaohong; Ghrib, Faouzi

    2016-02-01

    Suppressing unfavorable stay cable vibrations using cross-ties is becoming more popular on cable-stayed bridges though the mechanics of the formed cable network is yet fully understood. In practice, the main task in designing cross-ties or cable networks is to choose the cross-tie installation location, stiffness and number based on the main cable properties in the network. To have a more comprehensive picture of how to choose these design parameters to achieve higher in-plane network stiffness while minimizing the number of excited local modes, it is imperative to examine dynamic behavior of cable networks with general configurations. In the current study, an analytical model of a general cable network consisting of multiple main cables interconnected by multiple lines of transverse flexible cross-ties will be developed. A new term, defined as the local mode cluster, will be introduced to assess the severity of local mode excitation. Criteria for identifying the presence of local mode cluster will be proposed. A parametric study will be conducted to evaluate the impact of cross-tie installation location, stiffness and number on the network modal response. Results obtained from the present study will provide deeper insight into the selection of these system parameters to achieve the combined benefits of increasing network in-plane stiffness and minimizing the excitation of local modes.

  2. A Simple Analytical Approach to the Aeroelastic Stability Problem of Long-Span Cable-Stayed Bridges

    Science.gov (United States)

    Vairo, Giuseppe

    2010-01-01

    This paper deals with the aeroelastic stability problem of long-span cable-stayed bridges under an approaching crosswind flow. Starting from a continuous model of the fan-shaped bridge scheme with both H- or A-shaped towers, critical states of the coupled wind-structure system are identified by means of a variational formulation, accounting for torsional and flexural (vertical and lateral) bridge oscillations. The overall bridge dynamics is described by introducing simple mechanical systems with equivalent stiffness properties and, under the assumption of a prevailing truss-like bridge behavior, analytical estimates for dominant stiffness contributions are proposed. Several case studies are discussed and comparisons with experimental evidences as well as with available analytical and numerical results are presented. The proposed simplified approach proves to be consistent and effective for successfully capturing the main wind-bridge interaction mechanisms, and it could be considered as a useful engineering tool for the aeroelastic stability analysis of long-span cable-stayed bridges.

  3. Effects of fundamental factors on coupled vibration of wind-rail vehicle-bridge system for long-span cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    张明金; 李永乐; 汪斌

    2016-01-01

    In a wind-vehicle-bridge (WVB) system, there are various interactions among wind, vehicle and bridge. The mechanism for coupling vibration of wind-vehicle-bridge systems is explored to demonstrate the effects of fundamental factors, such as mean wind, fluctuating wind, buffeting, rail irregularities, light rail vehicle vibration and bridge stiffness. A long cable-stayed bridge which carries light rail traffic is regarded as a numerical example. Firstly, a finite element model is built for the long cable-stayed bridge. The deck can generally be idealized as three-dimensional spine beam while cables are modeled as truss elements. Vehicles are modeled as mass-spring-damper systems. Rail irregularities and wind fluctuation are simulated in time domain by spectrum representation method. Then, aerodynamic loads on vehicle and bridge deck are measured by section model wind tunnel tests. Eight vertical and torsional flutter derivatives of bridge deck are identified by weighting ensemble least-square method. Finally, dynamic responses of the WVB system are analyzed in a series of cases. The results show that the accelerations of the vehicle are excited by the fluctuating wind and the track irregularity to a great extent. The transverse forces of wheel axles mainly depend on the track irregularity. The displacements of the bridge are predominantly determined by the mean wind and restricted by its stiffness. And the accelerations of the bridge are enlarged after adding the fluctuating wind.

  4. Dynamic analysis and modal test of long-span cable-stayed bridge based on ambient excitation

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang-song; YAN Dong-huang

    2007-01-01

    To study the stifilless distilbution of girder and the method to identify modal parameters of cable-stayed bridge, a simplified dynamical finite element method model named three beams model was established for the girder with double ribs.Based on the simplified model four stiffness formulae were deduced according to Hamilton principle.These formulae reflect well the contribution of the flexural, shearing, free torsion and restricted torsion deformation, respectively.An identification method about modal parameters was put forward by combining method of peak value and power spectral density according to modal test under ambient excitation.The dynamic finite element method analysis and modal test were carried out in a long-span concrete cable-stayed bridge.The results show that the errors of frequencies between theoretical analysis and test results are less than 10%mostly,and the most important modal parameters for cable-stayed bridge are determined to be the longitudinal floating mode, the first vertical flexural mode and the first torsional mode, which demonstrate that the method of stifiness distribution for three beams model is accurate and method to identify modal parameters is effective under ambient excitation modal test.

  5. Experimental study on using electromagnetic devices on bridge stay cables for simultaneous energy harvesting and vibration damping

    Science.gov (United States)

    Shen, Wenai; Zhu, Songye; Zhu, Hongping

    2016-06-01

    Flexible bridge stay cables are often vulnerable to problematic vibrations under dynamic excitations. However, from an energy perspective, such excessive vibrations denote a green and sustainable energy source to some electronic devices (such as semi-active dampers or wireless sensors) installed on the same cables. This paper presents an experimental study on a novel dual-function system called electromagnetic damper cum energy harvester (EMDEH). The proposed EMDEH, consisting of an electromagnetic device connected to an energy-harvesting circuit (EHC), simultaneously harvests cable vibration energy and provides sufficient damping to the cables. A fixed-duty-cycle buck-boost converter is employed as the EHC, which emulates a resistive load and provides approximately optimal damping and optimal energy harvesting efficiency when operating in discontinuous conduction mode. A 5.85 m long scaled stay cable installed with a prototype EMDEH is tested in the laboratory under a series of harmonic and random excitations. The EMDEH can achieve a control performance comparable to passive viscous dampers. An average electrical power of 31.6 and 21.51 mW is harvested under harmonic and random vibrations, respectively, corresponding to the efficiency of 16.9% and 13.8%, respectively. Moreover, this experimental study proves that optimal damping and energy harvesting can be achieved simultaneously, which answers a pending question regarding such a dual-objective optimization problem. Self-powered semi-active control systems or wireless sensor networks may be developed for bridge stay cables in the future based on the proposed concept in this study.

  6. Ultimate strength analysis of long-span cable-stayed bridges; Chodai chachokyo no shukyoku kyodo kaiseki to kyodo ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X.; Yamaguchi, H. [Saitama Univ., Urawa (Japan)] Nagai, M. [Nagaoka Technical Coll., Niigata (Japan)

    1998-07-21

    Recently, span of cable-stayed bridges has been getting loner and longer, present situation is that cable-stayed bridges with span 600 to 800m class have been built inside and outside the country, and accurate determination of its ultimate strength has been an important problem statistically. However, concrete design method for evaluating load bearing stress of long-span cable-stayed bridge. Particularly of the main beam whose axial stress is dominating, has not been established so far. As for cable-stayed bridge, even for long-span, effect of plasticization of cross section on ultimate strength is severe because there is little effect of geometric nonlinearity and it is thought that accurate evaluation of ultimate strength only by elastic finite potential analysis is difficult. Accordingly, it is necessary to study the behavior by using combined nonlinear analysis considering the nonlinearity of the material in order to evaluate the safety and economy to long-span cable-stayed bridge. In this report, 3 dimensional analysis method was formularized taking into account the combine nonlinearity of multi-box girder and analysis program of ultimate strength behavior of long-span cable-stayed bridge was developed. 19 refs., 17 figs., 2 tabs.

  7. Some studies on structural planning of long-span cable stayed bridge; Choshikan shachokyo no kozo keikaku ni kansuru 2,3 no kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Endo, T. [NKK Corp., Tokyo (Japan)

    1997-06-20

    Feasibility of cabled-stayed bridges with 1000m-grade spans is discussed while re-examining the plan for constructing a Great Tatara Bridge to connect Honshu and Shikoku, Japan, and in this process various tasks and questions are isolated. Some which will be problems in designing the new bridge structure are taken up, including the load-bearing capability of the bridge as a whole, vibration of long cables, resistance to long-period earthquakes, and accuracy management during the construction work. Findings are stated below. A cable-stayed bridge is not significantly different from a suspension bridge and is sufficiently feasible until the span exceeds 1500m. When the span is longer, however, the bridge beam cross section needs be designed very prudently in view of the great axial force and wind load to be imposed on it. Effective for the assurance of load-bearing capability for a long-span cabled-stayed bridge is a structure in which load is elastically confined in the direction of the bridge axis. In connection with vibration damping for very long cables, it is verified that a new dimpled cable suits the purpose of suppressing wind load from increasing without reduction in damping effect. 28 refs., 23 figs., 7 tabs.

  8. Proposal and study of a long-span composite cable-stayed bridge with new hybrid girder; Atarashii gosei kozo shuketa wo mochiita chodai fukugo shachokyo no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Hishiki, Y.; Furuichi, K. [Kajima Corp., Tokyo (Japan)

    1999-09-30

    A hybrid or mixed structure (composite structures) are a matter of increasing concern which takes in each advantage of steel and concrete. A field of bridges is no exception, with the plan and construction carried out for the new type of composite bridge, such as a composite cable-stayed bridge and a composite extra dose bridge as a long span bridge, and a composite truss bridge and a corrugated steel plate web bridge as a medium-span bridge, with technological development becoming active in this field. In such a technological trend, a hybrid two-girder structure was devised, a structure consisting of a concrete filled steel pipe for a girder and a precast (PC) floor plate for a floor board, as the girder structure of a long-span cable-stayed bridge in the subject research; also, applicability was examined using, as an example, the composite cable-stayed bridge with hybrid girders employed for the span. This paper reports the result of the analysis of the entire system, the analysis made for the purpose of examining the characteristic and the feasibility of this hybrid girder. The analysis revealed the structural feasibility of the long-span composite cable-stayed bridge using two hybrid girders of concrete-filled steel pipes thus devised. (NEDO)

  9. Aerodynamic stability of cable-supported bridges using CFRP cables

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; YING Lei-dong

    2007-01-01

    To gain understanding of the applicability of carbon fiber reinforced polymer (CFRP) cable in cable-supported bridges, based on the Runyang Bridge and Jinsha Bridge, a suspension bridge using CFRP cables and a cable-stayed bridge using CFRP stay cables are designed, in which the cable's cross-sectional area is determined by the principle of equivalent axial stiffness.Numerical investigations on the aerodynamic stability of the two bridges are conducted by 3D nonlinear aerodynamic stability analysis. The results showed that as CFRP cables are used in cable-supported bridges, for suspension bridge, its aerodynamic stability is superior to that of the case using steel cables due to the great increase of the torsional frequency; for cable-stayed bridge,its aerodynamic stability is basically the same as that of the case using steel stay cables. Therefore as far as the wind stability is considered, the use of CFRP cables in cable-supported bridges is feasible, and the cable's cross-sectional area should be determined by the principle of equivalent axial stiffness.

  10. Parallel monostrand stay cable bending fatigue

    DEFF Research Database (Denmark)

    Winkler, Jan Pawel

    of damage and replacement of bridge stay cables due to wind and traffic-induced fatigue. The understanding of fatigue mechanisms in most steel structures is well established. However, in the case of cables composed of steel strands, many important aspects related with bending fatigue remain to be clarified......This dissertation investigates the bending fatigue response of high-strength steel monostrands and multistrand stay cables to cyclic transverse deformations. Increasing bridge stock numbers and a push for longer cable-supported span lengths have led to an increased number of reported incidents...... associated with variable loading, and different testing procedures. As most of the contemporary stay cables are comprised of a number of individual highstrength steel monostrands, the research study started with an extensive experimental work on the fatigue response of a single monostrand to cyclic flexural...

  11. Evaluation of damping property of long-span prestressed concrete cable-stayed bridges; Chodai PC shachokyo no gensui tokusei ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yamanobe, S.; Niihara, Y.; Minami, H.; Kono, T. [Kajima Corp., Tokyo (Japan)

    1999-09-30

    As to the dynamic design in the antiseismic design of PC cable-stayed bridges, evaluation of damping is important. Since it is difficult to evaluate damping property theoretically and analytically, a lot of studies have not been made about how to set up damping coefficients. In this study, using analytical models of existing long-span PC cable-stayed bridges, to clarify causes of damping of long-span PC cable-stayed bridge, the rate of strain energy in each member was examined. Equivalent damping coefficients of each member, effects of friction in movable bearing, and effects of basically radiational damping were studied. The correspondence with the results of the vibration experiments conventionally made were studied. (translated by NEDO)

  12. A Multiscale Finite Element Model Validation Method of Composite Cable-Stayed Bridge Based on Structural Health Monitoring System

    Directory of Open Access Journals (Sweden)

    Rumian Zhong

    2015-01-01

    Full Text Available A two-step response surface method for multiscale finite element model (FEM updating and validation is presented with respect to Guanhe Bridge, a composite cable-stayed bridge in the National Highway number G15, in China. Firstly, the state equations of both multiscale and single-scale FEM are established based on the basic equation in structural dynamic mechanics to update the multiscale coupling parameters and structural parameters. Secondly, based on the measured data from the structural health monitoring (SHM system, a Monte Carlo simulation is employed to analyze the uncertainty quantification and transmission, where the uncertainties of the multiscale FEM and measured data were considered. The results indicate that the relative errors between the calculated and measured frequencies are less than 2%, and the overlap ratio indexes of each modal frequency are larger than 80% without the average absolute value of relative errors. These demonstrate that the proposed method can be applied to validate the multiscale FEM, and the validated FEM can reflect the current conditions of the real bridge; thus it can be used as the basis for bridge health monitoring, damage prognosis (DP, and safety prognosis (SP.

  13. Application of a three-dimensional aeroelastic model to study the wind-induced response of bridge stay cables in unsteady wind conditions

    Science.gov (United States)

    Raeesi, Arash; Cheng, Shaohong; Ting, David S.-K.

    2016-08-01

    The possibility of bridge stay cables experiencing violent dry inclined cable galloping raises great concern in the engineering community. Numerous experimental and analytical studies have been conducted to investigate this phenomenon, most of which were in the context of steady wind past a rigid cylindrical body. Real stay cables however, are generally long and flexible. They are exposed to more "broad" range of atmospheric boundary layer type of wind velocity profile which is also unsteady and turbulent by nature. To better understand the physics underlying this type of wind-induced cable vibration and to elucidate various contributing factors, a more realistic analytical model which is capable of addressing the above elements is imperative. In the current paper, a three-dimensional aeroelastic model is proposed to study the aerodynamic response of an inclined and/or yawed slender flexible cylindrical body subjected to unsteady mean wind, with practical application to wind-induced vibrations of bridge stay cables under no precipitation condition. The non-linear aerodynamic forces derived in the present study are combined with the cable free vibration equations available in literature to obtain the equations of motion for the wind-induced vibration of stay cables, which are solved numerically by an explicit finite difference scheme. The proposed three-dimensional aeroelastic model and numerical solution technique are validated by comparing the predicted cable free vibration responses with existing data in the literature. The mechanism which triggers dry inclined cable galloping and the required conditions for its growth are explored. In addition, the impact of different initial conditions and various unsteady mean wind scenarios on this violent cable motion are investigated. Results show that the occurrence of dry inclined cable galloping is associated with an opposite-phase relation between the relative wind speed and the aerodynamic force along the direction of

  14. Parametrically excited oscillation of stay cable and its control in cable-stayed bridges"

    Institute of Scientific and Technical Information of China (English)

    孙炳楠; 汪至刚; 高赞明; 倪一清

    2003-01-01

    This paper presents a nonlinear dynamic model for simulation and analysis of a kind of parametrically excited vibration of stay cable caused by support motion in cable-stayed bridges. The sag, inclination angle of the stay cable are considered in the model, based on which, the oscillation mechanism and dynamic response characteristics of this kind of vibration are analyzed through numerical calculation. It is noted that parametrically excited oscillation of a stay cable with certain sag, inclination angle and initial static tension force may occur in cable-stayed bridges due to deck vibration under the condition that the natural frequency of a cable approaches to about half of the first model frequency of the bridge deck system. A new vibration control system installed on the cable anchorage is proposed as a possible damping system to suppress the cable parametric oscillation. The numerical calculation results showed that with the use of this damping system, the cable oscillation due to the vibration of the deck and/or towers will be considerably reduced.

  15. A multiscale finite element model validation method of composite cable-stayed bridge based on Probability Box theory

    Science.gov (United States)

    Zhong, Rumian; Zong, Zhouhong; Niu, Jie; Liu, Qiqi; Zheng, Peijuan

    2016-05-01

    Modeling and simulation are routinely implemented to predict the behavior of complex structures. These tools powerfully unite theoretical foundations, numerical models and experimental data which include associated uncertainties and errors. A new methodology for multi-scale finite element (FE) model validation is proposed in this paper. The method is based on two-step updating method, a novel approach to obtain coupling parameters in the gluing sub-regions of a multi-scale FE model, and upon Probability Box (P-box) theory that can provide a lower and upper bound for the purpose of quantifying and transmitting the uncertainty of structural parameters. The structural health monitoring data of Guanhe Bridge, a composite cable-stayed bridge with large span, and Monte Carlo simulation were used to verify the proposed method. The results show satisfactory accuracy, as the overlap ratio index of each modal frequency is over 89% without the average absolute value of relative errors, and the CDF of normal distribution has a good coincidence with measured frequencies of Guanhe Bridge. The validated multiscale FE model may be further used in structural damage prognosis and safety prognosis.

  16. Semi-active vibration control in cable-stayed bridges under the condition of random wind load

    Science.gov (United States)

    Heo, G.; Joonryong, Jeon

    2014-07-01

    This paper aims at an experimental study on the real-time vibration control of bridge structures using a semi-active vibration control method that has been in the spotlight recently. As structures are becoming larger and larger, structural harmful vibration caused by unspecified external forces such as earthquakes, gusts of wind, and collisions has been brought to attention as an important issue. These harmful vibrations can cause not only user anxiety but also severe structural damage or even complete failure of structures. Therefore, in view of structural safety and economical long-term maintenance, real-time control technology of the harmful structural vibration is urgently required. In this paper, a laboratory-scale model of a cable-stayed bridge was built, and a shear-type MR damper and a semi-active vibration control algorithm (Lyapunov and clipped optimal) were applied for the control of harmful vibration of the model bridge, in real time. On the basis of the test results, each semi-active control algorithm was verified quantitatively.

  17. Traveling Wave Resonance and Simplified Analysis Method for Long-Span Symmetrical Cable-Stayed Bridges under Seismic Traveling Wave Excitation

    OpenAIRE

    Zhong-ye Tian; Meng-lin Lou

    2014-01-01

    The seismic responses of a long-span cable-stayed bridge under uniform excitation and traveling wave excitation in the longitudinal direction are, respectively, computed. The numerical results show that the bridge’s peak seismic responses vary significantly as the apparent wave velocity decreases. Therefore, the traveling wave effect must be considered in the seismic design of long-span bridges. The bridge’s peak seismic responses do not vary monotonously with the apparent wave velocity due t...

  18. An application of Auto-regressive (AR model in predicting Aeroelastic Effectsof Lekki Cable Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Hassan Abba Musa

    2016-06-01

    Full Text Available In current practice, the predictive analysis of stochastic problems encompasses a variety of statistical techniques from modeling, machine, and data mining that analyse current and historical facts to make predictions about future. Therefore, this research uses an AR Model whose codes are incorporated in the MATLAB software to predict possible aero-elastic effects of Lekki Bridge based on its existing parametric data and the conditions around the bridge. It was seen that, the fluctuating components of the wind velocity as displayed by the fluctuant curve will result in the vibration of the structure, even strengthening the resonance effect of the structure. Therefore, it suggested that, the natural frequency of the bridge should be set aside far from system frequency considering direct parametric excitation of pedestrian or vehicular traffic speed.

  19. Structural Behavior of a Long-Span Partially Earth-Anchored Cable-Stayed Bridge during Installation of a Key Segment by Thermal Prestressing

    Directory of Open Access Journals (Sweden)

    Sang-Hyo Kim

    2016-08-01

    Full Text Available This study investigated structural behavior of long-span partially earth-anchored cable-stayed bridges with a main span length of 810 m that use a new key segment closing method based on a thermal prestressing technique. A detailed construction sequence analysis matched with the free cantilever method (FCM was performed using a three-dimensional finite element (FE model of a partially earth-anchored cable-stayed bridge. The new method offers an effective way of connecting key segments by avoiding large movements resulting from the removal of the longitudinal restraint owing to the asymmetry of axial forces in the girders near the pylons. The new method develops new member forces through the process of heating the cantilever system before installing the key segment and cooling the system continuously after installing key segments. The resulting forces developed by the thermal process enhance the structural behavior of partially earth-anchored cable-stayed bridges owing to decreased axial forces in the girders.

  20. 塔梁固结斜拉桥抗震性能分析%Seismic analysis of cable-stayed bridge with tower beam consolidation

    Institute of Scientific and Technical Information of China (English)

    赵子鹏

    2016-01-01

    Taking a typical cable-stayed bridge with tower beam consolidation as studying object,establish 3-D finite element model and analysis its natural vibration,the seismic performance of the main tower with different combinations of portrait + vertical and orientation + vertical is ana-lyzed when the cable-stayed bridge with single tower is on the level of different earthquake,so as to provide some reference for the seismic design of the single tower cable-stayed bridge.%以某采用塔、梁固结的独塔斜拉桥工程实例为背景,建立了该桥的空间有限元模型,并且进行了桥梁的模态分析,在不同地震水平作用下,分别采用纵向+竖向和横向+竖向两种作用组合,分析了主塔的结构抗震性能,为独塔斜拉桥的抗震设计提供参考。

  1. Influence of rubber buffer devices on collision between a cable-stayed bridge and its approach span%橡胶缓冲装置对斜拉桥及引桥碰撞影响研究

    Institute of Scientific and Technical Information of China (English)

    张文学; 吴海军; 陈士通

    2013-01-01

    针对大跨度斜拉桥与引桥之间碰撞研究不深入、对斜拉桥与引桥之间防碰撞措施研究不系统等问题,研究橡胶缓冲装置对斜拉桥与引桥之间碰撞响应的减震效果,分析橡胶缓冲装置结构参数对斜拉桥与引桥之间碰撞响应的影响规律.%The seismic behavior study of cable-stayed bridges at home and abroad is relatively perfect, and abundant achievements have been obtained. The aseismic performance of a cable-stayed bridge ordinarily can meet aseismic requirements, but cable-stayed bridge expansion joint damages and approach bridge beam collapses often happens under earthquakes. The study on the collision between a cable-stayed bridge and its approach span is not deep, and the anti-collision measures study is not systematical. Here, the shock absorption effect of rubber buffer devices on impact responses between a cable-stayed bridge and its approach span was investigated. The influence law of rubber buffer devices structural parameters on impact responses between a cable-stayed bridge and its approach span was analyzed in detail.

  2. Statistical analysis of modal properties of a cable-stayed bridge through long-term structural health monitoring with wireless smart sensor networks

    Science.gov (United States)

    Asadollahi, Parisa; Li, Jian

    2016-04-01

    Understanding the dynamic behavior of complex structures such as long-span bridges requires dense deployment of sensors. Traditional wired sensor systems are generally expensive and time-consuming to install due to cabling. With wireless communication and on-board computation capabilities, wireless smart sensor networks have the advantages of being low cost, easy to deploy and maintain and therefore facilitate dense instrumentation for structural health monitoring. A long-term monitoring project was recently carried out for a cable-stayed bridge in South Korea with a dense array of 113 smart sensors, which feature the world's largest wireless smart sensor network for civil structural monitoring. This paper presents a comprehensive statistical analysis of the modal properties including natural frequencies, damping ratios and mode shapes of the monitored cable-stayed bridge. Data analyzed in this paper is composed of structural vibration signals monitored during a 12-month period under ambient excitations. The correlation between environmental temperature and the modal frequencies is also investigated. The results showed the long-term statistical structural behavior of the bridge, which serves as the basis for Bayesian statistical updating for the numerical model.

  3. Traveling Wave Resonance and Simplified Analysis Method for Long-Span Symmetrical Cable-Stayed Bridges under Seismic Traveling Wave Excitation

    Directory of Open Access Journals (Sweden)

    Zhong-ye Tian

    2014-01-01

    Full Text Available The seismic responses of a long-span cable-stayed bridge under uniform excitation and traveling wave excitation in the longitudinal direction are, respectively, computed. The numerical results show that the bridge’s peak seismic responses vary significantly as the apparent wave velocity decreases. Therefore, the traveling wave effect must be considered in the seismic design of long-span bridges. The bridge’s peak seismic responses do not vary monotonously with the apparent wave velocity due to the traveling wave resonance. A new traveling wave excitation method that can simplify the multisupport excitation process into a two-support excitation process is developed.

  4. Health monitoring data analysis and comparison of prototype and laboratorial model for long-span cable-stayed bridge

    Science.gov (United States)

    Yang, Ou; Ou, Jinping

    2009-03-01

    Since 2004, Shandong Binzhou Yellow River highway bridge health monitoring (SHM) system has started to operate. Abundance data has been acquired during these years. To make full use of these data, a 1/40 scale laboratorial model has been built based on the design information of Shandong Binzhou Yellow River highway bridge. And a health monitoring system of the laboratorial model, which included loading system, local response monitoring subsystem and global response monitoring subsystem, has been designed and implemented. The dynamic performance of bridge model and prototype has been compared and the error analysis has been provided also. The numeric simulation of cable damage localization utilizing damage location vectors (DLVs) has been demonstrated. And the results indicated that using DLVs to localize the cable damage is feasible and accurate. The goal of these efforts is to utilize the convenience of the laboratorial environment to obtain the structural information in ideal state which is hard to get in field.

  5. Behaviors of super-long span prestressed cable-stayed bridge with CFRP cables and UHPC girder%CFRP拉索预应力超高性能混凝土斜拉桥力学性能分析

    Institute of Scientific and Technical Information of China (English)

    方志; 任亮; 凡凤红

    2012-01-01

    To discuss the applicability of carbon fiber reinforced polymer (CFRP) cables and reactive powder concrete ( RPC) in super-long span cable-stayed bridges, taking a 1 008 m cable-stayed bridge using steel girder and steel cables as example, a cable-stayed bridge with the same span using RPC (reactive powder concrete) as the girder and advanced composite material CFRP (carbon fiber reinforced polymer) as the cable was designed, in which the cable cross section was determined by the principles of equivalent cable strength and the beam cross section was determined considering the stiffness, shear capacity and local stability. Based on the method of finite element analysis, the comparative study of these two structures on their static properties, dynamic properties, stability and wind resistance were carried out. The results show that it is feasible for using RPC as the girder and CFRP as the cable so as to form a highly efficient, durable cable-stayed bridge of concrete structure and make its applicable span reach about 1 000 m long.%为了探讨碳纤维复合材料(carbon fiber reinforced polymer,CFRP)和超高性能活性粉末混凝土(reactive powder concrete,RPC)在超大跨度斜拉桥中应用的可行性,以主跨1008m的大跨度钢主梁斜拉桥设计方案为例,采用拉索的等强度原则将原桥钢索替换成CFRP索,考虑截面刚度、截面应力和局部稳定等要求,将原桥钢主梁替换成RPC主梁,拟订了一座等跨度的CFRP拉索、RPC主梁斜拉桥方案.采用有限元法分别对两种方案结构的静力特性、动力特性、稳定性能以及抗风性能等进行了分析与比较.结果表明:从结构受力性能角度而言,采用超高性能混凝土主梁和CFRP拉索构成千米级跨度混凝土斜拉桥的结构体系是可行的.

  6. First-passage probability of the deflection of a cable-stayed bridge under long-term site-specific traffic loading

    Directory of Open Access Journals (Sweden)

    Naiwei Lu

    2017-01-01

    Full Text Available Long-span bridges suffer from higher traffic loads and the simultaneous presence of multiple vehicles, which in conjunction with the steady traffic growth may pose a threat to the bridge safety. This study presents a methodology for first-passage probability evaluation of long-span bridges subject to stochastic heavy traffic loading. Initially, the stochastic heavy traffic loading was simulated based on long-term weigh-in-motion measurements of a highway bridge in China. A computational framework was presented integrating Rice’s level-crossing theory and the first-passage criterion. The effectiveness of the computational framework was demonstrated through a case study of a cable-stayed bridge. Numerical results show that the upper tail fitting of the up-crossing rate is an appropriate description of probability characteristics of the extreme traffic load effects of long-span bridges. The average daily truck traffic growth increases the probability of exceedance due to an intensive heavy traffic flow and results in a higher first-passage probability, but this increased trend is weakening as the continuous increase of the traffic volume. Since the sustained growth of gross vehicle weight has a constant impact on the probability of failure, setting a reasonable threshold overload ratio is an effective scheme as a traffic management to ensure the bridge serviceability.

  7. Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations--Ⅱ:Experiment

    Institute of Scientific and Technical Information of China (English)

    Guo Anxin; Y L Xu; Li Hui

    2007-01-01

    The possibility of using a multi-stage pendulum mass damper(MSPMD) to control wind-induced vibration of a single column tower of a cable-stayed bridge during construction was studied theoretically in part Ⅰ of this work.In this paper,the performance of the MSPMD for reducing bridge tower vibration is studied experimentally.A MSPMD model and a tower model of the bridge with geometry scaling of 1:100 were designed and manufactured.Calibration of the MSPMD model with different wire lengths is conducted to verify the analytical model of the damper.A series of tests for the uncontrolled freestanding tower,tower with cables,and tower with MSPMD model are then performed under harmonic and white noise excitations.The experimental results show that the responses of the tower model significantly decrease with the installation of the MSPMD model,which demonstrates the effectiveness of the MSPMD to mitigate the vibration of the bridge tower.

  8. Vertical vibration control system for PC cable-stayed bridge during cantilever construction; Shuketa jogedo seishin sochi ni yoru haridashi sekoji no PC shachokyo no seishin

    Energy Technology Data Exchange (ETDEWEB)

    Oshio, M.; Nakano, R.; Niihara, Y.; Yano, K.; Takeda, T. [Kajima Corp., Tokyo (Japan)

    1995-12-20

    A PC cable-stayed bridge under extension construction having long span length may have long-cycle vibration generated because of wind. The vibration puts workers working on main girders into a state of seasick causing the workability to drop. Therefore, with an objective to reduce vibration occurring on the main girders during construction, discussions were given on application of an active type vertical vibration absorbing device. The vibration absorbing device is an active system that a weight is driven vertically by a hydraulic actuator. The device was developed with a target that damping ratio when a maximum extension is 120 m becomes three times that when no vibration is absorbed for a 5-span continuous PC cable-stayed bridge with a length of 675 m, a central span of 260 m, and a width of 11 m. A cage housing the weight is connected with the actuator at its top by using pins, and the weight is supported being suspended from the top of the actuator. Vibration is absorbed by utilizing reactive force generated when the weight is driven vertically by the hydraulic actuator. The hydraulic actuator contains a gas spring that supports the dead weight of the weight. Experiments have verified the effectiveness of the vertical vibration absorbing device. 4 refs., 12 figs., 3 tabs.

  9. Study on the Aerodynamic Characteristics of a Single-pylon Cable-stayed Bridge Girder by Numerical Simulation and Wind Tunnel Test

    Directory of Open Access Journals (Sweden)

    Longqi Zhang

    2014-09-01

    Full Text Available The wind induced vibration is one of the key technical problems for long-span bridge design. Therefore, a study on the aerodynamic characteristics of a single-pylon cable-stayed bridge girder is carried out in this paper. The aerostatic coefficient of the bridge girder, including both construction state and service state, is investigated by wind tunnel test with varying wind attack angle. Then based on the computational fluid dynamics (CFD method, the flow field around the bridge girder is visualized numerically. The risk of vortex-induced vibration (VIV is qualitatively evaluated by analyzing the flow features and by considering the Scruton number (Sc. Later a dynamic section model is tested in wind tunnel and the VIV phenomenon is observed subsequently. Results show that the aerodynamic stability is assured by the positive slope of the lift coefficient. The VIV response is influenced by the structural damping and the bridge accessory. The amplitude of VIV response can be lower by increasing the structural damping. The maintenance track rail of the bridge girder also does some good for suppressing the VIV as long as the track rail is located at the appropriate place.

  10. Design of Cable-Stayed Bridge of Caofeidian Industry Zone Bridge No.1%曹妃甸工业区1号桥斜拉桥设计

    Institute of Scientific and Technical Information of China (English)

    陈亮; 卢永成; 周伟翔; 邵长宇

    2011-01-01

    The Caofeidian Industry Zone Bridge No. 1 is composed of navigable span bridge, non-navigable span bridges and approach bridges and is located in the cold and strong earthquake region in the northern part of China. A summarized account of the design of the navigable span bridge of the bridge is presented herewith. In accordance with the construction conditions and landscape requirements, the navigable span bridge is designed as a single pylon and single cable plane cable-stayed bridge with span arrangement 2 X 138 m, the pylon is the column pylon in shape of boat sail. The anchorage zone in the pylon is the steel anchor box exposed outside the pylon. The main girder is the steel and concrete composite girder having three cells and a single box. The stay cables are made up of φ7 mm galvanized parallel steel wires and the foundation of the pylon pier is the group pile foundation. The research of seismic resistance of the bridge show that for a major single pylon cable-stayed bridge located in the strong earthquake region, the rigid fixity system of pylon, girder and pier should be possibly avoided in order to reduce seismic response of the bridge structure.%曹妃甸工业区1号桥位于北方寒冷强震区,由通航孔桥、非通航孔桥及引桥组成,综述该桥通航孔桥设计.根据建设条件及景观要求,通航孔桥为跨径2×138 m独塔单索面斜拉桥;桥塔为独柱形,造型为船帆式;索塔锚固区采用外露式钢锚箱方案;主梁采用单箱三室钢-混凝土箱形结合梁;斜拉索采用φ7 mm镀锌平行钢丝;桥塔墩采用群桩基础.抗震性能研究表明,强震区大型独塔斜拉桥应尽量避免采用塔、梁、墩固结体系,以减小桥梁结构的地震响应.

  11. Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations——Ⅰ: Theory

    Institute of Scientific and Technical Information of China (English)

    Guo Anxin; Xu Youlin; Li Hui

    2007-01-01

    In this paper, wind-induced vibration control of a single column tower of a cable-stayed bridge with a multistage pendulum mass damper (MSPMD) is investigated. Special attention is given to overcoming space limitations for installing the control device in the tower and the effect of varying natural frequency of the towers during construction. First,the finite element model of the bridge during its construction and the basic equation of motion of the MSPMD are introduced.The equation of motion of the bridge with the MSPMD under along-wind excitation is then established. Finally, a numerical simulation and parametric study are conducted to assess the effectiveness of the control system for reducing the wind-induced vibration of the bridge towers during construction. The numerical simulation results show that the MSPMD is practical and effective for reducing the along-wind response of the single column tower, can be installed in a small area of the tower, and complies with the time-variant characteristics of the bridge during its entire construction stage.

  12. 基于力学与造价的CFRP-钢组合拉索斜拉桥设计理论%Design of Cable-stayed Bridges with CFRP-steel Composite Stay Cables Based on Mechanical and Economical Behaviors

    Institute of Scientific and Technical Information of China (English)

    熊文; 肖汝诚; CAIC S; 叶见曙

    2012-01-01

    To solve the problem resulting from the low structural stiffness, authors proposed a new design of cable-stayed bridges with composite carbon fiber reinforced polymer (CFRP)-steel stay cables, especially for the cable-stayed bridges with main spans of 1 400 ~ 2 800 m. More specifically, the CFRP stay cables with high strength-to-weight ratio and traditional steel stay cables with high elastic modulus were combined together for application in cable-stayed bridges, which could improve the entire stiffness of bridges. Through a parametric study concerning the equivalent stiffness and economical behavior, three design strategies for the composite cable- stayed bridges were proposed in details: the best equivalent stiffness with equal safety factor, best equivalent stiffness-to-cost ratio with equal safety factor and best equivalent stiffness with equal budget. The design procedure and design chart based on the proposed strategies were also provided. Finally, the feasibility of the proposed cable-stayed bridges was discussed through a case study of a cable-stayed bridge with a main span of 1 400 m. The results indicate that the proposed composite cable-stayed bridges can demonstrate a high equivalent stiffness and can be an excellent selection for the bridges with main spans of 1 400~2 800 m.%针对1400~2800m主跨斜拉桥整体刚度不足的问题,提出一种新型结构方案——碳纤维增强塑料(CFRP)-钢组合拉索斜拉桥。该方案将CFRP斜拉索与传统钢斜拉索同时应用于斜拉桥中,组合2种材料高强轻质及弹性模量高的优点,以:达.到提高斜拉桥整体刚度的设计目的。通过基于力学与造价的参数分析提出该组合拉索斜拉桥的3种设计原则:等安全系数等效刚度最优、等安全系数等效刚度性价比最优、等造价等效刚度最优,并分别给出详细的设计步骤及设计用图。最后,进行了多种方案1400m主跨斜拉桥试设计。结果

  13. INFLUENCE OF ENVIRONMENTAL FACTORS UPON FUNDAMENTAL VIBRATION FREQUENCY OF CABLES FOR CABLE-STAYED BRIDGE%环境因素对斜拉桥拉索振动基频的影响

    Institute of Scientific and Technical Information of China (English)

    吉伯海; 程苗; 傅中秋; 赵端端; 孙媛媛

    2013-01-01

    基于斜拉桥拉索有限元模型,分析了考虑拉索工程参数时阻尼器、梁体振动和温度三种环境因素对拉索振动基频的影响。结果表明:当阻尼器安装位置一定时,阻尼器对长索的基频影响大于短索的基频;当索长和阻尼器位置一定时,阻尼器对截面直径大的拉索基频的影响小于截面直径小的拉索基频;由于车辆荷载导致斜拉桥梁体振动,使得拉索的基频存在动态波动,因此在索力测量时,应选择车辆较少的时段以获得更加准确的基频;高温和低温均影响拉索基频,即拉索温度越高,基频越小;拉索温度越低,基频越大。%Based on the finite element model of cable for cable-stayed bridge , it was analyzed the influence of three environmental factors including damper , beam vibration and temperature upon the cable ’ s vibration fundamental frequency when considering engineering parameters of cable .The results show that when the damper ’ s installation position is fixed , the influence of the damper upon the long cable ’ s fundamental frequency is greater than the influence upon the short cable’s.When the cable’s length and the damper’s position are fixed, the influence of the damper upon the fundamental frequency of the cable which has large section diameter is less than the one has small section diameter .The fundamental frequency of the cable has dynamic fluctuations because of the cable -stayed bridge’s beam vibration caused by the vehicle load .To make the fundamental frequency more accurate , the time with a few vehicles may be selected when measuring the cable force .Temperature variation also has influence upon the fundamental frequency of the cable.Namely, the higher of the cable’s temperature, the smaller of the fundamental frequency;the lower of the cable ’ s temperature , the bigger of the fundamental frequency .

  14. 基于神经网络的混凝土斜拉桥健康状态评估%Health Condition Assessment of Concrete Cable-stayed Bridge Based on ANN

    Institute of Scientific and Technical Information of China (English)

    尚鑫; 徐岳; 马保林; 王春生

    2011-01-01

    According to the characteristics of concrete cable-stayed bridge and the data of a conjoined twin cable-stayed bridges sharing a single tower, the 3-dementional finite-element model (3D FEM) of the bridge is set up using structure analysis software, and the modes are analyzed, so the numerical simulating mode and test data for the bridge health evaluation is available. With Graphical User Interfaces (GUI) of Matlab software, artificial neural network(ANN) parame-ters(such as ANN type, web topology structure, transfer function in every layer, stamp parameter, data pretreatment and quantity of training examples ) are selected and the BPANN is built. According to the research on concrete cable-stayed bridge structure health condition assessment, the calculation process based on ANN is presented and is used in the conjoined twin cable-stayed bridges, and then the examples vectors are input and the constructed network is trained, so that a suitable assessment tool for concrete cable-stayed bridge is presented and the network is effective. The result shows that the exiting concrete cable-stayed bridge structure condition can be reflected effectually by this kind of assessment method.%根据混凝土斜拉桥的结构特点,以双连体独塔斜拉桥为工程依托,通过建立实桥动力有限元模型,以模态分析结果为桥梁健康状态评估提供数值模拟试验模型及试验数据.借助Matlab图形用户界面,选择神经网络参数(网络的类型、网络拓扑结构、各层传递函数、特征参数、数据前处理方法及训练样本个数),构建BP神经网络,在对混凝土斜拉桥结构健康状态评估模型研究的基础上,提出了基于人工神经网络的评估技术,并通过实桥应用,完成对样本矢量的输入,以及对所建网络的训练,为实现混凝土斜拉桥健康状态评估提供合适的工具.结果表明,该方法能够有效反映在用混凝土斜拉桥结构的健康状态.

  15. Identification of aeroelastic forces and static drag coefficients of a twin cable bridge stay from full-scale ambient vibration measurements

    DEFF Research Database (Denmark)

    Acampora, Antonio; Georgakis, Christos T.; Macdonald, J.H.G.;

    2014-01-01

    presents results from full-scale measurements on the special arrangement of twin cables adopted for the Øresund Bridge. The monitoring system records wind and weather conditions, as well as accelerations of certain cables and a few locations on the deck and tower. Using the Eigenvalue Realization Algorithm...

  16. Aerodynamic stability study of a long-span prestressed concrete cable-stayed bridge. Aerodynamic behavior of edge box girder under uniform flow; Chodai PC shachokyo no taifu anteisei ni kansuru kenkyu. Ichiyoryuchu ni okeru edge girder keishiki no kuriki tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, T. [Obayashi Corp., Tokyo (Japan)

    1999-01-10

    In recent years, the construction of long-span bridges is on the increase. Prestressed concrete cable-stayed bridges are dynamically very efficient structures of relatively low cost that blend in well with the landscape. Maintenance is also easy. Consequently, the adoption of edge box girders for cable-stayed bridges is increasing worldwide, but problems related to the aerodynamic stability of the structure have emerged. The aerodynamic stability of edge box girders for a prestressed concrete cable-stayed bridge was investigated under uniform flow conditions by conducting several wind tunnel experiments. As a result, the section of the bridge deck was optimized to prevent torsional flutter within an angle of attack varying from -5 to +5 degrees. It is therefore possible to guarantee the aerodynamic stability of long-span prestressed concrete cable-stayed bridges. (author)

  17. 非对称矮塔铁路斜拉桥塔梁施工监控研究%Construction Monitoring of Asymmetric Extradosed Railway Cable-stayed Bridge Tower Beam

    Institute of Scientific and Technical Information of China (English)

    孙福洋

    2016-01-01

    矮塔斜拉桥,又称部分斜拉桥,是近年来被广泛采用的一种桥梁结构形式。以天津西外环的津保铁路矮塔斜拉桥为工程背景,为确保施工的安全性,对其施工控制进行了研究。首先建立了津保斜拉桥的有限元模型,对结构稳定性和动力特性进行分析;其次建立了施工监测系统,对监测结果进行分析。分析结果表明,津保桥成桥后主梁线形与设计线形基本一致,主梁应力满足规范要求,斜拉桥成桥索力与设计索力基本一致,实时监测提高了津保桥按图施工的精确度。%The extradosed cable-stayed bridge,also known as the partially cable-stayed bridge,is widely used in the form of bridge structure in recent years.In this paper,the Jinbao Extradosed Cable-stayed Bridge at the west outer ring of Tian-jin is taken as the engineering background,and the construction control has been studied for the safety of construction. Firstly,the finite element model of the Jinbao Extradosed Cable-stayed Bridge is established to analyze the structural stabili-ty and dynamic feature of the bridge.Secondly,the construction monitoring system is established to analyze the monitoring results.The results of analysis show that the main beam linear of the Jinbao Bridge is basically the same as the design linear after completion.The stress of the main girder meets the requirements specification and cable tension of the bridge is basi-cally in accordance with the design cable force,the real-time monitoring improves the construction accuracy of the Jinbao Bridge according to the map.

  18. Application of Wireless Monitoring System to Structural Health Monitoring of Long-Spanned Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-cheng; QI Xin; Li Qiao

    2007-01-01

    The remote monitoring system applied to the construction control and health monitoring of the Nanjing Third Yangtze River Bridge is introduced. The system makes it possible to get the structure capabilities and environmental parameters of the bridge at the predetermined moment. It sends the collected data over a long distance to an assigned position for display and analysis. The related methods and working condition of the wireless monitoring system are discussed. The measured data during 48 h are employed to determine the feasibility for the closure of the bridge.

  19. Analysis of Influence of Cable Damage on Dynamic Characteristics of one Cable-stayed Bridge%某斜拉桥拉索损伤对其动力特性的影响研究

    Institute of Scientific and Technical Information of China (English)

    杨亮亮; 黄英丽; 王学博

    2012-01-01

    本文以某特大斜拉桥为工程背景,基于有限元软件,结合桥梁原始设计资料,建立了桥梁动力计算模型,对斜拉桥拉索损伤进行模拟研究.通过拉索有效面积的变化对斜拉桥拉索损伤进行模拟,分析不同拉索损伤下斜拉桥自振频率的变化规律,得出斜拉桥拉索损伤对竖向弯曲振型影响较大,而对侧向弯曲和扭转振型的影响较小的结论.同时,也认识到长索区拉索损伤对斜拉桥低阶振型影响较大,相反,短索区则对斜拉桥高阶振型的影响较大.%Taking a super cable-stayed bridge as background and combining with the original design information, a bridge calculation model is set up based on finite element program to simulate influence of cable damage on dynamic characteristics. The law of the dynamic characteristics with different damage is studied through the decrease of the lasso effective area. It can be conclude that the influence of cable damage has bigger influence to vertical bending mode than that on lateral bending and twisting vibration model. It is also realized that the change of higher modes is bigger when long lasso damage, on the other side, the change of lower modes will be large when the lasso damaged is in short area.

  20. Structural Design of Multi-Pylon Cable-Stayed Bridge with Corrugated Steel Webs for Chaoyang Bridge in Nanchang%南昌朝阳大桥波形钢腹板多塔斜拉桥结构设计

    Institute of Scientific and Technical Information of China (English)

    陈水生; 钟志斌; 桂水荣; 刘旭政; 钟汉清

    2014-01-01

    The PC composite box girder with corrugated steel webs is applicable to bridges with a variety of structural types ,which exhibits superior durability and economic features as com‐pared with the common concrete box girder .The cable‐stayed bridge with corrugated steel webs is regarded as the type of structure where composite box girder with corrugated steel webs is ingen‐iously used ,making better use of the properties of the two structures . The main navigational bridge of the Chaoyang Bridge in Nanchang is a (79+ 5 × 150+79) m continuous composite box girder cable‐stayed bridge with corrugated steel webs .The bridge has six pylons and the stay ca‐bles are arranged in single cable plane .In addition ,the bridge has two layers of decks ,on the up‐per deck ,dual eight vehicle lanes (four lanes each side) are arranged and pedestrian and non‐mo‐torized vehicle lanes are arranged on the lower deck .Based on the analysis and study undertaken , small side span‐to‐main span ratio was chosen .Due to the multiple pylons ,the load path from the intermediate pylons to the side pylons is long and the effect of ancillary piers in the side spans is minimal ,as a result ,no ancillary piers are installed .In the structural system ,the pylons and the main girder are fixed while the girder and piers are separated .The box girder is 43 .84 m wide , with transverse steel diaphragms .The stay cables are fanned out in single cable plane .The pylon looks like the Chinese character“合“ ,and double bearings are installed at the pylons .T he stay vi‐bration mitigation bearings are used as the vibration mitigation and isolation devices of the super‐structure ,which are installed below the two side pylons .%波形钢腹板PC组合箱梁适用于不同结构形式的桥梁,相比普通混凝土箱梁具有显著的耐久性和经济性,波形钢腹板斜拉桥将波形钢腹板组合箱梁应用到斜拉桥中,充分发挥了2种结构的特点。南昌朝

  1. Aseismic behavior assessment on framing cable-stayed bridge with linked tower%联塔分幅斜拉桥抗震性能评价

    Institute of Scientific and Technical Information of China (English)

    梁鑫; 王冲

    2011-01-01

    采用反应谱法对一座四索面联塔分幅斜拉桥进行了抗震性能评价.首先,对比研究了主塔墩底在假定固结和考虑桩土共同工作这两种边界约束处理方式下的动力特性.然后,按照两种超越概率对有桩模型进行了反应谱分析.讨论了两种振型组合方法和三组振型数的情况下结构地震响应的最大值.计算结果表明,桥梁结构的抗震性能满足要求,抗震结构体系采用半飘浮和阻尼器体系是合适的.%Four framing cable-stayed bridge with linked tower was used to asses the aseismic behavior. The research method was response spectrum. Considering that two boundary constraints, separately consolidation and pile-soil, work together, the dynamic characteristics of pier bottom from main tower was analyzes. Based on two different exceeding probabilities, pile model was tested by reponse spectrum method. Then with two vibration models assembled or three assembled, maximum of structural seismic response was computed. The result showed that this bridge construction meets the demand for aseismie behavior. Half floating and damper structural.systems are fit for anti-seismic.

  2. Numerical verification of geometry control method of the construction for super-span cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    Huang Can; Zhao Lei; Bu Yizhi

    2012-01-01

    Taking Sutong Bridge as the object investigated, the correctness of the geometry control method is verified by numerical simulation analysis. Taking the impact of geometric nonlinearity into account, the impacts of structural geo- metric profile induced by temporary loads and temperature field during the construction procedure are investigated. The simulation results indicate that only the stage state of the structure during construction is affected. Satisfied outcome of construction control can be achieved based on ~eometrv control method.

  3. 南平闽江大桥斜拉桥挂篮设计与施工技术%The Design and Construction Technology of Suspension Cradle of Nanping Minjiang Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    李向海

    2011-01-01

    Based on the practical construction experience of Minjiang Bridge of Nanping City Fujian Province,this paper refers to the main technical solutions and application of front-fulcrum suspension cradle in cable-stayed bridge and the design and construction technology of the suspension cradle.%结合福建省南平市闽江大桥工程实际情况,主要介绍了前支点挂篮在斜拉桥施工中的应用、挂篮的设计与施工技术,以及关键技术问题的解决。

  4. 潮白河矮塔斜拉桥健康监测方案设计%Chaobai River Extra-dosed Cable-stayed Bridge Health Monitoring System

    Institute of Scientific and Technical Information of China (English)

    齐钺; 田杰

    2012-01-01

    潮白河大桥为三塔矮塔斜拉桥,矮塔斜拉桥具有结构性能优良,经济指标优异的特点,受力以梁为主,以索为辅.本桥桥宽29.5m,跨径组合为72m+120m+120m+72m=384m,中间桥塔处为梁塔墩固结,两侧桥塔处为梁塔固结.主梁采用单箱3室箱形结构,梁高按照二次抛物线型式渐变.施工监控采集的数据可为后期健康监测系统提供原始指纹信息,本桥健康监测系统可实时掌握大桥运营过程中受力情况.%Chaobai River Bridge is a short-tower cable-stayed bridge that has three towers. Short-tower cable-stayed bridge has excellent structural performance, excellent economic indicators. The load carrying is mainly the beam, assisted by cable. This bridge width is 29.5m, span combination is 72m + 120m+120m+72m=384m, the middle of the bridge towers is the beam tower pier consolidation, both sides of the bridge tower are the beam tower consolidation. The main beam uses a single box with 3 rooms of box structures, the beam height changes gradually in accordance with cubic parabola. The data from construction monitoring can provide the original fingerprint information for post-health monitoring system. The health monitoring system can monster the real-time force in operation.

  5. 斜拉桥主塔施工索道管定位技术%The Positioning Technique of Stayed Bridge Main Tower Constructing Cable Duct

    Institute of Scientific and Technical Information of China (English)

    魏德文

    2012-01-01

    在斜拉桥主塔施工中,索道管准确、方便、快速定位是现场施工技术难点之一。详细叙述了在赤道几内亚Mbini大桥主塔上塔柱施工期间,采用空间定位技术对主塔索道管精确定位的过程。%The paper mainly discussed the space positioning technique in the construction of stayed bridge main tower for Mbini Bridge in Equatorial Guinea.

  6. 论斜拉桥墩台基础及桩基施工放样%On the cable-stayed bridge pier foundation and pile foundation construction stakeout

    Institute of Scientific and Technical Information of China (English)

    王成全

    2012-01-01

      结合实例介绍了斜拉桥墩台基础、桩基施工放样技术、墩台定位的方法、索塔施工测量放样以及高塔柱施工测量的施工方法。%  The cable-stayed bridge pier foundation, pile foundation construction stakeout technical positioning pier, Sarasota Construction Setting High Tower Construction Survey Construction Methods with examples.

  7. Research of the aerostatic and aerodynamic stability of super long-span cable-stayed bridges%超大跨度斜拉桥空气静力和动力稳定性研究

    Institute of Scientific and Technical Information of China (English)

    张新军; 孙海凌

    2014-01-01

    With the increase of span length,the cable-stayed bridge tends to be a more slen-der structural system,and consequently the wind stability becomes an important problem for its design and construction. Three-dimensional nonlinear aerostatic and aerodynamic stability anal-ysis of long-span bridges is used to investigate the aerostatic and aerodynamic stability of a su-per long-span cable-stayed bridge with main span of 1 400 m,and the results are compared with those of a suspension bridge with the similar main span,and considering from the aspect of wind stability,the availability of using the cable-stayed bridge in super long-span bridges whose main span exceeds 1 000 m is discussed. In addition,parametric analysis on the aerostat-ic and aerodynamic stability of super long-span cable-stayed bridges is conducted including the depth and width of the girder,structure style of the tower,the tower’s height-to-span ratio,the ratio of side span to main span,the auxiliary piers in the side span and the anchorage system of stay cables etc,and the key design parameters are pointed out,and also their reasonable values are proposed. The results show that as compared to the suspension bridge with the same main span,the cable-stayed bridge has greater structural stiffness,and becomes more stable under the static and dynamic wind action,and consequently becomes a favorable structural system for super long-span bridges whose main span exceeds 1 000 m;the super long-span cable-stayed bridge becomes more aerostatically and aerodynamically stable under the cases that the girder depth is increased,the girder width is decreased,the inverse Y-shaped tower is used,the tow-er’s height is increased,the side span is shortened,the auxiliary piers are installed in side span and the stayed cables are partially earth-anchored.%随着斜拉桥跨度的持续增长,结构更趋于轻柔,风作用下的结构稳定性已成为超千米主跨斜拉桥设计和研究的重要问题。采用

  8. The Tension Deformation and the Construction Survey Questions of GuoZiGou Cable-stayed Bridge Tower Beam%果子沟斜拉桥塔梁张拉的变形及施工测量问题

    Institute of Scientific and Technical Information of China (English)

    胡东武; 李霞

    2011-01-01

    This paper to Yili autonomous prefecture GuoZiGou cable-stayed bridge of the tower construction Z2 # as an example,the detailed description of the tower in the tower,the characteristics of asynchronous construction beam to the construction of the measurement of monitoring and measurement lofting combined,thereby improving job process,improve work efficiency,and to ensure the accuracy of the construction of the tower.%对新疆伊犁自治州果子沟斜拉桥Z2#主塔施工中针对主塔进行塔梁异步施工的特点,将施工中的测量监控与测量放样结合起来,从而改进工作流程,提高工作效率,确保主塔施工精度。

  9. Effects of ice accretion on the aerodynamics of bridge cables

    DEFF Research Database (Denmark)

    Demartino, C.; Koss, Holger; Georgakis, Christos T.;

    2015-01-01

    Undesirable wind induced vibrations of bridge cables can occur when atmospheric conditions are such to generate ice accretion. This paper contains the results of an extensive investigation of the effects of ice accretion due to in-cloud icing, on the aerodynamic characteristics of bridge hangers...... and stay cables. The aim of this paper is twofold; first, it was investigated the ice accretion process and the final shape of the ice accreted; then the aerodynamics of the ice accreted bridge cables was characterized, and related to the ice shape. Different climatic conditions, i.e. combinations...... of the ice accretions is given in the paper. Only for the bridge hanger case, a short description of the evolution of the ice accretions is given. The aerodynamic force coefficients were then measured with varying yaw angle, angle of attack and wind speed, and are presented and discussed in the paper...

  10. Nonlinear dynamic response of stay cables under axial harmonic excitation

    Institute of Scientific and Technical Information of China (English)

    Xu XIE; He ZHAN; Zhi-cheng ZHANG

    2008-01-01

    This paper proposes a new numerical simulation method for analyzing the parametric vibration of stay cables based on the theory of nonlinear dynamic response of structures under the asynchronous support excitation.The effects of important parameters related to parametric vibration of cables,I.e., characteristics of structure,excitation frequency,excitation amplitude,damping effect of the air and the viscous damping coefficient of the cables,were investigated by using the proposed method for the cables with significant length difference as examples.The analysis results show that nonlinear finite element method is a powerful technique in analyzing the parametric vibration of cables,the behavior of parametric vibration of the two cables with different Irvine parameters has similar properties,the amplitudes of parametric vibration of cables are related to the frequency and amplitude of harmonic support excitations and the effect of distributed viscous damping on parametric vibration of the cables is very small.

  11. First-passage probability of the deflection of a cable-stayed bridge under long-term site-specific traffic loading

    OpenAIRE

    Naiwei Lu; Mohammad Noori; Yang Liu

    2017-01-01

    Long-span bridges suffer from higher traffic loads and the simultaneous presence of multiple vehicles, which in conjunction with the steady traffic growth may pose a threat to the bridge safety. This study presents a methodology for first-passage probability evaluation of long-span bridges subject to stochastic heavy traffic loading. Initially, the stochastic heavy traffic loading was simulated based on long-term weigh-in-motion measurements of a highway bridge in China. A computational frame...

  12. Parametric Vibration and Vibration Reduction of Cables in Cable-stayed Space Latticed Structure

    Institute of Scientific and Technical Information of China (English)

    BAO Yan; ZHOU Dai; LIU Jie

    2008-01-01

    Mechanical model and vibration equation of a cable in cable-stayed sparse latticed structure (CSLS) under external axial excitation were founded. Determination of the mass lumps and natural frequencies supplied by the space latticed structure (SLS) was analyzed. Multiple scales method (MSM) was introduced to analyze the characteristics of cable's parametric vibration, and the precise time-integration method (PTIM) was used to solve vibration equation. The vibration behavior of a cable is closely relative to the frequency ratio of the cable and SLS. The cable's parametric vibration caused by the external axial excitation easily occurs if the frequency ratio of the cable and SLS is in a certain range, and the cable's vibration amplitude varies greatly even if the initial disturbance supplied by SLS changes a little. Furthermore, the mechanical model and vibration equation of the composite cable system consisting of main cables and assistant cables were studied. The parametric analysis such as the pre-tension level and arrangement of the assistant cables was carried out. Due to the assistant cables, the single-cable vibration mode can be transferred to the global vibration mode, and the stiffness and damping of the cable system are enhanced. The natural frequencies of the composite cable system with the curve line arrangement of assistant cables are higher than those with the straight-line arrangement and the former is more effective than the latter on the cable's vibration suppression.

  13. Preliminary probabilistic prediction of ice/snow accretion on stay cables based on meteorological variables

    DEFF Research Database (Denmark)

    Roldsgaard, Joan Hee; Kiremidjian, A.; Georgakis, Christos T.;

    The scope of the present paper is to present a framework for assessment of the probability of occurrence of ice/snow accretion on bridge cables. The framework utilizes Bayesian Probabilistic Networks and the methodology is illustrated with an example of the cable-stayed Øresund Bridge. The case...... study focuses on the ice/snow accretion due to the in-cloud icing or precipitation icing mechanisms and includes probabilistic assessments of the meteorological variables influencing the ice/snow accretion on the stay cables. Different probability distribution functions are utilized...... for the representation of the meteorological variables and evaluated both by goodness-of-fit test and qualitatively. Conditional probability curves are developed to predict the amount of ice accretion given a set of meteorological conditions using the Gaussian Kernel Smoothing method. The fitted probability distribution...

  14. Critical wind velocities for several kinds of typical vehicle running on a cable-stayed bridge deck%几种典型车辆在斜拉桥桥面行驶的临界风速研究

    Institute of Scientific and Technical Information of China (English)

    马麟; 韩万水; 刘健新; 李加武

    2011-01-01

    The critical wind velocity and running velocity were studied for three kinds of typical vehicle running on a cable-stayed bridge deck under action of strong side wind. The effects of the bridge's side buffeting and the following coordinate features of the vehicle's moving equations on the vehicle side deviation relative to the bridge deck were analyzed, the calculation formulas of its relative side slipping and velocity were obtained. Based on previous studies, a wind-vehicle-bridge coupling vibration system including vehicle side deviation and driver's behavior was studied, and the corresponding simulation code was improved and tested. A cable-stayed bridge was taken as an example, critical wind velocities of three kinds of typical automobile running on the bridge deck were obtained. Results showed that the critical wind velocity is not significantly influenced by controlling objectives of driver behavior; the accident types of different vehicles are possibly different; for box-type truck, its critical wind velocity of side slipping is always lower than that of overturning; but for cars like Santana and Jia-bao, overturning accident plays a controlling role when running velocity is high, while side slipping accident does when running velocity is low.%研究强侧风作用下三种典型汽车在斜拉桥桥面行驶时的临界风速和车速.分析汽车运动方程的随动坐标特性和桥梁的侧向抖振对汽车相对桥面侧偏的影响,得到侧偏位移及速率的计算式,在以往基础上,研究了考虑车辆侧偏和驾驶员行为的风-车-桥空间耦合振动系统,完善了仿真分析程序的功能.以某斜拉桥为实例,分析三种典型车辆在桥面行使的临界风速.分析结果表明:采用控制重心还是前轮侧滑的驾驶员模型不显著影响桥面汽车临界风速的大小;不同类型汽车的事故原因可能不同,对于箱式货车,侧滑事故起控制作用,对于桑塔纳和一汽佳宝,车速高时,侧倾

  15. Identification of aeroelastic forces on bridge cables from full-scale measurements

    DEFF Research Database (Denmark)

    Acampora, Antonio; Macdonald, J.H.G.; Georgakis, Christos

    2011-01-01

    Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various mechanisms have been suggested for their excitation, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding...... Bridge. The system records wind conditions and weather conditions, as well as accelerations of certain cables and a few locations on the deck and tower. Using state-of-the-art methods of output-only system identification, the vibration modes of the cables have been identified. From these modes...

  16. Aerodynamic coefficients of stationary dry inclined bridge cables in laminar flow

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos; Ricciardelli, Francesco

    2011-01-01

    Stay cables are the most flexible elements of cable-stayed bridges. When exposed to wind loading, they often undergo large amplitude vibrations, thus motivating serious design concerns. In most cases, vibrations are observed in the presence of water rivulets or ice accretions, which lead...... to an effective change in the cable cross section, and its aerodynamic properties. On the other hand, divergent, self-excited vibrations have been observed in the field also for dry, inclined stay cables, in warm temperatures. The need for reliable design guidelines for inclined stay cables has motivated...... conditions, i.e. dry, wet and icy, in laminar and turbulent flow, has been initiated at the new DTU/Force Climatic Wind Tunnel facility in Denmark. This paper covers selected results of the comparative study, i.e. aerodynamic coefficients of dry inclined cables in laminar flow conditions....

  17. Probabilistic Fatigue Life Prediction of Bridge Cables Based on Multiscaling and Mesoscopic Fracture Mechanics

    Directory of Open Access Journals (Sweden)

    Zhongxiang Liu

    2016-04-01

    Full Text Available Fatigue fracture of bridge stay-cables is usually a multiscale process as the crack grows from micro-scale to macro-scale. Such a process, however, is highly uncertain. In order to make a rational prediction of the residual life of bridge cables, a probabilistic fatigue approach is proposed, based on a comprehensive vehicle load model, finite element analysis and multiscaling and mesoscopic fracture mechanics. Uncertainties in both material properties and external loads are considered. The proposed method is demonstrated through the fatigue life prediction of cables of the Runyang Cable-Stayed Bridge in China, and it is found that cables along the bridge spans may have significantly different fatigue lives, and due to the variability, some of them may have shorter lives than those as expected from the design.

  18. Analysis of Static, Dynamic and Seismic Performance of Long Span Irregular-Shape Pedestrian Cable-Stayed Bridge%大跨人行异型斜拉桥静、动力及抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    刘世明; 赵顺波; 李晓克

    2012-01-01

    为研究异型斜拉桥结构安全,静、动力以及抗震性能是否满足规范要求,以某大跨人行异型斜拉桥为工程背景,采用MIDAS Civil有限元分析软件,结合桥梁施工方法,对结构进行了考虑混凝土的收缩、徐变、温度等作用的静力特性及动力特性、空气动力稳定以及抗震性能分析.结果表明:塔、梁各截面承载力均满足规范要求;结构基本周期比较短,能减少结构的地震位移,但对桥塔底部受力不利,主梁竖向弯曲的第1阶频率不符合规范(大于3 Hz)要求,需要进行特殊设计,自振特性表现出明显的相互耦合的特点,随着频率的提高,结构扭转所占比重增大,对该桥的横向稳定不利;空气动力稳定良好;在E1地震作用下,结构的应力响应较小,结构刚度较大.%To study the structural safety of long span irregular-shape pedestrian cable-stayed bridge and to check if the static, dynamic and seismic performance of the bridge can meet the relevant requirements in the codes, an actual pedestrian cable-stayed bridge of the same type was cited as an example. By means of the finite element analysis software MIDAS Civil and with reference to the construction methods to be used for the bridge, the static and dynamic characteristics, the aerodynamic stability and seismic performance of the structure were analyzed, taking into account of the action of concrete shrinkage, creep and temperatures. The results of the analysis indicate that the bearing capacity of various sections of the pylon and girder of the structure can meet the requirements in the codes, the basic period of the structure is short and can reduce the displacement of the structure caused by earthquake, but it is unfavorable to the force conditions of the pylon footing. The 1st order frequency of vertical bending of the main girder does not meet the requirements (greater than 3 Hz) in the codes and should be specially dealt with in the design. The

  19. 跨铁路站场斜拉桥荷载试验分析%Analysis on Loading Test of Cable-stayed Bridge Spanning Railway Station

    Institute of Scientific and Technical Information of China (English)

    刘邵平

    2011-01-01

    和平大桥位于城市主干道上,跨越徐州铁路站场,铁路交通量极大。为了检验成桥后该桥梁承载能力是否满足正常使用状况的要求以及评估实际结构的动力性能,对全桥展开荷载试验分析。研究结果表明,和平大桥的受力性能和正常使用状态极限承载力满足设计荷载等级城-A级要求,结构工作状况良好。%Heping bridge with heavy-volume traffic is located at urban arterial road and spans a railway station.To test wheather the bearing capacity under normal service loading could meet criterion or not and evaluate the dynamic characteristics of the bridge,loading test analysis is proposed in this paper.The results show that the mechanical behavior and the ultimate bearing capacity under normal service loading of Heping bridge meet the design load grade-A standard and Heping bridge is in good working condition.

  20. 不同体系斜拉桥车桥耦合共振效应研究%Vehicle-bridge coupled vibration of different types of cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    王凌波; 马印平; 蒋培文; 周勇军; 任伟

    2015-01-01

    共振是桥梁结构应当避免的一种现象,风、人群、地震等外荷载均与桥梁结构产生过共振现象从而造成严重后果,文章对不同体系斜拉桥车桥耦合共振效应进行研究,提出了车流作用下的斜拉桥车桥共振效应判定方法,对漂浮体系、半漂浮体系等斜拉桥进行了共振效应的可能性与判定条件分析,并给出了相关算例。结果表明:等间距车流对桥梁的激扰频率主要由相邻车辆时间间隔决定,漂浮体系斜拉桥由于基频较低,在等间距车流作用下存在车桥共振的可能性,其余体系斜拉桥车桥共振概率极低;建议漂浮体系斜拉桥运营时可在桥面各车道纵向不同位置分别设置减速标志,将车流“打乱”,减小共振概率。%Resonance is a phenomenon that should be avoided in bridge structures .T here are numerous cases of bridge resonance caused by wind , pedestrian and earthquake , leading to serious conse‐quences .In this paper ,the response of vehicle‐bridge coupled vibration of different types of cable‐stayed bridges is analyzed and the judging method under traffic flow is presented .T hen the possibility and criterion of the response of the resonance of floating system and half floating system are analyzed . The related numerical example is also given .The results show that the interval time between the vehi‐cles is the main influence factor of the excitation frequency under the condition of the equally spaced traffic flow .Cable‐stayed bridge of floating system has the relatively high possibility to cause vehicle bridge resonance for the reason of the low basic frequency under the equally spaced traffic flow ,com‐paring to the other types of cable‐stayed bridges .An appropriate way to reduce the possibility of the resonance is to set up the traffic signs of deceleration at different longitudinal positions .

  1. 斜拉桥主梁应变监测分析%Girder Strain Analysis of a Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    邵平

    2012-01-01

    The health monitoring system of the bridge maintenance management is an important means to ensure the safety operation. To grasp the working condition, strain analysis is necessary. With practical engineering of a bridge in Xinmi, appling finite-element analysis software of MIDAS/Civil to establish the space model, we analysis the stress of the girder in the construction stage and compare the academic value and the practical value. The conclusion will provide a reference to the same bridges.%基于健康监测系统的桥梁养护管理是保证其安全运营的重要手段.而对监测数据进行分析以把握结构的工作状态是一个必须环节.结合新密某桥梁的工程实践,运用有限元软件建立主梁有限元空间模型,模拟分析施工阶段主梁应力,并对应力理论值和实测值进行对比与分析.结论将为同类桥梁应力监测提供参考.

  2. Probabilistic Approach to Fatigue Assessment for Stay Cables

    DEFF Research Database (Denmark)

    Baussaron, Julien; Sørensen, John Dalsgaard; Toft, Henrik Stensgaard

    2013-01-01

    Many parameters used for predicting times to failure of structure due to fatigue are uncertain and their variations have a big influence on the real lifetime. This paper focus on a global methodology to take main sources of variability in fatigue prediction for stay cables into account. The first...

  3. Influence of Icing on Bridge Cable Aerodynamics

    DEFF Research Database (Denmark)

    Koss, Holger; Frej Henningsen, Jesper; Olsen, Idar

    2013-01-01

    In recent years the relevance of ice accretion for wind-induced vibration of structural bridge cables has been recognised and became a subject of research in bridge engineering. Full-scale monitoring and observation indicate that light precipitation at moderate low temperatures between zero and -5......°C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion....... The determination of these force coefficients require a proper simulation of the ice layer occurring under the specific climatic conditions, favouring real ice accretion over simplified artificial reproduction. The work presented in this paper was performed to study the influence of ice accretion on the aerodynamic...

  4. 斜拉桥索塔锚固区前壁竖向拉-压杆模型%Vertical STM in Facade Wall of Pylon Anchorage Zone of Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    陶齐宇; 刘扬

    2011-01-01

    To the tendon anchorage system in the wall of box pylon of cable-stayed bridge, the facade wall of cable-anchored pylon was researched using strut-and-tie model ( STM). According to the optimization principle of STM, the STM of single anchor was established by means of force method. On the basis of the STM of single anchor, the STM in the facade wall was preliminary built. The expression of internal force in ties about z, the vertical distance between the tie T3 and node 1, was established. Using topology optimization result (T2 = 0) and Cardan Formula, the value of z was determined, the STM in the facade wall was comprehensively solved. Thus, the distribution of compressive and tensile stresses in the facade wall under the action of vertical component of cable force was accurately reflected. Finally, through researching the pylon of Yibin Yangzte River Bridge, the parameter α3 =23.3° was proposed, and the STM in the facade wall was simplified. It has better precision and can be used to determine tendon specification in the anchorage zone of box pylon.%对斜拉桥箱形截面索塔塔壁预应力锚固体系,采用拉-压杆模型方法对拉索直接锚固的塔柱前壁进行研究.以力法为手段,依据拉-压杆模型的优化原理,确立了体内单锚的拉-压杆模型.以单锚拉-压杆模型为基础,初步构建前壁的拉-压杆模型.取z为拉杆(T3)与结点(1)间的竖向距离,采用力法建立以z为函数的拉杆内力的表达式,利用拓扑优化成果(T2=0)和卡尔丹公式,确定z的数值,自下而上全面解答了前壁的拉-压杆模型,从而准确反映在拉索竖向分力作用下前壁拉、压应力的分布状况.最后,通过对宜宾长江大桥索塔的实例研究,提出α3= 23.3°,简化了前壁拉-压杆模型,且具有较好的工程精度,可用于确定索塔锚固区的预应力筋的规格.

  5. Shake Table Test of Cable-stayed Bridge Pylon Subjected to Longitudinal Ground Motions%斜拉桥桥塔纵桥向振动台试验研究

    Institute of Scientific and Technical Information of China (English)

    嵇冬冰; 段昕智; 徐艳; 李建中

    2013-01-01

    为了解强震作用下我国斜拉桥桥塔的抗震性能以及震害现象,通过调研确定典型斜拉桥原型,对其H型混凝土桥塔进行纵桥向振动台试验研究.基于斜拉桥的动力特点及振型分析方法进行桥塔模型的简化设计、制作和安装,输入不同类型及不同强度的地震波,对桥塔模型进行了振动台试验.结果表明:相比一般的Elcentro波和Chichi地震波,相同加速度峰值地震输入下,场地人工波激起桥塔的地震反应最剧烈,且随着地震动输入的不断加强,桥塔下塔柱、中塔柱靠近下横梁部位先后不同程度地出现了裂缝开展延伸现象,其中塔底向上30 cm区域内损伤较明显,存在多条贯通裂缝,塔底截面最外侧钢筋屈服,模型整体刚度有明显下降趋势,但桥塔抗震性能依然表现良好.%In order to understand the behavior and possible earthquake induced damages of cable-stayed bridges,based on the dynamic characteristics of the bridge,a simplified H shape pylon is designed,constructed and then tested on a shake table subjected to monotonously increased intensities of selected ground motions.Compared with the other two records,the site specific ground motion caused more severe shaking on the pylon model even at the same PGAs,and with the increase intensity of the input,the cracks induced were mainly in horizontal direction,first appearing in the bottom of the pylon,and then in lower column and middle column area near the lower strut.Especially in the area 30 cm above the column bottom,several through cracks appeared and the outmost longitudinal bar yielded,and the integral stiffness of the model tended to decrease,but the pylon model still behaves quite good under a sequence of earthquake excitations.

  6. Optimal design of initative horizontal bracing structure of middle tower column of southern cable stayed bridge of Xiazhang sea-crossing bridge%厦漳跨海大桥南汊斜拉桥索塔中塔柱主动横撑的设计计算

    Institute of Scientific and Technical Information of China (English)

    林寅

    2011-01-01

    本文介绍了厦漳跨海大桥南汊斜拉桥索塔施工中,为消除中塔柱倾斜塔柱根部混凝土的不良应力状态所采用的主动横撑结构的构造特点,以及考虑了施工因素的该结构的设计计算方法,确保中塔柱根部在施工过程中不开裂。该计算方法对类似工程具有一定的指导意义。%This paper intensively introduces the structural characteristics of the adoption of initiative horizontal bracing structure in order to eliminate the bad stress of concrete in the root of leaned tower column during the cable tower construction of Southern Cable Stayed Bridge of Xia Zhang Sea-crossing Bridge,as well as the structural design calculation method considering the construction factors,which can make sure that the root of leaned tower would not cracked during the construction process,and thie could be a reference for similar engineering.

  7. 同向回转拉索锚固体系斜拉索施工技术%Construction Techniques for Stay Cables Provided with Isodirectionally Turning Stay Cable Anchor System

    Institute of Scientific and Technical Information of China (English)

    李景丰; 周伟明

    2015-01-01

    安徽五河定淮淮河特大桥主桥为独塔双索面混合梁斜拉桥,跨径布置为246 m+125 m,该桥采用钢绞线斜拉索,斜拉索采用同向回转拉索锚固体系,即斜拉索穿过桥面一侧锚具,绕过桥塔后锚回到桥面另一侧锚具,形成同一对编号斜拉索。同向回转拉索锚固体系由钢绞线拉索系统、夹持型大转角鞍座锚索系统及主梁锚拉板锚索系统3部分组成。斜拉索采用三角提升原理安装,利用穿索机推送及卷扬机牵引将主梁一侧的钢绞线送入HDPE外套管中,穿过鞍座后,通过穿索机推送及另外一台卷扬机牵引钢绞线回到主梁另一侧锚固区,钢绞线穿索就位后,采用单股对称张拉法进行斜拉索张拉,张拉到位后进行封锚处理。%The main bridge of Dinghuai Huaihe River Bridge in Wuhe ,Anhui is a hybrid girder cable‐stayed bridge with a single pylon ,double cable planes and with span arrangement 246 m+125 m .The stay cables of the bridge are the steel wire strand cables and are anchored by the isodi‐rectionally turning stay cable anchor system .That is ,a full long stay cable of the bridge is firstly extended out of its anchor at one side of the bridge deck and is led to the saddle in the pylon ,then the cable transversely turns around at the saddle and is finally led downwards and extended into the anchor at the other side of the deck to consequently form a pair of the cables of the same numbe‐ring .The isodirectionally turning stay cable anchor system is comprised of 3 parts of the stay cable system ,large turning angle clamping saddle anchor in the pylon and the anchor tensile plate anchor in the main girder .The stay cables of the bridge are installed ,using the principle of the triangle‐shape lifting .By the delivering of the cable threading machine and the hauling of the winch ,the steel wire strands of a cable on one side of the deck are led into the HDPE sheaths and the sheathed

  8. Optimization Analysis of Stayed-buckle Cable Forces of a Oversized Bridge Construction Based on the Linear Programming%基于线性规划的某特大桥施工扣索索力优选分析

    Institute of Scientific and Technical Information of China (English)

    张耀庭; 颜燕祥; 张正哲; 李艳芳; 张敏

    2014-01-01

    With the development of the large-span bridge engineering, the affirmance of the wire rope cable forces of the connection between the bridge superstructure and piers ( Abutment) has become a key technical problem in bridge design and construction process. The design of cable force is directly related to safety issues and the normal use in the construction and operational stage. Combined with the construction of a Bridge,the article presents the principle of linear programming to optimize cable force. The optimal method of cable force uses the cable dosage minimum as an objective function and the pre-tension force as optimal variables, and then uses the stress in key sections and the deflection in end of cantilever as constraint conditions. With the help of ANSYS software and MATLAB tools,the optimization of construction ( temporary) buckle cable tension of stage of the structure of linear work is achieved. Compared with the existing cable force methods, the method proposed in this paper to determine cable force can reduce the number of tune cable construction process and improve the accuracy of the design of cable force. For similar projects, it provides a new way of thinking to determine the steel cables of the relative optimum tensile force.%随着斜拉桥等大跨度桥梁工程的发展,桥梁上部结构与桥墩(台)之间连接的钢索索力的确定已成为桥梁设计与施工过程中的关键技术问题,索力取值合理与否直接关系到结构施工及运营阶段的安全与正常使用问题。本文结合某特大桥的施工,将线性规划原理引入到该桥的施工索力优化当中,以扣索用量最少为目标函数,以拉索索力大小为控制变量,以关键截面应力和悬臂端点挠度为约束条件;借助ANSYS软件和MATLAB工具,实现了结构线性工作阶段的施工(临时)扣索索力的优选分析。与已有的索力确定方法相比,本文提出的确定索力方法可减少施工过程

  9. Study on cable-stayed bridge: Several aspects of calculation and analysis of high-speed railway with speed of 350 km/h%时速350km/h高速铁路斜拉桥计算分析中参考的几个方面探析

    Institute of Scientific and Technical Information of China (English)

    高军

    2012-01-01

    Large span cable-stayed bridge has advantages of stiffness, low noise, low cost, easy repair and easy maintenance, so there are certain applications on high-speed rail. China's commonly used construction structure is small and medium-sized passenger railway bridge cross, but in the future some specific high-speed rails require the use of cable-stayed bridge. The pow-er of high-speed train on the bridge structure is much larger than that on the the ordinary railway bridge. Bridges larger deflection will directly affect the ride of the bridge rail, causing the structure to withstand great impact. So the impact factor, earthquake, wind, structural calculation schema, train security and comfort should be paid attention to let the calculation and analysis of the cable-stayed bridge's physical and mechanical properties and reliability meet the requirements of safety and comfort.%大跨度斜拉桥由于具有刚度大、噪声小、成本低、维修养护方便等特点,在高速铁路上得到了一定的应用.目前中国建设的几条客运专线桥梁普遍采用中小跨,但是将来一些特殊地段修建高速铁路对须采用斜拉桥,高速列车对桥梁结构的动力作用远大于普通铁路桥梁,桥梁出现较大的挠度会直接影响桥上轨道的平顺性,造成结构物承受很大的冲击力.在斜拉桥计算分析中应对冲击系数、抗震、抗风、结构计算图式、列车安全性和舒适性等方面引起注意,从而使计算分析的斜拉桥的物理、力学性能及结构可靠度满足高速铁路列车运行安全和乘客舒适的要求.

  10. Research on the Dumbbell Industry Integration Strategy of Mechanical Effect of Double Pylon Cable-stayed Bridge%“哑铃式”产业一体化战略集群与链式效应研究--基于双塔斜拉桥物理力学效应视角

    Institute of Scientific and Technical Information of China (English)

    刘永; 王达政; 张素珍

    2014-01-01

    Based on double pylon cable -stayed bridge physical mechanics effect ,this paper analyzes the in-tegration of the industry value chain cluster effect , the chain effect , the double pylon cable -stayed bridge physical and mechanical principle .It discusses the dumbbell industry integrated strategic model which high-lights the mechanical effect of double pylon cable -stayed bridge in constructing regional industry value chain---the cluster effect of the vertical gravity and the level of tension chain effect .It also explains that the "dumbbell industry integration strategy"model plays a research effect and far -reaching strategy role in balanced and powerfully driving rapid structural transformation and development of regional industrial econo-my.It has great reference to handling the relationship between the government and the market .%文章基于双塔斜拉桥物理力学效应视角,分析了产业价值链的集群效应、链式效应与双塔斜拉桥物理力学原理的融合,探讨了“哑铃式”产业一体化战略在区域产业价值链构筑中所彰显的双塔斜拉桥力学效应---垂直重力的集群效应与水平张力的链式效应,诠释了“哑铃式”产业一体化战略模型均衡有力拉动区域产业经济结构快速转型发展的效用与处理好政府与市场的关系有着深远战略指导意义。

  11. Anomaly Detection Algorithm for Stay Cable Monitoring Data Based on Data Fusion

    Institute of Scientific and Technical Information of China (English)

    Xiaoling Liu,Qiao Huang∗; Yuan Ren

    2016-01-01

    In order to improve the accuracy and consistency of data in health monitoring system, an anomaly detection algorithm for stay cables based on data fusion is proposed. The monitoring data of Nanjing No. 3 Yangtze River Bridge is used as the basis of study. Firstly, an adaptive processing framework with feedback control is established based on the concept of data fusion. The data processing contains four steps: data specification, data cleaning, data conversion and data fusion. Data processing information offers feedback to the original data system, which further gives guidance for the sensor maintenance or replacement. Subsequently, the algorithm steps based on the continuous data distortion is investigated,which integrates the inspection data and the distribution test method. Finally, a group of cable force data is utilized as an example to verify the established framework and algorithm. Experimental results show that the proposed algorithm can achieve high detection accuracy, providing a valuable reference for other monitoring data processing.

  12. 斜拉桥主梁大型 0 号块施工技术%Construction Techniques for Massive No .0 Main Girder Block of Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    付浩; 严杰; 尹振君; 潘立泉

    2015-01-01

    武汉西四环汉江特大桥主桥为(77+100+360+100+77 ) m预应力混凝土梁斜拉桥 ,主梁为π形结构 ,两边为单箱双室、中间为纵横梁加桥面板结构形式.主梁0号块宽44 m、长22 m ,采用钢管桩贝雷梁支架现浇施工.支架由底模系统、横梁(贝雷梁)、桩顶分配梁、砂筒、钢管支架组成 ,支架施工完后采用反力架预压钢管桩 ,边箱室顶板底模采用透水模板布施工.通过混凝土配合比优化 ,配制高耐久性、稳定性的C55高性能混凝土 ,并采用天泵和地泵从两个方向分层浇筑 ,桥面纵、横坡采用提浆整平机控制.在0号块混凝土强度成长期预张拉横向预应力 ,纵向预应力待1号和1′号块施工完采用连接器连接构成整束一次性张拉 ;预应力采用智能张拉系统张拉、智能压浆系统压浆.实践表明 ,该桥采用该施工技术成功克服了支架不均匀沉降 ,有效控制了裂纹的产生 ,保证了主梁0号块的施工质量与施工安全.%The main bridge of the Hanjiang River Bridge on the west Fourth Ring Road in Wu-han is a prestressed concrete girder cable-stayed bridge with span arrangement of (77+100+360+100+77) m.The two edge boxes (two-cell single box structure) together with the central lattice beam covered with deck slabs form theπ-shaped main girder.The No.0 block of the main girder , cast on scaffolds made up of steel pipe piles and bailey trusses ,is 44 m wide and 22 m long.The scaffolds are composed of the chassis ,floor beam (bailey truss) ,pile-top distributive beam ,sand bailer and steel pipe supports.After the completion of the construction of the scaffolds ,the steel pipe piles were pre-compressed using reaction frame ,and the chassis for the top plate of edge boxes are constructed by using permeable formwork cloth.During the concreting ,the concrete mixing proportion was optimized ,the C55 high-performance concrete with sound durability and stability was prepared ,and the layered

  13. Rain-Wind Induced Vibration Mitigation of Stay Cables by Aerodynamic Means

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; LI Ming-shui; LIAO Hai-li

    2009-01-01

    Stay cables with various surface profiles were tested in wind tunnel.Dimples and helical fillets were applied to mitigate the rain-wind induced vibration.The rain-wind excited responses of the cable with smooth surface were larger than those of the cables with dimples and helical fillets.At high Reynolds number,the drag coefficients of cables with dimples and helical fillets are much larger than those of smooth surface cable.

  14. Benchmark-problem investigation for seismic response of a large-span cable-stayed bridge based on nonlinear stochastic optimal control%基于非线性随机最优控制的大跨度斜拉桥地震响应 Benchmark 问题研究

    Institute of Scientific and Technical Information of China (English)

    余友熙; 刘中华; 余香林; 王守强

    2016-01-01

    Investigation of vibration control for benchmark problems on large-span,cable-stayed bridge is one of the most important research topics in the current International Symposium on Structural Control.This paper studied second-stage benchmark problems on the Bill Emerson Memorial cable-stayed bridge.In terms of Hamiltonian theory for nonlinear stochastic dynamics and control,the benchmark model under seismic excitations was investigated using MATLAB simulation analysis,based on the stochastic averaging method and stochastic dynamic-programming principle.Comparison of analysis results for optimal forces and performance-evaluation indices between the nonlinear stochastic optimal (NSO) control strategy and the linear quadratic Gaussian (LQG)control strategy revealed that the former control strategy mitigates the seismic response of the cable-stayed bridge more effectively than the latter,thereby enhancing structural dynamic stability and earthquake resistance.In conclusion,the NSO control strategy demonstrates better control effect and presents instructive references and practical significance for vibration control of bridge-engineering applications.%大跨度斜拉桥 Benchmark 问题的振动控制研究是当前国际结构控制研讨会的重要议题之一。以美国 Bill Emerson Memorial 斜拉桥第二阶段 Benchmark 模型为研究对象,在非线性随机动力学与控制的拟哈密顿理论体系框架下,运用基于随机平均法和随机动态规划原理的非线性随机最优(NSO)控制策略,对地震作用下的 Benchmark 模型进行MATLAB 仿真分析。将最优控制力和性能评价指标与线性二次型 Gauss(LQG)控制的计算结果进行对比,得出非线性随机最优控制策略能够更加有效地抑制斜拉桥的地震响应,提高结构的动力稳定性和抗震能力,具有更好的控制效果,对实际桥梁工程的振动控制具有较强的指导意义和适用价值。

  15. Experimental Investigation of Aerodynamic Instability of Iced Bridge Cable Sections

    DEFF Research Database (Denmark)

    Koss, Holger; Lund, Mia Schou Møller

    2013-01-01

    of bridge cables under wind action. This paper describes the experimental simulation of ice accretion on a real bridge cable sheet HDPE tube segment (diameter 160mm) and its effect on the aerodynamic load. Furthermore, aerodynamic instability will be estimated with quasi-steady theory using the determined...

  16. Effects of surface roughness and cross-sectional distortions on the wind-induced response of bridge cables in dry conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos T.

    Theoretical and experimental investigations to date assumed that bridge stay cables can be modelled as ideal circular cylinders and that their aerodynamic coefficients are invariant with wind angle-of-attack. These changes are neglected when the potential for bridge cable instability is evaluated...

  17. Stochastic finite element analysis of long-span bridges with CFRP cables under earthquake ground motion

    Indian Academy of Sciences (India)

    Özlem Çavdar; Alemdar Bayraktar; Süleyman Adanur; Hasan Basri Başaǧa

    2010-06-01

    Stochastic seismic analysis of long-span bridges with Carbon fibre reinforced polymer (CFRP) cables are presented in this study through combination of the advantages of the perturbation based stochastic finite element method (SFEM) and Monte Carlo simulation (MCS) method. Jindo cable-stayed and Fatih Sultan Mehmet (Second Bosporus) suspension bridges are chosen as an example. Carbon fibre reinforced polymer cable (CFRP) and steel cables are used separately, in which the cable’s cross sectional area is determined by the principle equivalent axial stiffness. Geometric nonlinear effects are considered in the analysis. Uncertainties in the material are taken into account and Kocaeli earthquake in 1999 is chosen as a ground motion. The efficiency and accuracy of the proposed algorithm are validated by comparing with results of MCS method. It can be stated that using of CFRP cables in long-span bridges subjected to earthquake forces is feasible.

  18. Comparison of several innovative bridge cable surface modifications

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos T.

    Over the last two decades, several bridge cable manufacturers have introduced surface modifications on the high-density polyethylene (HDPE) sheathing that is installed for the protection of inner cable strands or wires. The modifications are based on research undertaken predominantly in Europe an...

  19. Seismic response study on a multi-span cable-stayed bridge scale model under multi-support excitations. Part II:numerical analysis%多点激励下多跨斜拉桥缩尺模型的地震响应研究.部分2:数值分析

    Institute of Scientific and Technical Information of China (English)

    Rui ZHOU; Zhou-hong ZONG; Xue-yang HUANG; Zhang-hua XIA

    2014-01-01

    In recent years, local component destruction, collapse failure and the control of long-span cable-stayed bridges under strong multi-support excitations have received increasing attention. In this paper, two kinds of nonlinear finite element (FE) models are established to simulate the seismic responses and failure modes of a multi-span cable-stayed bridge scale model under multi-support excitations. One is the single girder model which is used to simulate the seismic response during four wave excita-tions. It can be concluded that the FE analysis results of the scale model are a good fit with those from the shaking table tests. The other one is the explicit dynamic FE model which is used to simulate the collapse and failure mechanisms of the scale model during strong earthquakes. The aggressive failure processes of the scale model under two different types of wave excitations were compared to reproduce the mechanisms in which the bearing at the middle tower failed under the El Centro (EC) wave (4.0 m/s2), and we also observed the connection failure of the cables and towers, and the elements failure of the upper beam in the middle tower, which occurred successively under a Jiangxin (JX) wave (4.0 m/s2). This simulation may be referenced as the basis for the collapse failure of a cable-stayed bridge with a large span during a strong earthquake.%研究目的:通过非线性动力有限元分析,模拟多塔斜拉桥在多点激励下的地震响应以及揭示其在强震下的倒塌破坏模式。创新要点:解决了多塔斜拉桥的非线性动力数值模拟技术,并首次模拟了多塔斜拉桥在强震下的破坏模式。研究方法:首先采用隐式的Newmark-β法求解多点地震激励下的非线性动力方程(图3),随后采用显式的中心差分格式对强震作用下桥梁的倒塌破坏过程进行数值仿真(图4)。重要结论:1.单主梁模型的数值结果可以很好地反映地震模拟振动台

  20. Analysis of Harmonic Vibration of Cable-Stayed Footbridge under the Influence of Changes of the Cables Tension

    Directory of Open Access Journals (Sweden)

    Pakos Wojciech

    2015-09-01

    Full Text Available The paper presents numerical analysis of harmonically excited vibration of a cable-stayed footbridge caused by a load function simulating crouching (squats while changing the static tension in chosen cables. The intentional synchronized motion (e.g., squats of a single person or group of persons on the footbridge with a frequency close to the natural frequency of the structure may lead to the resonant vibrations with large amplitudes. The appropriate tension changes in some cables cause detuning of resonance on account of stiffness changes of structures and hence detuning in the natural frequency that is close to the excitation frequency. The research was carried out on a 3D computer model of a real structure - a cable-stayed steel footbridge in Leśnica, a quarter of Wrocław, Poland, with the help of standard computer software based on FEM COSMOS/M System.

  1. Analysis of Harmonic Vibration of Cable-Stayed Footbridge under the Influence of Changes of the Cables Tension

    Science.gov (United States)

    Pakos, Wojciech

    2015-09-01

    The paper presents numerical analysis of harmonically excited vibration of a cable-stayed footbridge caused by a load function simulating crouching (squats) while changing the static tension in chosen cables. The intentional synchronized motion (e.g., squats) of a single person or group of persons on the footbridge with a frequency close to the natural frequency of the structure may lead to the resonant vibrations with large amplitudes. The appropriate tension changes in some cables cause detuning of resonance on account of stiffness changes of structures and hence detuning in the natural frequency that is close to the excitation frequency. The research was carried out on a 3D computer model of a real structure - a cable-stayed steel footbridge in Leśnica, a quarter of Wrocław, Poland, with the help of standard computer software based on FEM COSMOS/M System.

  2. Deck and Cable Dynamic Testing of a Single-span Bridge Using Radar Interferometry and Videometry Measurements

    Science.gov (United States)

    Piniotis, George; Gikas, Vassilis; Mpimis, Thanassis; Perakis, Harris

    2016-03-01

    This paper presents the dynamic testing of a roadway, single-span, cable-stayed bridge for a sequence of static load and ambient vibration monitoring scenarios. Deck movements were captured along both sideways of the bridge using a Digital Image Correlation (DIC) and a Ground-based Microwave Interfererometer (GBMI) system. Cable vibrations were measured at a single point location on each of the six cables using the GBMI technique. Dynamic testing involves three types of analyses; firstly, vibration analysis and modal parameter estimation (i. e., natural frequencies and modal shapes) of the deck using the combined DIC and GBMI measurements. Secondly, dynamic testing of the cables is performed through vibration analysis and experimental computation of their tension forces. Thirdly, the mechanism of cable-deck dynamic interaction is studied through their Power Spectra Density (PSD) and the Short Time Fourier Transform (STFT) analyses. Thereby, the global (deck and cable) and local (either deck or cable) bridge modes are identified, serving a concrete benchmark of the current state of the bridge for studying the evolution of its structural performance in the future. The level of synergy and complementarity between the GBMI and DIC techniques for bridge monitoring is also examined and assessed.

  3. Tensile force identification in cable-stayed structures: Hybrid system identification algorithm and experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Myung Hyun [POSCO, Incheon (Korea, Republic of); Hu, Jong Wan [Incheon National University, Incheon (Korea, Republic of)

    2014-11-15

    In this study, we investigate a method to detect tensile forces in cable-stayed structures using the combined sensitivity updating method and the advanced hybrid microgenetic algorithm. The proposed method allows us not only to avoid the trap of minimum at initial searching stage but also to find their final solutions in better numerical efficiency. The validity of the technique is numerically verified using a set of dynamic data obtained from a simulation of the cable model modeled using the finite element method. Then, the hybrid algorithm is applied to vibrating sagged cables in the laboratory scale test. The results obtained are in good agreement with the semi-analytical solutions and experimental results reported by other investigators. The results indicate that the new method is computationally efficient in characterizing the tensile force variation for cable-stayed structures.

  4. Performance enhancement of a rotational energy harvester utilizing wind-induced vibration of an inclined stay cable

    Science.gov (United States)

    Kim, In-Ho; Jang, Seon-Jun; Jung, Hyung-Jo

    2013-07-01

    In this paper, an innovative strategy for improving the performance of a recently developed rotational energy harvester is proposed. Its performance can be considerably enhanced by replacing the electromagnetic induction part, consisting of moving permanent magnets and a fixed solenoid coil, with a moving mass and a rotational generator (i.e., an electric motor). The proposed system is easily tuned to the natural frequency of a target structure using the position change of a proof mass. Owing to the high efficiency of the rotational generator, the device can more effectively harness electrical energy from the wind-induced vibration of a stay cable. Also, this new configuration makes the device more compact and geometrically tunable. In order to validate the effectiveness of the new configuration, a series of laboratory and field tests are carried out with the prototype of the proposed device, which is designed and fabricated based on the dynamic characteristics of the vibration of a stay cable installed in an in-service cable-stayed bridge. From the field test, it is observed that the normalized output power of the proposed system is 35.67 mW (m s-2)-2, while that of the original device is just 5.47 mW (m s-2)-2. These results show that the proposed device generates much more electrical energy than the original device. Moreover, it is verified that the proposed device can generate sufficient electricity to power a wireless sensor node placed on a cable under gentle-moderate wind conditions.

  5. Long span cable supported bridges - present technology and trends

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The activity within the field of long-span cable supported bridges has never been larger than at the end of the 20th century. The technology is well advanced to cope with the present challenges but it is also approaching its limits so if the trend towards ever increasing spans continues...... into the next century, further developments are required to ensure that the bridges will be stable, durable and constructible....

  6. 箱桁梁断面斜拉桥涡振性能及抑振措施的研究%Research on vortex-induced vibration and its control for cable-stayed bridge with box-truss composite girder

    Institute of Scientific and Technical Information of China (English)

    冯丛; 华旭刚; 胡腾飞; 陈强; 陈政清

    2016-01-01

    T he cable-stayed Dongting Lake railway bridge under construction was case-studied in this paper. A finite element modeling of the cable-stayed bridge with box-truss composite girder and its vortex-induced vibration were analyzed. T hree finite element schemes for modeling box-truss girder of the bridge,namely the spatial beam model ( SBM) ,spatial plate-beam model( SPBM ) and spatial shell model( SSM ) ,were compared in terms of modal frequency,equivalent mass and mass moment of inertia per unit length. It shows that the results from the SPBM and the SSM are basically the same,while the SBM can't accurately produce the equivalent mass unit length girder for some higher-order lateral modes. T he vortex-induce vibration of the box-truss composite girder was tested in wind tunnel by flexibly mounted rigid sectional model tests. T he results indicate that this cross-section type may experience large-amplitude vertical vortex-induced vibrations at wind attack angle of -3°,which is caused by the vortex shedding at the leading edge of the box-girder part of the cross-section. T he effects of aerodynamic appendix for suppression of vortex-induced vibrations w ere studied and it is found that tw o stabilizers beneath the open orthotropic deck dramatically reduce the vibration amplitude. T he vibration amplitude is within the limit given in design specification when the height of stabilizers is half of the box-girder height; and the vortex-induced vibrations completely diminish when the height of stabilizers is the same as the box-girder height.%以在建的洞庭湖铁路三塔斜拉桥为工程背景,分析了箱桁断面斜拉桥主梁的建模方法以及涡激共振性能。首先比较了主梁建模的空间杆系模型、梁壳组合模型以及三维壳体模型在模态频率、主梁单位长度等效质量和等效质量惯性矩的差异。结果表明,三种模型的模态分析结果基本相近,但空间杆系模型不能准确得到高阶侧弯模

  7. Study on the impacts of viscous fluid damper on anti-seismic property of lower tower cable-stayed bridge%粘滞阻尼器对矮塔斜拉桥抗震性能影响研究

    Institute of Scientific and Technical Information of China (English)

    张丹; 黄海新; 张晶

    2012-01-01

    Taking Yongding Xinhe Bridge in Tianjin as an engineering background,this paper tests and studies the mechanical properties of viscous fluid damper used in the engineering,and discusses the impacts of viscous fluid damper on anti-seismic performance by using time-history analysis method.The analysis shows that: setting vertical and horizontal viscous fluid damper can effectively reduce the displacement of critical parts under earthquake and improve internal force of structural components.%以天津永定新河特大桥为工程背景,对该工程所使用的粘滞流体阻尼器的力学性能进行了实验研究,利用时程分析法,讨论了粘滞流体阻尼器对该桥抗震性能的影响,分析表明:通过设置纵向和横向粘滞阻尼器,可以有效地降低结构在地震作用下关键部位的位移,改善结构构件的内力。

  8. 行波及相干效应对超千米跨度斜拉桥多维多点随机地震响应的影响%The Influence of Traveling Wave and Coherent Effects on Multi-dimensional and Multi-point Random Seismic Response of Super Long Span Cable Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    范晨阳; 郑史雄; 陈航; 张金

    2016-01-01

    为了研究行波及相干效应对超千米跨度公铁两用斜拉桥地震响应的影响,基于通用有限元软件ANSYS,借助高效的虚拟激励法分别得到考虑两种效应的结构地震响应值,通过对比研究,结果表明:(1)仅考虑行波效应时,在视波速取500 m/s工况下,主梁纵向位移和竖向位移出现最大均方根值,行波效应对主梁纵向位移响应影响最为显著;(2)仅考虑相干效应时,主梁纵向位移和横向位移在部分相干工况下出现最大均方根值,主梁跨中横向位移的均方根值为0.274 m,较一致激励(完全相干)增大了126.4%;(3)两种效应对结构1号边墩、2号辅助墩和3号主塔的不同地震响应的影响程度存在较大差异,需具体响应具体分析。通过各具体工况下的结果对比,得出超大跨度斜拉桥地震响应分析考虑行波和相干效应十分必要的结论。%In order to study the influence of traveling wave and coherent effects on seismic response of the super long span railway double purpose cable stayed bridge, the seismic response of the structures with two effects are obtained with the aid of the efficient virtual excitation method based on the general finite element software ANSYS. The results of the comparative study show that:( 1 ) when only the traveling wave effect is considered, the effect of the traveling wave on the longitudinal displacement of the main beam is the most significant, while the apparent wave velocity of 500 m/s is taken with the maximum root mean square value of both the longitudinal displacement and the vertical displacement of the main beam;( 2 ) when only the coherence effect is considered, the longitudinal displacement and transverse displacement of the main beam appear under partially coherent conditions, the root mean square value of the transverse displacement of the main beam is 0. 274 m, and the uniform excitation ( totally coherent) increases by 126. 4%; ( 3 ) the seismic responses of

  9. Effects of surface roughness and cross-sectional distortion on the wind-induced response of bridge cables in dry conditions

    DEFF Research Database (Denmark)

    Matteoni, G.; Georgakis, Christos T.

    2015-01-01

    Theoretical and experimental investigations to date have assumed that bridge stay cables can be modelled as ideal circular cylinders and that their aerodynamic coefficients are invariant with wind angle-of-attack. On the other hand it has been demonstrated that bridge cables are characterised......, determined in static conditions for an identical cable model as the one used for passive-dynamic tests, the in-plane aerodynamic damping is evaluated by employing a one-degree-of-freedom (1 DOF) quasi-steady analytical model. Similarly, it is shown that regions of instability associated with the occurrence...

  10. Comfort Evaluation of Riding Vibration for Large-span Cable-stayed Bridge%大型桥梁行车振动舒适性的烦恼率模型研究

    Institute of Scientific and Technical Information of China (English)

    李雪红; 周叶波; 徐秀丽; 刘伟庆; 李枝军

    2011-01-01

    针对目前国内外对行车振动舒适性的度量及具体判定上还有一定的模糊性,迫切需要定量化的评价方法.本文结合振动舒适度标准和国际上公认的振动舒适度实验,分析了概念隶属度值和相应的振动加速度对数值之间的关系,给出了烦恼率计算公式,提出了烦恼率的近似拟合曲线,并把烦恼率作为行车振动舒适性的量化指标,提出评价行车振动舒适性较精确的量化方法;并将其用于实际运营的大跨桥梁的行车振动舒适性评价.%According to disadvantage of fuzziness for judgment of riding comfort of the bridge, quantitative evaluation method is needed. Combining riding comfort standard and internationally accepted riding comfort experiment, definition of membership and relationship between corresponding vibration acceleration and value are analyzed; annoyance rate calculation formula is researched; approximate fitting curve of annoyance rate is put forward. A more accurate quantitative method to evaluate riding comfort is proposed, with annoyance rate as quantitative index of riding comfort.

  11. SUSPNDRS: a numerical simulation tool for the nonlinear transient analysis of cable support bridge structures, part 1: theoretical development

    Energy Technology Data Exchange (ETDEWEB)

    McCallen, D.; Astaneh-Asl, A. [California Univ., Berkeley, CA (United States)

    1997-06-01

    The work reprint on herein was aimed at developing methodologies and tools for efficient and accurate numerical simulation of the seismic response of suspension and cable-stayed structures. A special purpose finite element program has been constructed and the underlying theory and demonstration example problems are presented. A companion report [Ref 1] discusses the application of this technology for a major suspension bridge structure.

  12. Enhanced damping for bridge cables using a self-sensing MR damper

    Science.gov (United States)

    Chen, Z. H.; Lam, K. H.; Ni, Y. Q.

    2016-08-01

    This paper investigates enhanced damping for protecting bridge stay cables from excessive vibration using a newly developed self-sensing magnetorheological (MR) damper. The semi-active control strategy for effectively operating the self-sensing MR damper is formulated based on the linear-quadratic-Gaussian (LQG) control by further considering a collocated control configuration, limited measurements and nonlinear damper dynamics. Due to its attractive feature of sensing-while-damping, the self-sensing MR damper facilitates the collocated control. On the other hand, only the sensor measurements from the self-sensing device are employed in the feedback control. The nonlinear dynamics of the self-sensing MR damper, represented by a validated Bayesian NARX network technique, are further accommodated in the control formulation to compensate for its nonlinearities. Numerical and experimental investigations are conducted on stay cables equipped with the self-sensing MR damper operated in passive and semi-active control modes. The results verify that the collocated self-sensing MR damper facilitates smart damping for inclined cables employing energy-dissipative LQG control with only force and displacement measurements at the damper. It is also demonstrated that the synthesis of nonlinear damper dynamics in the LQG control enhances damping force tracking efficiently, explores the features of the self-sensing MR damper, and achieves better control performance over the passive MR damping control and the Heaviside step function-based LQG control that ignores the damper dynamics.

  13. Time-domain analysis of wind-induced buffet and wind-resistant measures for cable-stayed bridge with steel box girder at construction stage%大跨度钢箱梁斜拉桥施工过程风致抖振时域分析及抗风措施

    Institute of Scientific and Technical Information of China (English)

    张茜; 周绪红; 狄谨; 王继承

    2013-01-01

    以杭州湾跨海大桥北通航孔斜拉桥为背景,采用ANSYS有限元分析软件对其施工中最大双悬臂及最大单悬臂状态进行了风致抖振响应时域分析.采用谐波合成法进行了随机风场模拟,对塔、梁和索承受的风荷载分别进行了简化,并给出了静风力、抖振力和自激力的时域表达式及自激力在ANSYS中的实现方法;采用“鱼骨式”模型作为斜拉桥主梁的计算模型,分析考虑了结构的几何、气动非线性.分析结果表明:在施工阶段设计风荷载下,主梁悬臂端及塔顶处位移响应较小,风荷载效应与恒载效应组合后,塔根部截面最大拉应力为0.707 MPa;根据抖振响应分析结果和其他因素综合考虑,对杭州湾跨海大桥北通航孔斜拉桥提出了施工过程中有效可行的抗风措施.%Based on the project of north channel cable-stayed bridge of Hangzhou Bay Sea-crossing Bridge, the time-domain analysis of wind-induced buffet was carried out under the double and single jib condition by ANSYS. The random wind field was simulated by WAWS. Buffeting wind loads, which were exerted on tower, girder and cables, were simplified separately. The time-domain expressions of static wind force, buffeting force and full coupled auto-excited force, and how to exert the full coupled auto-excited force in ANSYS were proposed in this paper. Single beam elements were adopted to proceed the time-domain analysis, and the geometric and aerodynamic nonlinear of the structure was considered. Time-domain analysis results show that under the design wind loads at construction stage, the displacement response is smaller at the cantilever end of main girder and the top of pylon. The maximum tensile stress of the section at the root of pylon is 0. 707 MPa after combination of wind loads and dead loads. The wind resistance measures are suggested based on the results of the time-domain analysis and the influence of other factors. 3 tabs, 7 figs, 10

  14. In situ testing and nonlinear modelling for a cable-stayed timber footbridge

    Directory of Open Access Journals (Sweden)

    Bortoluzzi Daniele

    2014-01-01

    Full Text Available The authors had the chance to collect structural response measurements of a cable-stayed glued-laminated-timber (GLT footbridge located in Farra d’Alpago (not far from the town of Belluno, in North-Eastern Italy. A consistent geometrically nonlinear finite element model was generated and its parameters were calibrated on the experimental data. Finally, a model validation was carried out.

  15. 基于模态应变能变异指标的斜拉桥模型损伤识别研究%Experimental Study on Damage Identification of a Cable-stayed Bridge Model with Modal-strain-energy-damage Change Index

    Institute of Scientific and Technical Information of China (English)

    葛继平; 李胡生; 陈明

    2011-01-01

    基于动力测试采用模态应变能变化率方法对一座独塔斜拉桥模型进行了损伤识别实用性研究,识别过程基于动力模态分析,激励方式包括车辆激励、环境激励和冲击激励.从识别得到的各阶试验模态的模态应变能变异指标的计算结果可知:在合适的激励条件下,模态应变能指标可以识别梁式结构主梁的损伤位置和大小关系;激励的充分条件会影响模态应变能指标的识别效果,冲击激励产生的激励较充分,因而损伤识别的效果最好;各阶试验模态包含的损伤信息完备程度不同,建议综合多阶模态应变能变异指标的计算结果进行损伤识别.%Modal-strain-energy-damage change index based on dynamic test was carried on the damage recognition to a single tower cable-stayed bridge model.Recognition process was based on dynamic modal analysis.Exciting way included vehicles excitation, environment excitation and impact excitation.The results of modal strain energy damage change index from damage recognition of various experimental modal shapes show that, under the appropriate excitation condition, the modal strain energy damage change index could be served as to distinguish damage position and damage degree in beam structure; The degree of excitation sufficient condition will affect the damage recognition effect of modal-strain-energy-damage change index, the damage recognition effect of impact excitation is better for the sufficient excitation from impact load; Different experiment modal shape contains different amount of damage information, thus combining computed results from multi-step modal strain energy change index to the damage recognition is suggested.

  16. A preliminary probabilistic framework of the assessment of bridge cable fatigue

    DEFF Research Database (Denmark)

    Roldsgaard, Joan Hee; Georgakis, Christos T.; Faber, Michael Havbro

    , traffic load-ing, bridge specific parameters and the mechanisms that induce significant cable vibrations are the main input parameters. The suggested framework is illustrated on a case study considering the second longest hanger ca-ble of the Great Belt Bridge outlining how information with respect...

  17. Calculation method on shape finding of self-anchored suspension bridge with spatial cables

    Institute of Scientific and Technical Information of China (English)

    Yan HAN; Zhengqing CHEN; Shidong LUO; Shankui YANG

    2009-01-01

    Based on the spatial model, a reliable and accurate calculation method on the shape finding of self anchored suspension bridge with spatial cables was studiedin this paper. On the principle that the shape of the main cables between hangers is catenary, the iteration method of calculating the shapes of the spatial main cables under the load of hanger forces was deduced. The reasonable position of the saddle was determined according to the shape and the theoretical joint point of the main cables. The shapes of the main cables at completed cable stage werecalculated based on the unchanging principle of the zero-stress lengths of the main cables. By using a numerical method combining with the finite element method, one self-anchored suspension bridge with spatial cables was analyzed. The zero-stress length of the main cables, the position of the saddle, and the pre-offsetting of the saddle of the self-anchored suspension bridge were given. The reasonable shapes of the main cables at bridge completion stage and completed cable stage were presented. The results show that the shape-finding calculation method is effective and reliable.

  18. 桥梁缆索金属损伤无损检测方法%Nondestructive Testing Method for Metallic Flaws of Bridge Cables

    Institute of Scientific and Technical Information of China (English)

    武新军; 贲安然; 徐江

    2012-01-01

    缆索广泛应用于斜拉桥、悬索桥和拱形桥等桥梁结构中,其有效金属承载面积直接关系到桥梁安全。在分析桥梁缆索自身结构和使用工况的基础上,论述了桥梁缆索无损检测中遇到的难点,分析了可能应用于桥梁缆索金属损伤的无损检测方法的特点和局限性,其中声发射法可用于缆索的长期监测,但仅能给出相对检测结果;射线法和磁性检测法可用于缆索的逐点扫描检测,但检测移动辅助装置复杂;磁致伸缩导波检测方法可实现远距离的包括锚固区在内的金属损伤检测,但信号解释复杂。最后,提出了桥梁缆索磁致伸缩导波快速扫查和磁性精细扫查相结合的无盲区检测方法,该研究将促进桥梁缆索无损检测技术的深入发展。%Cables and wire ropes are mostly employed in the structure of cable-stayed bridges, suspension bridges and arch bridge. Its effective metallic loading area determines the safety of the bridge. Based on the analysis of the bridge cable structure and its working condition, main problems in nondestructive testing of bridge cables are described in this paper. Then, the possible method for NDT of bridge cables including their characteristics and limits are given. The acoustic emission testing method can be used in the cable on-line condition and only can give relative results of different cable conditions. The radiography and magnetic testing methods can scan along the cable, but the complicated auxiliary apparatus is required. The magnetostrictive guided wave testing method can detect far flaws of cables, which include the anchorage zone, but its signal interpretation requires complex knowledge. In the last, a blind zone free NDT method for the bridge cable which is to combine rapid scanning and magnetic precise testing together is proposed. The above research work will advance further development of nondestructive testing technique for the bridge cables.

  19. Research and Engineering Application of Viscous Dampers for Stay Cables%斜拉索粘滞阻尼器研发与工程应用

    Institute of Scientific and Technical Information of China (English)

    李荣庆; 盛能军; 张守利

    2014-01-01

    斜拉索粘滞阻尼器能抑制斜拉索振动,可作为斜拉索永久抑振措施。结合粘滞阻尼器理论原理,针对嘉绍大桥主航道桥斜拉索设计了阻尼器性能参数,并开发了阻尼器产品。对阻尼器进行性能试验及现场减振效果测试,结果表明:阻尼器性能稳定,各项性能指标均满足设计要求;实测对数衰减率达到6%以上,与理论值变化规律基本一致,具有良好的减振效果。%Viscous dampers was able to curb the vibration of stay cables ,which can be taken as the permanent vibration control measure for stay cables .Combined with the theories of the viscous dampers ,the performance parameters of the dampers for stay cables of the main naviga-tional channel bridge of Jiashao Bridge were designed and the viscous dampers were developed . The dampers were checked by the performance testing and field vibration efficiency testing .The results of the testings demonstrated that the dampers showed stable performance ,all the per-formance indexes could meet the design requirements .The measured logarithmic decrement was above 6% ,basically in compliance with the changing rule of the theoretical values ,proving that the dampers have sound vibration damping effect .

  20. 基于寿命函数的斜拉索系统维修更换策略研究%Stay-cable maintenance and replacement strategy based on lifetime functions

    Institute of Scientific and Technical Information of China (English)

    王立彬; 李爱群; 马小利; 丁盛

    2012-01-01

    Study on the deterioration of the stay-cables as well as the optimum maintenance strategies to get the best cost- benefit ratio throughout the life of the structure is always one of the most important issues in bridge engineering. Based on the lifetime functions of the stay-cables and the series-parallel cable system model, the failure probability of cable-stayed bridge and the structure deterioration was studied, and the effect on the failure probability by different maintenance and replacement strategies was analyzed. Using lifetime cost theory, the timing and the economy of the replacement of the stay-cables was further analyzed. With the application to a cable-stayed bridge, the applicability of the models was tested, the optimal replacement strategy is recommended with the objective of maximum life time and minimum maintenance cost. It shows that the life-cycle cost theory based on the lifetime functions of the whole cable system is an effective planning method for replacement of stay-cables.%展开寿命周期内拉索劣化规律和维修更换策略的研究,获得桥梁结构的最优成本一效益比,是缆索桥梁养护维修的重要研究内容之一。根据拉索寿命函数和拉索系统的串并联模型,研究斜拉桥拉索系统失效概率变化即结构劣化的规律,分析全寿命周期内不同维修更换措施对结构失效概率的影响。运用周期成本理论,进一步分析不同维修更换时间和更换策略的经济性。结合一斜拉桥模型,验证了模型的适用性,并且以延长使用寿命和累积维修费用最低为目标,获得该桥的最优维修策略。研究表明,寿命函数和周期成本理结合是确定斜拉桥拉索更换优化策略的有效途径,为工程拉索更换策略提供有益的参考。

  1. Fatigue of threaded rods in cable anchorages due to Vortex shedding

    NARCIS (Netherlands)

    Maljaars, J.; Snijder, H.H.

    2013-01-01

    The 'Hovenring' is a bicycle roundabout flyover built as a signature bridge with a central steel pylon carrying a circular bridge deck suspended through stay-cables. Shortly after installation of the bridge, the stay-cables turned out to vibrate in the wind due to vortex shedding. These vibrations h

  2. Effects of bridge cable surface roughness and cross-sectional distortion on aerodynamic force coefficients

    DEFF Research Database (Denmark)

    Matteoni, G.; Georgakis, C.T.

    2012-01-01

    Theoretical and experimental investigations to date have assumed that bridge cables can be modeled as ideal circular cylinders and the associated aerodynamic coefficients are invariant with the wind angle-of-attack. On the other hand, bridge cables are normally characterized by local alterations...... of their inherent surface roughness and shape, which might present a significant disturbance for the surrounding wind flow. The present study focuses on the experimental determination, based on static wind tunnel tests, of the aerodynamic coefficients of full-scale bridge cable section models both perpendicular...... and inclined to the flow, for varying wind angles-of-attack. The wind tunnel test results demonstrate that the aerodynamic coefficients of bridge cables can be significantly affected by the wind angle-of-attack....

  3. Recent monitoring of the Øresund Bridge: Observations of rain-wind induced cable vibrations

    DEFF Research Database (Denmark)

    Acampora, Antonio; Georgakis, Christos

    2011-01-01

    dampers were installed on the longest and second longest cable pairs. Although the bridge has not suffered from any significant vibration events since the installation of the new damping systems, smaller amplitude vibrations are recorded from time to time. Peak to peak amplitudes of up to three cable...

  4. Damage Localization of Cable-Supported Bridges Using Modal Frequency Data and Probabilistic Neural Network

    Directory of Open Access Journals (Sweden)

    X. T. Zhou

    2014-01-01

    Full Text Available This paper presents an investigation on using the probabilistic neural network (PNN for damage localization in the suspension Tsing Ma Bridge (TMB and the cable-stayed Ting Kau Bridge (TKB from simulated noisy modal data. Because the PNN approach describes measurement data in a Bayesian probabilistic framework, it is promising for structural damage detection in noisy conditions. For locating damage on the TMB deck, the main span of the TMB is divided into a number of segments, and damage to the deck members in a segment is classified as one pattern class. The characteristic ensembles (training samples for each pattern class are obtained by computing the modal frequency change ratios from a 3D finite element model (FEM when incurring damage at different members of the same segment and then corrupting the analytical results with random noise. The testing samples for damage localization are obtained in a similar way except that damage is generated at locations different from the training samples. For damage region/type identification of the TKB, a series of pattern classes are defined to depict different scenarios with damage occurring at different portions/components. Research efforts have been focused on evaluating the influence of measurement noise level on the identification accuracy.

  5. Radar-based dynamic testing of the cable-suspended bridge crossing the Ebro River at Amposta, Spain

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, Carmelo [Politecnico di Milano, Dept. of Architecture, Built environment and Construction engineering (ABC), Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Luzi, Guido [Centre Tecnòlogic de Telecomunicacions de Catalunya (CTTC), Division of Geomatics, Av. Gauss, 7 E-08860 Castelldefels (Barcelona) (Spain)

    2014-05-27

    Microwave remote sensing is the most recent experimental methodology suitable to the non-contact measurement of deflections on large structures, in static or dynamic conditions. After a brief description of the radar measurement system, the paper addresses the application of microwave remote sensing to ambient vibration testing of a cable-suspended bridge. The investigated bridge crosses the Ebro River at Amposta, Spain and consists of two steel stiffening trusses and a series of equally spaced steel floor beams; the main span is supported by inclined stay cables and two series of 8 suspension cables. The dynamic tests were performed in operational conditions, with the sensor being placed in two different positions so that the response of both the steel deck and the arrays of suspension elements was measured. The experimental investigation confirms the simplicity of use of the radar and the accuracy of the results provided by the microwave remote sensing as well as the issues often met in the clear localization of measurement points.

  6. Identification of aeroelastic forces on twin bridge cables from full-scale measurements in skew winds

    DEFF Research Database (Denmark)

    Acampora, Antonio; Macdonald, J.H.G.; Georgakis, Christos T.;

    2012-01-01

    Despite much research in recent years, large amplitude vibrations of inclined bridge cables continue to be of concern. Various mechanisms for the excitation have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced-velocity vortex shedding and excitation from...... of this paper is to identify the aeroelastic forces for in-plane and out-of-plane vibrations of bridge cables in dry conditions as in [2], but now for skewed winds. To achieve this, an output-only system identification employing the Eigenvalue Realisation Algorithm (ERA) [3] has been applied to selected...

  7. Construction techniques of super-length main cable of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Shen Liangcheng; Liang Jinda

    2011-01-01

    Taizhou Bridge is a highway three-pylon two-span bridge with span arrangement of 1 080 m + 1 080 m and the length of the main cable is more than 3 100 m. It is the longest cable in China. As the erection of the main cable needs to cross over three towers and the cables undulate acutely, general problems like the twist, spread and swell of strands and shedding of the zinc coating are prone to arise, which make it difficult to guarantee the quantity of cable traction construction. In this paper, the hauling, shaping and saddling of strands and sag adjusting are illustrated in detail and how to execute the refined construction control to guarantee the erection quality is also covered.

  8. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europe...... is found in Scandinavia - the 1210 m span of the Höga Kusten Bridge in Sweden.The Kvarnsund Bridge in Norway was at the completion in 1991 the longest cable-stayed bridge in the world, and the span of 530 m is still thge longest for cable-stayed bridges in concrete. The Øresund Bridge with its sapn of 490...... m is the longest among cable-stayed bridges for both road and railway traffic....

  9. 上海长江隧桥长重索施工技术%Technology for Installation of Long and Heavy Cable for Shanghai Yangtze River Tunnel Bridge

    Institute of Scientific and Technical Information of China (English)

    黄伟

    2012-01-01

    With the development of China's bridges, the span of cable-stayed bridges is growing and the difficulty of construction technology is increasing, making it first to solve the problem of cable installation. Combining with the construction characteristic of Shanghai Yangtze Bridge, portal crane is used to lift up the long and heavy cable to the bridge floor and a soft- hard combination method is selected to drive the long and heavy cable. In additional, through the analysis on its twisting direction, the measures to obtain anti-twist of long and heavy cable is adopted. So the safety and quality of cable construction have been improved greatly. It can provide references for other bridge buildings.%随着我国桥梁事业的发展,斜拉索桥的跨度要求越来越大,施工技术难度也越来越大,其中必须首先解决斜拉索的施工难题.结合上海长江大桥的施工特点使用门机吊来吊装长重索至桥面,采用软硬结合的方式对长重索进行牵引;在施工中通过对长重索扭转方向的分析,采取了一个防扭措施.使斜拉索施工的安全和质量有了较大提高,为其它桥梁建设提供参考经验.

  10. Study of Dynamic Performance Finite Element Modeling Methods for Box-Truss Composite Girder Railway Cable-Stayed Bridge%箱桁组合梁铁路斜拉桥动力特性有限元建模方法研究

    Institute of Scientific and Technical Information of China (English)

    张无畏; 胡腾飞; 陈长胜; 荣浩

    2016-01-01

    为实现箱桁组合梁铁路斜拉桥动力特性的精准模拟计算,对箱桁组合梁开口断面斜拉桥空间杆系模型、空间板梁组合模型和空间板壳模型3种有限元建模方法进行研究。以某跨径布置为(98+140+406+406+140+98) m的三塔双主跨箱桁组合梁铁路斜拉桥为背景,采用子空间迭代方法对比分析了不同模型的模态特性,并在此基础上计算了不同模型主梁单位长度的等效质量及其惯性矩。研究结果表明:3种模型计算得到的模态分析结果基本吻合,空间板梁组合模型和空间板壳模型得到的频率及主梁等效质量基本相同,但空间杆系模型不能准确得到高阶侧弯模态的主梁等效均布质量。作为特例,进一步对无桁架钢箱梁开口断面斜拉桥的动力特性进行分析,结果表明:空间板梁组合模型和空间板壳模型吻合良好,但空间杆系模型得到的1阶扭转模态下的主梁等效均布质量惯性矩误差接近9%;桁架对主梁的侧弯基频影响较小,但能提高主梁的竖弯基频和扭转基频,有利于桥梁抗风。%To realize the accurate simulation calculation of the dynamic performance of box‐truss composite girder railway cable‐stayed bridge ,the three finite element modeling schemes of the box‐truss composite girder cable‐stayed bridge with open cross section are studied ,including the spatial bar element model ,combined space plate and beam element model and spatial shell ele‐ment model .A three‐pylon two main spans box‐truss composite girder railway cable‐stayed bridge with span arrangement of (98+140+406+406+140+98) m was taken as the study background . The sub‐spatial iterative method was used to comparatively analyze the modal characteristics of the different models ,and based on w hich the unit length equivalent mass and inertia moment of the different main girder models were calculated .The results of the

  11. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  12. The numerical and experimental investigations of the near wake behind a modi- fied square stay-cable

    Institute of Scientific and Technical Information of China (English)

    沈顺成; 汪秒; 卢红; 邹琳

    2016-01-01

    The near wake structure, the wake-flow characteristics and the drag coefficients behind a modified square stay-cable (MSC) with sinusoidal variations of the cross-section area along the spanwise direction are investigated experimentally and numeri- cally. The Reynolds numbers are chosen as 100 and 500 for the laminar flow andRe=6 000 and 22 000 for the turbulent flow. The detailed near wake structures, the velocity fields and the force coefficients for the MSC are captured, the effect of the Reynolds number on the flow structure for the MSC is studied. The numerical and experimental investigations show that the free shear layers from the leading edge are widened and prolonged and then roll up into vortices further downstream the MSC, unlike a straight square stay-cable (SSC) under the same flow conditions. As a result, the distinct mean drag reduction and the fluctuating lift suppression are observed for all Reynolds numbers, a drag reduction of at least 15.8% and the rms lift coefficient reduction of up to 95% are observed, as compared with the case of a straight square stay-cable atRe=500.

  13. Effects of surface design on aerodynamic forces of iced bridge cables

    DEFF Research Database (Denmark)

    Koss, Holger

    2014-01-01

    In recent years the relevance of ice accretion for wind-induced vibration of structural bridge cables has been recognised and became a subject of research in bridge engineering. Full-scale monitoring and observation indicate that light precipitation at moderate low temperatures between zero and -5......°C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion...... influences the accretion of ice to an extent that the aerodynamic forces differ significantly amongst the designs. The experiments were conducted in a wind tunnel facility capable amongst others to simulate in-cloud icing conditions....

  14. Structural health monitoring approach for detecting ice accretion on bridge cable using the Haar Wavelet Transform

    Science.gov (United States)

    Andre, Julia; Kiremidjian, Anne; Liao, Yizheng; Georgakis, Christos; Rajagopal, Ram

    2016-04-01

    Ice accretion on cables of bridge structures poses serious risk to the structure as well as to vehicular traffic when the ice falls onto the road. Detection of ice formation, quantification of the amount of ice accumulated, and prediction of icefalls will increase the safety and serviceability of the structure. In this paper, an ice accretion detection algorithm is presented based on the Continuous Wavelet Transform (CWT). In the proposed algorithm, the acceleration signals obtained from bridge cables are transformed using wavelet method. The damage sensitive features (DSFs) are defined as a function of the wavelet energy at specific wavelet scales. It is found that as ice accretes on the cables, the mass of cable increases, thus changing the wavelet energies. Hence, the DSFs can be used to track the change of cables mass. To validate the proposed algorithm, we use the data collected from a laboratory experiment conducted at the Technical University of Denmark (DTU). In this experiment, a cable was placed in a wind tunnel as ice volume grew progressively. Several accelerometers were installed at various locations along the testing cable to collect vibration signals.

  15. Dynamic testing of cable structures

    Directory of Open Access Journals (Sweden)

    Caetano Elsa

    2015-01-01

    Full Text Available The paper discusses the role of dynamic testing in the study of cable structures. In this context, the identification of cable force based on vibration measurements is discussed. Vibration and damping assessment are then introduced as the focus of dynamic monitoring systems, and particular aspects of the structural behaviour under environmental loads are analysed. Diverse application results are presented to support the discussion centred on cable-stayed bridges, roof structures, a guyed mast and a transmission line.

  16. Monitoring and Failure Analysis of Corroded Bridge Cables under Fatigue Loading Using Acoustic Emission Sensors

    Directory of Open Access Journals (Sweden)

    Hui Li

    2012-03-01

    Full Text Available Cables play an important role in cable-stayed systems, but are vulnerable to corrosion and fatigue damage. There is a dearth of studies on the fatigue damage evolution of corroded cable. In the present study, the acoustic emission (AE technology is adopted to monitor the fatigue damage evolution process. First, the relationship between stress and strain is determined through a tensile test for corroded and non-corroded steel wires. Results show that the mechanical performance of corroded cables is changed considerably. The AE characteristic parameters for fatigue damage are then established. AE energy cumulative parameters can accurately describe the fatigue damage evolution of corroded cables. The failure modes in each phase as well as the type of acoustic emission source are determined based on the results of scanning electron microscopy. The waveform characteristics, damage types, and frequency distribution of the corroded cable at different damage phases are collected. Finally, the number of broken wires and breakage time of the cables are determined according to the variation in the margin index.

  17. Monitoring and failure analysis of corroded bridge cables under fatigue loading using acoustic emission sensors.

    Science.gov (United States)

    Li, Dongsheng; Ou, Jinping; Lan, Chengming; Li, Hui

    2012-01-01

    Cables play an important role in cable-stayed systems, but are vulnerable to corrosion and fatigue damage. There is a dearth of studies on the fatigue damage evolution of corroded cable. In the present study, the acoustic emission (AE) technology is adopted to monitor the fatigue damage evolution process. First, the relationship between stress and strain is determined through a tensile test for corroded and non-corroded steel wires. Results show that the mechanical performance of corroded cables is changed considerably. The AE characteristic parameters for fatigue damage are then established. AE energy cumulative parameters can accurately describe the fatigue damage evolution of corroded cables. The failure modes in each phase as well as the type of acoustic emission source are determined based on the results of scanning electron microscopy. The waveform characteristics, damage types, and frequency distribution of the corroded cable at different damage phases are collected. Finally, the number of broken wires and breakage time of the cables are determined according to the variation in the margin index.

  18. Galloping comparative analysis for transient main cables of suspension bridge during construction

    Science.gov (United States)

    Li, Shengli; Peng, Gang; Zhang, Haiting; Chen, Huai

    2011-04-01

    The cross-sectional shapes of two construction projects for the transient main cables are non-circular cross-sections during construction of the long-span suspension bridge, so the transient main cables can experience galloping instabilities. The galloping coefficients of the several representative cases of two construction projects for the transient main cables without wind-resistant measures for the long-span suspension bridge were investigated for the first time by means of the CFD method, referring to an erecting suspension bridge. Results show that for the project 1, at the early stages of the main cables construction, the galloping instabilities can occur, but at the later stages of that, the galloping instabilities cannot occur. For the project 2, there exists a lot of wind attack angles whose galloping coefficients are less than 0 at the whole construction stages. From the perspective for galloping instability the project 1 is better 2.Through the analysis and comparison the galloping performance of two kinds of construction projects for the transient main cables, the advantage and disadvantage for two construction projects is explained theoretically from the perspective for whether can result in the galloping instability.

  19. Energy conservation research of dehumidification system for main cable anticorrosion of suspension bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ce; Fan Liangkai; Feng Zhaoxiang; Pen Guanzhong

    2011-01-01

    The necessity of the main cable anticorrosion for suspension bridge is described, and operating principles and composition of main cable dehumidification system are analyzed. An idea using the waste heat of high temperature outlet air of dehumidification system to heat up regeneration air of rotary-type dehumidifier is put forward in this paper. The concrete scheme is to install a heat exchanger on air-out pipeline of roots blower and air-in pipeline of regeneration electric heater of rotary dehumidifier. Air preheated by the heat exchanger enters regeneration electric heater of rotary-type dehumidifier. Energy conservation of main cable dehumidification system for the Yangtze River highway bridge is calculated, and the results show that energy conservation rate can reach 44 %.

  20. Structural Health Monitoring approach for detecting ice accretion on bridge cable using the Haar Wavelet Transform

    DEFF Research Database (Denmark)

    Andre, Julia; Kiremidjian, Anne; Liao, Yizheng;

    2016-01-01

    Ice accretion on cables of bridge structures poses serious risk to the structure as well as to vehicular traffic when the ice falls onto the road. Detection of ice formation, quantification of the amount of ice accumulated, and prediction of icefalls will increase the safety and serviceability of...

  1. Vibration mitigation of a bridge cable using a nonlinear energy sink: design and experiment

    Directory of Open Access Journals (Sweden)

    Weiss Mathieu

    2015-01-01

    Full Text Available This work deals with the design and experiment of a cubic nonlinear energy sink (NES for horizontal vibration mitigation of a bridge cable. Modal analysis of horizontal linear modes of the cable is experimentally performed using accelerometers and displacement sensors. A theoretical simplified 2-dof model of the coupled cable-NES system is used to analytically design the NES by mean of multi-time scale systems behaviours and detection its invariant manifold, equilibrium and singular points which stand for periodic and strongly modulated regimes, respectively. Numerical integration is used to confirm the efficiency of the designed NES for the system under step release excitation. Then, the prototype system is built using geometrical cubic nonlinearity as the potential of the NES. Efficiency of the prototype system for mitigation of horizontal vibrations of the cable under for step release and forced excitations is experimentally demonstrated.

  2. Line-shape calculation method for suspension bridge catwalk considering different states of bearing cables

    Institute of Scientific and Technical Information of China (English)

    You Xinpeng; Zhang Zhaoxia; Yao Qingtao

    2012-01-01

    The line-shape of catwalk of long-span suspension bridge is obtained by using the segmental catenary method to carry out the iterative calculation, where all the bearing cables are considered as one cable, and transversal passages and gantry are treated as nodes which divide the catwalk into several segments. The difference of line-shape and force between catwalk bearing cable and gantry bearing cable is not usually considered, but the line-shape of two kinds of cables is actually inconsistent because of the constraints from gantries. Based on the segmental catenary method, considering the different states of bearing cables ( DSB calculation method), fine calculation is carried out. This method is applied to the design of a suspension bridge' s catwalk, and is compared with the traditional calculation method. It is obtained that the result is more reasonable and accurate by the coordination calculation method considering different states for two kinds of load-bearing cables, which is worth considering in the nrocess of design and optimization for catwalk.

  3. 波浪型斜拉索涡激振动实验研究%Experimental Study on the Vortex-induced Vibration of Wavy Stay Cabl

    Institute of Scientific and Technical Information of China (English)

    邹琳; 胡勇; 王汉封; 汪秒; 徐汉斌

    2015-01-01

    Considering the existing challenges in wind-induced vibration control of flexible stay-cables, a new modified wavy stay-cable was proposed to suppress the vibration and reduce the cable drag. By using hot-wire anemometer, laser displacement sensor, pressure scanning valve, smoke wire and some other experimental methods, the vortex-induced vibration (VIV) and the frequency lock-in phenomenon of the wavy stay cables at Re=6800-20480 were studied. The results were compared with those of the regular stay cable. The experimental results indicated that similar to the straight stay cable, the wavy stay cable with λ/D=2 and λ/D=6 can be induced the vibration easily at the same mass ratio and damping ratio. However, the vibration suppression effect of the wavy stay cables still exists. The vibration suppression effect of the wavy stay cable withλ/D=2 is better than that of the wavy stay cable with λ/D=6 . Compared with the straight stay cable, the maximum amplitude of the vortex-induced vibration can be reduced by 10%for the wavy-stay-cable, and the lock-in region is shortened. One of the main reasons is that the large variation of the modified wavy stay-cable surface can enhance the secondary spanwise vortex. Once the vortex vibration is induced, the large variation of the modified wavy stay-cable surface will interfere the vortex excitation so that the vortex shedding is controlled and the lift fluctuation is suppressed.%针对目前改变斜拉索表面形状来抑制斜拉索由风载荷引起的振动所遇到的问题,采用热线风速仪、激光位移器测量和烟线等实验方法,实验研究在Re=6800~20480区域内波浪型斜拉索涡致耦合振动及频率“锁定”现象,并引入直斜拉索作为对比。实验表明:在相同的质量比和阻尼比下,波浪型斜拉索λ/D=2和λ/D=6同直斜拉索同样容易被诱导振动,波浪型λ/D=2比波浪型λ/D=6的减震效果要好,和直斜拉索相比,波浪型λ/D=2的诱

  4. Parameters analysis for assistant cables of system for transient main cable and catwalk of long-span suspension bridges at construction stages

    Science.gov (United States)

    Li, Shengli; Ou, Jinping

    2009-03-01

    On the basis of static, dynamic and transient analysis for the prestressing cable structures, the parameters to control the vibration of the system for transient main cables and catwalk of some long-span suspension bridge at the construction stages with the assistant cables are investigated adopting the method of the finite element considering the geometry nonlinearity. The review and prospect to control vibration with assistant cables are summarized, the finite element modeling of the system for transient main cables and catwalk is established, and the influence of the position of the assistant cables, disposed fashion and the tensile forces upon the critical frequencies of the system for transient main cables and catwalk is researched. At the same time, the effect of the damp and the tensile forces of the assistant cables on the equivalent damping ratio of the system for transient main cables and catwalk inside and outside the plane is studied and the effect to control the vibration of the system is analysed. In the end, the influence of the transformation for the tensile forces about assistant cables upon those of the transient main cables and catwalk is also investigated. Results show that, to increase the critical frequencies of the system, the assistant cables should be laid vertically with the main cables and be located in interim span or between the tower and interim span, and to increase the amount of the assistant cables can increase the critical frequencies ,and to increase the rigidities of the assistant cables can improve the ones of the transient main cables but decrease the anti-torsion ability of the catwalks, and to increase the damp of the assistant cables can improve the vibration of the transient main cables inside and outside the plane but the result is little outside the plane, and in addition the effect of the rigidities of the assistant cables is larger outside the plane but is little inside the plane. The results also show that the

  5. Understanding and controlling wind-induced vibrations of bridge cables: Results from the Femern Crossing research project

    DEFF Research Database (Denmark)

    Georgakis, Christos T.; Jakobsen, J. B.; Koss, Holger;

    behind the cable vibrations that were observed on the cable-supported bridges forming part of the aforementioned crossings, Femern A/S commissioned a 5-year international collaborative research project, entitled “Understanding and controlling wind-induced vibrations of bridge cables”. The ultimate goal...... of the project has been the establishment of novel vibration mitigation schemes that could be readily, economically, and effectively implemented on a cable-supported bridge that might form part of the fixed link. In support of the proposed research, Femern A/S commissioned a new climatic wind tunnel, designed...... specifically for the testing of bridge cables. Five years after its initiation, the participants report the main results from the research project....

  6. 公轨两用部分斜拉桥耦合振动分析与行车舒适度评价%Analysis for Coupling Vibration and Evaluation for Comfort Degree of Driving on Part of Stayed-cable Bridges for both Highway Traffic and Light-rail Traffic

    Institute of Scientific and Technical Information of China (English)

    耿波; 袁佩; 尚军年

    2014-01-01

    以重庆东水门长江大桥为研究对象,建立车桥耦合动力系统,对其振动响应及行车舒适度进行研究。采用多刚体结构模拟车辆,空间杆系单元模拟桥梁,分别计算桥梁耦合轻轨车、桥梁耦合汽车、桥梁耦合轻轨车及汽车的动力响应,并对桥上轻轨车及汽车的行车舒适度作出评价。结果表明,轻轨车和汽车的行车舒适度均满足要求。%With Chongqing Dongshuimen Yangtze River Bridge as the object of research, this paper establishes a vehicle-bridge coupling dynamic system and studies its response to vibration and comfort degree of driving. The paper adopts multi-rigid-body structures to simulate vehicles and spatial link elements to simulate bridges, calculates dynamic responses of bridge coupling light-rail vehicles and automotives, respectively, and evaluates the comfort degree of driving of light -rail vehicles and automotives on bridges. The results show that the comfort degree of driving of both light-rail vehicles and automotives satisfies the requirements.

  7. 独塔空间缆索自锚式悬索桥动力特性研究%Study of Dynamic Characteristics of Single-Tower SelfAnchored Suspension Bridges with Spatial Cables

    Institute of Scientific and Technical Information of China (English)

    王玉田; 马宗志; 姜福香

    2011-01-01

    To study the dymamic characteristics of single-tower self-anchored suspension bridges with spatial cables, the Dagu River Shipping Channel Bridge (a self-anchored suspension bridge with spatial cables and with span arrangement (80 + 190 + 260 + 80) m) of Qingdao Bay Bridge was cited as an example, the finite element analysis software MIDAS Civil 2006 was used to establish the three-dimensional model for the whole bridge and the 10 orders of the natural vibration characteristcs of the bridge were caculated. The anlaysis of the dynamic characteristics reveals that in addition to the vibration characteristics of suspension bridges, the self-anchored suspension bridge also has the vibration characteristics of cable-stayed bridges, the global siffness of the bridge decreases to some extent as compared to that of a gound-anchored suspension bridge and the natural period of vibration of the bridge therefore becomes rather long.%为了研究独塔空间缆索自锚式悬索桥动力特性,以青岛海湾大桥大沽河航道桥[跨径(80+190+260+80)m的空间缆索自锚式悬索桥]为背景,利用MIDAS Civil 2006有限元分析软件建立全桥三维模型,计算出其前10阶自振特性.通过对其动力特性进行分析发现,该自锚式悬索桥除了具有悬索桥的振动特性之外,还有斜拉桥的振动特性;自锚式悬索桥的整体刚度相比地锚式悬索桥有所降低,因而其固有周期较长.

  8. Couplings in parametrically excited inclined cables systems

    OpenAIRE

    Michon, Guilhem; Berlioz, Alain; Lamarque, Claude-Henri

    2008-01-01

    Cables in stayed bridges are subjected to important dynamic solicitations for which dynamic model are now well established. Due to their design, such structures highlight resonance phenomena and instabilities frequently observed. Nevertheless, some structures exhibit important vibration amplitudes that can not be explained simply. Measurement recently performed on a bridge point a coupling of the cable with the deck or the pillar. The present paper suggests to consider the deck flexibility co...

  9. Buffeting response of long-span cable-supported bridges under skew winds. Part 1: theory

    Science.gov (United States)

    Zhu, L. D.; Xu, Y. L.

    2005-03-01

    A finite-element-based framework for buffeting analysis of long-span cable-supported bridges under skew winds is developed in the frequency domain utilizing the linear quasi-steady theory and the strip theory of aerodynamics in conjunction with the pseudo excitation method. A set of universal expressions for six components of buffeting forces is first derived in association with oblique cross-sections of bridge components, in which the buffeting forces are formed with respect to the wind coordinate system and then converted to those with respect to the structural coordinate system. Skew mean wind and three orthogonal components of velocity fluctuations can thus be easily handled without any further decomposition. The coherence between velocity fluctuations of wind turbulence at any two arbitrary spatial points is considered in the global wind coordinate system rather than in the global structural coordinate system. Aeroelastic stiffness and damping matrices due to self-excited forces are then taken into consideration in terms of the 18 flutter derivatives with respect to the oblique cross-sections. The pseudo-excitation method is finally employed to solve efficiently the fully coupled 3D buffeting problem of long-span cable-supported bridges under skew winds with the effects of multi-modes and spatial modes, inter-mode coupling and aerodynamic coupling, and the interaction among major bridge components being naturally included.

  10. Buffeting response of long-span cable-supported bridges under skew winds. Part 2: case study

    Science.gov (United States)

    Xu, Y. L.; Zhu, L. D.

    2005-03-01

    The finite-element-based framework for buffeting analysis of long-span cable-supported bridges under skew winds has been presented in Part 1 of this paper. The framework is now applied to the Tsing Ma Suspension Bridge in Hong Kong as a case study. The wind velocities and bridge responses measured by the Wind and Structural Health Monitoring System (WASHMS) of the bridge during Typhoon Sam in 1999 are first analyzed to find the skew wind characteristics surrounding the bridge, the modal damping ratios and acceleration responses of the bridge. The buffeting responses of the bridge under skew winds during Typhoon Sam are then computed using the wind characteristics and modal damping ratios measured from the field and the aerodynamic coefficients and flutter derivatives of the bridge deck and tower measured from the wind tunnel under skew winds. The computed acceleration responses of the bridge deck and cable are finally compared with the responses measured from the field. The comparison is found to be satisfactory in general and the case study forms a good practical demonstration for the verification of the proposed method for buffeting analysis of long-span cable-supported bridges under skew winds.

  11. Circuit bridging of digital equipment caused by smoke from a cable fire

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.J.; Anderson, D.J.

    1997-03-01

    Advanced reactor systems are likely to use protection systems with digital electronics that ideally should be resistant to environmental hazards, including smoke from possible cable fires. Previous smoke tests have shown that digital safety systems can fail even at relatively low levels of smoke density and that short-term failures are likely to be caused by circuit bridging. Experiments were performed to examine these failures, with a focus on component packaging and protection schemes. Circuit bridging, which causes increased leakage currents and arcs, was gauged by measuring leakage currents among the leads of component packages. The resistance among circuit leads typically varies over a wide range, depending on the nature of the circuitry between the pins, bias conditions, circuit board material, etc. Resistance between leads can be as low as 20 k{Omega} and still be good, depending on the component. For these tests, the authors chose a printed circuit board and components that normally have an interlead resistance above 10{sup 12} {Omega}, but if the circuit is exposed to smoke, circuit bridging causes the resistance to fall below 10{sup 3} {Omega}. Plated-through-hole (PTH) and surface-mounted (SMT) packages were exposed to a series of different smoke environments using a mixture of environmentally qualified cables for fuel. Conformal coatings and enclosures were tested as circuit protection methods. High fuel levels, high humidity, and high flaming burns were the conditions most likely to cause circuit bridging. The inexpensive conformal coating that was tested - an acrylic spray - reduced leakage currents, but enclosure in a chassis with a fan did not. PTH packages were more resistant to smoke-induced circuit bridging than SMT packages. Active components failed most often in tests where the leakage currents were high, but failure did not always accompany high leakage currents.

  12. Cluster analysis of stress corrosion mechanisms for steel wires used in bridge cables through acoustic emission particle swarm optimization.

    Science.gov (United States)

    Li, Dongsheng; Yang, Wei; Zhang, Wenyao

    2017-01-18

    Stress corrosion is the major failure type of bridge cable damage. The acoustic emission (AE) technique was applied to monitor the stress corrosion process of steel wires used in bridge cable structures. The damage evolution of stress corrosion in bridge cables was obtained according to the AE characteristic parameter figure. A particle swarm optimization cluster method was developed to determine the relationship between the AE signal and stress corrosion mechanisms. Results indicate that the main AE sources of stress corrosion in bridge cables included four types: passive film breakdown and detachment of the corrosion product, crack initiation, crack extension, and cable fracture. By analyzing different types of clustering data, the mean value of each damage pattern's AE characteristic parameters was determined. Different corrosion damage source AE waveforms and the peak frequency were extracted. AE particle swarm optimization cluster analysis based on principal component analysis was also proposed. This method can completely distinguish the four types of damage sources and simplifies the determination of the evolution process of corrosion damage and broken wire signals.

  13. Numerical Analysis of Unloaded Cable of Suspension Bridge%悬索桥空缆状态数值分析

    Institute of Scientific and Technical Information of China (English)

    左宪章; 李林; 肖军

    2012-01-01

    本文主要介绍悬索桥空缆状态数值分析方法.主要包括:基于无应力状态分析法和悬链线理论求解悬索桥空缆线形的数值迭代方法;等高、不等高悬链线求解方法及利用matlab编制相应程序实现空缆线形数据的求解.%This paper focuses on the introduction of numerical analysis method of unloaded cable of suspension bridge. Mainly includes: analysis based on stress-free, solving numerical iterative method of unloaded cable shape of suspension bridge with catenary theory;Catenary solution method with equal height and unequal height as well as preparing the corresponding program by using matlab to achieve the solution of unloaded cable shape data.

  14. Modeling and Experiments of Spray System for Cable Painting Robot

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jia-liang; Lü Tian-sheng; LI Bei-zhi

    2008-01-01

    Many cable-stayed bridges have been built in the world in the past decades,and cable-stayed structures have been adopted in many large constructions.The cable painting robot is safe and economically efficient for stay cable maintenance.In order to satisfy the need for spraying cables in hiigh attitude,an automatic cable spray system for cable painting robots is presented in this paper.Using the βdistribution,paint thickness distribution on a cylinder surface is modeled.The spray gun's number,angle and movement are analyzed to get coat evenness.Then a robotic spray system engineering prototype has been developed,which includes a cable electric running climbing base,a spray cover,four airless spray guns and a pressurized paint container.Experiments indicate that four airless spray guns can guarantee good coat quality for general stay cables.The field tests have been successfully conducted on Nanpu Bridge,Shanghai.

  15. Understanding of bridge cable vibrations and the associate flow-field through the full-scale monitoring of vibrations and Wind

    DEFF Research Database (Denmark)

    Acampora, Antonio

    such as cable vibrations amplitude, cables frequencies involved in the vibrations, wind directions, wind speeds and rainfall rates. Those indications are used to select full-scale cables vibrations for further analyses. In particular, aerodynamic damping is investigated by means of system identification...... procedures based on the Markov-Block-Hankel matrix. From identified aerodynamic damping from full-scale data, back-calculated aerodynamic coefficients of Øresund Bridge cable were obtained. Wind tunnel tests were performed on a scaled model of the actual cables both in dynamic and static tests to investigate...

  16. Super and Combinatorial Harmonic Response of Flexible Elastic Cables with Small Sag

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.; Kirkegaard, Poul Henning

    2002-01-01

    The paper deals with the analysis of cables in stayed bridges and TV-towers, where the excitation is caused by harmonically varying in-plane motions of the upper support point with the amplitude ;. Such cables are characterized by a sag-to-chord-length ratio below 0·02, which means that the lowes...

  17. 辅助墩对混合梁斜拉桥非线性静动力特性的影响%Impacts of auxiliary pier upon non-linear static and dynamic characteristics of single staved-cable bridge with composite beam

    Institute of Scientific and Technical Information of China (English)

    钟加峰

    2012-01-01

    利用有限元分析软件建立了混合梁独塔斜拉桥的空间模型,分析了混合梁独塔斜拉桥在有、无辅助墩情况下的非线性静动力特性的异同,讨论了在有、无辅助墩情况下对混合梁独塔斜拉桥非线性静动力特性的影响,得出了有指导意义的结论。%The paper establishes spatial model of single stayed-cable bridge with composite beam by using finite element analysis software, ana- lyzes similarities and differences of non-linear static and dynamic characteristics of single stayed-cable bridge with composite beam under the con- dition of with and without auxiliary pier, and discusses the impacts of within and without auxiliary pier upon non-linear dynamic and static char- acteristics of single stayed-cable bridge with composite beam, and finally draws some guiding conclusions.

  18. Optimization of System Transformation of Cable-stayed and Self-anchored Suspension Compound System%斜拉-自锚式悬索组合体系的体系转换优化

    Institute of Scientific and Technical Information of China (English)

    李海燕

    2012-01-01

    研究目的:对于新型体系桥梁的施工,应在施工前对桥梁的结构体系形式进行分析、研究,根据桥梁特点对施工方案进行优化,本文以汉中西二环斜拉-自锚式悬索组合体系桥为基础,分析、研究了新组合结构的结构特点及优化过程.研究结论:通过研究优化,满足了施工的安全、合理、可操作性等诸方面要求,消除了施工可能存在的巨大隐患,保证施工能安全、顺利进行.新型桥梁结构,应在施工前对桥梁结构特点进行分析,对施工方案进行优化,以更好地理解桥梁的结构特点,从而更加安全、可靠地完成施工过程.%Research purposes: For construction of the new - type system bridge, the analysis and research should be done on the structural system pattern before the construction and the construction plan should be optimized according to the characteristics of the bridge construction. Based on the cable - stayed and self - anchored suspension of the Hanzhong Second Ring Road, the analysis and study were done on the structure features of the new composite structure and the optimization process. Research conclusions:By research and optimization of the construction plan,the requirements of the construction safety, rationality and operability were met to make the construction going ahead smoothly and safely. For construction of new -type bridge structure, it was necessary to analyze the characteristics of the bridge structure and optimize the construction plan before construction. The characteristics of the bridge structure could be better understood by doing research on the optimization of the construction plan before construction. In this way, the construction could be finished safely and reliably.

  19. Understanding and simulating vibrations of plain bridge cables under varying meteorological conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia

    of the cable, which becomes large in amplitude and is accompanied by negative aerodynamic damping. On the other hand, when the surface tension of the cable is too low a steady upper and lower non-coherent water rivulets form. These are not sufficient for the excitation to get started, independently...... of the cable mass. The cable model was in fact manifestly stable and exhibited positive aerodynamic damping throughout the whole range of tested Reynolds number, being accompanied by limited peak-to-peak amplitude. A generalized quasi-steady 3 DOF analytical model for the prediction of the aerodynamic...... velocity. Based on the analytical solution of the eigenvalue problem, by applying the Routh-Hurwitz criterion, an expression of the minimum structural damping and structural stiffness required to prevent aerodynamic instabilities of galloping- and static divergence-type respectively are given....

  20. Comparison of the aerodynamics of bridge cables with helical fillets and a pattern-indented surface

    DEFF Research Database (Denmark)

    Kleissl, K.; Georgakis, C.T.

    2012-01-01

    of the surface pattern introduce a wind-angle of attack dependency that leads to a prediction of Den Hartog galloping instability. For yawed positions, flow transition was found to be independent of the relative cable-wind angle and therefore only governed by the along-wind flow velocity. The helically filleted...

  1. Non-linear stochastic response of a shallow cable

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther; Nielsen, Søren R.K.

    2004-01-01

    The paper considers the stochastic response of geometrical non-linear shallow cables. Large rain-wind induced cable oscillations with non-linear interactions have been observed in many large cable stayed bridges during the last decades. The response of the cable is investigated for a reduced two......, the chord elongation is modelled as a narrow-banded Gaussian stochastic process, and it is shown that all the indicated harmonic solutions now become instable with probability one. Instead, the cable jumps randomly back and forth between the two in-plane and the whirling mode of vibration. A theory...... component of the support point motion relative to a safe domain determined from the harmonic analysis of the problem....

  2. 大跨度斜拉桥的pushover分析%Pushover analysis for large span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    宋力; 张敏; 秦泗凤; 宋春杰

    2014-01-01

    为验证pushover方法对于大跨度斜拉桥的适用性,选用多种侧向载荷加载方式对具体斜拉桥进行分析,采用四条典型的地震波对结构进行动力时程分析.并将分析结果与时程分析结果进行了对比.Pushover方法较为简便,而非线性时程分析方法计算复杂、耗时长,在结构中应用并不广泛.结果表明,传统的均匀载荷分布模式的计算结果与时程分析结果对比存在误差,由于模态pushover分析方法和振型载荷分布模式考虑了高阶振型的影响,所得pushover曲线与时程分析所得的曲线基本吻合.说明pushover方法对结构进行抗震性能评估时,精度可以满足工程需要;选择合适的侧向载荷分布模式,可以有效提高pushover分析的精度.

  3. Nonlinear Dynamical Analysis for the Cable Excited with Parametric and Forced Excitation

    Directory of Open Access Journals (Sweden)

    C. Z. Qian

    2014-01-01

    Full Text Available Considering the deck vibration effect on the cable in cable-stayed bridge, using nonlinear structure dynamics theory, the nonlinear dynamical equation for the stayed cable excited with deck vibration is proposed. Research shows that the vertical vibration of the deck has a combined parametric and forced excitation effect on the cable when the angle of the cable is taken into consideration. Using multiscale method, the 1/2 principle parametric resonance is studied and the bifurcation equation is obtained. Despite the parameters analysis, the bifurcation characters of the dynamical system are studied. At last, by means of numerical method and software MATHMATIC, the effect rules of system parameters to the dynamical behavior of the system are studied, and some useful conclusions are obtained.

  4. Finite-element (FE modelling of bridge dynamics from exposure to moving load

    Directory of Open Access Journals (Sweden)

    G.M. Kadisov

    2013-12-01

    Full Text Available Solutions to the problem of cable-stayed bridge dynamics are received and analysed on the basis of two modelling options. According to the first one space-time finite-elements are used. The first three bridge vibration modes are shown to study cable-stayed bridge fluctuations when exposed to the vertical force moving at a constant speed and compile charts of time history strains in fixed sections of a deck. According to the second option a suspended superstructure is represented by a fold with absolutely rigid transverse membranes in joints of cables, a bridge tower is represented by a beam. Natural modes of the bridge are received by a solution of homogeneous system equations of the mixed method. Nodal lines of a fold for the first four natural modes are shown. The comparative description of applicability of the above-mentioned methods of solving problems of dynamics affected by moving load is given.

  5. Development of a new-type super-long bridge; Chochotaikyo ni tekigoshita shinkeishiki kyoryo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K.; Shimodoio, H.; Saito, T.; Nogami, C.; Oryu, T.; Morikawa, M. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1998-12-20

    In order to realize large strait-crossing projects in the near future, it is necessary to develop a new type of super-long span bridge, which has a superior aerodynamic stability and is cost effective. We have been proposed a new type of suspension bridge using a 2-box and 1-box combined girder to apply to such a project And this time, we propose the cable stayed suspension bridge using a 2- box and 1-box combined girder aiming for improvement of aerodynamic stability with increase of torsional rigidity. This paper describes the performance of this cable stayed suspension bridge obtained from aerodynamic analysis. As a result, it can be confirmed that this newly developed cable stayed suspension system has fine characteristics and shows more potential for economical construction than the early proposed suspension system. (author)

  6. Analysis and Study on Vibration of Pedestrian Cable Suspended Bridges%人行索道桥振动分析研究

    Institute of Scientific and Technical Information of China (English)

    何晓琴

    2015-01-01

    人行索道桥主梁刚度小、自重轻,行人过桥时易产生振动,影响桥梁正常使用。以某景区人行索道桥为研究对象,对其 TMD 阻尼器安装前和安装后2个工况进行人桥耦合振动分析研究,以验证结构振动特性和阻尼器安装效果。%The girders of pedestrian cable suspended bridges exhibit small rigidity and dead weight,and vibration is easy to produce when pedestrians walk across bridges,so normal operation of bridges is affected.With a pedestrian cable suspended bridge in some scenic region as an object of study,this paper analyzes and studies pedestrian -bridge coupling vibration under 2 operating conditions before and after installation of TMD dampers to validate vibration properties of structures and installation effect of dampers.

  7. Full Model Wind Tunnel Study on the Xia-Zhang Bridge Under Operation Stage

    Directory of Open Access Journals (Sweden)

    Ayad T. Saeed

    2010-01-01

    Full Text Available Problem statement: Long-span cable-stayed bridges under service and particular construction conditions are very susceptible to wind action due to their great flexibility, so the aerodynamic stability is becoming a major concern in the design and construction phrases. Cable-stayed bridges may exhibit wind-induced vibration phenomena such as flutter, buffeting and vortex oscillation under wind excitation. The study concentrated on the issues concerning the aerodynamic response of Xia-Zhang cable-stayed Bridge to make it safe and stable under wind action. Although there have been accumulating experience in the building of cable-stayed bridges and research on wind-resistant stability in Chinese Mainland, most of the research focuses on inland cable-stayed bridges or littoral ones of mid-length, but not on littoral ones whose main span is over 600 m. Therefore, wind-resistant performance research of north branch bridge of Xia-Zhang cross-sea Bridges is very necessary and important for its wind-resistant stability, safety and applicability in the operation condition. Approach: This study mainly presented the wind tunnel test program of the Xia-Zhang Bridge aeroelastic full model, including test method, test contents, test results and so on. Results: The test results contained Root Mean Square (RMS of accelerations and displacements as well as average values of displacements. Conclusion: The conclusions were as follows: (a In the uniform flow field, under the condition of entire bridge without rail may vibration divergence occur when α = 3°, V>122 m sec-1. (b No vortex-induced vibration with extreme amplitudes or static collapsing was detected in all the testing conditions. (c In the turbulent flow field, there were very obvious buffeting phenomena. Responses to turbulence are quite intense.

  8. Identification from the Natural Response of Vasco Da Gama Bridge

    DEFF Research Database (Denmark)

    Cunha, A.; Caetano, E.; Brincker, Rune;

    2004-01-01

    This paper describes the reanalysis of the ambient vibration data of Vasco da Gama cable-stayed bridge with the purpose of testing the efficiency and accuracy of two recent and promising identification methods in a large application: the Frequency Domain Decomposition (FDD) and the Stochastic...

  9. Environmental variability study on the measured responses of Runyang Cablestayed Bridge using wavelet packet analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The structural damage alarming method based on wavelet packet energy spectrum (WPES) for long-span cable-stayed bridges is presented through combination of ambient vibration test and wavelet packet analysis. The environmental variability in the measured WPES and damage alarming indices ERVD of the Runyang Cable-stayed Bridge are discussed in detail using the wavelet packet analysis of the measured acceleration responses of the bridge under daily environmental conditions. The analysis results reveal that the actual environmental conditions including traffic loadings, environmental temperature and typhoon loadings have remarkable correlations with the measured WPES. The changes of environmental temperature have a long-term trend influence on the WPES, while the influences of traffic and typhoon loadings on the measured WPES of the bridge present instantaneous changes because of the nonstationary properties of the loadings. The analysis results of the measured responses further reveal that the damage alarming indices ERVD can sensitively reflect the influences of environmental temperature and typhoon loadings on the dynamic properties of Runyang Cable-stayed Bridge. Therefore, the proposed structural damage alarming indices ERVD under ambient vibrations are suitable for real-time damage alarming for long-span cable-stayed bridges.

  10. Research on the Vibration Serviceability of a Cable-stayed Footbridge Based on Field Measurement%基于实测响应的斜拉人行桥人致振动舒适度研究

    Institute of Scientific and Technical Information of China (English)

    陈波; 王鑫; 刘浩; 胡健; 张文龙; 黄雨田

    2013-01-01

    The vibration serviceability of a large span cable-stayed footbridge was actively investigated.The basic information of a real large span cable-stayed footbridge was firstly introduced.The analytical model of the footbridge was established based on finite element method and the dynamic properties are computed.The dynamic properties of the footbridge were measured subjected to ambient excitation.In addition,the dynamic responses of the footbridge under humaninduced loading were also tested.The vibration serviceability of the cable-stayed footbridge was evaluated in line with the British Standard BS5400.The made observations indicate that the dynamic responses of the footbridge is obvious and discomfort feeling can be observed to some extent.%研究了大跨轻柔斜拉人行桥人致振动舒适度问题.基于有限元方法建立了某大跨度斜拉人行桥的分析模型并进行了动力特性分析;进行了该桥在环境脉动激励作用下的动力特性实测和不同人行荷载作用下的动力响应测试;依据英国规范BS5400评价了该桥的振动舒适度状况.结果表明,该桥在人行荷载作用下存在较为显著的振动响应和一定程度的振动舒适度问题.

  11. FRACTURE FAILURE MODES ANALYSIS OF BRIDGE CABLES%桥梁缆索特殊断口失效机理分析

    Institute of Scientific and Technical Information of China (English)

    左海宏; 田飞龙

    2012-01-01

    为延长桥梁缆索的使用寿命,必须确定其失效机理.通过调研国内外大量的桥检资料,将现场取回的桥梁缆索钢丝做断口电镜扫描( SEM)后,对缆索钢丝断口的两种特殊类型(阶梯状断口和杯口状断口)进行了失效机理分析.结果表明,阶梯状断口主要是由于腐蚀疲劳所致;在钢丝无明显锈蚀,当外界荷载超过钢丝的极限承载力时出现塑性破坏是导致杯口状断口的主要原因.%To lengthen the service life of bridge cables, its failure modes must be ascertained. According to investigation of bridge-testing data from home and abroad, and fracture analysis of steel wires of bridge cables fetched from testing ground using electron microscope scanning, two special fracture (cascade fracture & cup and cone-shaped fracture) failure modes of steel wires of bridge cables have been analyzed. The results show that cascade fracture mainly arises from corrosion fatigue;the main reason that leads to cup and cone-shaped fracture is plastic failure which is caused when steel wire corrosion is not serious and external load exceeds ultimate load carrying capacity of steel wire.

  12. Out-of-plane free vibration analysis of a cable-arch structure

    Science.gov (United States)

    Kang, H. J.; Zhao, Y. Y.; Zhu, H. P.

    2013-02-01

    Cable-arch structure has been widely used in many long-span structures such as cable roofs and cable-stayed arch bridges, but its dynamics is still not well understood. In this paper, the out-of-plane dynamic behavior of a cable-arch structure is investigated. The equations governing the out-of-plane free vibration of the structure are derived using d'Alembert's principle. A transfer matrix method is used to solve the governing equations and determine the frequencies of the out-of-plane vibration. The theories are then used to study two specific cases: free vibration of a model cable-arch and simulation of an arch erection process. The effects of some key parameters of cable and arch, such as tension of cable and radius, open-angle and shape of arch, are examined. The results indicate that in-plane and spatial cables can largely improve the out-of-plane dynamic behavior of arch structures, which are further verified by analyzing the out-of-plane buckling of cable-arch structures. The present work should be valuable and significant not only for the fundamental research but also engineering design of roofs and bridges.

  13. Calculations in bridge aeroelasticity via CFD

    Energy Technology Data Exchange (ETDEWEB)

    Brar, P.S.; Raul, R.; Scanlan, R.H. [Johns Hopkins Univ., Baltimore, MD (United States)

    1996-12-31

    The central focus of the present study is the numerical calculation of flutter derivatives. These aeroelastic coefficients play an important role in determining the stability or instability of long, flexible structures under ambient wind loading. A class of Civil Engineering structures most susceptible to such an instability are long-span bridges of the cable-stayed or suspended-span variety. The disastrous collapse of the Tacoma Narrows suspension bridge in the recent past, due to a flutter instability, has been a big impetus in motivating studies in flutter of bridge decks.

  14. 多功能独塔斜拉桥--保定桥%Multifunction Cable Stayed Bridge with only one pylon--Baoding Bridge

    Institute of Scientific and Technical Information of China (English)

    焦占武

    2006-01-01

    @@ 海河综合开发改造是天津市总体发展战略的重要组成部分,是天津整个经济上水平的需要.为进一步加快城市建设,提高城市载体功能,更好地塑造现代化国际港口大都市形象,天津市委、市政府做出了综合开发海河的伟大决策.努力把海河建成独具特色、国际一流的服务型经济带、文化带和景观带.保定桥正是位于海河之上的一艘风帆乍起的巨船,载着天津城市建设者的辛勤与梦想开始远航.

  15. Study on Removal Method of Inclined Bents and Effect of Tuned Mass Damper of Long-span Cable-stayed Bridge(Megami Bridge)

    OpenAIRE

    北原, 雄一

    2009-01-01

    長大斜張橋の計画において架設工法を決定する場合,架設地点の地形状況,気候等の現地条件および使用可能な架設技術を基に,その橋梁に最も適した架設工法が決定される.さらに長大斜張橋では,主桁架設にバランシング工法が採用されることが多いので,架設時の耐風安定性の検討も不可欠となる.このように多くの検討すべき事項が架設工法に影響を与えるため,過去の長大斜張橋の架設に関する技術情報では不十分であり架設地点の状況に応じた検証が必要となる.  このため,本研究は,長崎県の長崎湾に架設された女神大橋を研究対象として架設地点に応じた斜ベントの撤去工法の実証と架設系,完成系における制振装置の効果検証を目的とする....

  16. Experimental Study of Anchor Tensile Plate Cable Anchorage System in Concrete Girder of Actual Bridge%锚拉板式混凝土索梁锚固体系实桥试验研究

    Institute of Scientific and Technical Information of China (English)

    石雪飞; 周军勇; 胡可; 阮欣

    2016-01-01

    为研究索力作用下锚拉板式混凝土索梁锚固体系的受力性能,以五河淮河大桥为工程背景进行实桥试验和有限元分析。选取该桥0号节段混凝土锚拉板进行实桥试验,测试锚拉板在分级索力作用下的应力及变形,采用ANSYS软件建立有限元模型,计算2种连接方式下(考虑混凝土主梁与钢锚拉板的固结与滑移)的应力分布与锚拉板变形。结果表明,钢锚拉板与混凝土主梁在固结或滑移连接方式下,斜拉索锚固区域的应力分布基本相同,但连接区域的应力分布及锚拉板变位差别显著;测试的锚拉板应力和位移与荷载呈现良好线性相关性,最大测点应力296 M Pa ,结构仍处于弹性工作状态;锚拉板应力分布的实测值与有限元计算值吻合,板件应力扩散和传递效果良好;连接区域的实测应力和位移与滑移方式下的有限元分析较吻合,但摩擦系数不主导滑移结果。%To study the mechanical performance of the anchor tensile plate cable anchorage system in concrete girder under the action of the cable tension ,the test and finite element analysis of the steel anchor tensile plate stay cable anchorage system in the concrete main girder of the actu‐al bridge of Wuhe Huaihe River Bridge were carried out .The anchor tensile plate in the segment No .0 of the main girder of the bridge was selected and tested .The stress and displacement of the anchor tensile plate under the different levels of the stay cable tension were measured .The finite element model for the anchor tensile plate was set up ,using the software ANSYS and the stress distribution and the anchor tensile plate displacement under the 2 kinds of the connecting ways (the rigid fixity and sliding connecting of the anchor tensile plate with the concrete main girder ) were calculated .The results show that under the connecting ways of the rigid fixity or sliding connect‐ing of the anchor

  17. State-of-the-art of long-span bridge engineering in China

    Institute of Scientific and Technical Information of China (English)

    XIANG Haifan; GE Yaojun

    2007-01-01

    This paper introduces the state-of-the-art of long-span bridge engineering in China with emphases on recent long-span bridge projects,bridge deck configuration and material,design codes of long-span bridges and improvement of aerodynamic performance.The recent long-span bridge projects include thirty-eight completed suspension bridges,cable-stayed and arch bridges with a main span over 400 m,and eighteen major bridges are under construction.The bridge deck configuration and material,with prestressed concrete decks,steel-concrete composite decks and steel box decks together with several popular cross-sections,are presented.The third part briefly outlines four design codes,including static and dynamic design for highway long-span bridges,and the recent engineering experiences gained from several aerodynamic vibration control projects of long-span bridges are shared in the last part.

  18. Study on structural system of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Pei Minshan; Yuan Hong; Xu Liping; Zhu Bin

    2009-01-01

    Sutong Bridge, whose layout is [ (100 + 100 + 300) + 1 088 + ( 300 + 100 + 100) ] m, marks the largest span of cable-stayed bridges in the world. The complex natural condition at the bridge site and the strict requirements for resistance of wind and seismic action make it crucial to choose a favorable structural system to assure the function and safety of the bridge. The comparison among several optional structural systems for Sutong Bridge is illustrated. After detailed analysis is carried out for viscous damper and hydraulic buffer, super liquid viscous damper with additional displacement limitation is designed for the first application in bridge engineering. The parameters for the damper is analyzed and studied and the dampers are installed suecessfuUy after quality tests.

  19. 缆索吊装在高速公路箱形拱桥中的应用%The Application of Hoisting Cable on the Box Arch Bridge of Highway

    Institute of Scientific and Technical Information of China (English)

    刘晓燕

    2013-01-01

    缆索吊装指的是利用悬挂的缆索运输和安装构件的施工方法,本文介绍了缆索吊装在高速公路大跨径拱桥施工中的应用。%The hoisting cable refers to the method of using the suspended cable to transport and instal components in the co-nstruction. This article introduces the hoisting cable applied in the highway construction of long-span arch bridge.

  20. Construction and control technology of the main bridge superstructure of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Hong; Luo Chenbin; Zhang Yongtao; You Xinpeng

    2009-01-01

    The Sutong Yangtze River Bridge (short as Sutong Bridge) is now the largest span cable-stayed bridge in the world. The construction of the superstructure of the middle bridge covered several stages including erection of the big block girders for the side span, assistant span and tower area, erection of standard girders and closure of the middle span. The big block girders were hoisted by a floating crane, and the standard girders were hoisted by a double crane system on the deck. The pushing assistant method was adopted for the middle span closure construction. Furthermore, key technologies and innovative methods used in the processes of girder erection and cable assemblage in all stages were expatiated systematically. An all-stage self- adaptive geometry control method was used in the construction process. By accurately controlling the unstressed dimensions and shape of all structural components in each step, and realization that the control system and the controlled system adapt to each other, the goal was to make control of the final line shape and inner force of the bridge structure achievable. Two solutions, including GPS based and total station based dynamic geometry monitoring systems, were used to resolve the measure problem under the wide-range of wind-induced vibrations in the long cantilever state. Finally, research on the wind-induced vibration of the superstructure during the construction period was executed. Buffeting response analysis to the longest single and double cantilever states were carried out. The analysis and evaluation of wind resistance safety of the main girders under the longest single cantilever state was made, and corresponding wind resistance measures were suggested. The as-built geometric error and cable force error were controlled in a required design range, and this whole technological achievement can be a benchmark for construction of other large span cable-stayed bridges in the future.

  1. Design and Analysis of Main Saddle Structure for Self-anchored Suspension Bridge with Spatial Cables%空间缆索悬索桥主鞍座结构设计与分析

    Institute of Scientific and Technical Information of China (English)

    李建慧; 李爱群; 袁辉辉; 李喜平

    2009-01-01

    以南京江心洲大桥为工程背景,对空间缆索自锚式悬索桥主鞍座的相关问题进行研究.以大型通用有限元程序为平台,采用二次开发技术,建立精细化有限元模型,在此基础上采用合理的加载模式对其进行空间受力分析,并阐述与空间主鞍座相匹配的主缆切点简化修正方法.结果表明:空间主缆在成桥状态对主鞍座横向力的作用会造成鞍槽外侧壁应力大于内侧壁的应力;主缆横向体积力会对主鞍座压紧装置和鞍体产生梯度分布的竖向挤压力;自锚式悬索桥体系转换过程中缆索的几何非线性效应显著,体现在空缆到成桥状态主缆与主鞍座空间切点位置会有较大的变化.%Based on the Jianxinzhou Bridge in Nanjing, the issues related to the main saddle of the serf-anchored suspension bridge with spatial cables were studied. Refinement finite element model was established with secondary development technology based on the platform of general finite element program, reasonable load pattern was used for its spatial mechanical analysis, and the spatial main cable tangenty point correction method which matched with the main saddle was also discussed. The result shows that (1) external lateral wall stress of saddle groove is higher than the internal wall stress because of the role of lateral force from the main cable in the ~mished bridge state; (2) horizontal volume force of the main cable can generate a gradient distribution of vertical extrusion pressure on the saddle clamping device and the main saddle body; (3) the geometric nonlinear effect of self-anchored suspension bridge cable system in the constroction process is significant, which reflects from that the spatial tangent point position of main cable with main saddle changes a lot from free cable to finished cable state.

  2. Environmental variability study on the measured responses of Runyang Cablestayed Bridge using wavelet packet analysis

    Institute of Scientific and Technical Information of China (English)

    DING YouLiang; LI AiQun; LIU Tao

    2008-01-01

    The structural damage alarming method based on wavelet packet energy spectrum (WPES) for long-span cable-stayed bridges is presented through combination of ambient vibration test and wavelet packet analysis.The environmental variability in the measured WPES and damage alarming indices ERVD of the Runyang Ca-ble-stayed Bridge are discussed in detail using the wavelet packet analysis of the measured acceleration responses of the bridge under daily environmental condi-tions.The analysis results reveal that the actual environmental conditions includ-ing traffic Ioadings,environmental temperature and typhoon Ioadings have re-markable correlations with the measured WPES.The changes of environmental temperature have a long-term trend influence on the WPES,while the influences of traffic and typhoon Ioadings on the measured WPES of the bridge present instan-taneous changes because of the nonstationary properties of the Ioadings.The analysis results of the measured responses further reveal that the damage alarm-ing indices ERVD can sensitively reflect the influences of environmental tempera-ture and typhoon Ioadings on the dynamic properties of Runyang Cable-stayed Bridge.Therefore,the proposed structural damage alarming indices ERVD under ambient vibrations are suitable for real-time damage alarming for long-span ca-ble-stayed bridges.

  3. Design and construction of scour protection for deep-water group pile foundation structures of two pylons in the Sutong Bridge project

    Institute of Scientific and Technical Information of China (English)

    He Ping; Guan Yijun; Zhang Xiongwen; Zhang Qun; Zhou Jianhua

    2009-01-01

    Sutong Bridge, as a world-record cable-stayed bridge with its main span exceeding 1 000 m constructed in Yangtze River estuary region in China, is located at a site with complicated hydrologic conditions and poor geotechnical conditions and therefore, scour protection will be a decisive factor for ensuring smooth and successful construction of this bridge. This paper, starting from structural description of deep-water group pile foundation, analyzes impact to the bridge safety introduced by scour and its protection and further presents different solutions of scour protection for foundation structures of this bridge.

  4. Comparison of the aerodynamics of bridge cables with helical fillets and a pattern-indented surface in normal flow

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos

    2011-01-01

    -wind induced vibrations (RWIVs). The modifications are based on re-search undertaken predominantly in Europe and Japan, with two different systems prevailing; HDPE tubing fitted with helical surface fillets and HDPE tubing with pattern-indented sur-faces. In the US and Europe, helical fillets dominate, whilst...... pattern indented surfaces are more common in Asia. Research into the effectiveness of helical fillets and pattern-indented surfaces has shown that, besides their potential to suppress rain-wind induced vibrations, they are also modestly reducing drag forces at design wind velocities. This is of particular...... that different researchers, in different facilities, with varying wind-tunnel flow characteristics and performance, have developed each separately. As part of a comprehensive review of the aerodynamics of existing cable surface modifica-tions, the resulting static force coefficients obtained from wind...

  5. 五河定淮淮河特大桥索鞍安装施工技术%The five river Huai River Bridge saddle Installation Technology

    Institute of Scientific and Technical Information of China (English)

    梁学平

    2014-01-01

    五河定淮淮河特大桥斜拉索为同截面回转拉索体系,采用钢绞线拉索,以索塔斜置鞍座进行单向索锚索。鞍座为桥梁设计阶段专项研发产品,在此之前鞍座的定位安装无借鉴资料,故我项目针对索鞍安装定位存在的问题进行了分析研究,为索鞍式斜拉桥的推广应用提供依据。%Five Rivers given the Huai Huai River Bridge cable-stayed the same cross-section rotary cable system, strand cable, sarasota inclined saddle unidirectional cable anchor cable. Special saddle for the bridge design stage R & D products, before this saddle positioning instal no draw on data. Therefore, my project for the cable saddle instal ation positioning the problems analysis, To provide a basis for the promotion of the cable-stayed bridge saddles applications.

  6. Yibin Yangtze river bridge main cable wire strands of standard production process%宜宾南溪长江大桥主缆索股标准丝制作工艺

    Institute of Scientific and Technical Information of China (English)

    周曾令

    2015-01-01

    主缆是悬索桥的承重结构,是其关键结构之一,素有“生命线”之称。文章主要探究了宜宾南溪长江大桥主缆索股标准丝生产线设计原理及制作工艺,仅供参考。%Is main cable suspension bridge bearing structure, it is one of the key structure, known as the"lifeline". This paper mainly explores the yibin rival south Yangtze river bridge main cable wire strands of standard principle and production technology, production line design are for reference only.

  7. I-5/Gilman advanced technology bridge project

    Science.gov (United States)

    Lanza di Scalea, Francesco; Karbhari, Vistasp M.; Seible, Frieder

    2000-04-01

    The UCSD led I-5/Gilman Advanced Technology Bridge Project will design and construct a fully functional traffic bridge of advanced composite materials across Interstate 5 in La Jolla, California. Its objective is to demonstrate the use of advanced composite technologies developed by the aerospace industry in commercial applications to increase the life expectancy of new structures and for the rehabilitation of aging infrastructure components. The structure will be a 450 ft long, 60 ft wide cable-stayed bridge supported by a 150 ft A-frame pylon with two vehicular lanes, two bicycle lanes, pedestrian walkways and utility tunnels. The longitudinal girders and pylon will be carbon fiber shells filled with concrete. The transverse deck system will consist of hollow glass/carbon hybrid tubes and a polypropylene fiber reinforced concrete deck with an arch action. Selected cables will be composite. The bridge's structural behavior will be monitored to determine how advanced composite materials perform in civil infrastructure applications. The bridge will be instrumented to obtain performance and structural health data in real time and, where possible, in a remote fashion. The sensors applied to the bridge will include electrical resistance strain gages, fiberoptic Bragg gratings and accelerometers.

  8. Determination of aerodynamic damping of twin cables in wet conditions through passive-dynamic wind tunnel tests

    DEFF Research Database (Denmark)

    Eriksen, Mads Beedholm; Mattiello, E.; Georgakis, Christos T.

    2013-01-01

    Moderate amplitude cable vibrations continue to be reported on the cable-stayed Øresund Bridge, despite the presence of helical fillets and dampers. The vibrations are particularly notable in wet conditions, which would suggest a form of rain-wind induced vibrations (RWIV). A statistical...... operational modal analysis of the monitored vibrations revealed, in certain conditions and for specific wind velocities, the presence of negative aerodynamic damping.To investigate the observed aerodynamic damping of the twin cable arrangement further, a series of 1:2.3 scale passive-dynamic wind tunnel tests...... was performed at the DTU/FORCETechnology ClimaticWind Tunnel facility in Kgs. Lyngby, Denmark. Tests were performed for both dry and wet conditions, with and without helical fillets. The specific relative cable-wind angle tested was identified as critical from the aforementioned full-scale monitoring...

  9. Fatigue Analysis of Details in Steel Deck of Cable Stayed Bridges%斜拉桥钢桥面板细节疲劳分析

    Institute of Scientific and Technical Information of China (English)

    颜飞; 陈惟珍

    2012-01-01

    正交异性钢桥面板存在大量焊接疲劳薄弱坏节,活载反复作用下容易发生疲劳破坏,国内外针对钢桥面板的力学性能及细节疲劳研究主要考虑第二结构体系效应,通过混合有限元方法模拟斜拉桥第一结构体系效应对疲劳应力的影响,以全梁段板壳单元代替相应位置的鱼骨主梁,采用蒙特·卡洛方法模拟车流,加载于疲劳细节的应力影响面,选用Eurocode疲劳曲线验算各疲劳细节的累积损伤,结果表明受压梁段由于第一体系效应影响可不进行疲劳验算,而对受拉梁段钢桥面系进行疲劳评估时可以忽略全桥结构体系效应的影响.%There are a large number of welded fatigue weak points in steel deck which are prone to fatigue damage under cyclic loads. The second structural system effect has been mainly considered in domestic and international study of the mechanical properties and details fatigue of steel deck. The first structural system effect of fatigue stresses by replacing the corresponding position of fish bone beams with whole shell element through hybrid finite element method;and choosing the fatigue curve of Eurocode to calculate the cumulative damage of fatigue details. The results show that compression beam segment is no need for fatigue checking;while the effect of whole structural system can be ignored in fatigue assessment of tesion beam segment of steel deck.

  10. Project STAY.

    Science.gov (United States)

    Smith, Bert Kruger

    Project STAY (Scholarships to Able Youth), located in the barrio of San Antonio, Texas, helps young people stay in school beyond the secondary grades. The project provides outreach services to meet the needs of the students. Its primary service is to act as an advocate for these young people. The project recruits all types of youth from families…

  11. Influences of Deviation of Gravity and Cable Tension Force on Construction State of Cablestayed Concrete Bridges%自重和索力偏差对混凝土斜拉桥施工受力状态的影响

    Institute of Scientific and Technical Information of China (English)

    胡方健; 李国平

    2012-01-01

    The construction state of cable-stayed concrete bridges (CCB) built by segmental cantilever casting are influenced by many uncertain effects in construction. It is unsafe to evaluate the ultimate bearing capacities and service by the determinated methods oftered in the codes. In order to understand the states of CCB affected by uncertainty effects, a finite element model of CCB was researched by Latin hypercube sampling and the gravity and cable tension force (CTF) were taken as variables. The separate and combinationeffects of deviations of gravity and CTF on CCB were researched. The statistical distributions of normal stresses of CCB were obtained. The influences of different deviations of CTF on CCB were analyzed. The varieties of normal stress reliability of a section in relation to deviations of CTF were given. A conclusion is drawn" that deviations of gravity and CTF have great influences on construction state of CCB and their influencing locations are different. The deviation of CTF should be reduced in construction to decrease the variations of stresses. The indeterminate method needs to be adopted in design work, then the states which may appear in construcion can be known and the structural failure can be avoided.%采用分段浇筑施工的混凝土斜拉桥的施工状态受到诸多不确定性因素的影响,仅根据现有规范按照确定性方法来计算其承载力及使用性能是不安全的.为了研究混凝土斜拉桥在施工阶段不确定性因素影响下的受力状态,将混凝土自重和施工张拉索力作为变量,采用拉丁超方抽样法对一座混凝土斜拉桥进行了分析.分别研究了在上述两类变量单独和组合作用下桥梁的状态,统计了在给定分布的变量作用下的截面边缘应力的分布规律,分析了不同的索力张拉误差对桥梁应力状态的影响,最后给出了指定截面边缘正应力施工阶段可靠度随索力张拉误差的变化规律,

  12. In-plane Auto-Parametric Vibration of Inclined Cables under Random Transverse Excitation

    Institute of Scientific and Technical Information of China (English)

    WANG Bo; ZHANG Hai-long; XU Feng; GUO Cui-cui

    2008-01-01

    In-plane auto-parametric stochastic vibration of inclined cables subjected to Gaussian white noise in transverse bridge orientation is investigated. Based on Newton's laws of motion and Galerkin's modal truncation principle, the influences of geometry nonlinearity induced by sag and large displacement of cables and the initial equilibrium state are taken into account. Meanwhile, the three-dimensional non-linear differential equations of inclined cables for coupling vibration are deduced, equivalent stochastic linearization method is applied to derive the 1A-dimensional first-order nonlinear differential equations of state vectors, and the Runge-Kutta integration method is utilized to obtain the root mean square (RMS) response. Results show that when the transverse random excitation imposed on the stayed cable exceeds a critical value, the in-plane transverse vibration of the cable are excited due to the auto-parametric nonlinear coupling, and the critical value of random excitation increases with the damping ratio. In this motion, the cable response possesses non-stationary characteristics, even though the loading keeps stationary.

  13. 高地震烈度地区大跨度桥梁桩基础设计%The Pile Disign of Wide- span Bridge for High- intensity Earthquake Area

    Institute of Scientific and Technical Information of China (English)

    屈国

    2011-01-01

    The paper introduces the speciality of the pile disign of wide - span bridge in high - intensity earthquake area base on one wide -span cable -stayed bridge and give some suggestion.%结合某大跨度斜拉桥工程,介绍了高地震烈度地区大跨度桥梁桩基础设计的特殊性,提出合理建议。

  14. Stress and noises of steel box girders in Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Xue Tao; Chen Zhijian; Dong Xuewu

    2008-01-01

    Sutong Bridge is a cable-stayed bridge with a main span of 1 088 m.370 high-precision stress monitoring measured data show that in the process of hoisting the steel box girders,the stress of the main girders is in the fluctuant and complex state and many meteorological factors,such as sunshine radiation,temperature and wind,have important influence on the change of stress of the steel box girders.According to the real-time weather data,the stress data after the process of wavelet denoising from representative measuring points in different weather conditions is picked to estab-lish the stress response brought by meteorological factors with Layered Separation method,thereby basically eliminating the influence of meteorological factors on the stress of main girders,so that accurate and reliable stress data can be got for steel box girders adjustment and cable-tensioned construction control.

  15. Superconductor cable

    Science.gov (United States)

    Allais, Arnaud; Schmidt, Frank; Marzahn, Erik

    2010-05-04

    A superconductor cable is described, having a superconductive flexible cable core (1) , which is laid in a cryostat (2, 3, 4), in which the cable core (1) runs in the cryostat (2, 3, 4) in the form of a wave or helix at room temperature.

  16. 3 long bridges of dream were realized Opening of West Seto Motorway; Yume no 3 kakyo ga jitsugen/nishiseto jidoshado haitsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-06-10

    Onomichi-Imabari route/Setouchi Simanami Thruway, which adorned the finish of Honshu-Shikoku projects was completed on 1st, May. With this completion, 3 long bridges of dream were completely realized, following to Kojima-Sakaide (1988) and Kobe-Naruto (1998). This time, 5 bridges of this Motorway, the world's longest cable stayed bridge Tatara Long Bridge, world's first 3 continuous suspension bridge Kurushima Strait No.1{approx}No.3 bridge and New Onomichi Long Bridge, were opened. 10 bridges including 5 bridges (In-noshima Long Bridge, Ikeguchi Bridge, Omishima Bridge, Hakata/Oshima Long Bridge and Oshima Long Bridge) already under service connect 9 islands between Onomichi, Hiroshima Prefecture and Imabari, Ehime Prefecture, with a route 59 km long. Characteristic design was adopted for each bridge to demonstrate world's highest bridge erection technology of Japan. In a series of concrete construction to support superstructure of these bridges, underwater non-segregation type concrete with low hydration heat cement mainly for foundation and substructure, and high fluidity concrete for dense reinforcement layout were adopted. (translated by NEDO)

  17. Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

    Science.gov (United States)

    Celebi, M.

    2006-01-01

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

  18. Multifunction Analysis for the Stiffening Frames of Cable Pylon of Cable-stayed Bridge%斜拉桥索塔劲性骨架在施工中的多种功能

    Institute of Scientific and Technical Information of China (English)

    陈光新; 何雨微; 汤立志

    2003-01-01

    结合荆州长江公路大桥北汉通航孔桥200+500+200(m)PC斜拉桥索塔劲性骨架施工实际,分析了劲性骨架在索塔施工中的多种功能及其制作安装工艺,劲性骨架与索塔主筋、预应力系统、模板、拉索导管等各构件施工的相互协调技术.

  19. 斜拉桥索塔劲性骨架多功能研究%The Multifunction Analysis for the Stiffening Frames of Cable Pylon of Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    何雨微; 汤立志

    2002-01-01

    结合荆州长江公路大桥北汊通航孔桥200+500+200 m PC斜拉桥索塔劲性骨架施工实际,分析劲性骨架在索塔施工中的多种功能及其制作安装工艺,劲性骨架与索塔主筋、预应力系统、模板、拉索导管等各构件施工的相互协调技术.

  20. Multi-modal vibration amplitudes of taut inclined cables due to direct and/or parametric excitation

    Science.gov (United States)

    Macdonald, J. H. G.

    2016-02-01

    Cables are often prone to potentially damaging large amplitude vibrations. The dynamic excitation may be from external loading or motion of the cable ends, the latter including direct excitation, normally from components of end motion transverse to the cable, and parametric excitation induced by axial components of end motion causing dynamic tension variations. Geometric nonlinearity can be important, causing stiffening behaviour and nonlinear modal coupling. Previous analyses of the vibrations, often neglecting sag, have generally dealt with direct and parametric excitation separately or have reverted to numerical solutions of the responses. Here a nonlinear cable model is adopted, applicable to taut cables such as on cable-stayed bridges, that allows for cable inclination, small sag (such that the vibration modes are similar to those of a taut string), multiple modes in both planes and end motion and/or external forcing close to any natural frequency. Based on the method of scaling and averaging it is found that, for sinusoidal inputs and positive damping, non-zero steady state responses can only occur in the modes in each plane with natural frequencies close to the excitation frequency and those with natural frequencies close to half this frequency. Analytical solutions, in the form of non-dimensional polynomial equations, are derived for the steady state vibration amplitudes in up to three modes simultaneously: the directly excited mode, the corresponding nonlinearly coupled mode in the orthogonal plane and a parametrically excited mode with half the natural frequency. The stability of the solutions is also identified. The outputs of the equations are consistent with previous results, where available. Example results from the analytical solutions are presented for a typical inclined bridge cable subject to vertical excitation of the lower end, and they are validated by numerical integration of the equations of motion and against some previous experimental

  1. The Application of Fiber Bragg Grating in Bridge Prestressed Cable Force Monitoring%光纤光栅在桥梁预应力索索力监测中的应用

    Institute of Scientific and Technical Information of China (English)

    胡军; 陈宏波; 应汉雨

    2011-01-01

    For the prestressed concrete continuous beam construction, prestressed cable force long-term effective monitoring is always a challenge for the engineering staff. On account of the good long-term stability characteristics in fiber bragg grating sensor, the article designed a method of the long-term on-line monitoring for prestressed cable force of prestressed concrete continuous beam bridge and developed a small size of the fiber bragg grating sensor, which confirmed the association between the loss of prestressed cable tension and the occurrence of diseases in the prestressed concrete continuous beam bridge, such as the more common beam mid-span deflection, beam cracking and so on. The engineering application demonstrated the feasibility of the sensor and the monitoring program. The monitoring data shows that the FBG sensor is stable and reliable. The computer system created fingerprint database of changes in cable tension. This association plays a role of warning and preventing the appearance of diseases, and provides a scientific foundation for the bridge custody.%利用光纤光栅传感器长期稳定性好的特点,设计了一种预应力混凝土连续梁桥预应力索索力长期在线的监测方法,研制了一种小尺寸的光纤光栅传感器,印证预应力混凝土连续梁桥跨中下挠和梁体开裂等病害的发生与预应力索索力损失之间的关联.工程应用证明了该传感器及其实施方案的可行性,监测数据表明光纤光栅传感器运行稳定,检测数据可靠,仪表计算机系统建立的索力变化数据库,可为梁体病害的产生和预防起预警指示的作用,为桥梁管养提供科学依据.

  2. Research on the special lifting devices for steel box girders of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Wu Qihe; Luo Chengbin; Zhou Hanfa

    2009-01-01

    Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m. The steel box girder of main span includes five portions: back span large unit, large block of pylon, standard girder, back span closure girder and middle span closure girder. Each back span large unit is fabricated by welding several deck segments together in factory, and is erected by floating crane. As navigational clearance of the main bridge is high, the traditional truss lifting device can' t satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight. Hence, a kind of lighter lifting device for the erection of back span large units was accepted for this bridge. In this paper, the design and use of this lifting device is introduced.The upper structure used lifting gantry to install the standard girder segment by cantilever method. Because the bridge's navigation clearance is high, and the girder segment is wide and heavy, the meteorology and hydrology condition of the bridge district is abominable, and the requirements of long cable girder side pull-in, structure and performance propose high request to the lifting gantry. In this paper, the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.

  3. Field Application of Cable Tension Estimation Technique Using the h-SI Method

    Directory of Open Access Journals (Sweden)

    Myung-Hyun Noh

    2015-01-01

    Full Text Available This paper investigates field applicability of a new system identification technique of estimating tensile force for a cable of long span bridges. The newly proposed h-SI method using the combination of the sensitivity updating algorithm and the advanced hybrid microgenetic algorithm can allow not only avoiding the trap of local minimum at initial searching stage but also finding the optimal solution in terms of better numerical efficiency than existing methods. First, this paper overviews the procedure of tension estimation through a theoretical formulation. Secondly, the validity of the proposed technique is numerically examined using a set of dynamic data obtained from benchmark numerical samples considering the effect of sag extensibility and bending stiffness of a sag-cable system. Finally, the feasibility of the proposed method is investigated through actual field data extracted from a cable-stayed Seohae Bridge. The test results show that the existing methods require precise initial data in advance but the proposed method is not affected by such initial information. In particular, the proposed method can improve accuracy and convergence rate toward final values. Consequently, the proposed method can be more effective than existing methods in terms of characterizing the tensile force variation for cable structures.

  4. The application of structural health monitoring system technology using FBG to the No. 2 Wuhan bridge over the Yangtze river

    Science.gov (United States)

    Liu, Shengchun; Jiang, Desheng

    2008-12-01

    Bridge engineering offer many unique opportunities for the use of advanced optical fiber sensing technology. In this paper, the state-of-the-art of bridge structural health monitoring system(SHMS) based on optical fiber sensing technology are reviewed and some disadvantages in present SHMS based on optical fiber sensing technology for existing long-span bridge are indicated. In order to overcome those disadvantages, some fiber Bragg grating (FBG) products developed by authors and corresponding industrialization enterprise are introduced. Focusing on an existing long-span cable-stayed bridge-Wuhan Yangtze No.2 Bridge, the operational condition of the multi-parameter bridge SHMS mainly based on FBG sensors is presented. Some initial monitoring results show that the whole performance of the SHMS FBGbased is reliable and measuring data are reasonable.

  5. Modal identification of long-span Runyang Bridge using ambient responses recorded by SHMS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Runyang Bridge is a newly built cable-supported bridge that crosses the Yangtze River in China.The bridge is composed of one suspension bridge and one cable-stayed bridge.During the construction of the bridge,a structural health monitoring system(SHMS)was installed,which was designed by the Southeast University.Since the bridge was open to traffic,quantities of structural ambient responses have been recorded by the SHMS.And,it’s really important to extract structrural information from these records for health monitoring.This paper presents the study on modal identification of the bridge.The dynamic properites including modal frequencies,mode shapes and damping ratios are extracted from the ambient responses.Two identification methods are employed including the enhanced frequency domain decomposition and the stochastic subspace identification.The identified modal parameters from the two methods are compared.Results show that modal frequencies and mode shapes from the two methods are almost the same while the damping ratios are different.

  6. Modal identification of long-span Runyang Bridge using ambient responses recorded by SHMS

    Institute of Scientific and Technical Information of China (English)

    FEI QingGuo; LI AiQun; HAN XiaoLin; MIAO ChangQing

    2009-01-01

    Runyang Bridge is a newly built cable-supported bridge that crosses the Yangtze River in China.The bridge is composed of one suspension bridge and one cable-stayed bridge.During the construction of the bridge,a structural health monitoring system(SHMS)was installed,which was designed by the Southeast University.Since the bridge was open to traffic,quantities of structural ambient responses have been recorded by the SHMS.And,it's really important to extract structrural information from these records for health monitoring.This paper presents the study on modal identification of the bridge.The dynamic properites including modal frequencies,mode shapes and damping ratios are extracted from the ambient responses.Two identification methods are employed including the enhanced frequency domain decomposition and the stochastic subspace identification.The identified modal parameters from the two methods are compared.Results show that modal frequencies and mode shapes from the two methods are almost the same while the damping ratios are different.

  7. Dynamic characteristics and flutter performance of suspension bridge with double introverted main cables%内倾式双主缆悬索桥动力特性及颤振性能研究

    Institute of Scientific and Technical Information of China (English)

    夏锦林; 李珂; 葛耀君; 周超

    2016-01-01

    通过减小主跨为1 708 m悬索桥的主缆间距,分析了内倾式双主缆体系的动力特性和颤振性能.动力特性计算发现:减小主缆间距,能在维持竖弯基频的基础上有效提高扭转基频;附加的侧弯-扭转耦合振型在两个自由度上的等效质量均较小,且频率介于竖弯、扭转基频之间.为说明该振型的侧弯-扭转强耦合效应对颤振稳定性的影响,分别基于二维两自由度和三维全自由度状态空间方法对比分析了颤振性能.二维结果显示,小主缆间距时侧弯-扭转耦合振型较常规纯扭振型对颤振更不利;三维分析显示,主缆间距较小时,上述耦合振型参与程度较高,反之,纯扭振型参与较多,同时第二阶竖弯振型作用明显.结果表明:内倾式双主缆体系悬索桥的颤振稳定性受多振型影响,传统二维两自由度分析结果可能不安全,有必要进行三维全自由度颤振分析.%To investigate the dynamic characteristics and flutter performance of suspension bridges with double introverted main cables,a hypothetical bridge,with its main span 1 708 m,was taken into account by decreasing cables' transverse distance.Dynamic finite element analysis shows that,with the decreasing of cables' distance,system's fundamental torsional frequency can raise significantly,while the fundamental vertical frequency keeps steady.Meanwhile,a lateral and torsional coupled mode can be found,and its frequency is between fundamental vertical and torsional frequency.Both lateral and torsional equivalent mass of that mode remain in a rather low level.To research the influence of the coupled mode on system's flutter performance,the state-space approach was introduced into the analysis both two-dimensionally and three-dimensionally.It indicates through 2D analysis that,with a closer cables' distance,the coupled mode is more harmful.While by 3D analysis,the participation of that mode is higher when the cables' distance decreases

  8. An Embedded FBG Strain Sensor for Bridge Cable Tension Measurement%光纤光栅的缆索锚固区索力测量传感器设计

    Institute of Scientific and Technical Information of China (English)

    刘立; 陈伟民; 章鹏; 吴俊; 刘浩

    2012-01-01

    A Fiber Bragg Grating (FBG) embedded strain sensor is put forward. This method can make sure the survival of the sensor and solve the problem of over range measurement. It is mounted into the bridge anchor zone to detect the decay strain derived from cable body. Based on the analysis of bridge cable, design requests of this sensor are known as package structure, modulus of elasticity of package which must be matched up with the anchor material. Finally, epoxy glue with micro silicon is used as the package layer. To make sure the performance of the sensor, tensile tests are conducted by tensile testing machine, the results show that the linearity of sensor is 0.999 74, and the sensitivity is 2.74 pm/N, good in repeatability. And then the sensors arc put into the cable anchor, tensile test of the cable is implemented, and the sensor is good at linearity and repeatability.%在光纤光栅传感器测量缆索索力的应用中,为了保证传感器的存活率以及解决超量程测量的问题,设计了一种桥梁缆索锚固区植入式光纤光栅应变传感器.通过对桥梁缆索特性分析,对该传感器的封装结构、封装材料的弹性模量提出设计要求,并选择环氧树脂添加微细硅粉作为传感器封装层材料.利用拉力试验机对植入式应变传感器进行力学传感器性能实验,其线性度R2为0.999 74,灵敏度为2.74 pm/N,重复性好.把植入式传感器植入缆索锚固区,进行缆索张力实验.实验数据具有良好的线性度和重复性.

  9. Cable tensiometer

    Energy Technology Data Exchange (ETDEWEB)

    Park, B.V

    1989-05-30

    This patent describes a weight beam for measuring load on a cable. The weight beam consists of: a beam body; load cell means mounted on the beam body, the load cell means being spaced a predetermined distance from the beam body; clamp means connected to the load cell means and adapted to grip a cable whose tension is to be measured; and adjusting means connected to the load cell to deflect the cable and put the load cell under a tension load, the clamp means and the adjusting means being structurally distinct.

  10. Analysis and assessment of bridge health monitoring mass data—progress in research/development of "Structural Health Monitoring"

    Institute of Scientific and Technical Information of China (English)

    LI AiQun; DING YouLiang; WANG Hao; GUO Tong

    2012-01-01

    The "Structural Health Monitoring" is a project supported by National Natural Science Foundation for Distinguished Young Scholars of China (Grant No.50725828).To meet the urgent requirements of analysis and assessment of mass monitoring data of bridge environmental actions and structural responses,the monitoring of environmental actions and action effect modeling methods,dynamic performance monitoring and early warning methods,condition assessment and operation maintenance methods of key members are systematically studied in close combination with structural characteristics of long-span cable-stayed bridges and suspension bridges.The paper reports the progress of the project as follows.(1) The environmental action modeling methods of long-span bridges are established based on monitoring data of temperature,sustained wind and typhoon.The action effect modeling methods are further developed in combination with the multi-scale baseline finite element modeling method for long-span bridges.(2) The identification methods of global dynamic characteristics and internal forces of cables and hangers for long-span cable-stayed bridges and suspension bridges are proposed using the vibration monitoring data,on the basis of which the condition monitoring and early warning methods of bridges are developed using the environmental-condition-normalization technique.(3) The analysis methods for fatigue loading effect of welded details of steel box girder,temperature and traffic loading effect of expansion joint are presented based on long-term monitoring data of strain and beam-end displacement,on the basis of which the service performance assessment and remaining life prediction methods are developed.

  11. 集装箱装卸桥吊具卷缆系统防失控改造%Renovation of Spreader Cable Reel System of Bridge Container Crane for Preventing Runaway

    Institute of Scientific and Technical Information of China (English)

    徐新雷

    2012-01-01

    针对西门子电控系统集装箱桥吊吊具卷缆子系统在使用过程中发现的缺陷进行改造。通过修改西门子变频器参数,可有效避免桥吊吊具卷缆系统由于通信故障引发的失控,不但节约了成本,而且提高了桥吊可靠性。%Pointing against the shortcoming found out on son-system of Siemens Electric control system for spreader cable reel of container crane, a renovation has been carried out. It could avoid out of control aroused by communication trouble with revising parameters of frequency converter, which not only save cost, but also enhance reliability of bridge container crane.

  12. 76 FR 78159 - Safety Zone; Submarine Cable Installation Project; Chicago River South Branch, Chicago, IL

    Science.gov (United States)

    2011-12-16

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Submarine Cable Installation Project... the installation of submarine cables in the vicinity of the Madison Street Bridge. This temporary... the installation of submarine cables in the vicinity of the Madison Street Bridge. Entry into...

  13. Superconductor cable

    Science.gov (United States)

    Allais, Arnaud; Schmidt, Frank (Langenhagen, DE

    2009-12-15

    A superconductor cable includes a superconductive cable core (1) and a cryostat (2) enclosing the same. The cable core (1) has a superconductive conductor (3), an insulation (4) surrounding the same and a shielding (5) surrounding the insulation (4). A layer (3b) of a dielectric or semiconducting material is applied to a central element (3a) formed from a normally conducting material as a strand or tube and a layer (3c) of at least one wire or strip of superconductive material is placed helically on top. The central element (3a) and the layer (3c) are connected to each other in an electrically conducting manner at the ends of the cable core (1).

  14. Flow field analysis of a pentagonal-shaped bridge deck by unsteady RANS

    Directory of Open Access Journals (Sweden)

    Md. Naimul Haque

    2016-01-01

    Full Text Available Long-span cable-stayed bridges are susceptible to dynamic wind effects due to their inherent flexibility. The fluid flow around the bridge deck should be well understood for the efficient design of an aerodynamically stable long-span bridge system. In this work, the aerodynamic features of a pentagonal-shaped bridge deck are explored numerically. The analytical results are compared with past experimental work to assess the capability of two-dimensional unsteady RANS simulation for predicting the aerodynamic features of this type of deck. The influence of the bottom plate slope on aerodynamic response and flow features was investigated. By varying the Reynolds number (2 × 104 to 20 × 104 the aerodynamic behavior at high wind speeds is clarified.

  15. Current status of research on fatigue damage in steel box girder of cable-supported bridge in China%我国缆索支承桥梁钢箱梁疲劳损伤研究现状

    Institute of Scientific and Technical Information of China (English)

    吉伯海

    2014-01-01

    针对钢桥运营安全亟需关注的热点问题之一---缆索支承桥梁钢箱梁的安全性、耐久性,回顾我国钢箱梁疲劳损伤相关研究概况及主要成果,分析总结过去研究中存在的难点与热点问题,并对今后的发展方向提出了展望与建议。%The safety and durability of the steel box girder of cable-supported bridges has become a compelling subject in steel bridge safety operation. This paper provides a review on the research status and main results of fatigue damage in steel box girders in China, presents an analysis of the difficulties and pressing issues in previous research, and puts forward prospects and suggestions for the future development.

  16. Design of cable-girder anchorage system scheme in self-anchored suspension bridge%自锚式悬索桥缆-梁锚固系统方案设计

    Institute of Scientific and Technical Information of China (English)

    凌云

    2015-01-01

    本文根据已建以及待建自锚式悬索桥工程实例,将自锚式悬索桥工程中主缆在加劲梁梁端的锚固方案进行了总结分析,从施工方面、经济性以及美观性等方面指出了各种锚固方式的优缺点以及适应性。按照锚体材料的不同将现有锚固方式重新进行了分类,综合现有的分类方式提出了一套锚固系统方案设计流程。这种设计流程条理清楚、直观易理解,为今后的自锚式悬索桥主缆锚固系统设计提供指导,快速的形成锚固系统方案,提高设计效率,并获得更好的经济性和美观性。%According to the engineering examples of the self -anchored suspension bridges built and to be built , the cable -girder an-chored projects are summarized and analyzed.From the construction , economy and aesthetics aspects , the advantages adaptability of vari-ous ways of anchoring and are pointed out.According to the different materials of the existing anchorage , the way of anchoring is re -clas-sified and a set of anchor system design process is put forward based on the classification of the existing anchorage systems .This design process is clear , intuitive and easy to understand and can provide guidance for the design of self -anchored suspension bridge main cable anchorage system in the future.Using this design process , anchorage system scheme will be quickly put forward , the design efficiency can be improved and the bridge will be more economic and more beautiful.

  17. Carbon Fiber Reinforced Polymer for Cable Structures—A Review

    Directory of Open Access Journals (Sweden)

    Yue Liu

    2015-10-01

    Full Text Available Carbon Fiber Reinforced Polymer (CFRP is an advanced composite material with the advantages of high strength, lightweight, no corrosion and excellent fatigue resistance. Therefore, unidirectional CFRP has great potential for cables and to replace steel cables in cable structures. However, CFRP is a typical orthotropic material and its strength and modulus perpendicular to the fiber direction are much lower than those in the fiber direction, which brings a challenge for anchoring CFRP cables. This paper presents an overview of application of CFRP cables in cable structures, including historical review, state of the art and prospects for the future. After introducing properties of carbon fibers, mechanical characteristics and structural forms of CFRP cables, existing CFRP cable structures in the world (all of them are cable bridges are reviewed. Especially, their CFRP cable anchorages are presented in detail. New applications for CFRP cables, i.e., cable roofs and cable facades, are also presented, including the introduction of a prototype CFRP cable roof and the conceptual design of a novel structure—CFRP Continuous Band Winding System. In addition, other challenges that impede widespread application of CFRP cable structures are briefly introduced.

  18. Optical Fiber Grating Sensor for Force Measurement of Anchor Cable

    Institute of Scientific and Technical Information of China (English)

    JIANG Desheng; FU Jinghua; LIU Shengchun; SUI Lingfeng; FU Rong

    2006-01-01

    The development of the sensor suitable for measuring large load stress to the anchor cable becomes an important task in bridge construction and maintenance. Therefore, a new type of optical fiber sensor was developed in the laboratory - optical fiber grating sensor for force measurement of anchor cable (OFBFMAC). No similar report about this kind of sensor has been found up to now in China and other countries. This sensor is proved to be an effective way of monitoring in processes of anchor cable installation, cable cutting, cable force regulation, etc, with the accurate and repeatable measuring results. Its successful application in the tie bar cable force safety monitoring for Wuhan Qingchuan bridge is a new exploration of optical fiber grating sensing technology in bridge tie bar monitoring system.

  19. Assistant pullback technique for main span closure of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Luo Chengbin; Wu Qihe; Zhang Yongtao; You Xinpeng

    2009-01-01

    Sutong Bridge is a cable-stayed steel box girder bridge with a main span of 1 088 m. The erection of upper structure adopts geometry control method and requires no change to the unit's size and the structure's none-stress geometry. Before main span closure, the cantilever of girder reaches 540.8 m, the structure state is noticeably influenced by external circumstances, the main span closure face great difficulty. By abstracting the advantage of the pullback method abroad and the domestic temperature-cutting method, a new assistant pullback method have put forward and bring into practice actually. In this paper, the analysis key point of practice conditions, key parameter of practice, main measures of the method and the performance is introduced.

  20. Analysis and Research on Earthquake Resistant Performance of Liaohe Grand Bridge%辽河特大桥抗震性能分析研究

    Institute of Scientific and Technical Information of China (English)

    陈建荣

    2012-01-01

    Taking Liaohe grand bridge of coastal highway as an example,mechanical characteristics of cable-stayed bridge with large span locating at the region of high earthquake intensity and calculation method of mechanical analysis under earthquake are introduced.%以滨海公路辽河特大桥为例,介绍了位于高地震烈度地区的大跨度斜拉桥在地震作用下的受力特点以及动力分析计算方法。

  1. Insulation Degradation Diagnostic Technology to XLPE Cable

    Science.gov (United States)

    Uchida, Katsumi; Okamoto, Tatsuki

    XLPE power cables have been in use for long time now and some of them are approaching 30 years of their designed lifetime. However, under the present severe economic situation, it is necessary to use the existing apparatus as long as possible. So, degradation diagnostic methods with high reliability are needed earnestly. This paper explains the insulation degradation mechanism of XLPE power cables and the newest diagnostic methods on each voltage class. In 3.3-77kV classes, fairly high extents of the cable accidents depend on the water-tree degradation. For 3.3-6.6kV class cables, on-line diagnostic methods with high reliability to detect bridged water-trees have been developed and put in practical use. And, for 22-77kV classes, two promising off-line diagnostic methods to detect un-bridged water-trees have begun to carry out in on-site tests.

  2. Horizontal gust response of `Tatara Bridge` under construction; `Tatara ohashi` kasetsuji no taifu anteisei

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, K.; Iwasaki, T.; Tokushige, M.; Toriumi, R. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1999-03-01

    Wind tunnel tests of a long-span cable-stayed bridge under construction were conducted with two types of turbulent boundary layer simulations. The level of agreement between the wind tunnel measurements and a wind buffeting analysis varied with the type of turbulent boundary layer. An investigation of this behavior found that the aerodynamic admittance used in the buffeting analysis was different from the measured aerodynamic admittance. Past research showed that buffeting analysis based on strip theory, which assumes a spanwise correlation between the fluctuating wind velocity and the fluctuating aerodynamic loads, does not always hold. (author)

  3. Theory and model test for a cable lever mass damper%斜拉索杠杆质量减振器理论及模型试验研究

    Institute of Scientific and Technical Information of China (English)

    王波; 汪正兴

    2013-01-01

    为解决斜拉桥跨度增大带来的拉索振动问题,采用杠杆质量减振器(LMD)对斜拉索进行减振.介绍了LMD的构造特性及作用机理,建立了斜拉索-LMD系统振动方程,推导了LMD等效阻尼力模型及LMD与斜拉索各阶模态质量比,并对斜拉索前15阶模态对数衰减率进行了理论计算及模型试验研究.研究结果表明:LMD由于惯性项、刚度项及阻尼项的三重反馈作用,同时由于杠杆的调节放大作用,其减振效果优于相同安装高度的粘性剪切型阻尼器(VSD).LMD对桥梁景观影响较小、安装维护方便,可为千米级的斜拉桥拉索减振提供更可靠的解决方案.%In order to solve cable vibration problems due to span increase for a cable-stayed bridge,a lever mass damper (LMD) for cable vibration reduction was proposed.The structural characteristics and action mechanism of a LMD were introduced,the cable-LMD system's vibration equations were established.The equivalent damping force model of LMD and the modal mass ratios of LMD and the cable were deduced,and the cable logarithmic decay rates of the first 15 modes were studied through theoretical calculations and model tests.The results showed that due to three feedback functions of LMD inertia,stiffness and damping,and the adjusting amplification effect of the cable,the vibration reduction effect of LMD is better than that of a viscous shearing damper with the same installation height.Because of the better bridge landscape effect,and convenience for installation and maintenance,LMD provided a reliable solving scheme for cable vibration control of a cable-stayed bridge with thousand-meter scale span.

  4. Cable Sliding at Supports in Cable Structures

    Institute of Scientific and Technical Information of China (English)

    魏建东

    2004-01-01

    To develop an effective numerical method for the cable sliding problem in cable structures, two-node catenary cable element was built to model the cables based on analytical solution of elastic catenary. Cooperated with Newton method, continuation method was used to solve the nonlinear equations. This approach is more efficient than using Newton method only and has a wider range to select initial values for the process to converge. The relationship between the tension on a cable segment and its unstrained length was derived and used to calculate the unbalanced cable tensions at the supports. An example is presented to show the correctness and efficiency of the proposed method.

  5. VT Cable Systems 2013

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable dataset (CABLE2013) includes lines depicting the extent of Vermont's cable modem broadband system as of 6/30/2013 in addition to...

  6. Probabilistic Assessment of the Occurrence and Duration of Ice Accretion on Cables

    DEFF Research Database (Denmark)

    Roldsgaard, Joan Hee; Georgakis, Christos Thomas; Faber, Michael Havbro

    2015-01-01

    This paper presents an operational framework for assessing the probability of occurrence of in-cloud and precipitation icing and its duration. The framework utilizes the features of the Bayesian Probabilistic Networks. and its performance is illustrated through a case study of the cable-stayed Or......This paper presents an operational framework for assessing the probability of occurrence of in-cloud and precipitation icing and its duration. The framework utilizes the features of the Bayesian Probabilistic Networks. and its performance is illustrated through a case study of the cable......-stayed Oresund Bridge. The Bayesian Probabilistic Network model used for the estimation of the occurrence and duration probabilities is studied and it is found to be robust with respect to changes in the choice of distribution types used to model the meteorological variables that influence the two icing...... the model. The updated probabilities can be used as a decision support tool for the management of risk and safety with respect to falling ice....

  7. Bridge condition assessment based on long-term strain monitoring

    Science.gov (United States)

    Sun, LiMin; Sun, Shouwang

    2011-04-01

    In consideration of the important role that bridges play as transportation infrastructures, their safety, durability and serviceability have always been deeply concerned. Structural Health Monitoring Systems (SHMS) have been installed to many long-span bridges to provide bridge engineers with the information needed in making rational decisions for maintenance. However, SHMS also confronted bridge engineers with the challenge of efficient use of monitoring data. Thus, methodologies which are robust to random disturbance and sensitive to damage become a subject on which many researches in structural condition assessment concentrate. In this study, an innovative probabilistic approach for condition assessment of bridge structures was proposed on the basis of long-term strain monitoring on steel girder of a cable-stayed bridge. First, the methodology of damage detection in the vicinity of monitoring point using strain-based indices was investigated. Then, the composition of strain response of bridge under operational loads was analyzed. Thirdly, the influence of temperature and wind on strains was eliminated and thus strain fluctuation under vehicle loads is obtained. Finally, damage evolution assessment was carried out based on the statistical characteristics of rain-flow cycles derived from the strain fluctuation under vehicle loads. The research conducted indicates that the methodology proposed is qualified for structural condition assessment so far as the following respects are concerned: (a) capability of revealing structural deterioration; (b) immunity to the influence of environmental variation; (c) adaptability to the random characteristic exhibited by long-term monitoring data. Further examination of the applicability of the proposed methodology in aging bridge may provide a more convincing validation.

  8. Field Application of Automated Power Arc Spraying System on Steel Bridge Deck

    Institute of Scientific and Technical Information of China (English)

    YI Chun-long; SUO Shuang-fu; SUN Zhi; PANG Xu-nan

    2004-01-01

    The effective corrosion protection coating and high productive coating equipment for steel bridge deck has been a challenge for bridge engineers for many years. An automated power arc spraying system was first designed and field applied to coating the deck of Wuhan Junshan Yangtze River Bridge in high efficiency. This steel bridge is a continuous orthotropic deck box girder cable-stayed bridge with 962 m in length and 38.8 m in width, whose width is the No. 1 in China. The whole orthotropic deck with over 35,000 m2surface area was arc-sprayed a protective coating of zinc on site, followed by a sealant and SMA paving material. The side face and bottom of box girders were arc-sprayed with aluminum in factory.Field application indicated that the newly designed automated power arc spraying system with fan nozzle and separate primary & secondary atomizing air had some advantages over the conventional arc spraying system, such as automated operation,big arc spray current, high spraying rate, big breadth of each coat, even and small atomized particles, high density and low porosity of sprayed coating, and high adhesive strength to the substrate.Working procedure of surface preparation and automated arc spraying on bridge deck were introduced, and the quality of sprayed coating is controlled strictly. Field tests proved that the application of this automated power arc spraying system is successful and suitable for coating the steel bridge deck.

  9. Building Bridges One Line at a Time

    Science.gov (United States)

    Grigsby, Cathy Murray

    2012-01-01

    In this article, first-grade students were taught the different kinds of lines that were part of the construction of various bridges--the curved lines of the arches of stone bridges, straight lines connecting the cables of a suspension bridge, vertical lines, horizontal lines, and so on. They gained practice in drawing structures and in fine brush…

  10. Cable Tensiometer for Aircraft

    Science.gov (United States)

    Nunnelee, Mark (Inventor)

    2008-01-01

    The invention is a cable tensiometer that can be used on aircraft for real-time, in-flight cable tension measurements. The invention can be used on any aircraft cables with high precision. The invention is extremely light-weight, hangs on the cable being tested and uses a dual bending beam design with a high mill-volt output to determine tension.

  11. Identification of dynamic characteristics by field vibration test in Tsurumi Tsubasa bridge; Tsurumi Tsubasakyo no shindo jikken ni yoru doteki tokusei no dotei

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H. [Saitama University, Saitama (Japan). Faculty of Engineering; Takano, H.; Ogasawara, M.; Shimosato, T. [Metropolitan Expressway Public Corp., Tokyo (Japan); Kato, M.; Okada, J. [NKK Corp., Tokyo (Japan)

    1996-07-21

    Field vibration test of the Tsurumi Tsubasa Bridge, a long span cable stayed bridge, has been conducted. Focusing on its dynamic characteristics, an identification method from test results and its validity were investigated. The natural frequency identified using mode circle and resonance curve from steady vibration test agreed with that identified by the peak method from free damping test. Accordingly, there was no difference due to identification methods, and both methods provided appropriate accuracy. The natural vibration mode obtained from the steady vibration test agreed with that obtained by the eigenvalue analysis. The dispersion of experimental values, which indicates the adaptation to mode circle method, became a scale indicating reliability of identified values. When the damping obtained by the half power method for the microtremors test is compared with that identified from the steady vibration test and free damping test, it is required to compare them at lower amplitude level region, considering that the amplitude level of microtremors test is very low. For the dynamic characteristics of the Tsurumi Tsubasa Bridge, it was found that it has lower natural frequency and higher modal damping compared with other cable stayed bridges with similar scale of span. 18 refs., 13 figs., 4 tabs.

  12. Overall Design of Baitanhu Lake Bridge%白潭湖大桥总体设计

    Institute of Scientific and Technical Information of China (English)

    张全阳

    2014-01-01

    基于城市桥梁的景观要求,白潭湖大桥主桥采用纵向对称布置的(150+150) m混凝土独塔斜拉桥的设计方案。桥塔以拱为形态元素,采用椭圆形拱塔结构;主梁采用预应力混凝土单箱三室斜腹板箱梁,人行道置于斜拉索锚固区外侧;斜拉索采用扇形空间双索面布置,主梁上锚固采用混凝土齿块锚固形式,塔上锚固采用混凝土锚块+隔板的锚固形式;过渡墩采用花瓶形板式墩。桥塔采用爬模施工,桥塔横梁采用分节段浇筑,设置2 m合龙段;主梁采用分节段支架现浇施工,共分13个施工节段。有限元计算结果表明,结构受力满足规范要求。%Given the demands of landscape effect of city bridges ,the design scheme of a (150+150) m concrete single pylon cable-stayed bridge that is symmetrically arranged in the longitudinal direction is chosen for the main bridge of Baitanhu Lake Bridge .The pylon which is basically an arch is designed as an elliptic arched pylon structure .The main girder is the prestressed concrete three-cell single box structure with inclined webs .The sidewalk is arranged along the outer side of the anchorage zone of the stay cables . The stay cables are fanned out in spatial double cable planes ,which are anchored to the main girder via concrete teeth ,but anchored to the pylon with the assistance of concrete blocks and bulkheads .T he transitional piers are vase-shaped plate piers . The pylon is constructed by climbing formwork and the pylon cross beam is cast in segments with a 2 m long closure section .The main girder is cast in segments on scaffoldings and a total of 13 construction segments are made .The results of the finite element calculation indicate that the force conditions of the structure can meet the code requirements .

  13. Earthquake Response Analysis of Approach Bridge of Suramadu Sea-Crossing Bridge%苏拉马都大桥引桥抗震分析

    Institute of Scientific and Technical Information of China (English)

    郭河; 范轶峰

    2011-01-01

    苏拉马都大桥是印度尼西哑的一座特大型桥梁,其引桥为预应力混凝土连续箱梁结构,通过V形墩与主桥相连.由于桥址处抗震设防烈度较高,又是跨越马都拉海峡的特大型桥梁,其抗震性能尤为重要.采用两水平的抗震设计方法,从地震输入、地震反应谱分析、非线性时程分析、结构的抗震性能验算等方面对苏拉马都大桥引桥的抗震性能进行分析,结果表明,在2 500年1重现期的地震作用下,该桥的抗震性能均满足抗震设防要求.%Surammadu Bridge is an especially large bridge in Indonesia. Its structure style is prestressed concrete continuous box bridge and links with the main bridge by V-style pier. The seismic performance of Suramadu Bridge is particularly important because of the bridge across the Madula Strait and the high seismic intensity at the bridge site. In this paper, based on the antiseismic design of Suramadu Approach Bridge, seismic behavior of cable-stayed bridge is investigated by two-level earthquake-resistance method from the seismic input, the analysis of earthquake response spectrum, the analysis of nonlinear time history and the checking of structural earthquake-resistance performance. It is indicated that, the resistance of Suramadu Approach Bridge is larger than the requirement under the 2 500-year recurrence interval (2% in 50year) earthquake load.

  14. Benchmark control problem in the study of seismic response of cable-stayed bridges%斜拉桥地震响应振动控制Benchmark问题研究

    Institute of Scientific and Technical Information of China (English)

    王建国; 李雪峰

    2008-01-01

    文章建立了斜拉桥结构的有限元模型和振动控制Benchmark模型,采用LQG控制算法和最优控制理论,基于MATLAB环境的Simulink程序,对斜拉桥结构振动的主动控制以及Benchmark问题进行研究,给出了独塔双面索斜拉桥在随机干扰作用下振动控制的仿真结果.

  15. The application of the Monte-Carlo method in fail-safe analysis of cable-stayed bridge%Monte-Carlo法在斜拉桥可靠性分析中的应用

    Institute of Scientific and Technical Information of China (English)

    张爱林; 康浩

    2006-01-01

    主梁的可靠度对于斜拉桥整体结构的可靠度具有重要影响,通过采用Monte-Carlo法对斜拉桥主梁的可靠度进行分析,用Matlab的数值计算功能解决了Monte-Carlo法直接抽样的困难,得到比较精确的结果,以推广Monte-Carlo法.

  16. 基于模态综合理论的斜拉桥时域抖振分析方法%Analysis Method of Buffeting in Time Domain for Cable-stayed Bridge Based on Modal Integration Theory

    Institute of Scientific and Technical Information of China (English)

    孙航; 陈彦江; 盛洪飞

    2008-01-01

    基于大跨度斜拉桥风致抖振时域分析的复杂性,为提高时域分析效率,引入模态综合理论,提出一种斜拉桥抖振时域分析方法,并通过算例自编程序验证其正确性与可行性.考虑自然风的相关特性,采用谱解法将三维随机风场简化,横桥向和顺桥向风速谱采用沿高度变化的Simiu谱,竖向风速谱采用Lumley-Panofsky谱,编制程序实现大跨度斜拉桥随机风场的数值模拟,得到施加于结构上的风荷载时程.研究表明,大型结构的动力响应主要受若干低阶振型控制,因此在斜拉桥时域分析过程中引入模态综合理论,实现了抖振力和自激力的时域化过程,并且全面地考虑了气动阻尼、气动刚度和气动耦合作用的影响,有效地解决了考虑自激力的时域化过程复杂、计算代价过大的问题;最后通过编制程序对一座大跨度斜拉桥进行不同风速下的抖振时域分析,验证了其实用性.

  17. 港珠澳大桥青州航道桥工程特点及关键技术%Engineering Characteristics and Key Techniques of Qingzhou Ship Channel Bridge of Hong Kong-Zhuhai-Macao Bridge

    Institute of Scientific and Technical Information of China (English)

    刘明虎; 孟凡超; 李国亮

    2013-01-01

    The Qingzhou Ship Channel Bridge of the Hong Kong-Zhuhai-Macao Bridge is a steel box girder cable-stayed bridge with double pylons and double cable planes.In the design of the bridge,a variety of the new materials,new techniques and new workmanships have been applied.In this paper,the engineering characteristics and key techniques of the bridge are summarized.On the bridge,the steel box girders of the same structural types of the adjacent non-navigable span bridges are fully used as the counterweight and on the outer side spans of the bridge,the stay cables are not installed.The arrangement of the bridge in such a way is well appropriate to the local conditions of the bridge site and has notable comprehensive advantage.The structural support system of the bridge is the three-way system that can ensure the structural performance of the whole bridge to be optimal.The pylons have the crisscross steel struts of the “Chinese Knot” configuration,which are connected with the concrete pylon columns via the connecting boxes in a combined force transmitting mode of “ compression-shear” and the performance of the steel struts and connection is safe and reliable.The foundations for the bridge are the composite piles of variable diameter steel pipes and together with the reinforced concrete in the steel pipes,the composite sections of the piles that are to jointly bear the loads and are cost-saving and rational are formed.The pier shafts are formed by the precast segments.The segments are installed at the site and are connected each other by the φ75 mm thick prestressing bars.The steel box girders are of the optimized streamlined flat sections topped with the orthotropic steel deck plates and the fatigue performance of the girders are quite superior.The stay cables are the ones made up of the parallel steel wires and having tensile strength of 1 860 MPa.%港珠澳大桥青州航道桥为双塔双索面钢箱梁斜拉桥,该桥设计采用了多项新材料、新技术

  18. Advantages of using CFRP cables in orthogonally loaded cable structures

    Directory of Open Access Journals (Sweden)

    Bernd Zwingmann

    2016-07-01

    Full Text Available Carbon Fiber Reinforced Polymer (CFRP is an advanced composite material with advantages of high strength and light weight, giving it great potential to be a new, reliable cable material. Ideal structures for CFRP cables are orthogonally loaded cable structures, where cables are loaded orthogonally or approximately orthogonally by external loads. Using CFRP cables in such structures, e.g. cable roofs and cable facades, has advantages over traditional steel cable structures. In order to demonstrate this point, two typical orthogonally loaded cable structures, i.e. a CFRP spoked wheel cable roof and a CFRP cable net façade, were investigated in a case study. Their mechanical properties and economies are compared with that of the steel counterparts. Results show that CFRP cables can effectively improve the mechanical and economical performances of orthogonally loaded cable structures; furthermore, the advantages of applying CFRP cables for cable net facade are more obvious than that for spoked wheel cable roof.

  19. 悬索桥主缆线形确定的常用精确解析算法比较及电算高效实现方法研究%Comparison on common precise numerical analytical algorithms to determine main cables' curve shape in suspension bridges and study on highly effective methods of computation

    Institute of Scientific and Technical Information of China (English)

    景天虎; 李桅; 李青宁; 张品乐

    2011-01-01

    以悬索桥主缆线形确定的常用精确数值解析算法为研究对象,通过对它们的比较分析和公式推导发现:在主缆理想柔性、忽略泊松比效应的最基本假定下,主缆线形确定的精确数值解析法可归结为主缆自重集度按其有、无应力长度计算作为已知条件的两大类算法;并且证明了在每大类解析算法中的所有方法是完全等价的.研究还表明:第二类解析算法为“全精确解析算法”,第一类为“准精确解析算法”;在第一类算法中,主缆无应力长度公式的计算值偏小.仅就悬索桥主缆成桥态线形确定而言,主缆线形确定的两大类数值解析算法都具有很高的工程精度,但第二类算法的主缆自重集度的确定更为精确、更接近实际情况,实际计算时应优先使用它.另外,针对两类解析算法涉及到大量的超越方程求解和递推迭代计算的情况,提出了基于MATLAB软件的高精度电算实现方法.最后,给出一个超大跨径悬索桥的中跨主缆线形确定的验证算例.%The common precise numerical analytical algorithms to determine main cables' curve shape in suspension bridges were investigated. By means of comparison among these algorithms and formulae inference, it is found that these algorithms can be reduced to two big categories of analytical ones according to different known conditions that weight intensity loads of main cables are calculated in terms of their lengths with stress and without stress under the basic hypotheses that main cables are ideally flexible and the effect of Poisson ratio of their cross-sections is neglected. It is proved that all methods among big categories of analytical ones are equivalent to each other. Moreover, further studies show that the second big category of analytical algorithms is "thoroughly precise analytical ones" and the first is quasi- precise analytical ones, and the latter one under-evaluates the length of main cables

  20. Analysis and Experiment Research on Dehumidification and Anti-corrosion System of Main Cable of Suspension Bridge Based on Waste Heat Recovery%基于余热回收的悬索桥主缆除湿防腐系统节能分析与实验研究

    Institute of Scientific and Technical Information of China (English)

    彭关中; 缪小平; 范良凯; 贾代勇; 刘文杰; 马喜斌

    2011-01-01

    Main cable is one of the most important bearing components of suspension bridge, and also the irreplaceable component, known as the “lifeline” of the suspension bridge. The main cable is exposed to the atmosphere for a long time, and withstands the erosion of various adverse environments, which results in the rust and corrosion of steel wire of main cable. The dehumidification and anti-corrosion system will send dry air into the main cable,reduce the air relative humidity,so as to avoid rust and corrosion of steel wire, and improve the service life. In this paper, the principle and composition of the dehumidification and anticorrosion system of main cable were described, and a dehumidification and anti-corrosion system of main cable of suspension bridge based on the waste heat recovery was proposed. The test rig for testing the performance of heat exchanger was built up, and the experiment results indicated that when the regenerated air flowrate of the rotary dehumidifier was 1/3 of the rotary dehumidification air flowrate,with the increase of the rotary dehumidification air flowrate, the heat exchange efficiency of the heat exchanger would be improved,the temperature of the regenerated air would rise through the heat exchanger, which would reduce the heating capacity of regeneration electric heater, and save the energy consumption of the dehumidification and anti-corrosion system of main cable.Therefore, the waste beat recovery technology was favorable for the energy conservation of the dehumidification and anti-corrosion system of main cable.%主缆是悬索桥最重要的受力构件之一,且是不可更换构件,被称为悬索桥的"生命线".主缆长期暴露在大气环境中,经受着各种不利环境的侵蚀,导致主缆钢丝易产生锈蚀.主缆除湿防腐系统将干燥空气送入主缆,降低主缆内的空气湿度,从而避免主缆钢丝锈蚀.提高了主缆钢丝的使用寿命.本文阐述了主缆除湿防腐系统的原理及组

  1. Digital simulation of 3D turbulence wind field of Sutong Bridge based on measured wind spectra

    Institute of Scientific and Technical Information of China (English)

    Hao WANG; Zhou-hong ZONG; Ai-qun LI; Teng TONG; Jie NIU; Wen-ping DENG

    2012-01-01

    Time domain analysis is an essential implement to study the buffeting behavior of long-span bridges for it can consider the non-linear effect which is significant in long-span bridges.The prerequisite of time domain analysis is the accurate description of 3D turbulence winds.In this paper,some hypotheses for simplifying the 3D turbulence simulation of long-span cable-stayed bridges are conducted,considering the structural characteristics.The turbulence wind which is a 3D multivariate stochastic vector process is converted into four independent ID univariate stochastic processes.Based on recorded wind data from structural health monitoring system (SHMS) of the Sutong Bridge,China,the measured spectra expressions are then presented using the nonlinear least-squares fitting method.Turbulence winds at the Sutong Bridge site are simulated based on the spectral representation method and the Fast Fourier transform (FFT) technique,and the relevant results derived from target spectra including measured spectra and recommended spectra are compared.The reliability and accuracy of the presented turbulence simulation method are validated through comparisons between simulated and target spectra (measured and recommended spectra).The obtained turbulence simulations can not only serve further analysis of the buffeting behavior of the Sutong Bridge,but references for structural anti-wind design in adjacent regions.

  2. Design of Main Bridge of Xi′nan Bridge in Guigang City,Guangxi%广西贵港西南大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    李翠霞; 张巨生

    2015-01-01

    广西贵港市西南大桥主桥为(46+88+280+88+46) m双塔双索面预应力混凝土边主梁斜拉桥。主梁采用等高度带悬臂的矩形混凝土边主梁与“工”字形钢横梁相结合的形式,整幅桥面宽36.5m,设双向2.0%横坡。桥塔采用“鱼”状流线弧形框架钢筋混凝土结构,塔柱高102.5 m,采用外侧为“D”形圆弧段的箱形截面。桥塔设上、下横梁,均采用预应力混凝土单箱单室结构。全桥共设136根斜拉索,斜拉索采用φs 15.2 m m镀锌钢绞线索,空间双索面扇形布置。桥塔墩采用分离式基础,上、下游分离式基础中心距34.7 m ,其下各设9根φ2.5 m钻孔桩。承台为正方形钢筋混凝土结构。4号墩顶面设一圆端形塔座。%The main bridge of the Xi′nan Bridge in Guigang City ,Guangxi is a prestressed concrete edge main girders cable‐stayed bridge with double pylons ,double cable planes and with span arrangement (46+88+280+88+46) m .T he main girders of the bridge are of the structural type combining the rectangular concrete edge main girders having constant depth and cantilevers with the I‐shape steel cross beams .The width of the whole bridge deck is 36 .5 m and the deck is provided with dual 2 .0% transverse slopes .A pylon of the bridge is the“fish”‐shape streamlined arc frame reinforced concrete structure that is 102 .5 m in height and the outer side of the pylon is of the“D”‐shape round arc box section .The upper and lower cross beams of the pylon are all the prestressed concrete single‐cell single‐box structures .There are totally 136 stay cables arranged for the whole bridge .The stay cables are the φs 15 .2 mm galvanized steel wire strand cables and are arranged in fan shape and spatial double cable planes .The pylon pier is supported on the sep‐arated foundations .T he center‐to‐center distance of the foundations on the upstream and dow n‐stream sides is 34 .7

  3. Probabilistic Modeling and Risk Assessment of Cable Icing

    DEFF Research Database (Denmark)

    Roldsgaard, Joan Hee

    assessments together with the Bayesian pre-posterior decision analysis and builds upon the quantification of Value of Information (VoI). The consequences are evaluated for different outputs of the probabilistic model to provide a basis for prioritizing risk management decision alternatives. Each step...... the bridge cables, which can cause socioeconomically expensive closures of bridges and traffic disruptions. The objective is to develop a simple model that can be used to assess the occurrence probability of ice accretion on bridge cables from readily available meteorological variables. This model is used....... The damage assessment is performed using a probabilistic approach, based on a Bayesian Probabilistic Network, where the wind environment, traffic loading, bridge specific parameters and the mechanisms that induce significant cable vibrations are the main input parameters. It is outlined how information...

  4. UtilityTelecom_CABLE2005

    Data.gov (United States)

    Vermont Center for Geographic Information — The VT Cable System dataset (CABLE2005) includes lines depicting the extent of Vermont's cable system as of 12/31/2005. Numerous cable companies provide service in...

  5. Probabilistic Approach to Fatigue Assessment for Stay Cables

    DEFF Research Database (Denmark)

    Baussaron, Julien; Sørensen, John Dalsgaard; Toft, Henrik Stensgaard

    2013-01-01

    points of the structures, develop into critical cracks and failure due to fatigue. Many parameters used for predicting times to failure of structure due to fatigue are uncertain and their variations have a big influence on the real lifetime. This paper will focus on a global methodology to take...... of the material. Probabilistic Wöhler curves are fitted using available data, and used to represent the variability of material fatigue behaviour. Finally, the reliability is assessed using Monte Carlo simulations....

  6. Cable Television: Franchising Considerations.

    Science.gov (United States)

    Baer, Walter S.; And Others

    This volume is a comprehensive reference guide to cable television technology and issues of planning, franchising, and regulating a cable system. It is intended for local government officials and citizens concerned with the development of cable television systems in their communities, as well as for college and university classes in…

  7. Colleges and Cable Franchising.

    Science.gov (United States)

    Glenn, Neal D.

    After noting issues of audience appeal and financial and philosophical support for educational broadcasting, this paper urges community colleges to play an active role in the process of cable franchising. The paper first describes a cable franchise as a contract between a government unit and the cable television (CATV) company which specifies what…

  8. Horizontal gust response of 'Tatara Bridge' under construction. 'Tatara ohashi' kasetsuji no taifu anteisei

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, K.; Iwasaki, T.; Tokushige, M.; Toriumi, R. (Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan))

    1999-03-01

    Wind tunnel tests of a long-span cable-stayed bridge under construction were conducted with two types of turbulent boundary layer simulations. The level of agreement between the wind tunnel measurements and a wind buffeting analysis varied with the type of turbulent boundary layer. An investigation of this behavior found that the aerodynamic admittance used in the buffeting analysis was different from the measured aerodynamic admittance. Past research showed that buffeting analysis based on strip theory, which assumes a spanwise correlation between the fluctuating wind velocity and the fluctuating aerodynamic loads, does not always hold. (author)

  9. Real-Time Seismic Monitoring of Thenewcape Girardeau (mo) Bridge and Recorded Earthquake Response

    Science.gov (United States)

    çelebi, Mehmet

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. Design of the bridge accounted for the possibility of a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network consists of a superstructure and two free-field arrays and comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and free-field in the vicinity of the bridge. The paper also introduces the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to (1) assess the performance of the bridge, (2) check design parameters, including the comparison of dynamic characteristics with actual response, and (3) better design future similar bridges. Preliminary analyses of low-amplitude ambient vibration data and that from a small earthquake reveal specific response characteristics of this new bridge and the free-field in its proximity. There is coherent tower-cabledeck interaction that sometimes results in amplified ambient motions. Also, while the motions at the lowest (tri-axial) downhole accelerometers on both MO and IL sides are practically free-from any feedback from the bridge, the motions at the middle downhole and surface accelerometers are significantly influenced by amplified ambient motions of the bridge.

  10. Wind resistance challenges and fundamental research on long-span bridges%大跨度桥梁抗风技术挑战与基础研究

    Institute of Scientific and Technical Information of China (English)

    项海帆; 葛耀君

    2011-01-01

    With the rapid development of long span bridges in China, this paper focused on some engineering projects related to wind resistance challenges on three types of long span bridges, including flutter instability and control of suspension bridges, wind induced vibration of cable-stayed bridges and control of wind-rain induced cable vibration, vortex shedding vibration and control of arch bridges, and the refinements on aerodynamic flutterand buffeting of super long span bridges. It can be concluded that the intrinsic limit of span length due to aerodynamic stability is about 1 500 m for a traditional suspension bridge, and beyond or even approaching this limit, designers should be prepared to improve aerodynamic stability. The long-span cable-stayed bridges with a 1 000 m main span have high enough critical flutter speed, but the main aerodynamic concern is rain-wind induced vibration of long stay cables. Except one example of vortex-induced vibration, long-span arch bridges have no wind resistance problems. The fundamental research on wind resistance of long-span bridges was also introduced with the full-mode flutter analysis method as 3D bridge flutter precise analysis, the bridge buffeting frequency-domain analysis under skew wind action, the bridge flutter and buffeting reliability evaluation method based on second order theory and first passage theory, and the unveiling of bridge flutter evoluation process, generation mechanism and control law.%以我国30年大跨度桥梁的快速发展为研究背景,对3种大跨度桥梁的抗风技术挑战进行了基础性研究和应用性研究,着重探讨了悬索桥的颤振性能及其控制、斜拉桥风振性能与拉索风雨振控制、拱式桥涡激共振及其控制、特大桥梁风振精细化理论等一系列抗风关键问题.研究结果表明:悬索桥的颤振稳定性跨径上限约为1 500m,超过甚至接近这一上限时,必须采取措施改善加劲梁的抗风稳定性;千米级大跨度斜

  11. Vulnerability analysis for design of bridge health monitoring system

    Science.gov (United States)

    Sun, L. M.; Yu, G.

    2010-03-01

    The recent engineering implementation of health monitoring system for long span bridges show difficulties for precisely assessing structural physical condition as well as for accurately alarming on structural damages, although hundreds of sensors were installed on a structure and a great amount of data were collected from the monitoring system. The allocation of sensors and the alarming algorithm are still two of the most important tasks to be considered when designing the structural health monitoring system. Vulnerability, in its original meaning, is the system susceptibility to local damage. For a structural system, the vulnerability can thus be regarded as structural performance susceptibility to local damage of structure. The purpose of this study is to propose concepts and methods of structural vulnerability for determining monitoring components which are more vulnerable than others and the corresponding warning threshold once the damages occur. The structural vulnerability performances to various damage scenarios depend upon structural geometrical topology, loading pattern on the structure and the degradation of component performance. A two-parameters structural vulnerability evaluation method is proposed in this paper. The parameters are the damage consequence and the relative magnitude of the damage scenarios to the structural system, respectively. Structural vulnerability to various damage scenarios can be regarded as the tradeoff between the two parameters. Based on the results of structural vulnerability analysis, the limited structural information from health monitoring can be utilized efficiently. The approach of the design of bridge health monitoring system is illustrated for a cable-stayed bridge.

  12. Numerical Analysis of a Train-Bridge System Subjected to Earthquake and Running Safety Evaluation of Moving Train

    Directory of Open Access Journals (Sweden)

    Xun Yang

    2016-01-01

    Full Text Available This paper investigates the dynamic response of a train-bridge system subjected to earthquakes, and the running safety indices of the train on the bridge under earthquake are studied. Taking a long span cable-stayed bridge across the Huangpu River as an example, a full three-dimensional finite element model of the train-bridge system was established, in which the soil-bridge and rail-train interactions were considered. Parallel computing based on contact balance was utilized to deal with this large-scale numerical simulation problem. The dynamic nonlinear analysis was performed on a Hummingbird supercomputer using the finite element code LS-DYNA 971. The results show that the acceleration responses of the train subjected to an earthquake are much greater than the ones without earthquake input, and the running safety of a moving train is affected by both the earthquake intensity and the running speed of the train. The running safety of the moving train can be evaluated by the threshold curve between earthquake intensity and train speed. The proposed modeling strategies and the simulated results can give a reference prediction of the dynamic behaviour of the train-bridge subjected to an earthquake.

  13. Rapid cable tension estimation using dynamic and mechanical properties

    Science.gov (United States)

    Martínez-Castro, Rosana E.; Jang, Shinae; Christenson, Richard E.

    2016-04-01

    Main tension elements are critical to the overall stability of cable-supported bridges. A dependable and rapid determination of cable tension is desired to assess the state of a cable-supported bridge and evaluate its operability. A portable smart sensor setup is presented to reduce post-processing time and deployment complexity while reliably determining cable tension using dynamic characteristics extracted from spectral analysis. A self-recording accelerometer is coupled with a single-board microcomputer that communicates wirelessly with a remote host computer. The portable smart sensing device is designed such that additional algorithms, sensors and controlling devices for various monitoring applications can be installed and operated for additional structural assessment. The tension-estimating algorithms are based on taut string theory and expand to consider bending stiffness. The successful combination of cable properties allows the use of a cable's dynamic behavior to determine tension force. The tension-estimating algorithms are experimentally validated on a through-arch steel bridge subject to ambient vibration induced by passing traffic. The tension estimation is determined in well agreement with previously determined tension values for the structure.

  14. Down Syndrome in Adults: Staying Healthy

    Science.gov (United States)

    ... Shortfall Questionnaire Home Prevention and Wellness Staying Healthy Down Syndrome in Adults: Staying Healthy Down Syndrome in Adults: Staying Healthy Family HealthPrevention and WellnessStaying ...

  15. Cable Tester Box

    Science.gov (United States)

    Lee, Jason H.

    2011-01-01

    Cables are very important electrical devices that carry power and signals across multiple instruments. Any fault in a cable can easily result in a catastrophic outcome. Therefore, verifying that all cables are built to spec is a very important part of Electrical Integration Procedures. Currently, there are two methods used in lab for verifying cable connectivity. (1) Using a Break-Out Box and an ohmmeter this method is time-consuming but effective for custom cables and (2) Commercial Automated Cable Tester Boxes this method is fast, but to test custom cables often requires pre-programmed configuration files, and cables used on spacecraft are often uniquely designed for specific purposes. The idea is to develop a semi-automatic continuity tester that reduces human effort in cable testing, speeds up the electrical integration process, and ensures system safety. The JPL-Cable Tester Box is developed to check every single possible electrical connection in a cable in parallel. This system indicates connectivity through LED (light emitting diode) circuits. Users can choose to test any pin/shell (test node) with a single push of a button, and any other nodes that are shorted to the test node, even if they are in the same connector, will light up with the test node. The JPL-Cable Tester Boxes offers the following advantages: 1. Easy to use: The architecture is simple enough that it only takes 5 minutes for anyone to learn how operate the Cable Tester Box. No pre-programming and calibration are required, since this box only checks continuity. 2. Fast: The cable tester box checks all the possible electrical connections in parallel at a push of a button. If a cable normally takes half an hour to test, using the Cable Tester Box will improve the speed to as little as 60 seconds to complete. 3. Versatile: Multiple cable tester boxes can be used together. As long as all the boxes share the same electrical potential, any number of connectors can be tested together.

  16. Parameters of static response of carbon fiber reinforced polymer (CFRP) suspension cables

    Institute of Scientific and Technical Information of China (English)

    王立彬; 吴勇

    2015-01-01

    The feasibility of longer spans relies on the successful implementation of new high-strength light weight materials such as carbon fiber reinforced polymer (CFRP). First, a dimensionless equilibrium equation and the corresponding compatibility equation are established to develop the cable force equation and cable displacement governing equation for suspension cables, respectively. Subsequently, the inextensible cable case is introduced. The formula of the Irvine parameter is considered and its physical interpretation as well as its relationship with the chord gravity stiffness is presented. The influences on the increment of cable force and displacement byλ2 and load ratiop′are analyzed, respectively. Based on these assumptions and the analytical formulations, a 2000 m span suspension cable is utilized as an example to verify the proposed formulation and the responses of the relative increment of cable force and cable displacement under symmetrical and asymmetrical loads are studied and presented. In each case, the deflections resulting from elastic elongation or solely due to geometrical displacement are analyzed for the lower elastic modulus CFRP. Finally, in comparison with steel cables, the influences on the cable force equation and the governing displacement equation by span and rise span ratio are analyzed. Moreover, the influences on the static performance of suspension bridge by span and sag ratios are also analyzed. The substantive characteristics of the static performance of super span CFRP suspension bridges are clarified and the superiority and the characteristics of CFRP cable structure are demonstrated analytically.

  17. Theme: Staying Current--Horticulture.

    Science.gov (United States)

    Shry, Carroll L., Jr.; And Others

    1986-01-01

    This theme issue on staying current in horticulture includes articles on sex equity in horticulture, Future Farmers of America, career opportunities in horticulture, staying current with your school district's needs, staying current in horticulture instruction, staying current with landscape trade associations, emphasizing the basics in vocational…

  18. Electrical power cable engineering

    CERN Document Server

    Thue, William A

    2011-01-01

    Fully updated, Electrical Power Cable Engineering, Third Edition again concentrates on the remarkably complex design, application, and preparation methods required to terminate and splice cables. This latest addition to the CRC Press Power Engineering series covers cutting-edge methods for design, manufacture, installation, operation, and maintenance of reliable power cable systems. It is based largely on feedback from experienced university lecturers who have taught courses on these very concepts.The book emphasizes methods to optimize vital design and installation of power cables used in the

  19. Staying Well at Work.

    Science.gov (United States)

    Blai, Boris, Jr.

    Employee wellness directly affects business/industry operations and costs. When employees are helped and encouraged to stay well, this people-positive policy results in triple benefits: reduced worker absenteeism, increased employee productivity, and lower company expenditures for health costs. Health care programs at the worksite offer these…

  20. UtilityTelecom_CABLE2013

    Data.gov (United States)

    Vermont Center for Geographic Information — The VT Cable dataset (CABLE2013) includes lines depicting the extent of Vermont's cable modem broadband system as of 6/30/2013 in addition to those companies who do...

  1. Cable Diagnostic Focused Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Hartlein, R.A.; Hampton, R.N.

    2010-12-30

    This report summarizes an extensive effort made to understand how to effectively use the various diagnostic technologies to establish the condition of medium voltage underground cable circuits. These circuits make up an extensive portion of the electric delivery infrastructure in the United States. Much of this infrastructure is old and experiencing unacceptable failure rates. By deploying efficient diagnostic testing programs, electric utilities can replace or repair circuits that are about to fail, providing an optimal approach to improving electric system reliability. This is an intrinsically complex topic. Underground cable systems are not homogeneous. Cable circuits often contain multiple branches with different cable designs and a range of insulation materials. In addition, each insulation material ages differently as a function of time, temperature and operating environment. To complicate matters further, there are a wide variety of diagnostic technologies available for assessing the condition of cable circuits with a diversity of claims about the effectiveness of each approach. As a result, the benefits of deploying cable diagnostic testing programs have been difficult to establish, leading many utilities to avoid the their use altogether. This project was designed to help address these issues. The information provided is the result of a collaborative effort between Georgia Tech NEETRAC staff, Georgia Tech academic faculty, electric utility industry participants, as well as cable system diagnostic testing service providers and test equipment providers. Report topics include: •How cable systems age and fail, •The various technologies available for detecting potential failure sites, •The advantages and disadvantages of different diagnostic technologies, •Different approaches for utilities to employ cable system diagnostics. The primary deliverables of this project are this report, a Cable Diagnostic Handbook (a subset of this report) and an online

  2. Wavelet coefficient analysis for the quantitative determination of damage in tendons and cables

    Science.gov (United States)

    Rizzo, Piervincenzo; Lanza di Scalea, Francesco

    2005-05-01

    Wires, bars, multi-wire strands made of steel or composite materials are widely used in civil infrastructures as tensioning members in cable-stayed bridges, suspension bridges and prestressed concrete. The health monitoring of these components is a long-standing challenge in the NDE community. In the last few years, the authors have been conducting a study on the application of ultrasonic guided waves for the structural health monitoring of bars and multi-wire strands. This paper presents an application of a signal processing technique based on the Discrete Wavelet Transform (DWT) for the detection and the quantification of damage (in the form of small notches) in loaded seven-wire steel strands. The DWT is applied to ultrasonic signals generated and detected via magnetostrictive transducers. The detection and the quantification of damage in the strands are accomplished by constructing and computing a damage index based on the variance and the root mean square of the wavelet coefficient vector of the ultrasonic damage signatures. It is shown that the logarithmic value of the damage index is linearly dependent on the damage size. In the last portion of the paper an eight-dimensional damage index is constructed and it is fed to an artificial neural network that classifies the size and the location of the notch.

  3. Multistrand superconductor cable

    Science.gov (United States)

    Borden, Albert R.

    1985-01-01

    Improved multistrand Rutherford-type superconductor cable is produced by using strands which are preformed, prior to being wound into the cable, so that each strand has a variable cross section, with successive portions having a substantially round cross section, a transitional oval cross section, a rectangular cross section, a transitional oval cross section, a round cross section and so forth, in repetitive cycles along the length of the strand. The cable is wound and flattened so that the portions of rectangular cross section extend across the two flat sides of the cable at the strand angle. The portions of round cross section are bent at the edges of the flattened cable, so as to extend between the two flat sides. The rectangular portions of the strands slide easily over one another, so as to facilitate flexing and bending of the cable, while also minimizing the possibility of causing damage to the strands by such flexing or bending. Moreover, the improved cable substantially maintains its compactness and cross-sectional shape when the cable is flexed or bent.

  4. 荆岳长江公路大桥索塔锚固钢锚梁结构体系分析%Analysis of Steel Anchor Beam Structural System of Anchorage in Pylon of Jingyue Changjiang River Highway Bridge

    Institute of Scientific and Technical Information of China (English)

    张家元; 丁望星; 朱世峰

    2015-01-01

    荆岳长江公路大桥主桥为主跨816 m的双塔不对称混合梁斜拉桥,在成桥状态下,索塔锚固采用两端固定的钢锚梁结构体系。为研究钢锚梁平衡斜拉索索力的作用,验证超静定结构体系钢锚梁的合理性,采用ANSYS软件建立索塔锚固区有限元模型,分析钢锚梁施工过程中2种不同的支承体系方案,并通过足尺模型试验研究钢锚梁对斜拉索索力的分配比例。结果表明:斜拉索初张时采用边跨固定、中跨滑动,斜拉索张拉后两端固定结构体系的钢锚梁承担了斜拉索索力水平分力的83.7%,钢锚梁与塔壁对索力水平分力的分配比例为8∶2,该体系能够发挥钢锚梁平衡斜拉索索力的作用,且结构可靠度高。%The main bridge of Jingyue Changjiang River Highway Bridge is a asymmetric span hybrid girder cable‐stayed bridge with double pylons and with a main span of 816 m .The anchor‐age in a pylon of the bridge in completion state is of the steel anchor beam structural system with its two ends being fixed .To study the function of the anchor beam balancing the stay cable forces and to verify the rationality of the anchor beam of the statically indeterminate structural system , the software ANSYS was used to set up the finite element model for the anchorage in the pylon , 2 different support schemes adopted for construction of the anchor beam were analyzed and the ra‐tios of the stay cable forces distributed by the anchor beam were studied by means of the full‐scale model tests .The results of the study show that the anchor beam using the structural system with its side span end being fixed ,its central span end being slide at the time of initial tensioning of the stay cables and with its two ends being fixed after tensioning of the stay cables can bear 83 .7%horizontal component of the stay cable forces and the ratio of the horizontal component distributed by the anchor beam and pylon wall

  5. Optimization Analysis Model of Self-Anchored Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Pengzhen Lu

    2014-01-01

    Full Text Available The hangers of self-anchored suspension bridge need to be tensioned suitably during construction. In view of this point, a simplified optimization calculation method of cable force for self-anchored suspension bridge has been developed based on optimization theories, such as minimum bending energy method, and internal force balanced method, influence matrix method. Meanwhile, combined with the weak coherence of main cable and the adjacently interaction of hanger forces, a simplified analysis method is developed using MATLAB, which is then compared with the optimization method that consider the main cable's geometric nonlinearity with software ANSYS in an actual example bridge calculation. This contrast proves the weak coherence of main cable displacement and the limitation of the adjacent cable force influence. Furthermore, a tension program that is of great reference value has been developed; some important conclusions, advices, and attention points have been summarized.

  6. New Quality Control Algorithm Based on GNSS Sensing Data for a Bridge Health Monitoring System

    Directory of Open Access Journals (Sweden)

    Jae Kang Lee

    2016-05-01

    Full Text Available This research introduces an improvement plan for the reliability of Global Navigation Satellite System (GNSS positioning solutions. It should be considered the most suitable methodology in terms of the adjustment and positioning of GNSS in order to maximize the utilization of GNSS applications. Though various studies have been conducted with regards to Bridge Health Monitoring System (BHMS based on GNSS, the outliers which depend on the signal reception environment could not be considered until now. Since these outliers may be connected to GNSS data collected from major bridge members, which can reduce the reliability of a whole monitoring system through the delivery of false information, they should be detected and eliminated in the previous adjustment stage. In this investigation, the Detection, Identification, Adaptation (DIA technique was applied and implemented through an algorithm. Moreover, it can be directly applied to GNSS data collected from long span cable stayed bridges and most of outliers were efficiently detected and eliminated simultaneously. By these effects, the reliability of GNSS should be enormously improved. Improvement on GNSS positioning accuracy is directly linked to the safety of bridges itself, and at the same time, the reliability of monitoring systems in terms of the system operation can also be increased.

  7. New Quality Control Algorithm Based on GNSS Sensing Data for a Bridge Health Monitoring System.

    Science.gov (United States)

    Lee, Jae Kang; Lee, Jae One; Kim, Jung Ok

    2016-05-27

    This research introduces an improvement plan for the reliability of Global Navigation Satellite System (GNSS) positioning solutions. It should be considered the most suitable methodology in terms of the adjustment and positioning of GNSS in order to maximize the utilization of GNSS applications. Though various studies have been conducted with regards to Bridge Health Monitoring System (BHMS) based on GNSS, the outliers which depend on the signal reception environment could not be considered until now. Since these outliers may be connected to GNSS data collected from major bridge members, which can reduce the reliability of a whole monitoring system through the delivery of false information, they should be detected and eliminated in the previous adjustment stage. In this investigation, the Detection, Identification, Adaptation (DIA) technique was applied and implemented through an algorithm. Moreover, it can be directly applied to GNSS data collected from long span cable stayed bridges and most of outliers were efficiently detected and eliminated simultaneously. By these effects, the reliability of GNSS should be enormously improved. Improvement on GNSS positioning accuracy is directly linked to the safety of bridges itself, and at the same time, the reliability of monitoring systems in terms of the system operation can also be increased.

  8. The random field model of the spatial distribution of heavy vehicle loads on long-span bridges

    Science.gov (United States)

    Chen, Zhicheng; Bao, Yuequan; Li, Hui

    2016-04-01

    A stochastic model based on Markov random field is proposed to model the spatial distribution of vehicle loads on longspan bridges. The bridge deck is divided into a finite set of discrete grid cells, each cell has two states according to whether the cell is occupied by the heavy vehicle load or not, then a four-neighbor lattice-structured undirected graphical model with each node corresponding to a cell state variable is proposed to model the location distribution of heavy vehicle loads on the bridge deck. The node potential is defined to quantitatively describe the randomness of node state, and the edge potential is defined to quantitatively describe the correlation of the connected node pair. The junction tree algorithm is employed to obtain the systematic solutions of inference problems of the graphical model. A marked random variable is assigned to each node to represent the amplitude of the total weight of vehicle applied on the corresponding cell of the bridge deck. The rationality of the model is validated by a Monte Carlo simulation of a learned model based on monitored data of a cable-stayed bridge.

  9. Overall Design and Study of South and North Bridges of Xiazhang Sea-Crossing Bridge%厦漳跨海大桥南、北汊桥总体设计与研究

    Institute of Scientific and Technical Information of China (English)

    王福敏; 罗强; 李军

    2013-01-01

    厦漳跨海大桥主要由北汊桥、海门岛立交及收费服务区、南汊桥、海平立交四大部分组成,全长9.333 km.为适应复杂的自然与建设条件,对该桥桥位方案进行比选,并对项目中关键控制性工程(北汊主桥、南汊主桥)的桥型方案进行研究.经研究,最终确定北汊主桥采用主跨780m的五跨连续钢箱梁斜拉桥方案,南汊主桥采用主跨300 m的结合梁斜拉桥方案.针对项目中复杂的地质条件、高地震烈度和恶劣的风环境,分别采取设置适应性强的桩基础,对较差的桩基地质注浆;按抗震要求进行构造设计,在主桥塔梁处设置纵向阻尼器,引桥设置减隔震支座;北汊主桥采用一种翼型扶手栏杆、南汊主桥采用分流板抗风等措施进行处理.%The Xiazhang Sea-Crossing Bridge,totally 9.333 km long,is composed of four major parts of the north bridge,Haimen Island interchange and toll service area,south bridge and Haiping interchange.To accommodate the complicated natural and construction conditions of the bridge,the bridge site schemes were compared and the bridge type schemes for the critical control projects (the north and south main bridges) were studied.According to the study,it was finally determined that the 5-span continuous steel box girder cable-stayed bridge with a main span 780 m would be adopted for the north main bridge and the composite girder cable-stayed bridge with a main span 300 m would be adopted for the south main bridge.In consideration of the complicated geologic conditions,high intensity earthquake and harsh wind environment,the well adaptive pile foundations were respectively utilized.For the pile foundations at the locations with poor geology,the foundations would be grouted.The structures of the bridge were designed in compliance with the seismic resistance requirements.At the connections between the pylons and girders of the main bridges,the longitudinal dampers were arranged and on the piers

  10. 考虑缆-梁联合作用的自锚式悬索桥恒载状态计算方法研究%Study on the calculation method of the dead load state for the self-anchored suspension bridge considering the joint action of cable-stiffening girder

    Institute of Scientific and Technical Information of China (English)

    王邵锐; 周志祥; 高燕梅; 唐辉

    2015-01-01

    In most calculation methods for the reasonable finished bridge state of self-anchored suspension bridge, the combined action of cable-stiffening girder can not be considered in a single model, so repeated manual iteration or model boundary condition modification are usually adopted. For this reason, an analytical calculation method considering the combined action of cable-stiffening girder is proposed. Based on the stiffening girder deflection theory, the differential equilibrium equations, geometric equations, and the physical equations of the stiffening girder are used to derive the analytic relationship between the stiffening girder alignment and the suspender force. The end reaction force of the main cable is calculated from the suspender force using the segmental catenary theory. The solutions that meet the compatibility condition of the suspender force and the end reaction of the main cable is obtained by the iteration method. The calculation results by the proposed method agree well with the theoretical reasonable finished bridge state satisfying the principle of minimum potential energy of stiffening girder. The proposed method has the advantage of fast convergence speed and high precision that needed in practical engineering.%自锚式悬索桥合理成桥状态的已有算法中,很难在一个模型中同时考虑缆-梁的联合作用,需要通过反复手动迭代或是修改模型边界条件进行求解,较为繁琐。对此,笔者提出一种考虑缆-梁联合作用的恒载状态计算方法。该方法基于加劲梁的挠度理论,通过梁段的平衡微分方程、几何方程、物理方程推导出加劲梁的线形和索力的解析关系;主缆基于分段悬链线理论,通过已知吊索索力计算主缆端部反力;再用迭代方法得出满足以主缆端部反力和吊索索力为相容条件的解。计算结果表明,该方法能够考虑缆-梁联合作用,得到满足加劲梁最小应变

  11. TECHNICAL CHALLENGES AND REFINEMENT RESEARCH ON WIND RESISTANCE OF LONG-SPAN BRIDGES%大跨度桥梁抗风的技术挑战与精细化研究

    Institute of Scientific and Technical Information of China (English)

    葛耀君

    2011-01-01

    With the rapid development of long span bridges in China in past three decades, this paper presented technical challenges of wind resistance on three type long-span bridges, including flutter instability and control of suspension bridges, wind induced vibration of cable stayed bridges and control of wind-rain induced cable vibration, vortex induced vibration and control of arch bridges, and the refinements on aerodynamic flutter and buffeting of super long span bridges. It can be concluded that the intrinsic limit of a span length due to aerodynamic stability is about 1,500m for suspension bridges, and beyond or even approaching this limit, designers should be prepared to improve its aerodynamic stability. The cable-stayed bridges with a main span over 1000m have high enough critical flutter speed, but the main aerodynamic concern is the rain-wind induced vibration of long stay cables. Except one example of vortex-induced vibration, long-span arch bridges have no wind resistance problem. The refinement research on wind resistance of long-span bridges was also introduced with a full-mode flutter analysis method, the bridge buffeting frequency-domain analysis under skew wind action, the bridge flutter and buffeting reliability evaluation method based on second order theory and first passage theory, and the unveiling of a bridge flutter evolution process, generation mechanism and control law.%以我国30年大跨度桥梁的快速发展为研究背景,对三种大跨度桥梁的抗风技术挑战进行了分析,着重探讨了悬索桥的颤振性能及其控制、斜拉桥风振性能与拉索风雨振和拱式桥涡激共振及其控制,并提出了特大桥梁风振精细化理论和方法.研究结果表明:悬索桥的颤振稳定性跨径上限约为1500 m,超过甚至接近这一上限时,必须采取措施改善加劲梁的抗风稳定性;千米级大跨度斜拉桥仍具有足够高的颤振临界风速,其主要抗风问题是长拉索的风雨振动;大跨

  12. Perpendicular construction of bridge girder for long span suspension bridge under a rapid stream; Kyuchoryuka ni okeru chodai tsuribashi no hokoketa chokka tsuri koho no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, J.; Sakamoto, M.; Nakao, T.; Koga, N. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

    1996-06-20

    Perpendicular construction of bridge girder for a long span suspension bridge, which is to be constructed over the Kurushima Channel, an international route, has been investigated. For the construction of suspension bridge over channels, the overhang construction is generally employed. Bridge girder perpendicular construction, in which unit girder block is lifted from a carrier barge and directly constructed by means of lifting beams located at main cable, is a superb method in terms of cost, time, and safety. It is necessary to stay the carrier barge during the anchoring of girder block and lifting beams. Mooring of the carrier barge is required under a rapid stream, which results in the trouble of under way ships. A propulsion positioning system has been developed for the bridge girder carrier barge, by which the position/propulsion of four thrusters equipped at each corner of the barge can be automatically controlled. Thus, the perpendicular construction of bridge girder has been developed, in which mooring is not required even under the rapid stream. The position of barge can be maintained within a range of {plus_minus}2.5 m even under a rapid stream with a speed of 3 kn. The quick joint can be certainly connected for about one minute in the horizontal movement within {plus_minus}2.5 m and vertical movement within 0.5 m. For this perpendicular construction, the construction time can be shortened to around 16 to 17 minutes, which has been usually taken for three hours. 2 refs., 17 figs., 4 tabs.

  13. Preliminary evaluation of two new cable surface innovations

    DEFF Research Database (Denmark)

    Burlina, Celeste; Georgakis, Christos T.; Larsen, S.V.;

    2015-01-01

    In this paper, the aerodynamic performance of two innovative bridge cable surfaces with concave fillets are examined and compared with traditional helical fillets. To this end, an extensive wind-tunnel test campaign was undertaken to measure the aerodynamic static force coefficients up to a Reyno......In this paper, the aerodynamic performance of two innovative bridge cable surfaces with concave fillets are examined and compared with traditional helical fillets. To this end, an extensive wind-tunnel test campaign was undertaken to measure the aerodynamic static force coefficients up...... to a Reynolds number of 3.2 x 105. The tests confirmed the results obtained from the preliminary tests performed by Kleissl and Georgakis (2013) on the prototype cable surfaces with the concave fillets. Despite a more than 100% increase of the fillet height compared to a traditional helical fillet profile...

  14. Cable Television; A Bibliographic Review.

    Science.gov (United States)

    Schoenung, James

    This bibliographic review of publications in the field of cable television begins with an introduction to cable television and an outline of the history and development of cable television. Particular attention is given to the regulatory activities of the Federal Communications Commission and the unfulfilled potential of cable television. The…

  15. Reusable Hot-Wire Cable Cutter

    Science.gov (United States)

    Pauken, Michael T.; Steinkraus, Joel M.

    2010-01-01

    During the early development stage of balloon deployment systems for missions, nichrome wire cable cutters were often used in place of pyro-actuated cutters. Typically, a nichrome wire is wrapped around a bundle of polymer cables with a low melting point and connected to a relay-actuated electric circuit. The heat from the nichrome reduces the strength of the cable bundle, which quickly breaks under a mechanical load and can thus be used as a release mechanism for a deployment system. However, the use of hand-made heated nichrome wire for cutters is not very reliable. Often, the wrapped nichrome wire does not cut through the cable because it either pulls away from its power source or does not stay in contact with the cable being cut. Because nichrome is not readily soldered to copper wire, unreliable mechanical crimps are often made to connect the nichrome to an electric circuit. A self-contained device that is reusable and reliable was developed to sever cables for device release or deployment. The nichrome wire in this new device is housed within an enclosure to prevent it from being damaged by handling. The electric power leads are internally connected within the unit to the nichrome wire using a screw terminal connection. A bayonet plug, a quick and secure method of connecting the cutter to the power source, is used to connect the cutter to the power leads similar to those used in pyro-cutter devices. A small ceramic tube [0.25-in. wide 0.5-in. long (.6.4-mm wide 13-mm long)] houses a spiraled nichrome wire that is heated when a cable release action is required. The wire is formed into a spiral coil by wrapping it around a mandrel. It is then laid inside the ceramic tube so that it fits closely to the inner surface of the tube. The ceramic tube provides some thermal and electrical insulation so that most of the heat generated by the wire is directed toward the cable bundle in the center of the spiral. The ceramic tube is cemented into an aluminum block, which

  16. How to stay becoming

    DEFF Research Database (Denmark)

    Skrubbeltrang, Lotte Stausgaard; Nielsen, Jens Christian; Olesen, Jesper

    2016-01-01

    In this article we show how a hybridisation of elite sport and school in lower-secondary education in Denmark produces a particular kind of learning subject with dual tracks for development, and we ask what kind of actions the students apply in order to stay becoming along both tracks. We apply...... theoretical conceptions of ‘becoming’ inspired by Brembeck and Johansson that allow us to understand how the sports students live up to the code of conduct of the sports classes. The article is based on an ethnographic study carried out in four schools located in four regions of Denmark. We argue...

  17. Robotic Arm Biobarrier Cable

    Science.gov (United States)

    2008-01-01

    This image, taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander on the 14th Martian day of the mission (June 7, 2008), shows the cable that held the Robotic Arm's biobarrier in place during flight has snapped. The cable's springs retracted to release the biobarrier right after landing. To the lower right of the image a spring is visible. Extending from that spring is a length of cable that snapped during the biobarrier's release. A second spring separated from the cable when it snapped and has been photographed on the ground under the lander near one of the legs. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  18. Buoyant Cable Antenna System

    Science.gov (United States)

    2008-07-02

    comprise a mechanical jacket surrounding a hollow core enclosing the seismic sensor and signal transfer means. Elongated axial stress elements for...to S. H. Bittleston, discloses a semi-dry marine seismic streamer cable that consists of a number of connected streamer cable sections which each...transmitting axial loads and a radial reinforcement member for relieving radial loads are provided in the jacket . The core is filled with a fluid or fluid

  19. Railroad Bridges

    Data.gov (United States)

    Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

  20. AC Cable: Yokohama Project

    Science.gov (United States)

    Masuda, Takato

    High Temperature Superconducting (HTS) cables can transmit large amounts of electricity in a compact size with minimal losses. Therefore, they are expected to save the construction cost of underground lines in urban areas and decrease transmission losses. Several HTS cables have recently been demonstrated in networks around the world, and full-scale commercialization is expected in the near future. In Japan, the development of compact HTS cables suitable for urban deployment has been underway since the early 1990s. In 2007, a national project was started to verify their operational performance and long-term reliability in the grid. An HTS cable 240 m long was installed at the Asahi substation of the Tokyo Electric Power Company (TEPCO) in Yokohama; then a joint, terminations and cooling system was constructed in 2011. After successful performance tests, the cable was connected to the grid for the first time in Japan, and started to deliver electricity to 70,000 households in October 2012. This trouble-free in-grid service continued for over a year. We can conclude that the HTS cable system performs well and has the stability required for long-term in-grid operations.

  1. 30 CFR 77.605 - Breaking trailing cable and power cable connections.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Breaking trailing cable and power cable... OF UNDERGROUND COAL MINES Trailing Cables § 77.605 Breaking trailing cable and power cable connections. Trailing cable and power cable connections between cables and to power sources shall not be...

  2. 郑州市解放路跨线桥主桥设计与施工%Design and Construction of Main Bridge of Jiefang Road Overpass Bridge in Zhengzhou City

    Institute of Scientific and Technical Information of China (English)

    申国朝

    2012-01-01

    The main bridge of the Jiefang Road Overpass Bridge in Zhengzhou City is a cable-stayed bridge with twin pylons, single cable plane and with span arrangement (106 + 248 + 106) m and the bridge employs the structural system of rigid fixity of its pylons and main girder. The main girder of the bridge is of the prestressed concrete triple-cell single box of quasi-triangle section and has a 62 m long variable width portion at the side span on the west side. On both sides of a pylon, 15 pairs of stay cables made up of the low relaxation and high-strength galvanized parallel steel wires are arranged. The pylons are the concrete solid single-column ones of H-shape sections and the main piers are the vase shape hollow reinforced concrete structures supported on the frictional group bored pile foundations. The software Bridge Doctor V3. 03, MIDAS Civil and ANSYS were used to respectively build the plane finite element model for the bridge and the plane link and spatial plate-shell finite element models for the variable width portion. With these models, the global static force of the bridge and the force conditions of the portion were analyzed. In addition, a 1: 4 model for the variable width portion was also designed and made to carry out the model test. The results of the finite element analysis and model test showed that the force conditions of various parts of the bridge could meet the requirements in the codes. The part of the bridge spanning the passenger dedicated railway line on the east side was constructed by the rotation erection while the part of the bridge spanning the freight railway line on the west side was constructed by the covered form traveler.%郑州市解放路跨线桥主桥为双塔单索面斜拉桥,跨径布置为(106+248+106)m,采用塔、梁固结体系.该桥主梁为预应力混凝土单箱三室准三角形截面,西侧边跨设62 m长的变宽段.每个桥塔两侧布置15对斜拉索,斜拉索采用低松弛镀锌高强平行钢丝.桥塔采

  3. How to stay becoming

    DEFF Research Database (Denmark)

    Skrubbeltrang, Lotte Stausgaard; Nielsen, Jens Christian; Olesen, Jesper

    2016-01-01

    that the hybrid obliges students to follow a narrow developmental track with an ambitious goal of performing in both sport and school, and that the hybrid is threatened when a sports student prioritises either sport or school while he/she is still enrolled in the class.......In this article we show how a hybridisation of elite sport and school in lower-secondary education in Denmark produces a particular kind of learning subject with dual tracks for development, and we ask what kind of actions the students apply in order to stay becoming along both tracks. We apply...... theoretical conceptions of ‘becoming’ inspired by Brembeck and Johansson that allow us to understand how the sports students live up to the code of conduct of the sports classes. The article is based on an ethnographic study carried out in four schools located in four regions of Denmark. We argue...

  4. A Study on Earthquake-Resistance Performance of Main Bridge of Suramadu Sea-Crossing Bridge%苏拉马都跨海大桥主桥抗震性能研究

    Institute of Scientific and Technical Information of China (English)

    郭河; 李毅谦

    2011-01-01

    The seismic performance of Suramadu Bridge is particularly important because of the bridge across the Madula Strait and the high seismic intensity at the bridge site. In this paper, based on the antiseismic design of Suramadu Bridge, seismic behavior of cable-stayed bridge is investigated by two-level earthquake-resistance method from the seismic input, the analysis of earthquake response spectrum, the selection of the damping parameters, the analysis of nonlinear time history and the checking of structural earthquake-resistance performance. It is indicated that, the resistance of main bridge of Suramadu Bridge is larger than the requirement under the 2 500-year recurrence interval (2% in 50year) earthquake load.%苏拉马都跨海大桥由于桥址处抗震设防烈度较高,又是跨越马都拉海峡的特大型桥梁,其抗震性能尤为重要.采用两水平的抗震设计方法,从地震输入、地震反应谱分析、阻尼器参数的选取、非线性时程分析、结构的抗震性能验算等方面对苏拉马都跨海大桥的抗震性能进行了研究,结果表明,在2 500年重现期的地震作用下,该桥的主塔以及各基础的抗震性能均满足抗震设防要求.

  5. Cable-Dispensing Cart

    Science.gov (United States)

    Bredberg, Alan S.

    2003-01-01

    A versatile cable-dispensing cart can support as many as a few dozen reels of cable, wire, and/or rope. The cart can be adjusted to accommodate reels of various diameters and widths, and can be expanded, contracted, or otherwise reconfigured by use of easily installable and removable parts that can be carried onboard. Among these parts are dispensing rods and a cable guide that enables dispensing of cables without affecting the direction of pull. Individual reels can be mounted on or removed from the cart without affecting the other reels: this feature facilitates the replacement or reuse of partially depleted reels, thereby helping to reduce waste. Multiple cables, wires, or ropes can be dispensed simultaneously. For maneuverability, the cart is mounted on three wheels. Once it has been positioned, the cart is supported by rubber mounts for stability and for prevention of sliding or rolling during dispensing operations. The stability and safety of the cart are enhanced by a low-center-of-gravity design. The cart can readily be disassembled into smaller units for storage or shipping, then reassembled in the desired configuration at a job site.

  6. Space Flight Cable Model Development

    Science.gov (United States)

    Spak, Kaitlin

    2013-01-01

    This work concentrates the modeling efforts presented in last year's VSGC conference paper, "Model Development for Cable-Harnessed Beams." The focus is narrowed to modeling of space-flight cables only, as a reliable damped cable model is not yet readily available and is necessary to continue modeling cable-harnessed space structures. New experimental data is presented, eliminating the low-frequency noise that plagued the first year's efforts. The distributed transfer function method is applied to a single section of space flight cable for Euler-Bernoulli and shear beams. The work presented here will be developed into a damped cable model that can be incorporated into an interconnected beam-cable system. The overall goal of this work is to accurately predict natural frequencies and modal damping ratios for cabled space structures.

  7. VT Cable Modem Systems 2013

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The VT Cable Modem dataset (CABLEMOD2013) includes lines depicting the extent of Vermont's cable modem broadband system as of 6/30/2013. This data...

  8. Economical Aspects of Superconducting Cable

    Science.gov (United States)

    Ohya, Masayoshi

    High-temperature superconducting (HTS) cables are expected to resolve technical problems with power grids because they put large-capacity, low-loss power transmission into a compact package. One problem is replacing old 275-kV oil filled (OF) cables with cross-linked polyethylene insulated vinyl sheath cables (XLPE cables). This is difficult because XLPE cable has a lower transmission capacity than OF cable. In addition, the high concentration of public infrastructure underground makes it extremely difficult to build new ones. However, if 66-kV HTS cables can be installed inside existing underground conduits and can achieve a power capacity equivalent to conventional 275-kV cables, construction costs could be significantly reduced. Moreover, if XLPE cables are used for a 1,000 MVA-class transmission line, then three circuits of nine 275-kV single-core cables would be required, which would incur a transmission loss of 90 W/m/cct. Three circuits of three 66-kV Three-in-One HTS cables, however, with an AC loss of 1 W/m/ph@3 kA, heat invasion of 2 W/m, and cooling system efficiency of 0.1, would reduce transmission loss to less than three-fifths that of XLPE cables.

  9. High Temperature Superconducting Underground Cable

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, Roger, A.

    2010-02-28

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the world’s first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  10. The Danish Superconducting Cable Project

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1997-01-01

    The design and construction of a superconducting cable is described. The cable has a room temperature dielectric design with the cryostat placed inside the electrical insulation.BSCCO 2223 superconducting tapes wound in helix form around a former are used as the cable conductor. Results from...

  11. 30 CFR 75.607 - Breaking trailing cable and power cable connections.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Breaking trailing cable and power cable... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Trailing Cables § 75.607 Breaking trailing cable and power cable connections. Trailing cable and power cable connections...

  12. Handbook for photovoltaic cabling

    Energy Technology Data Exchange (ETDEWEB)

    Klein, D. N.

    1980-08-01

    This volume, originally written as part of the Interim Performance Criteria Document Development Implementation Plan and Procedures for Photovoltaic Energy Systems, is an analysis of the several factors to be considered in selecting cabling for photovoltaic purposes. These factors, correspoonding to chapter titles, are electrical, structural, safety, durability/reliability, and installation. A glossary of terms used within the volume is included for reference.

  13. Lightweight Electric Power Cable.

    Science.gov (United States)

    1982-09-01

    8I~ .4 111 162 MICROCi Pi RL’ LUHION TESI CHARI "LIGHTWEIGHT ELECTRIC POWER CABLE" FINAL TECHNICAL REPORT SEPTEMBER 30, 1981 to SEPTEMBER 30, 1982... Vulcanized by heat to crosslink. TPE (Thermoplastic Elastomer) - Polymers having elastomeric proper- ties. Used as thermoplastics - melt formed by

  14. Cable Aerodynamic Control

    DEFF Research Database (Denmark)

    Kleissl, Kenneth

    to a categorization of the different control technics together with an identification of two key mechanisms for reduction of the design drag force. During this project extensive experimental work examining the aerodynamics of the currently used cable surface modifications together with new innovative proposals have...

  15. Comparison of cable ageing

    Science.gov (United States)

    Plaček, Vít; Kohout, Tomáš

    2010-03-01

    Two cable types, which currently are used in nuclear power plants (NPP) and which are composed by jacket/insulation materials, i.e. PVC/PVC and PVC/PE, were exposed to accelerated ageing conditions, in order to simulate their behavior after 10 years in service. The cables were aged under two different test conditions: With relatively high accelerating ageing speed:Radiation ageing was carried out at room temperature at a dose rate of 2900 Gy/h, followed by thermal ageing at 100 °C. This accelerated ageing condition was fairly fast, but still in compliance with the standards. With moderate ageing speed:The radiation and thermal ageing was performed simultaneously (superimposed) at a dose rate of 2.7-3.7Gy/h and a temperature of 68-70 °C. Such a test condition seems to be very close to the radiation and temperature impact onto the cables in the real NPP service. Finally, mechanical properties were measured to characterize the ageing status of the cables. The purpose of this study was to compare degradation effects, derived from both ageing methods, and to demonstrate that results obtained from high values of accelerating parameters and from fast ageing simulation can be very different from reality. The observed results corroborated this assumption.

  16. Pediatrics and Cable Television.

    Science.gov (United States)

    Wallerstein, Edward; And Others

    The Department of Community Medicine of the Mount Sinai School of Medicine (New York City), in cooperation with the TelePrompTer Corporation and with funding from the Health Services and Mental Health Administration of the Department of Health, Education, and Welfare, has developed a bidirectional television system using coaxial cable which links…

  17. Flat conductor cable commercialization project

    Science.gov (United States)

    Hogarth, P.; Wadsworth, E.

    1977-01-01

    An undercarpet flat conductor cable and a baseboard flat conductor cable system were studied for commercialization. The undercarpet system is designed for use in office and commercial buildings. It employs a flat power cable, protected by a grounded metal shield, that terminates in receptacles mounted on the floor. It is designed to interface with a flat conductor cable telephone system. The baseboard system consists of a flat power cable mounted in a plastic raceway; both the raceway and the receptacles are mounted on the surface of the baseboard. It is designed primarily for use in residential buildings, particularly for renovation and concrete and masonry construction.

  18. 乌苏大桥主桥上部结构设计与计算%Design and Calculation of Superstructure of Main Bridge of Wusu Bridge

    Institute of Scientific and Technical Information of China (English)

    康晋; 肖海珠; 徐伟

    2011-01-01

    The main bridge of the Wusu Bridge is a single pylon and single cable plane cablestayed bridge with span arrangement (140+140) m and with a structural system of rigid fixity of the pylon, pier and girder. A summarized account of the design and calculation of the superstructure of the bridge is presented herewith. The main girder of the bridge is a composite girder with long cantilevers, the central part of the girder is designed as a two-cell and single-box steel girder and the steel cantilever at each side of the girder is the variable depth I-beam and is provided wiht a trough stringer at the far side, which are all topped with 25 cm thick concrete deck slabs connected with the girder via shearing studs. The part of the main girder close to the pylon is designed as a prestressed concrete box girder to facilitate the fixity of the girder with the pylon. The pylon is the single column pylon, 117 m in height. The stay cables, made up of low relaxation galvanized high strength parallel steel wire strands, are of the harp pattern cable plane arranged in the central alignment of the bridge deck. The finite element software MIDAS Civil 2006 and the SCDS programme are employed to calculate and analyze structure of the bridge. The results of the calculation and analysis indicate that the static, stability and dynamic characteristics of the bridge can meet the requirements in the relevant codes.%乌苏大桥主桥为独塔单索面斜拉桥,跨径布置为(140+140) m,采用塔、墩、梁固结体系,综述该桥上部结构设计与计算.主梁为带大挑臂的钢箱结合梁,中间钢箱梁采用单箱双室截面,两侧钢挑臂为变高度工字形梁,挑臂端部设槽形小纵梁;混凝土桥面板厚25 cm,与钢梁通过剪力钉连接;塔根部主梁采用预应力混凝土箱梁,以方便与桥塔固结;桥塔采用独柱式塔,高117 m;斜拉索为竖琴形中央平行索面布置,采用低松弛镀锌高强度平行钢丝束.采用有限元软件MIDAS Civil

  19. Stay away from asthma triggers

    Science.gov (United States)

    Asthma triggers - stay away from; Asthma triggers - avoiding; Reactive airway disease - triggers; Bronchial asthma - triggers ... to them. Have someone who does not have asthma cut the grass, or wear a facemask if ...

  20. Method to improve superconductor cable

    Science.gov (United States)

    Borden, A.R.

    1984-03-08

    A method is disclosed of making a stranded superconductor cable having improved flexing and bending characteristics. In such method, a plurality of superconductor strands are helically wound around a cylindrical portion of a mandrel which tapers along a transitional portion to a flat end portion. The helically wound strands form a multistrand hollow cable which is partially flattened by pressure rollers as the cable travels along the transitional portion. The partially flattened cable is impacted with repeated hammer blows as the hollow cable travels along the flat end portion. The hammer blows flatten both the internal and the external surfaces of the strands. The cable is fully flattened and compacted by two sets of pressure rollers which engage the flat sides and the edges of the cable after it has traveled away from the flat end portion of the mandrel. The flattened internal surfaces slide easily over one another when the cable is flexed or bent so that there is very little possibility that the cable will be damaged by the necessary flexing and bending required to wind the cable into magnet coils.

  1. EIGENFREQUENCY ANALYSIS OF CABLE STRUCTURES WITH INCLINED CABLES

    Institute of Scientific and Technical Information of China (English)

    William Paulsen; Greg Slayton

    2006-01-01

    The approximate eigenfrequencies for the in-plane vibrations of a cable structure consisting of inclined cables, together with point masses at various points were computed. It was discovered that the classical transfer matrix method was inadequate for this task, and hence the larger exterior matrices were used to determine the eigenfrequency equation. Then predictions of the dynamics of the general cable structure based on the asymptotic estimates of the exterior matrices were made.

  2. Dielectric spectroscopy measurements on very low loss cross-linked polyethylene power cables

    Science.gov (United States)

    Liu, Tong; Fothergill, John; Dodd, Steve; Nilsson, Ulf

    2009-08-01

    The principles of dielectric spectroscopy are reviewed and the techniques in both time and frequency domains are explored in search of appropriate methods for measurement on low loss XLPE cables. By combining the techniques of frequency response analyzer, transformer ratio bridge and discharging current measurements, some preliminary tests results on homopolymer XLPE model cables have been presented and analyzed, in a wide frequency range of 10-4Hz~2×104Hz. Dielectric loss mechanisms of XLPE cables are discussed based on the measurement results.

  3. Dielectric spectroscopy measurements on very low loss cross-linked polyethylene power cables

    Energy Technology Data Exchange (ETDEWEB)

    Liu Tong; Fothergill, John; Dodd, Steve [University of Leicester, LE1 7RH (United Kingdom); Nilsson, Ulf, E-mail: tl57@leicester.ac.u [Borealis AB, SE-444 86 Stenungsund (Sweden)

    2009-08-01

    The principles of dielectric spectroscopy are reviewed and the techniques in both time and frequency domains are explored in search of appropriate methods for measurement on low loss XLPE cables. By combining the techniques of frequency response analyzer, transformer ratio bridge and discharging current measurements, some preliminary tests results on homopolymer XLPE model cables have been presented and analyzed, in a wide frequency range of 10{sup -4}Hz{approx}2x10{sup 4}Hz. Dielectric loss mechanisms of XLPE cables are discussed based on the measurement results.

  4. Design Specifications for a Novel Climatic Wind Tunnel for the Testing of Structural Cables

    DEFF Research Database (Denmark)

    Georgakis, Christos; Koss, Holger; Ricciardelli, Francesco

    2009-01-01

    of cable vibrations already preoccupy both the owners and designers. In this connection, the Danish owners/operators Femern Bælt A/S, together with Storebælt A/S, are funding a collaborative research project to examine the ways of reducing the risk of cable vibrations on a bridge solution. A novel climatic...... wind tunnel facility, dedicated to the testing of structural cables, is being developed as part of this research project. This paper describes the specifications and considerations for the construction of such a facility....

  5. 14 CFR 23.689 - Cable systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Cable systems. 23.689 Section 23.689... Systems § 23.689 Cable systems. (a) Each cable, cable fitting, turnbuckle, splice, and pulley used must meet approved specifications. In addition— (1) No cable smaller than 1/8 inch diameter may be used...

  6. Cable networks, services, and management

    CERN Document Server

    2015-01-01

    Cable Networks, Services, and Management is the first book to cover cable networks, services, and their management, in-depth, for network operators, engineers, researchers, and students. Thirteen experts in various fields have contributed their knowledge of network architectures and services, Operations, Administration, Maintenance, Provisioning, Troubleshooting (OAMPT) for residential and business services, cloud, Software Defined Networks (SDN), as well as virtualization concepts and their applications as part of the future directions of cable networks. The book begins by introducing architecture and services for Data Over Cable Service Interface Specification (DOCSIS) 3.0/ 3.1, Converged Cable Access Platform (CCAP), Content Distribution Networks (CDN, IP TV, and Packet Cable and Wi-Fi for Residential Services. Topics that are discussed in proceeding chapters include: operational systems and management architectures, service orders, provisioning, fault manageme t, performance management, billing systems a...

  7. Cable Bacteria in Freshwater Sediments

    OpenAIRE

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B.; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the fre...

  8. Study for reasonable value of friction coefficient between main cable and saddle

    Institute of Scientific and Technical Information of China (English)

    Deng Ting; Luo Xiheng

    2012-01-01

    The value of friction coefficient between the main cable and saddle, relates to not only the anti-slippage stability of three-tower suspension bridge, but also the reasonable stiffness of the middle tower and the magnitude of rigidity of the whole bridge. First, the paper does some comparative studies about the relevant provisions of international norms, and then, summarizes the relevant load test results both at home and abroad. Finally, the paper draws the appropriate anti-slippage safety factor for the most unfavorable load in accordance with international load standards, and discusses the rationality and feasibility of the friction coefficient of 0.2 between main cable and saddle.

  9. STATIC ANALYSIS OF CABLE STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    HUANG Yan; LAN Wei-ren

    2006-01-01

    Based on the nonlinear geometric relation between strain and displacement for flexible cable, the equilibrium equation under self-weight and influence of temperature was established and an analytical solution of displacement and tension distribution defined in Eulerian coordinate system was accurately obtained. The nonlinear algebraic equations caused by cable structure were solved directly using the modified Powell hybrid algorithm with high precision routine DNEQNE of Fortran. For example, a cable structure consisting of three cables jointly supported by a vertical spring and all the other ends fixed was calculated and compared with various methods by other scholars.

  10. Electromagnetic transients in power cables

    CERN Document Server

    da Silva, Filipe Faria

    2013-01-01

    From the more basic concepts to the most advanced ones where long and laborious simulation models are required, Electromagnetic Transients in Power Cables provides a thorough insight into the study of electromagnetic transients and underground power cables. Explanations and demonstrations of different electromagnetic transient phenomena are provided, from simple lumped-parameter circuits to complex cable-based high voltage networks, as well as instructions on how to model the cables.Supported throughout by illustrations, circuit diagrams and simulation results, each chapter contains exercises,

  11. Power applications for superconducting cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Hansen, Steen; Jørgensen, Preben

    2000-01-01

    High temperature superconducting (HTS) cables for use in electric ac power systems are under development around the world today. There are two main constructions under development: the room temperature dielectric design and the cryogenic dielectric design. However, theoretical studies have shown...... that the insertion of these cables in the network is not without problems. The network stability requirements may impose severe constraints on the actual obtainable length of superconducting cables. Load flow considerations show that it may be difficult to use these high current cables to their full extent. Short...

  12. Aerodynamics of bridge hangers in smooth and turbulent flow and implications on aeroelastic stability

    DEFF Research Database (Denmark)

    Demartino, Cristoforo; Ricciardelli, Francesco; Georgakis, Christos T.

    2015-01-01

    by an extruded High Density PolyEthylene (HDPE) circular sheath [1]. In the last 20 years, several bridge cable manufacturers have introduced surface modifications on HDPE sheath in order to reduce the drag and to ensure the aerodynamic stability in all climatic conditions. In the case of plain HDPE sheaths......, of mechanical damage occurring during transport and installation, as well as of the ageing process due to the exposure to environmental factors. Few experimental works are already available dealing with the effects of imperfections on the aerodynamics of bridge cables. For example, Matteoni and Georgakis...... of a full scale yawed bridge cable section model, for varying Reynolds numbers and wind angles-of-attack, using passive dynamic wind tunnel tests. They demonstrated that the in-plane aerodynamic damping of a bridge cable section and the overall dynamic response are strongly affected by changes in the angle...

  13. Vibration characteristics and damage detection in a suspension bridge

    Science.gov (United States)

    Wickramasinghe, Wasanthi R.; Thambiratnam, David P.; Chan, Tommy H. T.; Nguyen, Theanh

    2016-08-01

    Suspension bridges are flexible and vibration sensitive structures that exhibit complex and multi-modal vibration. Due to this, the usual vibration based methods could face a challenge when used for damage detection in these structures. This paper develops and applies a mode shape component specific damage index (DI) to detect and locate damage in a suspension bridge with pre-tensioned cables. This is important as suspension bridges are large structures and damage in them during their long service lives could easily go un-noticed. The capability of the proposed vibration based DI is demonstrated through its application to detect and locate single and multiple damages with varied locations and severity in the cables of the suspension bridge. The outcome of this research will enhance the safety and performance of these bridges which play an important role in the transport network.

  14. Computation simulation of the nonlinear response of suspension bridges

    Energy Technology Data Exchange (ETDEWEB)

    McCallen, D.B.; Astaneh-Asl, A.

    1997-10-01

    Accurate computational simulation of the dynamic response of long- span bridges presents one of the greatest challenges facing the earthquake engineering community The size of these structures, in terms of physical dimensions and number of main load bearing members, makes computational simulation of transient response an arduous task. Discretization of a large bridge with general purpose finite element software often results in a computational model of such size that excessive computational effort is required for three dimensional nonlinear analyses. The aim of the current study was the development of efficient, computationally based methodologies for the nonlinear analysis of cable supported bridge systems which would allow accurate characterization of a bridge with a relatively small number of degrees of freedom. This work has lead to the development of a special purpose software program for the nonlinear analysis of cable supported bridges and the methodologies and software are described and illustrated in this paper.

  15. Advanced aerostatic analysis of long-span suspension bridges

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    As the span length of suspension bridges increases, the diameter of cables and thus the wind load acting on them, the nonlinear wind-structure interaction and the wind speed spatial non-uniformity all increase consequently, which may have unnegligible influence on the aerostatic behavior of long-span suspension bridges. In this work, a method of advanced aerostatic analysis is presented firstly by considering the geometric nonlinearity, the nonlinear wind-structures and wind speed spatial non-uniformity. By taking the Runyang Bridge over the Yangtze River as example, effects of the nonlinear wind-structure interaction, wind speed spatial non-uniformity, and the cable's wind load on the aerostatic behavior of the bridge are investigated analytically. The results showed that these factors all have important influence on the aerostatic behavior, and should be considered in the aerostatic analysis of long and particularly super long-span suspension bridges.

  16. The subsurface geology along the route of the new bridge at Ada Ciganlija Island (Belgrade, Serbia

    Directory of Open Access Journals (Sweden)

    Knežević Slobodan

    2012-01-01

    Full Text Available The largest single-pylon, cable-stayed bridge in the world was opened in Belgrade on January 1, 2012 and it passes over the tip of the Ada Ciganlija Island. Its monumentality, architectural design and construction innovations became a new symbol of Belgrade. Core samples from the boreholes drilled for the construction of the bridge revealed a relatively complex subsurface geological structure. An Upper Cretaceous-Paleogene flysch formation and Middle Miocene Sarmatian sediments were found near the surface on the right bank of the Sava River. However, at the tip of Ada Ciganlija, the Upper Cretaceous-Palaeogene flysch strata were found below several different Miocene and Quaternary units. In the deepest borehole DB-6, the flysch deposits were found at a depth of 80 meters. On the left bank of the Sava River in New Belgrade, only Upper Miocene Pannonian marls and Pleistocene and Holocene alluvial deposits were drilled. Based on a comparative analysis of the borehole sections and structural characteristics of the rocks, it could be concluded that the Pre-Quaternary units cascade subsided along sub-parallel faults towards N-NW. [Projekat Ministarstva nauke Republike Srbije, br. 176015

  17. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

    Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

  18. Photonic-powered cable assembly

    Science.gov (United States)

    Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

    2013-01-22

    A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

  19. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  20. Electromagnetic Transients in Power Cables

    DEFF Research Database (Denmark)

    Silva, Filipe Faria Da; Bak, Claus Leth

    For more than a century, overhead lines have been the most commonly used technology for transmitting electrical energy at all voltage levels, especially on the highest levels. However, in recent years, an increase in both the number and length of HVAC cables in the transmission networks......, the majority of publications tend to ignore HVAC cables, which is understandable as the use of long HVAC cables was not very common until recent years. This book proposes to address some of the transient phenomena that may occur when operating power networks with HVAC cables. The book is written as a textbook...... for this information in Ph.D. theses and scientific papers. To finish the chapter, we study short-circuits in cables, which can be rather different from short-circuit in OHLs, because of the current returning in the screen. The screen can also be bonded on different configurations, influencing both the magnitude...

  1. On Staying with Our Students

    Science.gov (United States)

    Jennings, Marianne

    2009-01-01

    This paper describes the author's experience and strategy in teaching business law and ethics. Jennings shares how business scandals have changed her three decades of teaching and describes how she has found a way of connecting with students by introducing some cognitive dissonance that stays with them when they are asked to do something in their…

  2. A strange bridge by Leonardo

    CERN Document Server

    Huylebrouck, Dirk

    2013-01-01

    On folio 855 recto of the Codex Atlanticus, Leonardo da Vinci drew three 'easily movable' bridges, but one of them is enigmatic: all 'replicas' in Leonardo museums and exhibitions come as a surprise, to say the least, to any engineer or architect whose attention is drawn to it. This is the case for models in Amboise (France), Chicago and Portland (USA), Florence (Italy) and for the one of the traveling exhibition by the Australian company 'Grande Exhibitions' that already visited 40 major cities in the world. All 'replicas' of the bridge model attributed to Leonardo have pillars standing on the deck of the bridge, while the deck is suspended by cables attached on these pillars. At first sight this problem does not catch the attention of the observer, as the bridge seems to be a mixed form of a beam and a suspension bridge, but it was not overlooked by my colleague architect-engineer Dr. Laurens Luyten (Gent, Belgium). Yet, after a TV-interview in Brussels so much pressure was exerted by some of the museum col...

  3. Effectiveness of Advanced Stay Strong, Stay Healthy in Community Settings

    Directory of Open Access Journals (Sweden)

    Emily M. Crowe MS

    2015-07-01

    Full Text Available The goal of this research was to investigate the effectiveness of the 10-week, University of Missouri (MU Extension strength training program Advanced Stay Strong, Stay Healthy (ASSSH. It was hypothesized that the program can improve strength, balance, agility, and flexibility—all physical measures of falling among seniors. Matched pair t tests were used to compare differences in five physical measures of health, body composition, and percent body fat (%BF. Two-way ANOVA was conducted to examine the age effects on changes in physical health from the start and finish of the exercise program. Following programming, participants significantly improved strength, flexibility, and balance, and significantly reduced %BF (p < .05. Our data indicate that ASSSH can improve the physical health of senior citizens and can successfully be translated into community practice by MU Extension professionals.

  4. Torsional stiffness degradation and aerostatic divergence of suspension bridge decks

    Science.gov (United States)

    Zhang, Z. T.; Ge, Y. J.; Yang, Y. X.

    2013-07-01

    The mechanism of aerostatic torsional divergence (ATD) of long-span suspension bridges is investigated. A theoretical analysis on the basis of a generalized model is presented, showing that the vertical motion of a bridge deck is crucial to the torsional stiffness of the whole suspended system, and that the vertical motion of either cable with a magnitude beyond a certain threshold could result in a sudden degradation of the torsional stiffness of the system. This vertical motion-induced degradation of stiffness is recognized as the main reason for the ATD. Long-span suspension bridges are susceptible to such a type of divergence, especially when they are immersed in turbulent wind fields. The divergences that occur in turbulent wind fields differ significantly from those in smooth wind fields, and the difference is well explained by the generalized model that the loosening of any one cable could result in the vanishing of the part of stiffness provided by the whole cable system. The mechanism revealed in this paper leads to a definition of the critical wind speed of the ATD in a turbulent flow; that is, the one resulting in a vertical motion so large as to loosen either cable to a stressless state. Numerical results from the nonlinear finite-element (FE) analysis of the Xihoumen suspension bridge, in conjunction with observations from wind tunnel tests on an aero-elastic full bridge model, are in support of the viewpoint presented in this study.

  5. Cable Bacteria in Freshwater Sediments.

    Science.gov (United States)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-09-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage.

  6. Cable Television: Citizen Participation in Planning.

    Science.gov (United States)

    Yin, Robert K.

    The historical background of citizen participation in local affairs and its relevance at the onset of community concern about cable television are briefly discussed in this report. The participation of citizens, municipal officials, and cable operators in laying the groundwork for a cable system as well as the pros and cons of cable television as…

  7. 14 CFR 25.689 - Cable systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Cable systems. 25.689 Section 25.689... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Control Systems § 25.689 Cable systems. (a) Each cable, cable fitting, turnbuckle, splice, and pulley must be approved. In addition— (1) No...

  8. 14 CFR 27.1365 - Electric cables.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Electric cables. 27.1365 Section 27.1365... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Electrical Systems and Equipment § 27.1365 Electric cables. (a) Each electric connecting cable must be of adequate capacity. (b) Each cable that would...

  9. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

  10. Stay-Behind og Firmaet

    DEFF Research Database (Denmark)

    Heiberg, Morten Rievers

    En række hemmelige og illegale grupper, der havde deres udspring i de europæiske modstandsbevægelser, opbyggede i tiden efter 1945 et bevæbnet net, der gik under betegnelsen 'stay-behind'. Der var tale om enheder, som skulle være klar til at udføre militære operationer bag fjendens linjer i tilfæ...

  11. Staying Safe in the Water

    Centers for Disease Control (CDC) Podcasts

    2008-05-15

    In this podcast, Dr. Julie Gilchrist, a pediatrician and medical epidemiologist from CDC’s Injury Center, talks about staying safe in the water. Tips are for all audiences, with a focus on preventing drownings and keeping children safe in and around the pool, lake, or ocean.  Created: 5/15/2008 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 5/19/2008.

  12. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2015-01-01

    A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post-tensioning......, and gives a large positive bending moment below the load and a smaller negative bending moment in the unloaded side. When the Pearl-Chain Bridge concept is compared to other pre-fabricated arch bridge solutions we find a number of advantages when using Pearl-Chain Bridges: Straight elements, combination...

  13. Determination of aerodynamic damping and force coefficients of filleted twin cables in dry conditions through passive-dynamic wind tunnel tests

    DEFF Research Database (Denmark)

    Mattiello, E.; Eriksen, M. B.; Georgakis, Christos T.

    Moderate amplitude vibrations continue to be reported on the Øresund Bridge cables, although fitted with fillets and dampers. To further investigate the aerodynamics of the bridge’s twin-cable arrangement, 1:2.3 scale passive-dynamic wind tunnel tests of the cables were performed at the DTU....../FORCE Technology Climatic Wind Tunnel facility. The measured aerodynamic damping of the twin-cable arrangement in dry conditions was compared to the values obtained from full-scale monitoring and from an analytical model using static force coefficients. The comparison revealed broad agreement in the investigated...

  14. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  15. Military Adaptation of Kevlar for Portable Bridge Reinforcement Cables.

    Science.gov (United States)

    1980-06-18

    W 3 104 tensionSmember ------ tecnology o WESTMINSTER, CALIFORNIA FIGURE A9_______- SPECIMEN S-3f -CST- Ll DATE ’IM1 17 ’(S i~7.3~o~l~7 - I~ok...to be run over sheaves or other obstructions that might push it back. For short term emergency use or for testing purposes the tails can be wrapped

  16. Shape modification of bridge cables for aerodynamic vibration control

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos

    2010-01-01

    and faceted cylinders are found to suffer from either dry inclined galloping, ”drag crisis” or Den Hartog galloping, the shrouded cylinder is found to be completely stable for all wind angles of attack, albeit with a slight increase in drag at traditional design wind velocities. The wavy cylinder is found...

  17. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

    Department of Homeland Security — The NBI is a collection of information (database) describing the more than 600,000 of the Nation's bridges located on public roads, including Interstate Highways,...

  18. Brookhaven superconducting cable test facility

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, E.B.; Gibbs, R.J.

    1976-08-17

    Construction has started on an outdoor testing station for flexible ac superconducting power transmission cables. It is intended to serve as an intermediate step between laboratory-scale experiments and qualification testing of prototype-scale cables. The permanent equipment includes a 500 W supercritical helium refrigerator using a screw compressor and multistage turbine expanders. Helium storage for 250,000 cu ft of helium at 250 psi is provided. Initially, the cables will be tested in a horizontal cryostat some 250 ft long. High-voltage 60 Hz tests will be performed with the cable in a series resonant mode with a maximum line to ground capability of 240 kV, this is adequate for a 138 kV system design. Impulse testing up to about 650 kV is planned. The cable conductor will be energized by current transformers, initially at about 4 kA and later up to fault levels of 40 kA. The refrigerator is now at the site and testing on a dummy load will commence in the Fall of 1976. The cryostat will be installed in 1977 followed about a year later by the first cable tests.

  19. Numerical Modelling of Rain-Wind-Induced Vibration: Erasmus Bridge, Rotterdam

    NARCIS (Netherlands)

    Geurts, C.; Vrouwenvelder, T.; Staalduinen, P.C. van; Reusink, J.

    1998-01-01

    Shortly after completion, the main span cables of the Erasmus Bridge in Rotterdam showed aerodynamic instabilities with large amplitudes. These instabilities were recognised as rain-wind-induced vibrations. Temporary measures were installed on the bridge, and a year later, tuned hydraulic dampers we

  20. Optical Measurement of Cable and String Vibration

    Directory of Open Access Journals (Sweden)

    Y. Achkire

    1998-01-01

    Full Text Available This paper describes a non contacting measurement technique for the transverse vibration of small cables and strings using an analog position sensing detector. On the one hand, the sensor is used to monitor the cable vibrations of a small scale mock-up of a cable structure in order to validate the nonlinear cable dynamics model. On the other hand, the optical sensor is used to evaluate the performance of an active tendon control algorithm with guaranteed stability properties. It is demonstrated experimentally, that a force feedback control law based on a collocated force sensor measuring the tension in the cable is feasible and provides active damping in the cable.

  1. Running Safety of Freight Train Passing Long-Span Cable-Stayed Railway Bridge under Cross Wind%横风作用下货物列车通过大跨度铁路斜拉桥的走行安全性研究

    Institute of Scientific and Technical Information of China (English)

    郭向荣; 何玮; 朱志辉; 何旭辉

    2016-01-01

    根据弹性系统动力学总势能不变的原理,以轨道不平顺作为自激励、风荷载作为外部激励,建立考虑风荷载作用的车桥系统耦合振动方程,对横风作用下满载和空载2种运营工况下货物列车通过大跨度铁路斜拉桥时的走行安全性进行研究.结果表明:在桥面风速为25 m·s-1情况下,当车速低于100 km·h-1时满载货物列车的脱轨系数和轮重减载率均未超标,而车速高于40 km·h-1时空载货物列车的脱轨系数和轮重减载率均超标;相对于满载工况,空载工况下桥梁与列车的动力响应受车速和桥面风速的影响较大,而受列车在桥面迎、背风位置的影响较小;在横风作用下,货物列车通过大跨度铁路斜拉桥时,空载工况的车辆响应明显大于满载工况,因此货物列车以空载状态通过大跨度铁路斜拉桥时应根据桥面风速合理降低车速.

  2. 结合梁斜拉桥的空间非线性静力分析及自振特性的研究%Spatial static non-linear analysis of cable-stayed bridge with composite girder and study of its eigenvibration problem

    Institute of Scientific and Technical Information of China (English)

    石现峰; 李建斌; 张彦玲

    2003-01-01

    针对板桁结合斜拉桥的空间受力特点,综合考虑引起斜拉桥结构几何非线性三种因素的影响,建立了板桁结合斜拉桥结构的空间几何非线性有限元分析理论.编制了斜拉桥的空间几何非线性静力分析程序和动力分析程序,应用所编软件,分析了一座板桁结合斜拉桥在自重恒载作用下的结构内力,并对该桥的自振特性进行了计算.

  3. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  4. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  5. Why trains stay on tracks

    Science.gov (United States)

    Shayak, B.

    2017-03-01

    In this article, we give both qualitative and quantitative explanations of why a train stays on its track, in spite of perturbations that could cause it to derail. We show that train stability originates from the conical shape of the wheels, which gives rise to a restoring normal force in response to a lateral disturbance. We first demonstrate translational stabilization in a simple situation where the rails are assumed frictionless and the steering motion of the wheel is neglected. We then develop a more comprehensive model, taking friction and steering into account. We show that rolling friction couples the rotational motion to the translational motion, enhancing overall stability. Finally, we find approximate formulae for the parameters governing stability, and show good agreement with parameters of a real railway coach.

  6. Umbilical cable recovery load analysis

    Science.gov (United States)

    Yan, Shu-wang; Jia, Zhao-lin; Feng, Xiao-wei; Li, Shi-tao

    2013-06-01

    Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field. The severe ocean environment makes great challenges to umbilical maintenance and repair work. Damaged umbilical is usually recovered for the regular operation of the offshore production system. Analysis on cables in essence is a two-point boundary problem. The tension load at the mudline must be known first, and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation. The recovery analysis also involves umbilical-soil interaction and becomes more complicated. Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed. The analysis results provide a theoretical reference for offshore on-deck operation.

  7. Umbilical Cable Recovery Load Analysis

    Institute of Scientific and Technical Information of China (English)

    YAN Shu-wang; JIA Zhao-lin; FENG Xiao-wei; LI Shi-tao

    2013-01-01

    Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field.The severe ocean environment makes great challenges to umbilical maintenance and repair work.Damaged umbilical is usually recovered for the regular operation of the offshore production system.Analysis on cables in essence is a two-point boundary problem.The tension load at the mudline must be known first,and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation.The recovery analysis also involves umbilicalsoil interaction and becomes more complicated.Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed.The analysis results provide a theoretical reference for offshore on-deck operation.

  8. 47 CFR 76.640 - Support for unidirectional digital cable products on digital cable systems.

    Science.gov (United States)

    2010-10-01

    ... products on digital cable systems. 76.640 Section 76.640 Telecommunication FEDERAL COMMUNICATIONS... Standards § 76.640 Support for unidirectional digital cable products on digital cable systems. (a) The requirements of this section shall apply to digital cable systems. For purposes of this section, digital...

  9. Online Cable Tester and Rerouter

    Science.gov (United States)

    Lewis, Mark; Medelius, Pedro

    2012-01-01

    Hardware and algorithms have been developed to transfer electrical power and data connectivity safely, efficiently, and automatically from an identified damaged/defective wire in a cable to an alternate wire path. The combination of online cable testing capabilities, along with intelligent signal rerouting algorithms, allows the user to overcome the inherent difficulty of maintaining system integrity and configuration control, while autonomously rerouting signals and functions without introducing new failure modes. The incorporation of this capability will increase the reliability of systems by ensuring system availability during operations.

  10. IntelliCable Interface Specification

    Science.gov (United States)

    2016-07-14

    manager on how to use this. Some will factor the priority into account and always consume the highest priority while others...Battlefield Air Operations power manager uses a 10 pin Glenair Mighty Mouse connector with default keying . Pin 9 is specified as the IntelliCable pin. A BAO...standard Soldier Power Manager uses a 7 pin Glenair Mighty Mouse Connector, using alternative keying distinct from the Land Warrior battery specification, and the Li-145 battery. Pin 3 is defined as the IntelliCable pin.

  11. Motility of Electric Cable Bacteria

    OpenAIRE

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner; Schramm, Andreas; Nielsen, Lars Peter

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces with a highly variable speed of 0.5 ± 0.3 μm s−1 (mean ± standard deviation) and time between reversals of 155 ± 108 s. They frequently moved forward in loops, and formation of twisted loops revealed ...

  12. North American Submarine Cable Association (NASCA) Submarine Cables

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data show the locations of in-service and out-of-service submarine cables that are owned by members of NASCA and located in U.S. territorial waters. More...

  13. Anti-slip security assessment between main cable and saddle of the middle pylon under extreme vehicle loads

    Institute of Scientific and Technical Information of China (English)

    Cui Jia; Ruan Xin; Zhou Xiaoyi

    2011-01-01

    The traffic condition of Taizhou Yangtze River Bridge is obtained to a certain extent, according to the traffic investigation nearby Taizhou Bridge. The statistical characteristics of the traffic conditions are acquired by statistical analysis. Simulation of the extreme vehicle loads and the sensitive analysis of load parameters are carried out based on these data complemented, which would guide the determination of the frictional coefficient between the main cables and the saddle.

  14. 30 CFR 18.45 - Cable reels.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Cable reels. 18.45 Section 18.45 Mineral... § 18.45 Cable reels. (a) A self-propelled machine, that receives electrical energy through a portable cable and is designed to travel at speeds exceeding 2.5 miles per hour, shall have a...

  15. 47 CFR 32.2421 - Aerial cable.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Aerial cable. 32.2421 Section 32.2421... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2421 Aerial cable. (a) This account shall include the original cost of aerial cable and of drop and block wires served by...

  16. 47 CFR 32.2423 - Buried cable.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Buried cable. 32.2423 Section 32.2423... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2423 Buried cable. (a) This account shall include the original cost of buried cable as well as the cost of other material...

  17. 47 CFR 32.2422 - Underground cable.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Underground cable. 32.2422 Section 32.2422... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2422 Underground cable. (a) This account shall include the original cost of underground cable installed in conduit and...

  18. 21 CFR 890.1175 - Electrode cable.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrode cable. 890.1175 Section 890.1175 Food... DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1175 Electrode cable. (a) Identification. An electrode cable is a device composed of strands of insulated electrical conductors...

  19. Aspen Notebook: Cable and Continuing Education.

    Science.gov (United States)

    Adler, Richard; Baer, Walter S.

    This is the first of a planned series of Aspen Notebooks on cable television (CATV). Part I reports on research conducted by the Aspen Workshop on Uses of the Cable. It describes the status of continuing education and the history of educational television and explores the prospects created by cable's development for extending access to continuing…

  20. Cable Television Report and Suggested Ordinance.

    Science.gov (United States)

    League of California Cities, Sacramento.

    Guidelines and suggested ordinances for cable television regulation by local governments are comprehensively discussed in this report. The emphasis is placed on franchising the cable operator. Seventeen legal aspects of franchising are reviewed, and an exemplary ordinance is presented. In addition, current statistics about cable franchising in…

  1. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...... Belgrade), Leo Pekkala (Finnish Centre for Media Education and Audiovisual Media/MEKU), Julie Uldam (Network on Civic Engagement and Social Innovation) and Gabriella Velics (Community Media Forum Europe)....

  2. Mathematical bridges

    CERN Document Server

    Andreescu, Titu; Tetiva, Marian

    2017-01-01

    Building bridges between classical results and contemporary nonstandard problems, Mathematical Bridges embraces important topics in analysis and algebra from a problem-solving perspective. Blending old and new techniques, tactics and strategies used in solving challenging mathematical problems, readers will discover numerous genuine mathematical gems throughout that will heighten their appreciation of the inherent beauty of mathematics. Most of the problems are original to the authors and are intertwined in a well-motivated exposition driven by representative examples. The book is structured to assist the reader in formulating and proving conjectures, as well as devising solutions to important mathematical problems by making connections between various concepts and ideas from different areas of mathematics. Instructors and educators teaching problem-solving courses or organizing mathematics clubs, as well as motivated mathematics students from high school juniors to college seniors, will find Mathematical Bri...

  3. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  4. 中朝鸭绿江界河公路大桥耐久性技术研究%Study of Durability Enhancing Techniques for Yalu Boundary River Highway Bridge Connecting China and DPR Korea

    Institute of Scientific and Technical Information of China (English)

    闫大伟

    2014-01-01

    The Yalu Boundary River Highway Bridge is a two-pylon steel box girder cable-stayed bridge with a main span of 636 m .The bridge site is located where the climate is harsh in winter and the meteorological condition is complex ,creating challenges for the durability of the bridge .By the combined use of both the theoretical and experimental methods ,a number of studies were conducted ,including the mixing proportion design of the frost-resisting high performance concrete that has high flow state and is able to resist sea water erosion ,the feasibility of - 10 ~ - 5℃ low temperature welding techniques and the externally-installed vibration absorbers for stay ca-bles .The results of the study indicate that the chosen compressive strength ,shrinking behavior , impermeability and frost and thaw resistant performance of concrete all have superior indexes which meet the design requirements .The trial plates were made to take shape by the welding tech-niques applied to real bridges .The tensile strength in the welding joints of trial plates and the yielding strength ,tensile strength and the extension rate after break of the metals in the welding joints could meet the requirements .The feasigility of - 10 ~ - 5 ℃ low temperature welding is proved feasible .And according to the testing results ,the quality control measures for the steel box girder heat preservation ,preheating and other low temperature welding were determined . The pendulum leverage mass vibration dampers featuring the eddy current damping and friction damp -ing for stay cables have sound vibration damping effect and temperature stability .The application of the aforementioned techniques ensures that the bridge has sound durability .%中朝鸭绿江界河公路大桥为主跨636 m 的双塔双索面钢箱梁斜拉桥,桥址处气候严寒,气象条件复杂。为解决桥梁耐久性问题,通过理论与试验相结合的方法,进行高流态耐海水侵蚀的抗冻性高性

  5. Simplified Analytical Method for Optimized Initial Shape Analysis of Self-Anchored Suspension Bridges and Its Verification

    Directory of Open Access Journals (Sweden)

    Myung-Rag Jung

    2015-01-01

    Full Text Available A simplified analytical method providing accurate unstrained lengths of all structural elements is proposed to find the optimized initial state of self-anchored suspension bridges under dead loads. For this, equilibrium equations of the main girder and the main cable system are derived and solved by evaluating the self-weights of cable members using unstrained cable lengths and iteratively updating both the horizontal tension component and the vertical profile of the main cable. Furthermore, to demonstrate the validity of the simplified analytical method, the unstrained element length method (ULM is applied to suspension bridge models based on the unstressed lengths of both cable and frame members calculated from the analytical method. Through numerical examples, it is demonstrated that the proposed analytical method can indeed provide an optimized initial solution by showing that both the simplified method and the nonlinear FE procedure lead to practically identical initial configurations with only localized small bending moment distributions.

  6. Design of Danyang Road Bridge in Heze City%菏泽市丹阳路大桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟

    2015-01-01

    菏泽市丹阳路大桥为(40+100+240+100+40) m 双塔中央单索面半飘浮体系混凝土斜拉桥。该桥塔、墩固结,主梁与塔、墩间设置横、竖向支座和纵向液压阻尼器;主梁采用单箱三室斜腹板截面,高3.6m。桥塔采用顺桥向人字形的独柱混凝土塔,高68.2m,单箱单室矩形空心截面。人字形塔柱穿过主梁,与墩身顺接,墩身采用十字形空心薄壁截面,矩形承台,布置33根φ2.0m钻孔灌注桩。辅助墩和交接墩均采用花瓶形双柱式框架墩,矩形承台,布置8根φ1.5m钻孔灌注桩。斜拉索采用φ7 mm镀锌高强平行钢丝束。采用MIDAS Civil 2006和SCDS平面程序对该桥进行计算分析,结果表明该桥各项检算均满足规范要求。%T he Danyang Road Bridge in Heze City is a semi‐floating system concrete cable‐stayed bridge with double pylons ,a central single cable plane and with span arrangement (40+100+240+100+40) m .T he pylons and piers of the bridge are rigidly fixed and in betw een the main girder and pylons and piers ,the lateral and vertical bearings and the longitudinal hydraulic damp‐ers are arranged .The cross section of the main girder is the section of triple‐cell single box with in‐clined webs and the girder is 3 .6 m in depth .In the longitudinal direction of the bridge ,a pylon is the single‐column concrete pylon in the shape of inverted Y ,is 68 .2 m in height and the cross sec‐tion of the pylon is the rectangular hollow section of single‐cell single box .The inverted Y‐shape pylon passes through the main girder and is smoothly fixed with the pylon pier .The cross section of the pylon pier is the crisscross hollow thin‐wall section and the pier stands on the rectangular pile cap under w hich 33 nos .of φ2 .0 m bored piles are arranged .T he auxiliary piers and boundary piers are all the vase‐shape double‐column frame piers and respectively stand on each rectangular

  7. Improving Energy Efficiency Cable Production

    Directory of Open Access Journals (Sweden)

    Iashutina Olga

    2016-01-01

    Full Text Available During the energy calculation is made at different temperatures of the heating surface. The influence of the speed of pulling on the cost of the finished products of cable products. The interrelation of speed broaching and temperature of the heating surface.

  8. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... the averaged spectral densities(ASD). From the ASD the eigenfrequencies of the structure can be identified. This information can be used in the main analysis, where alle modal parameters are extracted from the spectral densities. Due to long cabling and low response levels (small ambient loads) the response...

  9. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    1998-01-01

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... the averaged spectral densities(ASD). From the ASD the eigenfrequencies of the structure can be identified. This information can be used in the main analysis, where alle modal parameters are extracted from the spectral densities. Due to long cabling and low response levels (small ambient loads) the response...

  10. Modeling Magnetic Fields from a DC Power Cable Buried Beneath San Francisco Bay Based on Empirical Measurements.

    Science.gov (United States)

    Kavet, Robert; Wyman, Megan T; Klimley, A Peter

    2016-01-01

    The Trans Bay Cable (TBC) is a ±200-kilovolt (kV), 400 MW 85-km long High Voltage Direct Current (DC) buried transmission line linking Pittsburg, CA with San Francisco, CA (SF) beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable's path; these included the San Francisco-Oakland Bay Bridge (BB), the Richmond-San Rafael Bridge (RSR), the Benicia-Martinez Bridge (Ben) and an area in San Pablo Bay (SP) in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field) to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable's contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing) were virtually identical to the measured values. The modeling

  11. Modeling Magnetic Fields from a DC Power Cable Buried Beneath San Francisco Bay Based on Empirical Measurements.

    Directory of Open Access Journals (Sweden)

    Robert Kavet

    Full Text Available The Trans Bay Cable (TBC is a ±200-kilovolt (kV, 400 MW 85-km long High Voltage Direct Current (DC buried transmission line linking Pittsburg, CA with San Francisco, CA (SF beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable's path; these included the San Francisco-Oakland Bay Bridge (BB, the Richmond-San Rafael Bridge (RSR, the Benicia-Martinez Bridge (Ben and an area in San Pablo Bay (SP in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable's contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing were virtually identical to the measured values. The

  12. Offshore Cable Installation - Lillgrund. Lillgrund Pilot Project

    Energy Technology Data Exchange (ETDEWEB)

    Unosson, Oscar (Vattenfall Vindkraft AB, Stockholm (Sweden))

    2009-01-15

    This report describes the installation method and the experiences gained during the installation of the submarine cables for the offshore wind farm at Lillgrund. The wind farm consists of 48 wind turbines and is expected to produce 0.33 TWh annually. Different aspects of the installation, such as techniques, co-operation between the installation teams, weather conditions and regulatory and environmental issues are described in this report. In addition, recommendations and guidelines are provided, which hopefully can be utilised in future offshore wind projects. The trenches, in which the submarine cables were laid, were excavated weeks before the cable laying. This installation technique proved to be successful for the laying of the inter array cables. The export cable, however, was laid into position with difficulty. The main reason why the laying of the export cable proved more challenging was due to practical difficulties connected with the barge entrusted with the cable laying, Nautilus Maxi. The barge ran aground a number of times and it had difficulties with the thrusters, which made it impossible to manoeuvre. When laying the inter array cables, the method specification was closely followed, and the laying of the cables was executed successfully. The knowledge and experience gained from the offshore cable installation in Lillgrund is essential when writing technical specifications for new wind plant projects. It is recommended to avoid offshore cable installation work in winter seasons. That will lower the chances of dealing with bad weather and, in turn, will reduce the risks

  13. Cable Harness Assembly Planning in Virtual Environment

    Institute of Scientific and Technical Information of China (English)

    LIU Jianhua; NING Ruxin; BAI Shuqing; WANG Bile

    2006-01-01

    Based on the analysis of characteristic of cable harness planning in virtual environment, a discrete control node modeling (DCNM) method of cable harness in virtual environment and the cable harness assembly routing technique based on it are proposed. DCNM converts a cable harness into continuous flexed line segments connected by a series of section center points, and the design can realize cable harness planning through controlling those control nodes. This method of cable harness routing in the virtual environment breaks the status that virtual assembly process planning is just suitable for the rigid components at present, and impulse the virtual assembly process planning to be more practical. Relation algorithms have been verified in a self-developed system named virtual cable harness assembly planning (VCHAP) system, and this VCHAP system has been applied in assembly process planning of aerospace-related products.

  14. Gjoea power cable; a green solution

    Energy Technology Data Exchange (ETDEWEB)

    Dretvik, Svein-Egil

    2010-07-01

    An alternative to today's power generation offshore using either gas or diesel, is alternating current (AC) electric power cable from shore. The power from shore through the AC cable gives high savings for the environment. The cable replaces 4 gas turbines with a total CO2 disposal of 240 00 tonnes each year which represents the disposal of 100 000 cars. ABB was awarded the contract which includes engineering, fabrication and installation of the power cable from Mongstad to the Gjoea platform which will be the longest AC cable in the world with a total length of 100 km. The presentation will include system design, qualification of dynamic power cable, cable fabrication experiences, testing at fabrication yard and installation aspects. (Author)

  15. Self-healing cable apparatus and methods

    Science.gov (United States)

    Huston, Dryver (Inventor); Esser, Brian (Inventor)

    2007-01-01

    Self-healing cable apparatus and methods are disclosed. The cable has a central core surrounded by an adaptive cover that can extend over the entire length of the cable or just one or more portions of the cable. The adaptive cover includes a protective layer having an initial damage resistance, and a reactive layer. When the cable is subjected to a localized damaging force, the reactive layer responds by creating a corresponding localized self-healed region. The self-healed region provides the cable with enhanced damage resistance as compared to the cable's initial damage resistance. Embodiments of the invention utilize conventional epoxies or foaming materials in the reactive layer that are released to form the self-healed region when the damaging force reaches the reactive layer.

  16. Power applications for superconducting cables in Denmark

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Østergaard, Jacob; Olsen, S. Krüger

    1999-01-01

    In Denmark a growing concern for environmental protection has lead to wishes that the open country is kept free of overhead lines as far as possible. New lines under 100 kV and existing 60/50 kV lines should be established as underground cables. Superconducting cables represent an interesting...... alternative to conventional cables, as they are able to transmit two or more times the energy than a conventional cable. HTS cables with a room temperature dielectric design are especially interesting as a target for replacing overhead lines. Superconducting cables in the overall network are of interest...... in cases such as transmission of energy into cities and through areas of special interest. The planned large groups of windmills in Denmark generating up to 2000 MVA or more both on dry land and off-shore will be an obvious case for the application of superconducting AC or DC cables. These opportunities...

  17. High Voltage Cable Splicing and Cable Termination Techniques

    Science.gov (United States)

    1976-08-01

    solid dielectric insulations currently used are high-molecular-weight polyethylene (EP) and cross-linked poly- ethylene ( XLPE ). The EP insulation is...rated for 750 C a maximum temperature, and the XLPE insulation is rated for 900C maximum temperature. These insulation materials provide the conductor...The cost of installing PILC with copper conductors is compared to the cost of installing XLPE cable with aluminum conductors in Table 1. The

  18. Geoportal "READY:Prepare, Prevent, Stay Informed"

    Science.gov (United States)

    Sole, Aurelia; Albano, Raffaele; Giuzio, Luciana; Manfreda, Salvatore; Maggio, Massimo; Presta, Aldo; Albano, Giovanni

    2014-05-01

    Information, communication, and training at all levels of a hydrogeological risk prevention culture is useful and necessary to develop the awareness among the people; this awareness can only lead to the correct application of the rules and correct behaviours that reduce the risk. A territorial system is more vulnerable to a calamitous event if there is little risk knowledge, in terms of knowledge of phenomenology of the event itself, of its own way to manifest and of the actions needed to mitigate their harmful effects. So, the Geoportal "READY: Prepare, Prevent, Stay Informed," developed by the School of Engineering at the University of Basilicata in collaboration with Paesit srl and Wat-TUBE, a spin-off of University of Basilicata, aims to inform people in an easy and correct way. This can improve the knowledge of the territory in order to promote the consciousness and awareness of the risks affecting the territory, in geo-localized form, even through using the memory of past disasters and precise directions on what to do for a tangible reduction of the risk. The Geoportal stores and dynamically integrates a series of layers that, individually, have a lower utility, but integrated into the web-based platform represent, for the prevention of the risks of the citizens, the anatomy for medicine. In fact, it makes the data not only available but concretely accessible. It is created on the "MapServer" platform, an open source web mapping suggested by the European Directives in the field of geographic database publication, and covers the Italian territory. It is designed to increase the knowledge of the areas at potential flood and landslide risk, delineated by the Authorities in the "P.A.I. (Piano di Assetto Idrogeologico"), and the elements which could possibly be involved in potential events with a particular attention to the critical infrastructures, such as bridges, railways and so on, and relevant structures, such as schools and hospitals. It permits the

  19. Direct-detect Type Residual Charge Method with Short-term Voltage Up-down for Water Tree Deterioration Diagnosis in XLPE Cable

    Science.gov (United States)

    Ootaka, Iwao; Aoki, Masaru; Togashi, Hirotaka; Tsujimoto, Tomiyuki; Nakade, Masahiko

    Water tree is one of the unique type of deterioration in XLPE cable, which is the primary cause of aging breakdown. Water tree, which bridges between conductor and shield, can be detected easily, such as DC leakage current method. However, 22kV class or above XLPE cable, most of breakdown occurs before water tree bridges, and there used to be no effective method for detecting non-bridged water tree. In this paper, we've found residual charge in harmful water tree relaxes quickly with AC voltage application. To detect this type of residual charge, we've developed new diagnosis method with “direct-detect type residual charge method" and “short-term voltage up-down method". This new method found to be very effective for diagnosing over 22kV class XLPE cable lines.

  20. Improvement of the laying technology of cable and installation quality%提高电缆敷设工艺改进安装质量

    Institute of Scientific and Technical Information of China (English)

    索力钢

    2014-01-01

    This paper introduced the method of cable bridge secondary design and cable tube secondary design,described the preparation work need to do before laying cables,emphatically elaborated the technology requirements of cable laying,in order to ensure the rationality of cable laying,promoted the normal production and operation of power plant.%介绍了电缆桥二次设计与电缆管二次设计的方法,对敷设电缆前需做的准备工作进行了说明,着重对电缆敷设的技术要求作了分析阐述,以确保电缆敷设的合理性,促进电厂正常生产运行。

  1. Condition Monitoring of Power Cables

    OpenAIRE

    Lewin, P L; L. Hao; Swaffield, D J; Swingler, S.G.

    2007-01-01

    A National Grid funded research project at Southampton has investigated possible methodologies for data acquisition, transmission and processing that will facilitate on-line continuous monitoring of partial discharges in high voltage polymeric cable systems. A method that only uses passive components at the measuring points has been developed and is outlined in this paper. More recent work, funded through the EPSRC Supergen V, UK Energy Infrastructure (AMPerES) grant in collaboration with UK ...

  2. Stay vane and wicket gate relationship study

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2005-01-19

    This report evaluates potential environmental and performance gains that can be achieved in a Kaplan turbine through non-structural modifications to stay vane and wicket gate assemblies. This summary is based primarily on data and conclusions drawn from models and studies of Lower Granite Dam. Based on this investigation, the study recommends (1) a proof of concept at Lower Granite Dam to establish predicted improvements for the existing turbine and to further refine the stay vane wicket gate designs for fish passage; and (2) consideration of the stay vane wicket gate systems in any future turbine rehabilitation studies.

  3. Low Friction Cryostat for HTS Power Cable of Dutch Project

    NARCIS (Netherlands)

    Chevtchenko, O.; Zuijderduin, R.; Smit, J.; Willen, D.; Lentge, H.; Thidemann, C.; Traeholt, C.

    2012-01-01

    Particulars of 6 km long HTS AC power cable for Amsterdam project are: a cable has to fit in an annulus of 160 mm, with only two cooling stations at the cable ends [1]. Application of existing solutions for HTS cables would result in excessively high coolant pressure drop in the cable, possibly affe

  4. Broadband description of the copper cable transfer function

    NARCIS (Netherlands)

    Waal, D.C.H.

    2007-01-01

    This report is describes the characteristics of two different copper cables, namely the coax cable and the twisted pair cable. By using the Maxwell equations we can describe the coax cable and the twisted pair cable with the Bessel functions. By these Bessel functions we can simulate the two seconda

  5. 30 CFR 75.603 - Temporary splice of trailing cable.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Temporary splice of trailing cable. 75.603... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Trailing Cables § 75.603 Temporary splice of trailing cable. One temporary splice may be made in any trailing cable. Such trailing cable...

  6. Study on effects of environmental temperature on dynamic characteristics of Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    Miao Changqing; Chen Liang; Feng Zhaoxiang

    2011-01-01

    The dynamic characteristics of three-tower and two-span suspension bridge are analyzed at different global temperatures. An equivalent cable inner force method is proposed to consider temperature effects and to study the effects of environmental temperature on dynamic characteristics of Taizhou Yangtze River Bridge. The result demonstrates that the effects of temperature can not be neglected in static or dynamic analysis of Taizhou Yangtze River Bridge. The relationship between temperature and frequency is negative. The effects of temperature should be taken into account in experimental modal analysis of long-span bridges and damage identification.

  7. 基于 WIM 数据的上海某大桥钢箱梁应力谱研究%Fatigue Stress Spectrum Study of the Steel Box Girder of Shanghai Certain Bridge,Based on the Analysis of WIM Data

    Institute of Scientific and Technical Information of China (English)

    徐昊; 胡明敏

    2014-01-01

    斜拉桥以其自身的优点成为当今大跨度桥梁中的主流桥型,然而,投入使用一段时间后,由于运营车辆总重和交通量交替变化,钢桥所面临的疲劳问题正日趋严重。本文以上海某大桥为工程背景,利用动态称重系统采集到的车辆载荷相关数据,依据等效疲劳损伤原理,推导出代表实际运营车辆载荷谱,采用泄水法,建立南塔钢箱梁的细节应力谱,为上海某大桥疲劳损伤及寿命评估提供可靠依据。%Cable-stayed Bridge becomes the main stream bridge in the large span bridge construction because of its advantages and was built all over the world .However ,after a period of time ,the fatigue problem of the steel bridge faced with is becoming more and more serious .The representative of actual operation vehicle load spectrum is deduced with the vehicle load data collected by the dynamic weighing system and the equivalent fatigue damage theory based on the Shanghai Certain Bridge . The paper also adopted the discharge water method to build the stress spectrum of the steel box girder of The South Tower and to provide the reliable ba-sis for fatigue damage and life assessment of Shanghai Yangtze River Bridge .

  8. Having Twins? How to Stay Healthy

    Science.gov (United States)

    ... Listen Español Text Size Email Print Share Having Twins? How to Stay Healthy Page Content Article Body ... the eyes of obstetricians. Many would call a twin pregnancy a high-risk pregnancy , but don’t ...

  9. Senior Living: Staying Positive and Moving Forward

    Science.gov (United States)

    ... Past Issues Feature: Senior Living Staying Positive and Moving Forward Past Issues / Summer 2009 Table of Contents ... page please turn Javascript on. For Juanita Kuhn, moving to an independent living facility is just the ...

  10. Staying Socially Active Nourishes the Aging Brain

    Science.gov (United States)

    ... fullstory_163679.html Staying Socially Active Nourishes the Aging Brain Researchers suggest making friends of all ages ... and Human Services. More Health News on: Healthy Aging Recent Health News Related MedlinePlus Health Topics Healthy ...

  11. 鄂东长江大桥施工过程非线性稳定性分析%Stability Analysis of Edong Yangtze River Bridge during Construction

    Institute of Scientific and Technical Information of China (English)

    赵雷; 孙才志; 杨兴旺

    2012-01-01

    为探讨大跨度混合梁斜拉桥施工过程中结构非线性稳定性的变化规律及其影响因素,以鄂东长江大桥为研究对象,按照结构型式及施工工序的特点,采用LSB和ANSYS有限元软件计算大桥施工过程非线性稳定安全系数并获得结构失稳形态,分析了非线性因素对静力稳定性的影响规律.此外,探讨了混合梁斜拉桥设计与施工工程参数——钢混结合部位置、索梁锚固方式、施工临时荷载及横向风荷载与大桥施工过程非线性稳定性的关系.结果表明,上述工程参数对施工过程非线性稳定性有不同程度的影响,但总体上并非其控制性因素.%In order to research the change law of non-linear stability and its influencing factors of a long-span composite cable-stayed bridge during construction, by taking Edong Yangtze River bridge as research subject, LSB and ANSYS models were built based on the structure type and construction sequence of the bridge to calculate the non-linear stability safety factors during bridge construction and obtain the instability mode. The influencing law of non-linear factors to static stability was analyzed. In addition, the relationships among the stability during construction and steel-concrete connection position, cable-beam anchorage mode, temporary construction loads and cross-wind load were investigated. The research results show that the above factors have different effects on the stability during construction, but they are not controlling factors.

  12. How do you like them cables?

    CERN Multimedia

    Sergei Malyukov

    Cabling work is not for clautrophobic people! Cables are like the blood vessels and nervous system of ATLAS. With the help of all these cables, we can power ATLAS, control the detector and read out the data. Like the human blood vessels, they penetrate inside the ATLAS volume, reaching each of its elements. The ATLAS developers started to think about design of services, cables and pipes at the very first stages of the project. The cabling project has been developing most intensively during the last five years, passing through the projection and CAD design phases, then the installation of cable trays and finally the cables. The cable installation itself took two and a half years and was done by teams of technicians from several institutes from Russia, the Czech Republic and Poland. Here are some numbers to illustrate the scale of the ATLAS cabling system. More than 25000 optical fiber channels are used for reading the information from the sub-detectors and delivering the timing signals. The total numbe...

  13. Nonlinear Finite Element Analysis of Ocean Cables

    Institute of Scientific and Technical Information of China (English)

    Nam-Il KIM; Sang-Soo JEON; Moon-Young KIM

    2004-01-01

    This study has focused on developing numerical procedures for the dynamic nonlinear analysis of cable structures subjected to wave forces and ground motions in the ocean. A geometrically nonlinear finite element procedure using the isoparametric curved cable element based on the Lagrangian formulation is briefly summarized. A simple and accurate method to determine the initial equilibrium state of cable systems associated with self-weights, buoyancy and the motion of end points is presented using the load incremental method combined with penalty method. Also the Newmark method is used for dynamic nonlinear analysis of ocean cables. Numerical examples are presented to validate the present numerical method.

  14. Feasibility Study on Tension Estimation Technique for Hanger Cables Using the FE Model-Based System Identification Method

    Directory of Open Access Journals (Sweden)

    Kyu-Sik Park

    2015-01-01

    Full Text Available Hanger cables in suspension bridges are partly constrained by horizontal clamps. So, existing tension estimation methods based on a single cable model are prone to higher errors as the cable gets shorter, making it more sensitive to flexural rigidity. Therefore, inverse analysis and system identification methods based on finite element models are suggested recently. In this paper, the applicability of system identification methods is investigated using the hanger cables of Gwang-An bridge. The test results show that the inverse analysis and systemic identification methods based on finite element models are more reliable than the existing string theory and linear regression method for calculating the tension in terms of natural frequency errors. However, the estimation error of tension can be varied according to the accuracy of finite element model in model based methods. In particular, the boundary conditions affect the results more profoundly when the cable gets shorter. Therefore, it is important to identify the boundary conditions through experiment if it is possible. The FE model-based tension estimation method using system identification method can take various boundary conditions into account. Also, since it is not sensitive to the number of natural frequency inputs, the availability of this system is high.

  15. Aerodynamic challenges in span length of suspension bridges

    Institute of Scientific and Technical Information of China (English)

    XIANG Haifan; GE Yaojun

    2007-01-01

    The potential requirement of extreme bridge spans is firstly discussed according to horizontal clearances for navigation and economical construction of deep-water foundation. To ensure the technological feasibility of suspen- sion bridges with longer spans, the Static estimation of feasi- ble span length is then made based on current material strength and weight of cables and deck. After the performances of the countermeasures for raising the aerodynamic stability are reviewed, a trial design of a 5 000 m suspension bridge, which is estimated as a reasonable limitation of span length, is finally conducted to respond to the tomorrow's challenge in span length of suspension bridges with the particular aspects, including dynamic stiffness, aerodynamic flutter and aerostatic stability.

  16. Seismic studies of the San Francisco-Oakland Bay Bridge

    Energy Technology Data Exchange (ETDEWEB)

    Astaneh-Asl, A; Larsen, S; McCallen, D

    1999-08-17

    Computational simulation plays a central role in the engineering analysis and design of major bridge structures and accurate simulations are essential for the development of earthquake resistant and economical structural designs. This paper describes new methodologies and computational tools which have recently been developed for simulating earthquake ground motions and the seismic response of cable supported bridges. The simulation tools are described and an example application for an important long-span suspension bridge is demonstrated. The application portion of the study has particular focus on the potential damaging effects of long period displacement pulses and permanent ground displacements which can occur when a bridge is located in the near-field of a major earthquake fault.

  17. Braided tubular superelastic cables provide improved spinal stability compared to multifilament sublaminar cables.

    Science.gov (United States)

    Tremblay, Jaëlle; Mac-Thiong, Jean-Marc; Brailovski, Vladimir; Petit, Yvan

    2015-09-01

    This study investigates the use of braided tubular superelastic cables, previously used for sternum closure following sternotomy, as sublaminar fixation method. It compares the biomechanical performance of spinal instrumentation fixation systems with regular sublaminar cables and proprietary superelastic cables. A hybrid experimental protocol was applied to six porcine L1-L4 spinal segments to compare multifilament sublaminar cables (Atlas, Medtronic Sofamor Danek, Memphis, TN) with proprietary superelastic cables. First, intact total range of motion was determined for all specimens using pure moment loading. Second, pure moments were imposed to the instrumented specimens until these intact total ranges of motion were reproduced. Compared to the intact specimens, the use of superelastic cables resulted in stiffer instrumented specimens than the use of multifilament cables for all the loading modes except axial torsion. Consequently, the superelastic cables limited the instrumented segments mobility more than the multifilament cables. Spinal instrumentation fixation systems using superelastic cables could be a good alternative to conventional sublaminar cables as it maintains a constant stabilization of the spine during loading.

  18. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders

    2016-01-01

    Classical flutter of suspended bridge decks can be avoided if the torsional frequencies are lower than the vertical. Wind tunnel tests of single boxes and twin box section models with torsional natural frequencies above and below the vertical frequency has been conducted. Flutter was avoided in all....... In order to design aerodynamically stable suspension bridges with low torsional natural frequencies it is suggested to increase the mass moment of inertia and provide adequate torsional stiffness by the main cables spacing....

  19. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders;

    2016-01-01

    Classical flutter of suspended bridge decks can be avoided if the torsional frequencies are lower than the vertical. Wind tunnel tests of single boxes and twin box section models with torsional natural frequencies above and below the vertical frequency has been conducted. Flutter was avoided in a....... In order to design aerodynamically stable suspension bridges with low torsional natural frequencies it is suggested to increase the mass moment of inertia and provide adequate torsional stiffness by the main cables spacing....

  20. The Selling of Cable Television 1972.

    Science.gov (United States)

    National Cable Television Association, Inc., Washington, DC.

    The 1972 Cable Television Marketing Workshop reviewed in depth a wide variety of marketing and public relations techniques as they pertain to cable television. The workshop was attended by representatives of commercial television systems throughout the United States; it was intended to disseminate the sales and marketing experience of those…

  1. First Russian long length HTS power cable

    Science.gov (United States)

    Volkov, Eduard P.; Vysotsky, Vitaly S.; Firsov, Valery P.

    2012-11-01

    The Russian R&D Program for superconducting power devices is underway, supported both by government and electric power companies. In this program R&D on HTS power cables is considered as most advanced and close to commercialization. In the framework of the program, several, heavily instrumented, 5 m cables have been tested following by the 30 m - 3 phase experimental power cable development and testing in 2008-2009. The latest achievement is development and testing of the first long length 3 × 200 m power cable with rating 1.5/2 kA-20 kV. In parallel with just the cable development the innovative cryogenic system has been developed as well for the cable cooling. The system is using neon as working substance and radial turbo-machines in refrigerator. Cooling power is up to ∼8 kW at 65 K, inter-maintenance time ∼30,000 h. The cryogenic pump with superconducting motor can be used to provide subcooled liquid nitrogen flow ∼0.1-1.5 kg/s at 0.1-2.5 MPa pressure. After extensive tests at special test facility, HTS power cable and cryogenic system are planning to be installed at some substation in Moscow utility grid. In this review some details about Russian HTS power application program, 200 m cable and cryogenic system designs and tests results are presented.

  2. 76 FR 32866 - Cable Landing Licenses; Correction

    Science.gov (United States)

    2011-06-07

    ... Systems Agency in the regulations that we published in the Federal Register of January 14, 2002, 67 FR... COMMISSION 47 CFR Part 1 Cable Landing Licenses; Correction AGENCY: Federal Communications Commission. ACTION... streamlined processing of cable landing license applications. Need for Correction As published, the...

  3. Community Cable Television--Hungarian Perspectives.

    Science.gov (United States)

    Szekfu, Andras

    This paper argues that, although community cable television is one of the most dynamic (although experimental) elements of the Hungarian media structure, it is well on its way toward institutionalization. It is suggested that whether community cable television is able to retain the spontaneity, innovativeness, and elasticity of its early days may…

  4. Joystick With Cable Springs Offers Better Feel

    Science.gov (United States)

    Kerley, James; Ecklund, Wayne

    1992-01-01

    Improved joystick allows motion in 6 degrees of freedom, biased toward central position and orientation by 16 segments of cable serving as springs. Improvement in feel and control results from nonlinear compliance of cable-spring assembly. Nonlinear variations accommodate natural reactions of hand and brain. Operator functions as part of feedback control loop. More comfortable, increases ability to exert control and reduces fatigue.

  5. Cable Television: The Process of Franchising.

    Science.gov (United States)

    Johnson, Leland L.; Botein, Michael

    In an effort to insure that cable television franchising procedures at the local level are based on a competitive and well-conceived selection process, this report discusses some of the most important steps of the franchising process. Not only does it show how the community should assess its needs and appraise the merits of the cable operator, but…

  6. Pay Cable: A Viable Advertising Medium?

    Science.gov (United States)

    Krugman, Dean M.; Barban, Arnold M.

    Cable television, which cannot only clarify local signals to weak signal areas but can also bring in distant signals to areas which have been receiving few signals, has the capacity to present special television programs to customers for extra fees. The number of pay cable subscribers is growing and industry projections are that it will reach 20…

  7. Key Techniques for Design of Edong Changjiang River Highway Bridge%鄂东长江公路大桥设计关键技术

    Institute of Scientific and Technical Information of China (English)

    胡明义; 黄冰释; 余俊林; 唐守峰

    2011-01-01

    The main bridge of Edong Changjiang River Highway Bridge is a semi-floating system hybrid girder cable-stayed bridge with double pylons, double cable planes and with a main span 926 m. The main girder of the bridge was designed as the PK (Pasco-Kennewick Bridge) cross section of separated twin boxes, of which the part of the girder for the central span is of the steel box girder, the parts of the girder for the side spans are of the prestressed concrete (PC) box girders and a steel and concrete joint section was set on each side of the central span at a distance of 12. 5 m to the center of a pylon. To ensure a smooth transition between the steel and concrete structure, the multi-cell force transmission structure with PBL shear connectors was used for the joint section. The cable-to-pylon anchorage is the steel anchor box structure built in the column of a pylon. To control the development of concrete cracks in the anchorage zone in the pylon, the prestressing strands of 12φs 15. 24 were set in the concrete pylon wall on the side of the anchorage. To enhance the structural durability and service life, the durability of reinforced concrete and corrosion protection of steel structure were designed and the life cycle cost concept was applide to the design. The inspection and maintenance accesses for all principal components of the bridge were provided and the inspection and maintenance cycles, replacement criteria, workmanship and technical requirements were formulated as well.%鄂东长江公路大桥主桥为主跨926 m的双塔双索面半飘浮体系混合梁斜拉桥,主梁采用分离式双箱PK断面形式,中跨为钢箱梁,边跨为PC箱梁,钢-混凝土结合段设于中跨距桥塔中心12.5m处.为使钢结构与混凝土结构平稳过渡,钢-混凝土结合段采用PBL剪力连接器的多格室传力构造.索塔锚固采用在塔柱内置钢锚箱的构造,为控制锚固区混凝土裂缝开展,在锚固侧混凝土塔壁内设置12(o)s15.24预应力

  8. Nuclear power plant cable materials :

    Energy Technology Data Exchange (ETDEWEB)

    Celina, Mathias Christopher; Gillen, Kenneth T; Lindgren, Eric Richard

    2013-05-01

    A selective literature review was conducted to assess whether currently available accelerated aging and original qualification data could be used to establish operational margins for the continued use of cable insulation and jacketing materials in nuclear power plant environments. The materials are subject to chemical and physical degradation under extended radiationthermal- oxidative conditions. Of particular interest were the circumstances under which existing aging data could be used to predict whether aged materials should pass loss of coolant accident (LOCA) performance requirements. Original LOCA qualification testing usually involved accelerated aging simulations of the 40-year expected ambient aging conditions followed by a LOCA simulation. The accelerated aging simulations were conducted under rapid accelerated aging conditions that did not account for many of the known limitations in accelerated polymer aging and therefore did not correctly simulate actual aging conditions. These highly accelerated aging conditions resulted in insulation materials with mostly inert aging processes as well as jacket materials where oxidative damage dropped quickly away from the air-exposed outside jacket surface. Therefore, for most LOCA performance predictions, testing appears to have relied upon heterogeneous aging behavior with oxidation often limited to the exterior of the cable cross-section a situation which is not comparable with the nearly homogenous oxidative aging that will occur over decades under low dose rate and low temperature plant conditions. The historical aging conditions are therefore insufficient to determine with reasonable confidence the remaining operational margins for these materials. This does not necessarily imply that the existing 40-year-old materials would fail if LOCA conditions occurred, but rather that unambiguous statements about the current aging state and anticipated LOCA performance cannot be provided based on

  9. Fiber reinforced polymer composites for bridge structures

    Directory of Open Access Journals (Sweden)

    Alexandra CANTORIU

    2013-12-01

    Full Text Available Rapid advances in construction materials technology have led to the emergence of new materials with special properties, aiming at safety, economy and functionality of bridges structures. A class of structural materials which was originally developed many years ago, but recently caught the attention of engineers involved in the construction of bridges is fiber reinforced polymer composites. This paper provides an overview of fiber reinforced polymer composites used in bridge structures including types, properties, applications and future trends. The results of this study have revealed that this class of materials presents outstanding properties such as high specific strength, high fatigue and environmental resistance, lightweight, stiffness, magnetic transparency, highly cost-effective, and quick assembly, but in the same time high initial costs, lack of data on long-term field performance, low fire resistance. Fiber reinforced polymer composites were widely used in construction of different bridge structures such as: deck and tower, I-beams, tendons, cable stands and proved to be materials for future in this field.

  10. Predicting Length of Psychiatric Hospital Stay in Children and Adolescents.

    Science.gov (United States)

    Leininger, Michele; Stephenson, Laura A.

    Length of stay in psychiatric inpatient units has received increasing attention with the external pressures for treatment cost-effectiveness and evidence that longer hospital stays do not appear to have significant advantages over shorter hospital stays. This study examined the relationship between length of psychiatric hospital stay and…

  11. Bridges in Complex Networks

    CERN Document Server

    Wu, Ang-Kun; Liu, Yang-Yu

    2016-01-01

    A bridge in a graph is an edge whose removal disconnects the graph and increases the number of connected components. We calculate the fraction of bridges in a wide range of real-world networks and their randomized counterparts. We find that real networks typically have more bridges than their completely randomized counterparts, but very similar fraction of bridges as their degree-preserving randomizations. We define a new edge centrality measure, called bridgeness, to differentiate the importance of a bridge in damaging a network. We find that certain real networks have very large average and variance of bridgeness compared to their degree-preserving randomizations and other real networks. Finally, we offer an analytical framework to calculate the bridge fraction and average bridgeness for uncorrelated random networks with arbitrary degree distributions.

  12. Simulation of the cabling process for Rutherford cables: An advanced finite element model

    Science.gov (United States)

    Cabanes, J.; Garlasche, M.; Bordini, B.; Dallocchio, A.

    2016-12-01

    In all existing large particle accelerators (Tevatron, HERA, RHIC, LHC) the main superconducting magnets are based on Rutherford cables, which are characterized by having: strands fully transposed with respect to the magnetic field, a significant compaction that assures a large engineering critical current density and a geometry that allows efficient winding of the coils. The Nb3Sn magnets developed in the framework of the HL-LHC project for improving the luminosity of the Large Hadron Collider (LHC) are also based on Rutherford cables. Due to the characteristics of Nb3Sn wires, the cabling process has become a crucial step in the magnet manufacturing. During cabling the wires experience large plastic deformations that strongly modify the geometrical dimensions of the sub-elements constituting the superconducting strand. These deformations are particularly severe on the cable edges and can result in a significant reduction of the cable critical current as well as of the Residual Resistivity Ratio (RRR) of the stabilizing copper. In order to understand the main parameters that rule the cabling process and their impact on the cable performance, CERN has developed a 3D Finite Element (FE) model based on the LS-Dyna® software that simulates the whole cabling process. In the paper the model is presented together with a comparison between experimental and numerical results for a copper cable produced at CERN.

  13. Results of monitoring large carbon fiber post-tensioning systems in a balanced Cantilever Brdige (Dintelharbour Bridge, The Netherlands)

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Kaptijn, N.; Hageman, J.G.; Kuilboer, C.P.M.

    2012-01-01

    Steel post-tensioning systems and stay cables are susceptible to corrosion. Carbon fiber systems are not. However, there was no experience on the long term behavior of such post-tensioned elements. Four external tendons (75 m long), stressed to a load of 2650 kN, were applied in a large balanced can

  14. Research on the stiffening girder erection sequence of three-tower suspension bridge

    Institute of Scientific and Technical Information of China (English)

    Zheng Runqing; Luo Xiheng

    2012-01-01

    Compared to the conventional two-tower suspension bridge, the three-tower suspension bridge has obviously different characteristics in structural performance because of the extra middle tower and main span. The construction sequence for the stiffening girder is significantly different between the three-tower suspension bridge and the two-tower suspension bridge. The tangential angle of the main cable is one of the controlling factors of the stiffening girder erection stage for a suspension bridge. According to 5 feasible cases for the stiffening girder erection scheme in Taizhou Bridge, the research about the tangential angle in each case mentioned above was made, and some factors that should be taken into account for the erection scheme of stiffening girder were pointed out.

  15. Self-healing cable for extreme environments

    Science.gov (United States)

    Huston, Dryver R. (Inventor); Tolmie, Bernard R. (Inventor)

    2009-01-01

    Self-healing cable apparatus and methods disclosed. The self-healing cable has a central core surrounded by an adaptive cover that can extend over the entire length of the self-healing cable or just one or more portions of the self-healing cable. The adaptive cover includes an axially and/or radially compressible-expandable (C/E) foam layer that maintains its properties over a wide range of environmental conditions. A tape layer surrounds the C/E layer and is applied so that it surrounds and axially and/or radially compresses the C/E layer. When the self-healing cable is subjected to a damaging force that causes a breach in the outer jacket and the tape layer, the corresponding localized axially and/or radially compressed portion of the C/E foam layer expands into the breach to form a corresponding localized self-healed region. The self-healing cable is manufacturable with present-day commercial self-healing cable manufacturing tools.

  16. Staying in "the stream of life"

    DEFF Research Database (Denmark)

    Rasmussen, Birgitte; Delmar, Charlotte; Dolmer, Ilone

    2009-01-01

    Staying in the stream of life is about being the author of one's own meaningful life. It takes into account life phenomena embodied in the maintenance aspect of health care; dignity in relation to identity and integrity; and an understanding of the dialectical relation between frailty and strength....

  17. Stay Safe and Healthy This Winter!

    Centers for Disease Control (CDC) Podcasts

    2010-11-23

    In this podcast for kids, the Kidtastics offer some simple ways to stay safe and healthy during the winter holiday season.  Created: 11/23/2010 by CDC Office of Women’s Health.   Date Released: 11/23/2010.

  18. Study on the Fault Location Method for Power Cables using the Time-frequency Analysis

    Science.gov (United States)

    Kobayashi, Shin'ichi; Morimoto, Nozomi; Miyajima, Kazuhisa; Hozumi, Naohiro

    The pulse radar method is one of fault location methods for power cables. It locates the breakdown point by measuring the delay time of the echo or the discharge signal coming from the breakdown point. The equipment for the pulse radar method is more compact compared with the Murray loop bridge, and its operation is more simple because sensitive adjustments of proportion are not needed. However the signal propagating through the cable is distorted depending on the distance and frequency, leading to a poor accuracy for the location. In this report, signal processing in the time-frequency domain is proposed to solve this problem. The pulse waveforms received at two different terminals of the cable were extracted by a window function, and subsequently Fourier transformed in order to calculate the phase difference at an appropriate frequency. A special care was taken for un-wrapping the folded phase spectrum. The phase difference was interpreted as the time lag at an identical frequency. The technique was applied to the fault location for a full size XLPE cable line.

  19. 47 CFR 32.2424 - Submarine & deep sea cable.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic...

  20. 47 CFR 76.612 - Cable television frequency separation standards.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable television frequency separation standards... SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Technical Standards § 76.612 Cable television frequency separation standards. All cable television systems which operate in the frequency bands...

  1. 30 CFR 75.828 - Trailing cable pulling.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trailing cable pulling. 75.828 Section 75.828... Longwalls § 75.828 Trailing cable pulling. The trailing cable must be de-energized prior to being pulled by any equipment other than the continuous mining machine. The cable manufacturer's recommended...

  2. 47 CFR 76.614 - Cable television system regular monitoring.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable television system regular monitoring. 76... SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Technical Standards § 76.614 Cable television system regular monitoring. Cable television operators transmitting carriers in the frequency bands...

  3. 47 CFR 32.2426 - Intrabuilding network cable.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Intrabuilding network cable. 32.2426 Section 32... Intrabuilding network cable. (a) This account shall include the original cost of cables and wires located on the... between buildings on one customer's same premises. Intrabuilding network cables are used to...

  4. 46 CFR 111.60-4 - Minimum cable conductor size.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4...-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-4 Minimum cable conductor size. Each cable conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must...

  5. Bending behavior of lapped plastic ehv cables

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, G H; Muller, A C

    1980-01-01

    One of the factors delaying the development of lapped polymeric cables has been their reputed poor bending characteristics. Complementary programs were begun at BNL several years ago to mathematically model the bending of synthetic tape cables and to develop novel plastic tapes designed to have moduli more favorable to bending. A series of bend tests was recently completed to evaluate the bending performance of several tapes developed for use in experimental superconducting cables. The program is discussed and the results of the bend tests are summarized.

  6. DC Characterization of the Coaxial Superconducting Cable

    Science.gov (United States)

    Šouc, J.; Gömöry, F.; Vojenčiak, M.; Frolek, L.; Isfort, D.; Ehrenberg, J.; Bock, J.

    2008-01-01

    Coaxial cable model with superconducting core and superconducting shield conductor was constructed and tested in DC regime. While the core was already examined in our previous works, in this contribution the detailed study of the superconducting shield conductor in DC conditions is presented. It consists of 16 ReBCO coated tapes with critical current 35 A each connected in parallel. Using shunts with known values placed in series the currents in individual tapes were possible to measure. Distribution of the total cable current into the individual tapes was monitored and its influence on critical current of the cable is discussed.

  7. Understanding losses in three core armoured submarine cables

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da; Ebdrup, Thomas; Bak, Claus Leth

    2016-01-01

    . For practical an economical reasons the preferred choice of cable for both the array and the transmission cables are three-core armoured submarine cables. Therefore, it has becoming increasingly important to be able to calculate the ampacity of such cables accurately. At present time, the ampacity of three......-core armoured submarine cables is calculated according to IEC 60287-1-1 [1]. Various measurements conducted both by cable manufacturers and transmission system operators (TSO) have shown that using the cable rating method stated in IEC 60287-1-1 underestimates the cable ampacity [2]-[6]. Furthermore....... However, research performed in this paper shows that while the armour is responsible for the extra losses, the main calculation error for typical HVAC submarine cables may be in the screen’s loss factor (λ1). Overestimation of the cable losses may result in core cross-sections too large with more material...

  8. Application Designs of Cable Modem System%Cable Modem系统应用设计

    Institute of Scientific and Technical Information of China (English)

    占亿民; 潘永跃; 王晖; 夏卉

    2002-01-01

    本文总结了Cable Modem系统的原理和CMTS的关键功能,系统介绍了南京电视台Cable Modem系统的设计思路和设计方法.采用源IP地址路由技术实现了用户子网划分和区分服务,并且支持基于Cable Modem系统的专网接入业务.

  9. Simplified modeling of EM field coupling to complex cable bundles

    OpenAIRE

    Schetelig, B.; J. Keghie; Kanyou Nana, R.; Fichte, L.-O.; S. Potthast; Dickmann, S.

    2010-01-01

    In this contribution, the procedure "Equivalent Cable Bundle Method" is used for the simplification of large cable bundles, and it is extended to the application on differential signal lines. The main focus is on the reduction of twisted-pair cables. Furthermore, the process presented here allows to take into account cables with wires that are situated quite close to each other. The procedure is based on a new approach to calculate the geometry of the simplified cable and us...

  10. Condition Monitoring of Cables Task 3 Report: Condition Monitoring Techniques for Electric Cables

    Energy Technology Data Exchange (ETDEWEB)

    Villaran, M.; Lofaro, R.; na

    2009-11-30

    For more than 20 years the NRC has sponsored research studying electric cable aging degradation, condition monitoring, and environmental qualification testing practices for electric cables used in nuclear power plants. This report summarizes several of the most effective and commonly used condition monitoring techniques available to detect damage and measure the extent of degradation in electric cable insulation. The technical basis for each technique is summarized, along with its application, trendability of test data, ease of performing the technique, advantages and limitations, and the usefulness of the test results to characterize and assess the condition of electric cables.

  11. Switching Restrikes in HVAC Cable Lines and Hybrid HVAC Cable/OHL Lines

    DEFF Research Database (Denmark)

    da Silva, Filipe Miguel Faria; Bak, Claus Leth; Balle Holst, Per

    2011-01-01

    The disconnection of HV underground cables may, if unsuccessful, originate a restrike in the circuit breaker, leading to high overvoltages, and potentially damaging the cable and near equipment. Due to the cable high capacitance and low resistance the voltage damping is slow, resulting, half...... a cycle after the disconnection, in a voltage of approximately 2 pu at the circuit breaker terminals. In case of restrike in that instant, it is theoretical possible to attain an overvoltage of 3 pu. The overvoltage can be even larger in hybrid cable-Overhead Lines (OHL), due to voltage magnifications...

  12. Study of Vertical Seismic Response of Concrete Self-Anchored Suspension Bridges

    Institute of Scientific and Technical Information of China (English)

    刘春城; 石磊; 张哲

    2004-01-01

    Based on the variational prineiple of incomplete generalized potential energy with large deflection, the vertical nonlinear vibrational differential equation of self-anchored suspension bridge is presented by taking the effect of coupling of flexural and axial action into consideration. The linear vertical equation is obtained by omitting the nonlinear term, and the pseudo excitation method(PEM). Taking the self-anchored concrete suspension bridge over Lanqi Songhua river for an example, the expected peak responses of main beam, towers and cables are calculated. And the seismic spatial effects on vertical seismic response of self-anchored suspension bridges are discussed.

  13. Frequency Dependent Losses in Transmission Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdóttir, Unnur Stella

    2011-01-01

    Denmark is taking on the exciting project of undergrounding the electricity transmission grid. In 2009 it was decided by the Danish government to underground large parts of the 400 kV and the entire 132-150 kV transmission network before the end of 2030. For ensuring network stability...... and economical gain, such severe network changes necessitate correct estimation and optimisation of load conditions in the cable grid. Both IEC and IEEE have published standards for rating transmission cables' current carrying capacity. These standards are based on assumptions of a number of parameters...... of better calculation of the AC resistance of transmission cable conductors, in particular regarding higher frequencies. In this way, also losses under harmonics can be covered. Furthermore, the model is suitable for modelling of transient attenuation in high voltage cables. The AC resistance is calculated...

  14. Chinese Market for Fibres and Cables

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This article presents a summary of Chinese market of optical fibres and cables based on the development of the optical communications industry. Analysis shows that the market will keep growing for sometime in the future.

  15. Ecology: Electrical Cable Bacteria Save Marine Life.

    Science.gov (United States)

    Nielsen, Lars Peter

    2016-01-11

    Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide.

  16. Practical Damping Identification of FAST Cable Suspension

    Directory of Open Access Journals (Sweden)

    Jinghai Sun

    2014-03-01

    Full Text Available FAST focus cabin is suspended and driven by 6 parallel large span cables. Low stiffness of cables makes the cabin sensitive to disturbance and difficult to control. Structural damping then becomes a key factor that can improve control ability. Therefore, a reasonable damping estimation is important for system design. In this paper, a practical damping identification method is developed based on Ibrahim-time-domain algorithm. The method shows satisfied performance on accuracy and reliability in simulation test and is utilized in vibration experiments to identify damping ratios of both single cable model and FAST 3 m scale cable suspension model. Finally, a preliminary analysis of the damping properties is given out based on the results of identification.

  17. Parametric study on responses of a self-anchored suspension bridge to sudden breakage of a hanger.

    Science.gov (United States)

    Qiu, Wenliang; Jiang, Meng; Huang, Cailiang

    2014-01-01

    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.

  18. Parametric Study on Responses of a Self-Anchored Suspension Bridge to Sudden Breakage of a Hanger

    Directory of Open Access Journals (Sweden)

    Wenliang Qiu

    2014-01-01

    Full Text Available 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.

  19. Reconfigurable Buoyant Cable Antenna with Improved Gain

    Science.gov (United States)

    2010-07-28

    consists of a number of connected streamer cable sections, which each comprise a mechanical jacket surrounding a hollow core enclosing seismic sensor and...of insulation. A buoyancy layer/ jacket is either injection molded or extruded in place onto the core to make the final structure a solid object...systems: [0008] U.S. Patent No. 5,745,436, issued April 28, 1998, to Bittleston, discloses a semi-dry marine seismic streamer cable that

  20. A Cable-Shaped Lithium Sulfur Battery.

    Science.gov (United States)

    Fang, Xin; Weng, Wei; Ren, Jing; Peng, Huisheng

    2016-01-20

    A carbon nanostructured hybrid fiber is developed by integrating mesoporous carbon and graphene oxide into aligned carbon nanotubes. This hybrid fiber is used as a 1D cathode to fabricate a new cable-shaped lithium-sulfur battery. The fiber cathode exhibits a decent specific capacity and lifespan, which makes the cable-shaped lithium-sulfur battery rank far ahead of other fiber-shaped batteries.