WorldWideScience

Sample records for bridge cables

  1. 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...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

  2. 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.

  3. 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.

  4. 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.

  5. 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...... forces of different bridge cables types. The experiments were conducted in a wind tunnel facility capable amongst others to simulate incloud icing conditions....

  6. 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 Strö...

  7. 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.

  8. Optimal Sensor Placement for Stay Cable Damage Identification of Cable-Stayed Bridge under Uncertainty

    OpenAIRE

    Li-Qun Hou; Xue-Feng Zhao; Rui-Cong Han; Chun-Cheng Liu

    2013-01-01

    Large cable-stayed bridges utilize hundreds of stay cables. Thus, placing a sensor on every stay cable of bridges for stay cable damage identification (SCDI) is costly and, in most cases, not necessary. Optimal sensor placement is a significant and critical issue for SCDI. This paper proposes the criteria for sensor quantity and location optimization for SCDI on the basis of the concept of damage identification reliability index (DIRI) under uncertainty. Random elimination (RE) algorithm and ...

  9. 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...

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

    International Nuclear Information System (INIS)

    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.

  11. 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.

  12. 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.

  13. Cable force monitoring system of cable stayed bridges using accelerometers inside mobile smart phone

    Science.gov (United States)

    Zhao, Xuefeng; Yu, Yan; Hu, Weitong; Jiao, Dong; Han, Ruicong; Mao, Xingquan; Li, Mingchu; Ou, Jinping

    2015-03-01

    Cable force is one of the most important parameters in structural health monitoring system integrated on cable stayed bridges for safety evaluation. In this paper, one kind of cable force monitoring system scheme was proposed. Accelerometers inside mobile smart phones were utilized for the acceleration monitoring of cable vibration. Firstly, comparative tests were conducted in the lab. The test results showed that the accelerometers inside smartphones can detect the cable vibration, and then the cable force can be obtained. Furthermore, there is good agreement between the monitoring results of different kinds of accelerometers. Finally, the proposed cable force monitoring system was applied on one cable strayed bridge structure, the monitoring result verified the feasibility of the monitoring system.

  14. 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.

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

    DEFF Research Database (Denmark)

    Koss, Holger; Lund, Mia Schou Møller

    2013-01-01

    The accretion of ice on structural bridge cables changes the aerodynamic conditions of the surface and influences hence the acting wind load process. Full-scale monitoring indicates that light precipitation at moderate low temperatures between zero and -5°C may lead to large amplitude vibrations...... 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. 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.

  17. 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...... of temperature, wind speed and yaw angle of accretion, were reproduced in a climatic wind tunnel, giving rise to different types of accretion. These were chosen such to generate the most common natural ice formations expected to produce bridge cable vibrations. A description of the geometric characteristics...... 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...

  18. 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.

  19. 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.

  20. 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.

  1. Comparison of several innovative bridge cable surface modifications

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos T.

    into the effectiveness of helical fillets and pattern-indented surfaces has shown that, be-sides their purported ability to suppress rain-wind induced vibrations, they also modestly reduce drag forces at design wind velocities. This is of particular interest to bridge designers, as wind on stay planes of long......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...... and Japan, with two different prevailing systems: HDPE tubing fitted with helical fillets and tubing with pattern-indented surfaces. In the US and Europe, helical fillets dominate, whilst pattern indented sur-faces are more common in Asia, particularly for long-span cable-stayed bridges. Research...

  2. Optimum design of concrete cable-stayed bridges

    Science.gov (United States)

    Martins, Alberto M. B.; Simões, Luís M. C.; Negrão, João H. J. O.

    2016-05-01

    The design of cable-stayed bridges involves a significant number of design variables and design objectives. The concrete cable-stayed bridge optimization is formulated here as a multi-objective optimization problem with objectives of minimum cost, minimum deflections and minimum stresses. A numerical method is developed to obtain the optimum design of such structures. This numerical method includes: structural analysis, sensitivity analysis and optimization. The structural analysis accounts for all the relevant effects (concrete time-dependent effects, construction stages and geometrical nonlinear effects). The structural response to changes in the design variables is achieved by a discrete direct sensitivity analysis procedure, and an entropy-based approach was used for structural optimization. The features and applicability of the proposed method are demonstrated by numerical examples concerning the optimization of a real-sized concrete cable-stayed bridge.

  3. 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 ......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...

  4. Influence of the Non-linear Effects in the Design of Viscous Dampers for Bridge Cables

    OpenAIRE

    Acar, Yalda; Jingstål, Pontus

    2014-01-01

    In this master thesis the performance of external viscous dampers attached to cables in cable-stayed bridges have been studied. A comparison has been performed between a linear and a non-linear cable model. The comparison was carried out for two bridge cables, one from the Dubrovnik Bridge and the other from the Normandie Bridge. The performance of the dampers have been measured in terms of maximum achieved damping ratio and minimum amplitude of vibration. The analysis was performed using the...

  5. 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.

  6. Thermal Effect of the Cable-Stayed Bridge Tower

    Institute of Scientific and Technical Information of China (English)

    ZhangHai-long; LiJun; LiuChang-guo; JiangTian-hua; Weijun

    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.

  7. 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.

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

    OpenAIRE

    Haijun Wang; Jiandong Wang; Hua Wei

    2014-01-01

    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...

  9. Overlapping reliable control for a cable-stayed bridge benchmark

    OpenAIRE

    Bakule, Lubomir; Paulet-Crainiceanu, Fideliu; Rodellar Benedé, José; Rossell Garriga, Josep Maria

    2005-01-01

    The brief presents a reliable 1-out-2 reduced order control design strategy for a cable-stayed bridge benchmark using two overlapping subsystems and the linear quadratic Gaussian (LQG) design. Reliability with regard to controller failures is considered. Local controllers are designed for reduced order subsystems of expanded system. They are implemented and evaluated on the original overall system model. Two different sets of numerical experiments of reliable control design within 1-out-2 con...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Aerodynamic control of bridge cables through shape modification: A preliminary study

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos

    2011-01-01

    This paper examines the viability of modifying bridge cable shape and surface for the purpose of controlling wind-induced vibrations. To this end, an extensive wind-tunnel test campaign was carried out on various cable shapes about the critical Reynolds number region. Cable shapes were chosen...

  16. 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...

  17. 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 modern...... cable-stayed bridges are often designed as twin cables with a spacing of, say 1m. In such cases, it is suggested in the paper to suppress the mentioned in-plane types of vibrations by means of a tuned mass–damper (TMD) placed between the twin cables at their midpoints. The TMD divides the stay into four...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

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

    DEFF Research Database (Denmark)

    Acampora, Antonio; Georgakis, Christos

    2011-01-01

    In 1999, 2m amplitude cable vibrations were observed on the Øresund Bridge. The vibrations were attributed to a change in cable shape due to sleet accretion. Subsequent monitoring of the bridge, though, revealed other vibration events due to rain-wind induced mechanisms and parametric excitation...... 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...... (Svensson et al., 2004) – albeit of smaller amplitudes. After two significant cable vibration events, inspections of the cable anchorages revealed failures in the damping systems that had been installed to prevent oscillations. Improvements in the damping systems were introduced and additional tuned mass...

  3. 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...... the deck and/or towers. Since 2010, the Technical University of Denmark has been monitoring the vibrations of the twin inclined cables of the Øresund Bridge. From the acquired data, Georgakis and Acampora [1] showed that the cable aerodynamic damping can be determined for wind orthogonal to the twin cables...... 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...

  4. Optic fiber sensor-based smart bridge cable with functionality of self-sensing

    Science.gov (United States)

    He, Jianping; Zhou, Zhi; Jinping, Ou

    2013-02-01

    Bridge cables, characterized by distributed large span, serving in harsh environment and vulnerability to random damage, are the key load-sustaining components of cable-based bridges. To ensure the safety of the bridge structure, it is critical to monitor the loading conditions of these cables under lengthwise random damages. Aiming at obtaining accurate monitoring at the critical points as well as the general information of the cable force distributed along the entire cable, this paper presents a study on cable force monitoring by combining optical fiber Bragg grating (FBG) sensors and Brillouin optical time domain analysis/reflectory (BOTDA/R) sensing technique in one single optical fiber. A smart FRP-OF-FBG rebar based cable was fabricated by protruding a FRP packaged OF-FBG sensor into the bridge cable. And its sensing characteristics, stability under high stress state temperature self-compensation as well as BOTDA/R distributed data improvement by local FBG sensors have been investigated. The results show that FRP-OF-FBG rebar in the smart cable can deform consistantly along with the steel wire and the cable force obtained from the optical fiber sensors agree well with theoretical value with relative error less than ±5%. Besides, the temperature self-compensation method provides a significant cost-effective technique for the FRP-OF-FBG based cables' in situ cable force measurement. And furthermore, potential damages of the bridge cable, e.g. wire breaking and corrosion, can be characterized and symbolized by the discontinuity and fluctuation of the distributed BOTDA data thereafter accuracy improved by local FBG sensors.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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....

  10. 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....... 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 whether the design of bridge cable surface...

  11. 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

    In this paper, the aerodynamics of bridge cables with helical fillets and a pattern-indented surface are examined. To this end, an extensive wind-tunnel test campaign was undertaken to measure the static force coefficients about the critical Reynolds number region, with varying relative cable...

  12. Wind loads analysis at the anchorages of the Talavera de la Reina cable stayed bridge

    Directory of Open Access Journals (Sweden)

    L. Rosa

    2014-06-01

    Full Text Available This paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge.

  13. 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.

  14. 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.

  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. 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.

  17. 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.

  18. 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.

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

    DEFF Research Database (Denmark)

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

    In this paper, a basic and preliminary framework for the assessment of cumulative bridge cable fatigue damage due to wind-induced vibrations is presented. The damage assessment is performed using a probabilistic approach, based on a Bayesian Probabilistic Network, where the wind environment......, 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...... to meteorological and site-specific condi-tions can be utilized to assess the probability of occurrence of ice-induced vibrations. The fatigue stress in the cable bending mode is evaluated together with the corresponding fatigue lifetime. The modeling scheme shows flexibility in the sense that the individual...

  20. 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.

  1. 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.

  2. 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.

  3. Shape modification of bridge cables for aerodynamic vibration control

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos

    2010-01-01

    In this paper, the viability of modifying cable shape and surface for the purpose of controlling wind-induced vibrations is examined. To this end, an extensive wind-tunnel test campaign was carried out on various cable sections in the critical Reynolds number region under both smooth and turbulent...

  4. 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.

  5. Integrated System of Structural Health Monitoring and Intelligent Management for a Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2014-01-01

    Full Text Available 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.

  6. 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.

  7. Active control implementation in cable-stayed bridges for quasi-static loading patterns

    OpenAIRE

    Crusells Girona, Miquel; Aparicio Bengoechea, Ángel Carlos

    2016-01-01

    The following paper deals with active control implementation in cable-stayed bridges. Recent developments in structural active control of cable-stayed bridges are focused on the adaptability to dynamic effects produced by earthquakes or extreme winds (El Ouni et al., 2012; Pakos and Wojcicki, 2014; Domaneschi et al., 2015a,b). Nevertheless, no attention has been paid to the static or quasi-static case. As stated by Housner et al. (1996), Song et al. (2006) or Gilewski and Al Sabouni-Zawadzka ...

  8. Aerodynamic force coefficients of plain bridge cables in wet conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos T.

    In this paper, the aerodynamic forces and force coefficients from preliminary static wind tunnel tests on a plain cable in wet conditions are presented. The presented results are for several different relative cable wind-angles. A comparison is made with tests in dry conditions. In dry conditions...... aerodynamic damping. Analysis of the fluctuating lift component shows the presence of “enhanced” vortex shedding at specific wind velocities – similar to what might be observed in the presence of a tripping wire......., tests were performed for wind velocities between 2 and 31 m/s, whilst in wet conditions tests were performed for the range of wind velocities where rain rivulet formation was found possible, i.e. between 8-18 m/s. For all of the tested relative cable-wind angles in wet conditions, a reduction...

  9. 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 %.

  10. 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...

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Research of rigid cable suspension bridge%刚性索悬索桥研究

    Institute of Scientific and Technical Information of China (English)

    李映; 林长川

    2001-01-01

    Rigid cable suspension bridge,whose main cable and h anger are rigid,can solve some problems of normal suspension bridge such as fati gue of hanger and lower rigidity of the structure.The analysis,design and constr uction of rigid cable suspension bridge are discussed in this paper,and a practi ce of this type of bridge—The Guanghua Bridge in Changzhou,Jiangsu province are given in the paper.%刚性索悬索桥是指主缆及吊杆为刚度较大的构件组 成的悬索桥.它解决了中小跨度时常规悬索桥刚度差、吊杆易疲劳等问题.文中介绍了刚性 索悬索桥的计算分析、构造措施和施工方法,给出了工程实例——于1999年12月建成通车的 江苏常州广化桥,说明刚性索悬索桥是一种很有应用前景的桥型.

  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. 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....

  19. Automatic construction management of inclined cable in Heira bridge; Heirahashi ni okeru syazai keburu seko kanri no jidoka

    Energy Technology Data Exchange (ETDEWEB)

    Kajiyama, K.

    1996-03-01

    First one sided PC inclined cable bridge based on precast block additional method is constructed at Heira in Japan. Measurements of main girder deflection and main tower displacement values are considered as necessary factors in construction of inclined cable bridge. Efficient and rapid tension force supervision of inclined cable in every stage of construction is required for the above mentioned purpose. Automatic management of tension of inclined cable in Heira bridge construction is considered in this investigation. Construction of measuring system, installation, tension force adjustment and its decision management process, required special characteristics of tension, calculation sheet`s process et., are explained. Following observations are noted when precast method is compared with cast in place method for Heira bridge. Construction cycle of main girder is small and cycle until end of tension for 1 block construction to last block construction is equal to 1.6/day/block. 12 figs., 1 tab.

  20. 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.

  1. 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.

  2. Pushover analysis for the seismic response prediction of cable-stayed bridges under multi-directional excitation

    OpenAIRE

    Cámara Casado, Alfredo; Astiz Suárez, Miguel Angel

    2012-01-01

    Cable-stayed bridges represent nowadays key points in transport networks and their seismic behavior needs to be fully understood, even beyond the elastic range of materials. Both nonlinear dynamic (NL-RHA) and static (pushover) procedures are currently available to face this challenge, each with intrinsic advantages and disadvantages, and their applicability in the study of the nonlinear seismic behavior of cable-stayed bridges is discussed here. The seismic response of a large number of fini...

  3. Modification of the stress-state of cable-stayed bridge due to staggered erection of their superstructure

    OpenAIRE

    Lozano Galant, Jose Antono; Ruiz Ripoll, Lidia; Payá Zaforteza, Ignacio Javier; Turmo Coderque, José

    2014-01-01

    In current practice, the effects of the evolutionary erection of cable-stayed bridge superstructure are rarely included into the simulation of its tensioning process. In fact, stay forces in service are usually defined in early stages of design, when the construction process has not even been conceived in detail yet. In order to fill this gap, the effects of the evolutionary erection of cable-stayed bridge superstructure throughout the tensioning process are studied in this paper. This study ...

  4. Influence of wind angle of attack and isotropic turbulence on wind-induced vibrations of ice-accreted bridge cables

    OpenAIRE

    Pospíšil, S.; Trush, A. (Arsenii); Kuznetsov, S. (Sergeii); Kozmar, H.; Náprstek, J. (Jiří)

    2016-01-01

    Bridge-supporting cables and mast guys with high flexibility and low damping often experience vibrations with large amplitudes that may have consequently destructive effects on supported structures. Surface roughness and ice accretion are important issues, as they can considerably alter aerodynamic characteristics of bridge cables. This study describes wind-tunnel experiments on vortex-induced vibration of cylindrical section models with the deliberately adjusted natural frequency f = 5 Hz. T...

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

    OpenAIRE

    Xiaoguang Deng; Muyu Liu

    2015-01-01

    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...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Passive Control System for Mitigation of Longitudinal Buffeting Responses of a Six-Tower Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Fangfang Geng

    2016-01-01

    Full Text Available This paper presents an investigation of mitigation of longitudinal buffeting responses of the Jiashao Bridge, the longest multispan cable-stayed bridge in the world. A time-domain procedure for analyzing buffeting responses of the bridge is implemented in ANSYS with the aeroelastic effect included. The characteristics of longitudinal buffeting responses of the six-tower cable-stayed bridge are studied in some detail, focusing on the effects of insufficient longitudinal stiffness of central towers and partially longitudinal constraints between the bridge deck and part of bridge towers. The effectiveness of viscous fluid dampers on the mitigation of longitudinal buffeting responses of the bridge is further investigated and 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 results of the parametric investigations show that, by appropriate use of viscous fluid dampers, the top displacements of central towers and base forces of bridge towers longitudinally restricted with the bridge deck can be reduced significantly, with hampering the significant gain achieved in the base forces of bridge towers longitudinally unrestricted with the bridge deck. And the optimized parameters for the viscous fluid dampers can be determined from Pareto-optimal fronts using the NSGA-II that can satisfy the desired performance requirements.

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

    International Nuclear Information System (INIS)

    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

  17. Structural behaviour and design criteria of under-deck cable-stayed bridges subjected to seismic action

    OpenAIRE

    Cámara Casado, Alfredo; Ruiz Teran, Ana M.; Stafford, Peter J.

    2012-01-01

    SUMMARY: Under-deck cable-stayed bridges are very effective structural systems for which the strong contribution of the stay cables under live loading allows for the design of very slender decks for persistent and transient loading scenarios. Their behaviour when subjected to seismic excitation is investigated herein and a set of design criteria are presented that relate to the type and arrangement of bearings, the number and configuration of struts, and the transverse distribution of stay ca...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. Hybrid networking sensing system for structural health monitoring of a concrete cable-stayed bridge

    Science.gov (United States)

    Torbol, Marco; Kim, Sehwan; Chien, Ting-Chou; Shinozuka, Masanobu

    2013-04-01

    The purpose of this study is the remote structural health monitoring to identify the torsional natural frequencies and mode shapes of a concrete cable-stayed bridge using a hybrid networking sensing system. The system consists of one data aggregation unit, which is daisy-chained to one or more sensing nodes. A wireless interface is used between the data aggregation units, whereas a wired interface is used between a data aggregation unit and the sensing nodes. Each sensing node is equipped with high-precision MEMS accelerometers with adjustable sampling frequency from 0.2 Hz to 1.2 kHz. The entire system was installed inside the reinforced concrete box-girder deck of Hwamyung Bridge, which is a cable stayed bridge in Busan, South Korea, to protect the system from the harsh environmental conditions. This deployment makes wireless communication a challenge due to the signal losses and the high levels of attenuation. To address these issues, the concept of hybrid networking system is introduced with the efficient local power distribution technique. The theoretical communication range of Wi-Fi is 100m. However, inside the concrete girder, the peer to peer wireless communication cannot exceed about 20m. The distance is further reduced by the line of sight between the antennas. However, the wired daisy-chained connection between sensing nodes is useful because the data aggregation unit can be placed in the optimal location for transmission. To overcome the limitation of the wireless communication range, we adopt a high-gain antenna that extends the wireless communication distance to 50m. Additional help is given by the multi-hopping data communication protocol. The 4G modem, which allows remote access to the system, is the only component exposed to the external environment.

  5. 矮塔斜拉桥结构力学行为研究与设计实践%Cable Force Optimization and Design Practice of Low Tower Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    沐云秋

    2016-01-01

    With the development of bridges technology, as a combination bridge between the cable-stayed bridge and continuous girder that cable-stayed bridge with Low Towers is more and more applied, in recent ten years. This bridge belongs to the low tower cable-stayed bridge of pylon girder pier of Twin Towers and double cable plane. Extradited cable-stayed bridge has many mechanical properties are intermediate between the continuous rigid frame bridge and cable-stayed bridge, is by the beam bending, compression and cable tension to bear vertical loads. This design uses the MIDAS/Civil analysis program, provides analysis of data for each part of the design timely, and optimizes the cable which have a surplus volume of safety factor. The girder stress condition is further improved by appropriately adjusting the cable force.%随着桥梁技术的发展,矮塔斜拉桥作为介于斜拉桥和连续梁(刚构)之间的一种组合体系桥型,近十年来应用较多.本桥就属于塔梁墩固结的双塔双索面矮塔斜拉桥.矮塔斜拉桥有许多力学特性都介于连续刚构和斜拉桥之间,是以梁的受弯、受压和索的受拉来承受竖向荷载.本次设计采用MIDAS/Civil分析程,及时为各个设计环节提供分析数据并对安全系数有富余量的拉索进行优化,通过适当调整索力进一步改善主梁的受力状况.

  6. 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.

  7. 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

  8. Soil-structure interaction modeling effects on seismic response of cable-stayed bridge tower

    Science.gov (United States)

    Raheem, Shehata E. Abdel; Hayashikawa, Toshiro

    2013-12-01

    A nonlinear dynamic analysis, including soil-structure interaction, is developed to estimate the seismic response characteristics and to predict the earthquake response of cable-stayed bridge towers with spread foundation. An incremental iterative finite element technique is adopted for a more realistic dynamic analysis of nonlinear soil-foundation-superstructure interaction system under great-earthquake ground motion. Two different approaches to model soil foundation interaction are considered: nonlinear Winkler soil foundation model and linear lumped-parameter soil model. The numerical results show that the simplified lumped-parameter-model analysis provides a good prediction for the peak response, but it overestimates the acceleration response and underestimates the uplift force at the anchor between superstructure and pier. The soil bearing stress beneath the footing base is dramatically increased due to footing base uplift. The predominant contribution to the vertical response at footing base resulted from the massive foundation rocking rather than from the vertical excitation.

  9. 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.

  10. Study in the design and manufacture process of the elastic cable anchor box in steel box girder of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Gu Bifeng; Chen Ce; Ding Lei

    2011-01-01

    Taizhou Yangtze River Highway Bridge is a large span suspension bridge with three pylons. The elastic cables are installed to connect the steel tower and the steel box girder. The constraints can increase the safety coefficient of the middle saddle, and improve the stress conditions of the middle pylon and decrease the deflection in the middle of the main girder, as well as the longitudinal displacement of the main girder caused by live loads. The anchorage boxes of the elastic cable are installed in the wind fairing outside the vertical web plate of the box girder. Two anchor boxes form a pair and are arranged parallelly. Eight anchor boxes are installed in the bridge. In this paper, the design scheme and the technical difficulties in manufacturing are briefly discussed with the precision control techniques.

  11. 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.

  12. 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.

  13. 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.

  14. Innovation on Energy Power Technology (23)Completion of Installation of 500kV Cable along the Large-scale Bridges

    Science.gov (United States)

    Maekawa, Yuichi

    This paper describes an outline of the Honshu-Shikoku Interconnecting Transmission Line which includes the first large-scale cable line. The most significant feature of this transmission line is the installation of 500kV cables along various types of bridges. This brought many previously unknown technical hurdles such as techniques to overcome movements and vibrations of a series of large bridges. These hurdles were cleared through various efforts and techniques by the concerned parties.

  15. 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.

  16. 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.

  17. 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.

  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. The Design and Construction of Cable Crane of Glass Channel Bridge%玻璃沟大桥缆索吊机设计与施工

    Institute of Scientific and Technical Information of China (English)

    王鸽; 肖稀; 曾建伟; 吴智宇

    2014-01-01

    以玻璃沟大桥为背景,对工作主索、起重索、锚梁、牵引索的设计进行了详细的分析计算,并介绍了吊运缆索吊机承重主索的工作原理,对高原上类似桥梁的施工具有一定的参考价值。%Based on the glass channel bridge, this paper analyzes and calculates the design of the main cable, the hoisting cable, anchor beam and cable in detail, and introduces the working principle of lifting cable crane load bearing cable, which provides a certain reference for the similar bridge construction on the plateau.

  20. Static Load Test and Calculation on Multi-tower Cable-Stayed Bridge with Tie-down Cables%多塔下拉索斜拉桥静力荷载试验和计算分析

    Institute of Scientific and Technical Information of China (English)

    肖明葵; 王肖巍; 刘纲

    2011-01-01

    The static load test and the finite element analysis of the multi-tower cable-stayed bridge with tie-down cables are carried out. The test and analysis model of the bridge is created by referencing to the actual structure of a Changjiang River bridge. The static mechanical behaviors of such bridge with tie-down cables and the normal multi-tower cable-stayed bridge are comparatively analyzed by the static load test and the finite element analysis. It is shown that the structural system of the cable-stayed bridge with tie-down cables can effectively improve the structural rigidity and reduce the bending moment of the main beams, pylons and piers. According to the results, the best scheme about the location and number of tie-down cables is proposed.%针对加有下拉索的多塔斜拉桥这种新型的桥梁结构体系,参考某长江大桥实际工程建模,通过缩尺静力实验和有限元计算分析对比加劲索加下拉索多塔斜拉桥与常规无加劲索多塔斜拉桥的静力力学性能.试验和分析表明,加下拉索多塔斜拉桥结构体系可以有效提高结构刚度,减少塔墩根部以及主梁跨中的弯距.对比试验结果,提出了最佳的下拉索设置方案.

  1. 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

    , for varying Reynolds numbers and wind angles-of-attack. Using passive-dynamic wind tunnel tests, it is shown that the in-plane aerodynamic damping of a bridge cable section, and the overall dynamic response, is strongly affected by changes in the wind angle-of-attack. Using the drag and lift coefficients......, 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......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...

  2. 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.

  3. 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

  4. 矮塔混凝土斜拉桥成桥索力优化研究%Study of cable force optimization of completed low-pylon cable stayed concrete bridge

    Institute of Scientific and Technical Information of China (English)

    耿继东; 王雪枫

    2012-01-01

    在研究一般斜拉桥成桥索力优化方法的基础上,针对矮塔混凝土斜拉桥结构受力特点,依据影响矩阵调值原理,提出了以结构整体弯曲能量最小为目标、以主梁主塔单元的弯矩和轴力以及部分关键节点的位移为约束条件的矮塔混凝土斜拉桥索力优化方法。应用MIDAS/CIVIL2010"未知荷载系数"模块,对某混凝土矮塔斜拉桥实际工程进行成桥索力优化。分析结果表明,此种方法可以方便得到满足设计要求的合理成桥索力。%On the basis of in studying the method of cable force optimization of completed common cable stayed bridge,aiming at the stress characteristics of low-pylon cable stayed concrete bridge structure,according to influence matrix tone pitch theory,the method of cable force optimization of low-pylon cable stayed concrete bridge that takes minimum bending energy in whole structure as its target,and references the bending moment and axial force of unit of main beam and tower and the displacement of part key nodes as the constrain conditions is proposed.This paper uses MIDAS/CIVIL2010 "unknown load factor" module to do cable force optimization of the low-pylon cable stayed concrete bridge project.The analysis results show that this method can get reasonable completed cable force that meets design requirement easily.

  5. 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. PMID:22666009

  6. 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.

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

    DEFF Research Database (Denmark)

    Matteoni, Giulia; Georgakis, Christos; Ricciardelli, Francesco

    2011-01-01

    experimental and theoretical research in the last two decades, even though a definitive understanding of the flow around inclined cables under various surface conditions has not been achieved. A comparative study on the aerodynamic coefficients of stationary inclined stay cables, under various surface...... 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....

  8. Feasibility Study of Micro-Wind Turbines for Powering Wireless Sensors on a Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Billie F. Spencer

    2012-09-01

    Full Text Available In this study, the feasibility of using micro-wind turbines to power wireless sensors on a cable-stayed bridge is comprehensively investigated. To this end, the wind environment around a bridge onto which a turbine is installed is examined, as is the power consumption of a wireless sensor. Feasible alternators and rotors are then carefully selected to make an effective small wind generator (known as a micro-wind turbine. Using the three specially selected micro-wind turbines, a series of experiments was conducted to find the turbine best able to generate the largest amount of power. Finally, a horizontal-axis micro-wind turbine with a six-blade rotor was combined with a wireless sensor to validate experimentally its actual power-charging capability. It is demonstrated that the micro-wind turbine can generate sufficient electricity to power a wireless sensor under moderate wind conditions.

  9. 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.

  10. 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

    Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various excitation mechanisms have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding and excit......Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various excitation mechanisms have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding......-scale measurements are compared with the theoretical damping matrices based on the quasi-steady theory, using three different sets of wind tunnel measurements of static force coefficients on similar shaped twin or single cables, with good agreement. The damping terms are found to be dependent on Reynolds number...... in dry conditions.Finally, static drag coefficients are back-calculated from the full-scale vibration measurements, for first time, with reasonable agreement with direct wind tunnel measurements. The remaining discrepancies are believed to be due to the higher turbulence intensity on site than...

  11. 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.

  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. Study on structural system of multi-pylon cable-stayed bridge%多塔斜拉桥的结构体系研究

    Institute of Scientific and Technical Information of China (English)

    喻梅; 廖海黎; 李乔; 马存明; 李明水

    2015-01-01

    T he intermediate pylons of multi-pylon cable-stayed bridges cannot be anchored to fixed points by backstays,indicating that it is possible to cause greater horizontal displacements in the top of towers under the action of external loads. T herefore,it is important to obtain adequate structural stiffness in the design of multi-pylon cable-stayed bridges. In this paper,the structural systems of multi-pylon cable-stayed bridges were investigated. T he effect of structural system on mechanical behavior of multi-pylon cable-stayed bridges was analyzed by using a three-pylon cable-stayed bridge and a four-pylon cable-stayed bridge model. T he deflection and internal force of models for different structural systems were compared. T he results indicated that the best structural system of multi-pylon cable-stayed bridges w as the system that had enough structural stiffness and less secondary internal force resulted from concrete shrinkage,creep and temperature effect. Recommendations were given for determining structural system in the design of multi-pylon cable-stayed bridges.%多塔斜拉桥由于没有背索将其中间塔锚固到固定点,在活载作用下多塔斜拉桥的塔顶将产生过大的水平位移并导致主梁过大变位。如何确保结构的整体刚度是多塔斜拉桥设计中的关键环节。本文分析了多塔斜拉桥的结构体系,通过对不同结构体系的三塔及四塔斜拉桥模型的数值分析及比较,研究了结构体系对多塔斜拉桥力学行为的影响。结果显示,多塔斜拉桥理想的结构体系是能保证结构具有足够的整体刚度,并使混凝土收缩徐变及温度变化等因素在结构中不致产生过大次内力的体系。同时给出了有益于设计中选择多塔斜拉桥结构体系的结论和建议。

  14. 双链式悬索桥地震反应特征研究%Seismic response characteristics of double cables suspension bridge

    Institute of Scientific and Technical Information of China (English)

    丁南宏; 林丽霞; 钱永久; 王常峰

    2012-01-01

    Damping in double cables suspension bridge composed of steel reinforcement beams and reinforced concrete tower is non-classical, which leads to coupled equations of motion in main coordinate system. Based on the complex damping theory, the equivalent viscous damping ratio was derived, which can be used to describe energy dissipation characteristics of non-classical damping system approximately. The seismic response of double chains suspension bridge was analyzed through a pratical example, considering the geometric nonlinearity and non-classical damping, and numerical calculation was presented for seismic response of the bridge subjected to independent effect or combination effect of three orthogonal components of seismic wave respectively. Single cable suspension bridge can be taken as a special case of double cable suspension bridge, after the main cable shape coefficient was introduced. The dynamic responses of double cable suspension bridge and single cable suspension bridge were compared to reveal the ristics of seismic response of double cable suspension bridge. The study has a positive significance on structural form selection, dynamic performance evaluation and reinforcement design of such type of bridges.%双链式悬索桥采用钢加劲梁和钢筋混凝上索塔,使得阻尼在全桥中呈非经典阻尼耗能特性,导致主坐标系中的运动方程耦联.基于复阻尼理论求解等效粘滞阻尼比,以近似描述非经典阻尼体系的阻尼耗能特性.考虑几何非线性及非经典阻尼因素,对一座双链式悬索桥进行了地震反应谱和时程反应分析.引入主缆形状系数,将单链式悬索桥作为双链式悬索桥的特例,就同跨度同矢高的双链式悬索桥和单链式(普通式)悬索桥地震反应进行对比分析,揭示双链式悬索桥地震反应特征.双链式悬索桥地震反应特征的研究对该类桥设计选型、动力性能评估及抗震加固设计都有重要的工程意义.

  15. 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...

  16. Dynamic Characteristic Analysis of Long Span Cable-Stayed Pipeline Bridges%大跨度斜拉管线桥的动力特性分析

    Institute of Scientific and Technical Information of China (English)

    伍小平; 胡世德; 冯启民; 黄万春

    2001-01-01

    本文结合一实际工程结构——斜拉管线桥,从动力分析模型的建立、计算结果与实测结果的比较以及与普通斜拉桥的比较等几个方面研究了这种新型结构的动力特性。结果表明:恒载初始内力对斜拉管线桥的动力特性影响很大;尽管与斜拉桥结构相似,但二者的动力特性却有很大差别%In this paper, the dynamic characteristic of a new type of structure-long span cablestayed pipeline bridge is investigated from the establishment of the dynamic analysis model,comparison between the computed results and the test results, comparision with common calbestayed bridges. The conclusion indicated that the initial internal force caused by the dead weight of the cable-stayed pipeline bridge has a great influence on the dynamic characteristics of the bridge. The dynamic characteristics of the cable-stayed pipeline bridge are different from that of the cable-stayed bridge, although having similar structural type.

  17. 斜塔无背索斜拉桥研究%Research on the Inclined Pylon Cable-stayed Bridge without Back Stay

    Institute of Scientific and Technical Information of China (English)

    王运航; 李娜

    2014-01-01

    斜塔无背索斜拉桥受力特性与常规的直塔斜拉桥有较大的差异,造成了其设计以及施工的特殊性。本文以长沙洪山大桥为工程背景,对无背索斜拉桥的受力特性、施工以及桥塔的重量分布和倾角进行了探讨,为今后同类桥梁的结构设计提供了参考。%The characteristics of inclined pylon cable-stayed bridge without back stay is different from straight tower cable-stayed bridge, lead to the particularity of its design and construction. Taking Changsha Hongshan bridge engineering as the example, and discusses the stress characteristics, co-nstruction of cable-stayed bridge without back stay and weight distribution and dip angle of bridge tower, so as to provide certain reference for the similar bridges structural design.

  18. 某矮塔斜拉桥主梁受力分析研究%Analysis of Main Girder Stress of a Low Tower Cable -stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    郑报文; 张安林; 夏伟

    2014-01-01

    矮塔斜拉桥是介于连续梁桥和普通斜拉桥之间的新型桥梁,其受力以主梁为主,拉索为辅。本文通过有限元软件M IDAS建立全桥模型,对主梁最大双悬臂状态及成桥状态进行受力分析,并获得相关结论,可为同类桥型设计提供参考依据。%Low tower cable-stayed bridge is a new type of hybrid structure between continuous bridge and cable-stayed bridge based in the main girder and cable supplement of the force .Finite element software called Midas/Civil was used to build up calculation model of the bridge ,then focused on ana‐lyzing the structural behavior at the stages as follows :the maximum twin cantilever ,end of construc‐tion state .On the basis of it ,proposes the maximum internal force of construction process shall be the control basis ,and need further analysis of NO .0 block of similar bridge ,in the hope of providing ref‐erence to the similar bridge .

  19. 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.

  20. 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

    Over the last two decades, several bridge cable manufacturers have introduced surface modi-fications on the high-density polyethylene (HDPE) sheathing that is often installed for the protection of inner strands. The main goal of this is rain rivulet impedance, leading to the suppression of rain......-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...

  1. 空间扭背索组合梁斜塔斜拉桥极限承载力分析%Analysis about Ultimate Bearing Capacity of Space-Twisting Cable Composite Beam Leaning Tower Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    任伟; 刘刚; 刘利

    2015-01-01

    为进一步研究新兴空间扭背索组合梁斜塔斜拉桥的力学行为,以某主跨220 m 的空间扭背索组合梁斜塔斜拉桥为研究背景,采用非线性数值分析方法,并通过现场实测值验证数值模型的有效性,讨论了该桥的非线性响应和稳定性,同时用塑性铰法理论对结构极限承载能力进行了计算。研究发现:与常规斜拉桥相比,由于扭背索索长均匀,降低了拉索垂度影响差异;由于扭背索对主塔的水平约束作用较小,主塔较容易出现失稳;由不同工况分析得出,空间扭背索组合梁斜塔斜拉桥的破坏断面位于中塔柱顶部,锚固区下缘。本文研究结论可为类似桥型的进一步研究提供借鉴。%In order to further study the mechanical behavior of emerging bridge type———space‐twisting cable composite beam leaning tower cable‐stayed bridge ,one space‐twisting cable composite beam cable‐stayed bridge with 220 m main span was taken as example ,nonlinear nu‐merical analysis method was adopted ,and the effectiveness of numerical model was proved by field measured values .T he nonlinear response and stability of the bridge w ere discussed ,and the ulti‐mate bearing capacity was calculated by plastic hinge method .Research shows that :compared with conventional cable‐stayed bridge ,because the length of twisted cable is uniform ,the cable sag effect difference is little;because the horizontal restraint of twisted cable to main tower is little , main tower is easy to appear instability ;from the analysis on different working condition ,it is con‐cluded that the damaged section of space‐twisting cable composite beam inclined tower cable‐stayed bridge is located at the top of middle pylon ,the bottom edge of anchorage zone .

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

    OpenAIRE

    Hassan Abba Musa; Dr. A. Mohammed

    2016-01-01

    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 fluc...

  3. Anti-slip Performance of Interface between Carbon Fiber-Reinforced Plastic Main Cable and Cable Clamp for Large-Span Suspension Bridges%大跨悬索桥CFRP主缆-索夹界面抗滑移性能

    Institute of Scientific and Technical Information of China (English)

    诸葛萍; 章子华; 汪思聪; 丁勇; 强士中

    2014-01-01

    In order to solve the slip problem between main cable and clamp at saddles of large-span suspension bridges,the anti-slip performance of the interface between carbon fiber reinforced plastic (CFRP)cable and cable clamp was investigated. The frictional coefficient calculation formula of the interface was derived according to the equilibrium condition between the cable tension and the friction force on the interface. Based on this formula,the friction coefficient of the cable-clamp interface was obtained through laboratory model test using a cable composed of 19 CFRP tendons. Then,the test results of frictional coefficient were used to analyze the anti-slip performance of the main cable-clamp system of a CFRP cable suspension bridge with a main span of 3 500 m,where the CFRP tendons had a spirally indented surface. The results show that the friction coefficient of the CFRP main cable-cable clamp interface is up to 0. 331,which is higher than that of steel cable,and meet the requirement of engineering application. Therefore,when the CFRP tendons with a spirally indented surface are applied to the main cables of large-span suspension bridges,the cable-clamp interface is good enough to meet the requirement in anti-slip performance even if the cable clamps are designed in conventional shape and with an inner surface not granulated specially.%为解决大跨悬索桥碳纤维增强复合材料(CFRP)主缆鞍座处的抗滑移问题,研究了CFRP主缆-索夹界面的抗滑移性能,根据力的平衡原理推导了CFRP索股-索夹界面的摩擦因数计算式,结合模型试验和计算式,测试了19丝CFRP索股-索夹界面的摩擦因数.利用摩擦因数实测值对3500 m跨悬索桥CFRP主缆索夹处抗滑移性能进行了实桥应用分析.结果表明:压纹类CFRP丝主缆-索夹界面的摩擦因数超过钢主缆-索夹界面,达到0.331,可满足相应的应用要求;大跨悬索桥主缆采用压纹类CFRP丝时,索夹内表

  4. Construction Controlling Technology of a Spacial Irregular Shape Cable-stayed Bridge with a Single Pylon and Four Cable Planes%独塔四索面空间异型斜拉桥施工控制技术

    Institute of Scientific and Technical Information of China (English)

    谢韶

    2014-01-01

    宁波外滩大桥主桥为独塔四索面异型斜拉桥结构,为保证全桥结构在施工过程中和成桥状态下的安全和稳定性,确保成桥状态的线形和结构内力符合设计要求,进行了施工模拟计算和分析。在各个主要施工阶段分别监测主塔应力和线形、主梁应力和线形、斜拉索索力,通过监测数据判断施工过程中各项控制内容是否符合要求,从而确定此研究控制理论和方法在工程实例中的可行性。%The main bridge of the Waitan Bridge in Ningbo has a spatial irregular shape cable-stayed bridge with a single pylon and four cable planes.To ensure the whole bridge structure security and stability in the construction and bridge completion process,and the linear and structure internal force meet the design requirements in bridge completion status,construction simulation calculation and a-nalysis was performed.The main tower stress and linear,the main girder stress and linear,and the cable force was monitored in main stages of construction,which can decide whether the main control content meet the requirements and determine the feasibility of the control theory and method in prac-tice.

  5. 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 .

  6. 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.

  7. 双塔双索面支座体系混合式结合梁斜拉桥设计%Design of Double Pylons and Cable Plane Supporting System Hybrid Composite Girder Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    谢波; 程应刚

    2014-01-01

    以洸府河大桥为工程背景,进行了双塔双索面支座体系混合式结合梁斜拉桥的平面、纵断面和横断面设计,介绍了主桥的桥跨布置、桥梁方案,同时进行了中跨结合梁钢主梁、中跨结合梁混凝土桥面板、边跨混凝土主梁、主梁钢-混结合段、斜拉索、主塔和基础的设计,并进行了结构计算。%The plane,longitudinal section and cross section design of double pylons and cable plane supporting system hybrid composite girder cable-stayed bridge was carried out on the background of Guang Fuhe bridge.This paper introduced the bridge span arrangement and scheme,and conducted the design and structure calculation of steel girder in composite girder at midspan,concrete deck in composite girder at midspan,concrete main girder at side span ,steel-concrete mixing section,cable, tower and foundation.

  8. 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.

  9. 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.

  10. 粉房湾长江大桥斜拉索安装技术%Installation Techniques for Stay Cables of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    高杰; 黄克起; 代龙

    2012-01-01

    粉房湾长江大桥主桥为公轨两用双层桥面钢桁梁斜拉桥,为了将斜拉索穿过索导管、顺利牵引至塔柱内箱,并保证锚固在主梁同一截面上的4根斜拉索同时对称张拉,设计制作了张拉杆、软牵引2套张拉系统.斜拉索施工方法如下:在上游塔柱各设置1台塔吊用于塔端斜拉索安装及空中展索;在塔顶布置卷扬机,将斜拉索牵引入索导管并提升塔柱内的千斤顶、撑脚、张拉杆等塔内设备;在塔顶布置工字钢扁担梁支撑塔顶卷扬机;在桥面塔柱安装卷扬机将索头提升至索导管位置;采用卷扬机及导向滑轮组、手拉葫芦将梁端索头牵引到位;采用千斤顶张拉斜拉索.%The main bridge of Fenfangwan Changjiang River Bridge is a double-deck light rail-cum-road steel truss girder cable-stayed bridge. To lead the stay cables through the cable ducts in the pylons and smoothly haul the cables to the boxes inside the pylon columns and also to ensure that the 4 stay cables anchored in the same section of the main girder could be tensioned simultaneously and symmetrically, two sets of the tensioning systems of the tensioning rods and the soft hauling devices were designed and fabricated. The construction methods for installation of the cables were mainly as follows: a tower crane was set at each pylon column on the upstream side and was used for installing the stay cables on the pylons and for stretching the cables in the air. At the top of the pylon, the winch was set to haul and lead the cables thorough the cable ducts and at the same time, the equipment inside the pylon column, like the jacks, distant spacer and tensioning rods, were lifted and the I-steel spreading beam was arranged to support the winch atop the pylon. On the pylon column at the deck, the winch was set as well to lift the cable ends to the cable ducts, the cable ends were hauled in place by the winch, guiding pulley blocks and chain block and the cables

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

    DEFF Research Database (Denmark)

    Matteoni, Giulia

    -scale monitoring, wind tunnel testing and theoretical modelling. An extensive wind tunnel test campaign was then undertaken in order to further understand the onset conditions and characteristics of instability in the different climatic conditions described in the literature. Tests were separated into two...... exhibits marked variations. This variation is sufficient to generate negative quasi-steady aerodynamic damping, and thus to potentialy lead to galloping instability. Passive dynamic wind tunnel tests were subsequently undertaken for a cable section model of the same type as the one tested in static......-to-peak amplitudes and aerodynamic damping, changes consistently with Reynolds number, for the tested wind angles-of-attack. In fact, for selected angles-of-attack, the response was stable thoughout the whole tested range of Reynolds number, while for other angles, negative aerodynamic damping, accompanied by large...

  12. 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.

  13. 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.

  14. Cable Aerodynamic Control

    DEFF Research Database (Denmark)

    Kleissl, Kenneth

    This dissertation investigates the possibility of preventing wind-induced cable vibrations on cable-stayed bridges using passive aerodynamic means in the form of cable surface modifications. Especially the phenomenon of rainwind induced vibrations, which is known as the most common type...... of these vibrations and capable of inducing severe vibrations. The recent increase in the number of cable stayed bridges continuously becoming longer and lighter have resulted in a high number of observations of cable vibrations. A detailed literature review of the various types of passive means led...... with a sudden change in the lift during the flow transition, which could be the reason for a dry limited amplitude vibration observed only for cables with helical applications. Dry inclined galloping was only seen with the plain reference cable model, even though only the helically filleted cable was capable...

  15. 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。

  16. Pre-stressing Effect Analysis in Cable-tower Anchorage Zone of Cable-stayed Bridge%斜拉桥桥塔拉索锚固区预应力效应分析

    Institute of Scientific and Technical Information of China (English)

    王宏祥

    2014-01-01

    斜拉桥桥塔多采用 A 型或倒 Y 型的结构形式,其索塔锚固区域处于复杂空间受力状态,普通钢筋混凝土结构已经难以满足受力要求。结合某斜拉桥索塔锚固区的混凝土拉应力超限的现象,进行合理预应力配束。建立三维 ANSYS 有限元实体模型,对施加预应力后的索塔锚固区进行局部应力分析。分析表明:合理施加预应力可以有效改善索塔锚固区的受力性能,克服了普通钢筋混凝土结构拉应力超限的问题,且预应力钢束布置并不引起桥塔的附加位移。%Type A or inverted type Y are widely adopted in the bridge towers of cable-stayed bridges ,and the cable-tower anchorage zones are under complex spatial stress .Based on a cable-stayed bridge whose concrete tension stress in its ca-ble-tower anchorage zone is beyond the limits ,the pre-stressed steel bars were reinforced rationally .Then ,the finite ele-ment model is established by using ANSYS so as to analyze the local stress state of the cable-tower anchorage zone after prestressing .The results indicate that the reasonable layout of the pre-stressed steel in cable-tower zone could effectively improve the local mechanical behavior ,and overcome the phenomenon that the concrete tension stress is beyond the lim-its .Moreover ,the layout of the pre-stressed steel would not cause the additional displacement of the bridge pylon .

  17. Stress analysis of cable-pylon anchorage zones of an arch-tower cable-stayed bridge%拱塔斜拉桥索塔锚固区应力分析

    Institute of Scientific and Technical Information of China (English)

    郝翠; 王建国; 曹新垒

    2011-01-01

    Taking an arch-tower cable-stayed bridge as the research obi ect, the spatial stress analysis of its cable-pylon anchorage zones is carried out with finite element analysis software ANSYS. Based on the stress analysis of the cable-pylon anchorage zones under different operation conditions, the features of stress distribution of the anchorage zones are summarized and the stress attenuation along the pylon height which is induced by the cable tension or pre-stress is studied. The results obtained can provide useful suggestions for the related designs.%文章以某拱塔斜拉桥为研究对象,运用有限元分析软件ANSYS对其索塔锚固区进行空间应力分析;通过索塔锚固区不同工况下的应力分析,总结了锚固区应力分布特性,并研究了锚固区应力在索力及预应力单独作用时沿高度方向的衰减情况,为相关设计给出了相应的建议.

  18. Experimental Research on Dynamic Characteristics of Cable- stayed Bridge of Liaohe River Grand Bridge of Coastal Highway%滨海公路辽河特大桥斜拉桥动力特性试验研究

    Institute of Scientific and Technical Information of China (English)

    邓昌宁

    2012-01-01

    Taking the part of cable - stayed bridge of Liaohe River Grand Bridge of coastal highway of Liaoning province as an example, the method of utilizing ansys finite element software to make theoretical analysis on dynamic characteristics of cable - stayed bridge with double tower and double cable steel box girder is introduced, and technical points of dynamic test like field modal test ( pulsation test) of large bridge, slide down, vehicle jump, brake and so on are researched. Through the analysis and comparison of theoretical calculation value and field test result, it shows that the bridge has good dynamic behavior of structure and better wind - resistant stability. Under the effect of general vehicle load, the bridge has good character of service without stress and resonance phenomenon.%以辽宁省滨海公路辽河特大桥斜拉桥部分为例,介绍了利用ansys有限元软件进行双塔双索面钢箱梁斜拉桥动力特性理论分析的方法,研究了大型桥梁现场模态测试(脉动试验)、跑车、跳车、刹车等动态试验的技术要点,通过对理论计算值与现场测试的结果进行分析比较,表明该桥具有良好的结构动力特性,抗风稳定性较好,在常规车辆荷载的作用下,不易出现受迫共振现象,具有良好的使用性能。

  19. Study on key technology of bridge stay cable manufacturing%大桥斜拉索制造关键技术研究

    Institute of Scientific and Technical Information of China (English)

    游胜意; 张海良; 罗国强; 张德勤; 倪晓峰

    2013-01-01

    Galvanized steel wire for bridge must meet torsion value no less than 8 times,relaxation ratio no more than 2.5%,tensile strength no less than 1 670 MPa.The production process of galvanized steel wire for bridge stay cable and stay cable was introduced.Baosteel B82MnQL wire rod was chose to produce diameter 7.0 mm galvanized steel wire,zinc layer mass fraction is no less than 300 g/m2.In production process of galvanized steel wire,steel wire surface quality,straightness and heading performance were improved.The method of decreasing torsion of stay cable is as follows:to improve pulling method of stranding and extrusion process,to improve stranding corner to keep stay cable stranding pitch stability,to improve cable lapping tension.The new type stay cable sealing system is researched.The improvement measures of stay cable fatigue properties are as follows:to improve galvanized steel wire surface quality uniformity,straightness and diameter accuracy.The galvanized steel wire stay cable can meet special requirements of customers after it is tested and used.%大桥用镀锌钢丝必须同时满足扭转≥8次,松弛率≤2.5%,抗拉强度≥1 670 MPa.介绍大桥斜拉索用镀锌钢丝和斜拉索制作工艺.选用宝钢B82MnQL盘条生产φ7.0 mm镀锌钢丝,锌层面质量≥300 g/m2.镀锌钢丝生产过程中应提高钢丝表面质量、直线度及镦头性能.降低斜拉索索体扭转的方法:改进绞制与挤塑工序牵引方式;改进绞制弯道以保持斜拉索绞制节距稳定;改进索体绕包张力.对新型斜拉索密封体系进行研发.斜拉索疲劳性能改进措施:提高镀锌钢丝表面质量均匀性、直线性和直径精度.生产的镀锌钢丝斜拉索经检验和使用,能够满足用户的特殊要求.

  20. 斜拉桥索塔锚固区节段足尺模型试验与分析%Test and analysis on full scale segmental model of cable tower anchorage zone in cable stayed bridge

    Institute of Scientific and Technical Information of China (English)

    郭凡; 杨永清; 周厚斌; 刘国军

    2012-01-01

    A FEM model of the cable tower anchorage zone section in certain cable stayed bridge was built to analyze the spatial stress field,and the values obtained by spatial stress analysis and full scale model test were compared.The evaluation of the operating capability and safety of the bridge tower was brought forward.The frictional coefficient values of the U-shaped plastic corrugated pipes and the extension values of tendons were analyzed.Stress distribution and deformation under U-shaped and small radius ring prestressed tendons and cable force were investigated.Some suggestions about constitution and design were given to similar force analysis of cable tower anchorage zone as references.%对某斜拉桥索塔锚固区节段建立有限元计算模型进行空间应力分析,并与足尺模型试验得出的结果相比较,对该桥塔锚固区工作性能及安全性进行评价。测试分析U形塑料波纹管孔道摩阻系数和钢束伸长值,研究了小半径环向U形预应力束与拉索作用下的锚固区应力与变形情况,提出构造及设计上的建议,为设计与施工提供依据,也可为同类斜拉桥索塔锚固区的受力分析提供借鉴。

  1. 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.

  2. 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.

  3. 黄冈公铁两用长江大桥斜拉索安装技术%Installation Techniques for Stay Cables of Huanggang Changjiang River Rail-cum-Road Bridge

    Institute of Scientific and Technical Information of China (English)

    左宏献; 张士轩; 付东

    2013-01-01

    The main bridge of Huanggang Changjiang River Rail-cum-Road Bridge is a steel truss girder cable-stayed bridge with double pylons, double cable planes and with span arrangement (81 + 243 + 567 + 243 + 81) m. On both sides of a pylon of the bridge, each 19 pairs of the stay cables are provided and for the whole bridge, there are totally 152 nos. of the cables. In this paper, the installation techniques for the cables are summarized. In the process of installation of the cables, the fully rotary deck crane was used to lift each reel of the cables to the bridge deck and the cables were stretched there by the fixed cable stretching reel with the aid of the deck crane. The installation scheme was that the cables on the pylons were installed first and those at the deck level were installed late. For the installation of the cables on the pylons, the tower cranes and the lifting frames at the tops of the pylons were used while for the installation of the cables at the deck level, the cables were hauled by the winches and pulley blocks. When the cables were hauled in place, the cables were anchored and after the installation of the cables at the deck level was completed, the cables No. 3~8 were directly rigidly hauled in the pylons and the cables No. 9~19 were first softly (with maximum soft hauling force being 1 200 kN) and then rigidly hauled in the pylons. In compliance with the design requirements, the cables were synchronously and symmetrically tensioned in steps and the installation of the whole 4 000 t stay cables of the bridge were finally completed within 7 months.%黄冈公铁两用长江大桥主桥为双塔双索面钢桁梁斜拉桥,跨度布置为(81+243+567+243+81)m.每桥塔两侧各设置19对斜拉索,全桥共有斜拉索152根,对该桥斜拉索安装技术进行总结.采用全回转架梁吊机将整盘斜拉索吊至桥面;采用全回转架梁吊机配合桥面上固定式放索盘进行桥面展索;斜拉索总体挂设采用先塔后梁的方案,

  4. MAIN TOWER CATHETER POSITIONING CABLE-STAYED BRIDGE CONSTRUCTION TECHNOLOGY%斜拉桥主塔索导筒定位施工技术

    Institute of Scientific and Technical Information of China (English)

    陈志强

    2012-01-01

    福建闽江大桥工程斜拉桥主塔索导筒采取了以钢骨架为定位基础的关键技术与施工措施,通过“全站仪与CAD软件结合定位精调钢骨架”与“索导筒微调架”等关键技术措施的应用,在保证作业人员安全、施工快捷、技术稳定要求的同时,降低了高塔塔身的施工偏差,符合高精度施工的规范要求.%Combined with the Fujian Minjiang bridge project, introduces the main pylon of cable-stayed bridge cable guide tube in steel frame for positioning based on the key technology and construction measures, Through the" total station and CAD software combined with positioning precision adjustable steel skeleton" and "cable guide tube spinner rack" and a series of key technical measures in application, ensure safety of working personnel, construction of fast, stable technique requirements at the same time, reduce the tower tower construction error, consistent with the high accuracy construction specification.

  5. 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.

  6. 铁路矮塔斜拉桥索塔锚固区局部应力分析%Stress Analysis of Cable-pylon Anchorage Zones of Extra-dosed Cable-stayed Bridge in Railway

    Institute of Scientific and Technical Information of China (English)

    陈兴冲; 赵霆; 刘尊稳; 丁明波

    2012-01-01

    An extra-dosed cable-stayed bridge is taking as the practical engineering background to make the finite element analysis of the main tower by large software Ansys. The size and distribution of the concrete stress of the anchorage zones in 3 200 kN design loads are obtained, which verifies the security of the pylon design,enriches spatial stress analysis of the anchorage zone of extra-dosed cable-stayed bridge and plays a positive role in the design and construction of the project.%以某矮塔斜拉桥为实际工程背景,采用Ansys大型软件对其主塔进行了有限元分析.得出了在3200kN的设计荷栽作用下,其锚固区混凝土应力的大小及分布情况,验证了索塔设计的安全性,丰富了矮塔斜拉桥索塔锚固区的空间应力分析,对工程的设计与施工起到了积极作用.

  7. 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.

  8. 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.

  9. Economic and Mechanical Properties of Super-long Span Cable-stayed Bridge with V-shaped Pylon%超大跨度V塔斜拉桥的经济与力学特性

    Institute of Scientific and Technical Information of China (English)

    张杨永; 肖汝诚

    2009-01-01

    Two finite element models are established for super-long span cable-stayed bridges with V-shaped pylon or with conventionally erected pylon. Then, some economic and mechanical properties are given by comparative study method. Compared with the bridge with the erected pylon,constructive materials can be saved from the bridge with V-shaped pylon. From the derived formula of material saving of pylon and cables, the optimum effect occurs when the inclination of V-shaped pylon is half of the inclination of farthest cable,and the pylon materials save 6% while cable materials save 1%. Since the V-shaped pylon cable-stayed bridge has a lower height of tower and the shortened hoisting cable and the decreased moment of tower root by about 26%, the inclination of cables in this structural system is larger and the overall stiffness is increased. As a result, the stability factor is improved. In addition, the V-shaped pylon cable-stayed bridge manifests a better resistance than conventional bridge under horizontal wind load, which is more adaptable to the development of cable-stayed bridge towards a longer span.%建立了超大跨度V塔斜拉桥和常规直立索塔斜拉桥的有限元分析模型.通过对比研究,给出了V塔斜拉桥的一些经济、力学特性.和常规直立索塔体系斜拉桥相比,当V塔斜拉桥的塔柱倾角为对应跨最外侧拉索倾角之半时,节省量最优,但此时塔柱材料用量仅节省6%,拉索用量节省1%,总节省量并不大.V塔斜拉桥能够降低塔高,减小拉索悬挂长度,增大拉索倾角,使得结构整体刚度增加,稳定性系数得以提高,算例中塔根弯矩比常规体系小26%左右.另外,V塔体系能更好地抵抗横向风荷载的作用,满足斜拉桥向更大跨度方向发展的需求.

  10. 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.

  11. 双肋斜拉拱桥横向稳定性的实用计算%Practical Calculation of the Lateral Destabilization of Double Rib Cable-stayed Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    陆伟; 罗世东

    2011-01-01

    The cable-stayed arch bridge is a new form of bridge structure, which combines characteristis of the cable-stayed bridge and the arch bridge. The stability of arch is different from the normal arch bridge because the cable shares the load with the arch rib. On the basis of the energy principle, the text deduces a practical method for calculation of the lateral destabilization critical loading of the double rib cable-stayed arch under the premise of considering the factors of the stiffness of bridge floor and non-oriented conservative loadings of hanger and cable. The precision of the method is verified via an example. Analysis on the influence of parameters of the cable-stayed arch bridge on its lateral destabilization critical loading is made with the practical method. The parameters include the pretension stress, the inclination of cable, the scope of cables arranged on the arch and the distance between bridge tower and arch.%斜拉拱桥是一种将斜拉桥和拱桥相结合的新型桥梁结构形式,索拱共同受力使得拱的稳定性区别于一般拱桥.本文基于能量原理,在综合考虑桥面刚度、吊杆非保向力、斜拉索非保向力的前提下,推导双肋斜拉拱横向失稳临界荷载的实用计算方法,并通过算例验证实用计算方法的正确性,借助实用方法分析斜拉索参数:斜拉索预张拉力、斜拉索倾角、在拱上布索范围、主塔与拱的距离等对双肋斜拉拱横向失稳临界荷载的影响.

  12. 三塔斜拉桥设计参数分析%Analysis of Design Parameters for Three-Pylon Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    杨庸; 雷俊卿

    2016-01-01

    To study the mechanical behavior of the three‐pylon cable‐stayed bridge structure , combined with the real design cases of three‐pylon composite girder cable‐stayed bridge projects , the finite element model of three‐pylon composite girder cable‐stayed bridge was established to car‐ry out parametric study on the effect of the measures taken ,such as to superimpose stay cables , install stay cables between pylons ,improve pylon stiffness and add auxiliary piers ,and the varia‐tion law of their load bearing behaviors is concluded .The results of the calculation demonstrate that the load bearing capacity of the intermediate pylon ,main girder and stay cables can be effec‐tively improved by adding superimposed cables ,stiffening cables between pylons and auxiliary piers to side spans ,and the pier‐top horizontal displacement and the mid‐span deflection of the main girder can also be reduced .T he pier‐top displacement can be reduced by enhancing the stiff‐ness of the intermediate pylon .The increase of the stiffness of side pylons has little influence on the structure .The increase of the height of the intermediate pylon is capable of improving the in‐ternal force of the pylons ,but accelerating the pier‐top displacement .T he results of the calculation can provide reference for the design of configuratiion of three‐pylon composite girder cable‐stayed bridge structure .%为研究三塔斜拉桥结构的力学行为特征,为三塔斜拉桥设计提供参考,结合三塔结合梁斜拉桥工程设计实例,建立三塔结合梁斜拉桥的有限元模型,对斜拉索重叠布置、塔间斜拉索、提高桥塔刚度及采用辅助墩等措施进行参数分析,总结其受力行为的变化规律。计算结果显示:设置重叠索、设置塔间加劲索、边跨设置辅助墩可有效改善中塔、主梁、斜拉索受力,减少塔顶水平位移值及跨中主梁挠度值;提高中塔刚度可以减少塔顶位

  13. 大跨度斜拉桥斜拉索阻尼减振技术研究进展%Research Advancement of Damping Techniques for Stay Cables of Long Span Cable-Stayed Bridges

    Institute of Scientific and Technical Information of China (English)

    汪正兴; 王波; 柴小鹏

    2015-01-01

    T he vibration mechanism of the stay cables of long span cable‐stayed bridges is com‐plex ,the hazards of the vibration are severe and therefore ,the additional damping techniques need to be applied to suppress the vibration .In this paper ,the researches of the vibration characteristics of the stay cables and vibration suppression mechanism of the dampers applicable to the stay cables are summarized .The Scruton numbers of the longest stay cables of 34 cable‐stayed bridges are firstly collected and calculated .The calculations of the Scruton numbers are analyzed and compared to the existing theoretic analysis and wind tunnel test results ,are verified by the conclusions from the implemented projects and the target damping parameters for the vibration suppression corre‐sponding to each potential vortex‐induced vibration ,rain vibration ,parameter resonance ,internal resonance and wake galloping are determined .Then the damping action mechanism ,displacement transfer types and durability of the common dampers are respectively analyzed and compared and the applicable ranges of the different dampers are put forward .Finally ,in the two aspects of the action mechanism and test verification ,the advantages of the damping efficiency of the lever mass damper (LMD) are particularly introduced and the further research fields of the damping tech‐niques for the stay cables are pointed out .%斜拉索振动机理复杂且危害严重,需要采取附加阻尼技术抑制斜拉索的振动,对斜拉索的振动特性和阻尼器的减振机理进行研究总结。首先计算34座斜拉桥最长索的Scruton数,与已有的理论分析、风洞试验结果进行对比分析,并采用工程实践结论进行验证,确定了斜拉索可能发生的涡激振动、风雨振、参数共振和内共振、尾流驰振等各自对应的抑振目标阻尼参数;然后对常见阻尼器的阻尼作用机理、位移传递形式、耐久性分别进行对比分析

  14. Local Stress Analysis on Cable Tower of Single Tower and Double Cable Plane Cable-stayed Bridge Based on Submodel Method%基于子模型法的独塔斜拉桥索塔局部受力分析

    Institute of Scientific and Technical Information of China (English)

    孙文会; 曹玉贵; 庄劲松; 冯万里; 朱桂林

    2014-01-01

    抚州赣东大桥主桥为独塔双索面异型结构斜拉桥,斜拉桥索塔交汇处的锚固区部位受力非常复杂。为掌握双索面独塔斜拉桥结构复杂区域的受力情况,本文首先采用MIDAS Civil软件建立桥梁的整体有限元模型,计算桥梁在不同荷载工况下桥塔的受力状态,然后选取索塔受力最不利的工况,应用子模型法,建立索塔的精细化有限元模型,对索塔的各个组成部分进行详细的受力分析。分析结果表明:索塔交汇处的锚固区部位总体满足受力要求,但局部应力集中现象比较严重,设计中应引起重视,建议通过适当的增加配筋解决应力集中现象,确保局部构造设计安全合理。索塔局部受力分析结果为设计和施工提供了依据,对同类桥型的设计具有一定的参考意义。%The main bridge of the Gandong Bridge in Fuzhou is a irregular shaped cable-stayed bridge with a single pylon and double cable planes. The stress of interchanges of pylons of anchorage zone of the cable-stayed bridge is rather complicated. In order to investigate the mechanical characteristics of the complex structure area for single tower and double cable plane cable-stayed bridge, full scale structural model is simulated by MIDAS Civil software. After analyzed different load states, the most unfavorable stress state is selected. Submodeling method is used to refined finite element model of the bridge tower, and different parts of bridge tower are analyzed. The results indicate that the interchanges of pylons of anchorage zone can generally meet the stress requirement but the stress concentration is relatively severe and special attention is suggested to pay to design. Some reinforcement should be added at the area of stress concentration and make sure the local structure design is safe and rational. The results can be referenced to design and construction, which would have significance for design reference of

  15. Time series synthetic aperture radar interferometry over the multispan cable-stayed Rio-Antirio Bridge (central Greece): achievements and constraints

    Science.gov (United States)

    Parcharidis, Issaak; Foumelis, Michael; Benekos, George; Kourkouli, Penelope; Stamatopoulos, Constantine; Stramondo, Salvatore

    2015-01-01

    The aim of the present study is to monitor by means of multitemporal synthetic aperture radar (SAR) interferometry the stability of the fully suspended cable-stayed Rio-Antirio Bridge (RAB) as well as the ground deformation of its surrounding area. The bridge is located in a region characterized by high hazard susceptibility, therefore, the monitoring of its behavior is of significant interest to mitigate potential risks. Envisat ASAR descending and TerraSAR-X ascending acquisitions were exploited using the persistent scatterer interferometry technique covering the periods 2002 to 2010 and 2010 to 2012, respectively. For both periods, ground displacement rates ranging from -12 to +12 mm/year indicate the absence of a significant deformation source acting during the period of investigation. Of interest is the differential motion pattern between Rio and Antirio for both SAR geometries, signifying the contribution of horizontal motion components, meanwhile allowing the quantification of the relative vertical displacement rates of these regions. For the RAB infrastructure, displacement histories were obtained from TerraSAR-X data analysis only for the stable part of the bridge, namely the viaducts and the four pylons, possibly due to the oscillation of its suspended part and the uncertainty of phase measurements over the pavement. The common behavior of the pylons was confirmed with an overall subsidence between -2 and -3 mm/year. The highest rates were observed for pylons established on specific soil types and were attributed to sediment consolidation.

  16. SEISMIC ANALYSIS OF CABLE STAYED BRIDGE WITH THREE SLANTED PYLON%大跨度三塔斜拉桥地震响应分析

    Institute of Scientific and Technical Information of China (English)

    陈阳; 陈明明; 祝文澜

    2012-01-01

    结合某大跨三塔斜拉桥工程设计实例,采用有限元分析程序ANSYS建立动力计算模型.用子空间迭代法对桥梁的动力特性进行了计算,根据桥址场地地震动参数,用反应谱法和时程分析法进行地震反应对比分析.建议在大跨度斜拉桥抗震设计中,以反应谱分析结果作为抗震设计依据,以时程分析结果作为复核.%In this paper, a long-span cable-stayed bridge with three-tower is investigated, a 3D finite element model was established by the software ANSYS. The dynamics characteristics of the bridge are analyzed by sub-space iteration method. According to the earthquake dynamic parameters of the bridge site the earthquake response is analyzed using the earthquake response spectrum method and the time history analytical method. It suggests that response spectrum analysis results can be used as a basis while the time-history analysis results as review for seismic design.

  17. 非线性粘滞阻尼器对大跨CFRP索斜拉桥抗震性能影响研究%Study of Impact of Nonlinear Viscous Dampers on Seismic Performance of Long Span Cable-Stayed Bridge with CFRP Cables

    Institute of Scientific and Technical Information of China (English)

    刘荣桂; 邓程远; 蔡东升; 周士金; 李十泉; 陈蓓

    2011-01-01

    To study the applicability and design parameter selection for seismic-reduction control of the viscous dampers for cable-stayed bridge with carbon fiber reinforced plastics (CFRP)cables, the Sutong Bridge was taken as the research object, the finite element model of the cablestayed bridge with steel cables was established and the model of the bridge with the CFRP cables was then obtained by replacement of the steel cables according to the principle of equivalent axial rigidity. The time-history method was used to conduct the parameter sensitivity analysis of the selected object functions and the effect of the seismic-reduction control of the viscous dampers for the bridges respectively with the CFRP cables and steel cables was compared to find out rational value range of the design parameters of the dampers. The results of the analysis show that the dampers attached at the ends of the main girders of the bridges have very good supplementary action to the seismic-reduction control. At the time the parameters of the dampers are identical, the bridge with the CFRP cables can achieve better effect of the seismic-reduction control.%为探讨碳纤维复合材料(CFRP)索斜拉桥的阻尼器减震控制适用性及设计参数选取,以苏通大桥为背景,建立钢索斜拉桥的有限元模型,根据等轴向刚度准则换索得到CFRP索斜拉桥模型.采用时程分析法对所取目标函数作参数敏感性分析,并对2种索的斜拉桥减震控制效果进行比较,得到粘滞阻尼器设计参数的合理取值范围.分析表明:主梁端附加阻尼器对斜拉桥结构的减震控制有很好的补充作用;阻尼器参数相同时,CFRP索斜拉桥可获得较优的减震效果.

  18. The Vertical Rotating Structure Design of Cable-stayed Bridge Pylon Based on the Finite Element%基于有限元的斜拉桥索塔竖转结构件设计

    Institute of Scientific and Technical Information of China (English)

    张宝宏

    2014-01-01

    Using vertical method forward the steel tower type cable-stayed bridge body mounted, to save time, reduce the co-st.%利用竖转法进行钢塔式斜拉桥塔身安装,以达到节省工期、降低成本的目的。

  19. 北京某矮塔斜拉桥的设计与施工实践%Study on Design and Construction of one Extradosed Cable-Stayed Bridge in Beijing

    Institute of Scientific and Technical Information of China (English)

    庄年; 应伟强

    2011-01-01

    The main bridge of Tongzhou Yudaihe Bridge is a kind of prestressed concrete extradosed cable-stayed bridge with four span three pylon and double-cable-plane. Spans are attributed as (45 + 85 + 85 +45) m. The middle tower girder and pier are fixed. The side tower girder and pier are separated and supports mounted on the top of pier. Taking this bridge as an example, the characteristics of bridge type and force principle of the extradosed cablestayed bridge are simply analyzed. In this paper, the design conception and design gist of this type bridge are mainly introduced, and the construction scheme and construction techniques of this bridge are discussed.%北京通州玉带河大桥主桥为4跨3塔双索面预应力混凝土矮塔斜拉桥,主桥孔跨为45+85+85+45m,采用中塔塔梁固结、边塔塔梁与墩分离、墩顶设支座的结构形式.本文以该桥为例,浅析了预应力混凝土部分斜拉桥的桥型特点、受力特性,主要介绍了该类桥型的设计构思及要点,论述了该桥施工方案的选择及施工要点.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. Seismic Displacements Control for Yong-jiang Railway CableStayed Bridges Located in Ningbo%宁波甬江铁路斜拉桥的地震位移控制

    Institute of Scientific and Technical Information of China (English)

    杨喜文

    2011-01-01

    大跨度斜拉桥通常采用漂浮体系或半漂浮体系以延长结构的基本周期,从而在强震作用下可以减小结构的地震惯性力,但地震位移较大.以甬江铁路斜拉桥为工程背景,在参数分析的基础上确定了合理的阻尼器参数,研究了粘滞阻尼器在地震位移控制中的作用,并与不设阻尼器的情况进行了比较,结果表明:粘滞阻尼器可以有效控制大跨度斜拉桥的地震位移,改善塔底的地震剪力,明显减小低重心斜拉桥的塔底地震弯矩.%Floating or semi-floating systems are usually employed for long-span cable-stayed bridges; these bridges always have longer base periods. Though the earthquake forces of these type cable-stayed bridges are smaller, the seismic displacement is bigger than those with other systems. This paper takes Yong-jiang Railway cable-stayed bridge in Ningbo as an example to study the role of viscous damper in controlling the seismic displacement. The rational parameters of viscous damper were determined after parameter analysis,and then the seismic displacements of the bridge, with or without viscous dampers, were compared. The result showed that viscous damper was efficient in controlling seismic displacement of long-span cable-stayed bridge; the seismic shear forces at bottom of towers were reduced slightly and the seismic moments at bottom of towers were reduced in a larger extent for the cable-stayed bridge with low gravity center.

  5. 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.

  6. Probe into Construction Methods for Erection of Main Cables of Norway Harlow Grand Bridge in AS Method%挪威哈罗格兰德大桥 AS 法架设主缆施工方法探讨

    Institute of Scientific and Technical Information of China (English)

    杨宗根

    2015-01-01

    With construction of upper structure of Norway Harlow Grand Bridge as an example,in combination with the technical specifications for construction of European bridges,this paper probes into application of the AS method in erection construction of main cables of suspension bridges to provide a reference for compilation of construction plans of our national suspension bridges.%以挪威哈罗格兰德大桥上部结构施工为例,结合欧洲桥梁施工技术规范,探讨 AS 法在悬索桥主缆架设施工中的应用,对我国悬索桥施工方案编制提供参考。

  7. 某大跨度斜拉桥静载试验及结构状态评定%Static Load Test and Structural State Assessment of a Long-span Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    陈楠

    2014-01-01

    The static load test is done to a cable-stayed bridge, and the bridge specialized software Dr Bridge 3.0 is used for finite element simulation. Comparison of the measured value and the calculated value shows taht the strength and stiffness of the bridge can meet the requirements of design and use.%通过对该斜拉桥进行静载试验检测,并应用桥梁专用软件桥梁博士3.0进行有限元模拟计算。将试验结果的实测值与模拟计算得出的计算值进行比较,经对比分析可知,该桥的强度和刚度均满足设计和使用要求。

  8. 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.

  9. 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。

  10. 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

  11. Influencing Factors Analysis of Dynamic Characteristics for Single Pylon Cable-stayed Bridge%独塔斜拉桥动力特性影响因素分析

    Institute of Scientific and Technical Information of China (English)

    杜蓬娟; 孙建刚; 谭素杰

    2012-01-01

    Taking single tower and single cable plane cable-stayed bridge as the research object,through the establishment of finite element model of the bridge,we analyzed the dynamic characteristics.The first 10 order frequencies and modes are given.Based on it,the influence on the structural dynamic characteristics is researched with the changes of the mass,the vertical and transverse stiffness of main girder,stiffness of tower,cable stiffness.The influence laws are analyzed.The results can provide the reference for the similar bridge dynamic research.%以独塔单索面混凝土斜拉桥为研究对象,通过建立有限元模型,对其进行动力特性分析,并给出该桥的前10阶频率和振型。在此基础上,研究了质量变化、主梁竖向刚度、主梁横向刚度、塔柱刚度、斜拉索参数单一变化对结构动力特性的影响,并对其影响规律进行了分析,研究结果可为同类桥的动力研究提供参考。

  12. 云桂铁路南盘江特大桥扣锚素系统施工设计%Construction Design for Fastening-Anchoring Cable System of Nanpanjiang Bridge on Yunnan-Guangxi Railway

    Institute of Scientific and Technical Information of China (English)

    樊秋林

    2013-01-01

    南盘江特大桥是云桂铁路全线的重难点控制性工程,也是世界铁路中斜拉扣挂+分环分段组合法模注拱圈混凝土最大跨度的混凝土拱桥,主桥为单跨416m上承式钢管外包混凝土拱桥.扣锚索系统主要由扣塔、扣点、扣索、锚索及锚碇系统组,扣塔由主体5号、6号交界墩、0号段及其上部钢塔组成;扣点利用Q345B钢板在劲性骨架上弦管节点位置焊接而成;扣锚索均采用7φ5 mm(φj15.24,Rby=1 860 MPa)钢绞线束;锚碇采用岩锚和桩基承台锚碇两种形式.利用此系统进行劲性骨架单节段整体斜拉扣挂悬臂拼装、斜拉扣挂+分环分段组合法模注外包混凝土,为解决高山深谷条件下大跨度钢管外包混凝土拱桥的安全快速施工提供了参考.%As a super major bridge, Nanpanjiang Bridge is an important and difficult control project on Yunnan-Guangxi Railway. With the longest span in this kind of bridges in the world, it belongs to the concrete arch bridge with casting arch ring concrete which was erected by cable-stayed fastening-hanging method plus piecewise combination method, and its main bridge is a deck type concrete-encased steel tube arch bridge with a span of 416 meters. Its fastening-anchoring cable system was made mainly from several subsystems, including the fastening tower, fastening point, fastening cable, anchoring cable and anchorage device. The fastening tower was composed of No, 5 and No. 6 border pier, No. 0 segment and upper steel tower. Q345B steel plate was welded at the tube joint of upper chord of the stiff frame and then was taken as the fastening point. Both the fastening cable and the anchoring cable were composed of 7φ5 (φj15. 24, Rby = 1 860 MPa) steel stranded wires respectively. Two anchorage methods including rock anchorage and pile cap anchorage were employed. With this system, the construction of the stiff frame by segmental cable-stayed fastening-hanging cantilever assembling method, and

  13. 斜拉桥索塔施工过程的模拟分析%Simulation Analysis of Cable-stayed Bridge Pylon Construction Process

    Institute of Scientific and Technical Information of China (English)

    李厚民; 李强; 万润

    2012-01-01

    With Shennongxi cable-stayed bridge pylon as the research object,the article used the finite element analysis software Midas/Civil to establish the pylon's spatial model,cond- ucted the simulation analysis on two construction plans of pylon with temporary support and without temporary support,and the results showed that:the temporary support steel pipe in the pylon leaning-tower column construction process can reduce the stress of leaning-tower column and can optimize the stress state of pylon.%文章以神农溪斜拉桥索塔为研究对象,运用有限元分析软件Midas/civil建立索塔的空间模型,对索塔有临时支撑和无临时支撑两种施工方式进行模拟分析,结果表明:在索塔斜塔柱施工过程中添加临时支撑钢管减小了斜塔柱的应力,优化了索塔的应力状态。

  14. Construction Technique of Dragging Stay Cables with Parallel Steel Wire Strands into Anchorages for the Second Jiujiang Changjiang River Bridge%九江二桥平行钢丝斜拉索牵引入锚施工技术

    Institute of Scientific and Technical Information of China (English)

    吴小斌; 杜俊; 李东辉

    2014-01-01

    The main bridge of the Second Jiujiang Changjiang River Bridge is a two-pylon six-span asymmetrical hybrid girder cable-stayed bridge with a main span of 818 m and with double ca-ble planes .The stay cables are composed of the φ7 mm parallel steel wires ,each having a nominal tensile strength of 1 670 MPa .By the comparative analysis of the dragging construction techniques of dragging carried out by hoisters ,soft dragging ,strong dragging and a combination of the two , it was determined to drag the stay cables via a combined application of the above dragging tech -niques ,taking into consideration of the facts that the stay cables are very heavy and long and the difference between the cable forces in the central span and the side spans are great .According to the actual characteristics of the construction ,the auxiliary facilities for the stay cables installation were prepared ,including lifting portal mounted on pylon tops and the platform used to drag the ca-bles into the anchorages on the girder ,by which the problems of the insufficient hoisting capacity and the difficult installation of the dragging devices were resolved .To improve the efficiency of stay cable installation ,the short cables were installed by the steel strand elongation method ,effec-tively reducing the dragging force in the pressing anchorages in the girder and accelerating the speed of the cable′s entering into the anchorages in the girder .The long cables were dragged into the anchorages by the soft dragging and combined application of the aforementioned methods ,re-solving the difficulty of dragging the long cables into the anchorages in the girder .%九江二桥主桥为主跨818 m 的六跨不对称双塔双索面混合梁斜拉桥,斜拉索采用平行钢丝斜拉索,钢丝直径7 mm ,抗拉强度标准值1670 MPa 。通过对卷扬机牵引、软牵引、硬牵引及软硬组合牵引等牵引施工工艺的对比分析,结合该桥的斜拉索超重超长、中边跨索

  15. Parallel monostrand stay cable bending fatigue

    DEFF Research Database (Denmark)

    Winkler, Jan Pawel

    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...... 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....... The thesis starts with a literature review of the state-of-the-art in the fields of stay cable fatigue testing and cable fatigue resistance. The study helped to systemize the understanding of the fatigue characteristics of bridge cables subjected to cyclic transverse displacements, failure mechanisms...

  16. Design and Analysis of Cable-pylon Anchorage Zone for Huaian Minj iang Bridge in Fuzhou%福州淮安闽江大桥索塔锚固区设计与分析

    Institute of Scientific and Technical Information of China (English)

    朱朝阳

    2016-01-01

    斜拉桥索塔锚固区受力复杂,对全桥结构安全具有重大影响。结合斜拉桥混凝土桥塔工程实例,介绍了主塔锚固区的设计思路,采用有限元软件建立实体模型研究锚固区应力分布情况和受力特性。结果表明:设置环向预应力对主塔锚固区侧壁受力改善显著,锚固齿块应力集中明显,应适当加大齿块尺寸,加强锚下配筋和横向钢筋配置。%The structure behavior of cable-pylon anchorage zone is complicated,and it has a great in-fluence on the safety of the whole bridge structure.Based on the example of cable-stayed bridge con-crete tower proj ect,the design mentality of cable-pylon anchorage zone was introduced,and the solid models was set up by using finite element software to analyze the stress distribution and mechanical characteristic of cable-pylon anchorage zone.The results show that:setting ring pre-stress can signifi-cantly improve the sidewall's stress states of cable-pylon anchorage zone,the stress concentration of anchor block lower edge is distinct,anchor block size should be increased properly and the disposition steel bar under anchorage and the transverse steel bar should be strengthened.

  17. 双排支座设置对多塔斜拉桥的影响%Influence on internal force of multi-pylon cable-stayed bridge by setting double row bearings

    Institute of Scientific and Technical Information of China (English)

    曹珊珊; 雷俊卿; 张坤

    2013-01-01

    Stiffness problem is one of the prominent problems of multi-pylon cable-stayed bridge. Based on the existing method of improving the stiffness and the geometry nonlinear effect of the long span cable-stayed bridges, the finite element model has been built in this paper. The stiffness, the way of force transmission and the distribution of internal force of six tower cable-stayed bridge are analysed by setting double row bearings with different distance. As a result, stiffness can be improved 10%. There is a best region for space between double row bearings. Besides, there's the influence on internal force of towers and cables.%为解决目前多塔斜拉桥最为突出的刚度问题,以既有提高结构刚度的措施为基础,借助依托项目,采用空间桥梁有限元专用程序,考虑大跨度斜拉桥中的几何非线性效应,分析研究了设置不同支座间距的双排支座对六塔斜拉桥刚度和传力系统及内力分布等方面的影响.结果表明:双排支座的设置可以提高斜拉桥刚度10%以上,对主梁的内力分布存在最优支座间距区间,对索塔和拉索亦均有相应影响.

  18. Design of Curve Cable-Stayed Bridge with Steel-Box Hybrid Girder for Four-Track Railway%四线铁路钢箱混合梁弯斜拉桥设计研究

    Institute of Scientific and Technical Information of China (English)

    罗世东; 饶少臣

    2011-01-01

    According to the mechanical characteristics of the curve cable-stayed bridge of four-track railway, the structure design and research on the cable, girder, bridge towers and foundation construction were launched by space bar finite element static analysis method in terms of the cable-stayed bridge architecture, the bridge stiffness, shrinkage and creep, and geometric nonlinearity etc. FEM analysis was used to study the stress distribution of the orthotropic steel box decks under the combined effect of the vertical and horizontal bending, shear lag and torsion warping. With FEM simulation, the local stress analysis and structure research were carried out on several aspects, such as the joint section of steel box girder and the prestressed concrete beam, the consolidation area between the main girder and the crossbeam of the bridge tower as well as the upper and lower steel anchor boxes for stay cable. Vehicle-bridge coupled time-varying analysis method was adopted to study the train running dynamic performance. Response spectrum method and seismic time history analysis method were used to study and analyze the seismic performance and seismic measures of the structure. Analyses show that about 3 m distance between the diaphragm and the web plates adopted for the steel box girder plays important role in improving the main beam structure in the curve cable-stayed bridge of four-track railway. Good train operation performance indicates that 1/900 deflection-span ratio adopted for the bridge to control the structural stiffness is more reasonable. E-type steel damping bearing has improved the seismic performance of the bridge.%根据四线铁路弯斜拉桥的受力特点,采用空间杆系有限元静力分析方法,围绕斜拉桥结构体系、桥梁整体刚度、收缩徐变、几何非线性等方面对其展开拉索、主梁、桥塔、基础的构造设计与研究.采用有限元仿真分析技术,研究正交异性桥面板的弯钢箱梁在受纵横向弯曲

  19. Coupling vibration of wind-vehiche-bridge system for long-span steel truss cable-stayed bridge%大跨度钢桁梁斜拉桥风-车-桥系统耦合振动

    Institute of Scientific and Technical Information of China (English)

    李永乐; 李鑫; 向活跃; 廖海黎

    2012-01-01

    A long-span road-rail steel truss cable-stayed bridge was taken as an engineering example, the aerodynamic coefficients of vehicle and bridge at different states were measured through wind tunnel test with the section models of vehicle and bridge. Wind-vehicle-bridge system was simulated at different wind speeds, vehicle speeds and vehicle load states by using the self-developed software BANSYS. The influences of vehicle position and two trains passing each other on the system were discussed. Computation result shows that wheel load reduction rate exceeds safety limit value when vehicle speed is up to 100 km ~ h-1 and wind speed is 25 m ~ s ~. When vehicle speed is up to 120 km ~ h 1, vehicle vertical acceleration exceeds comfortable limit value. When wind speed is higher, the wheel load reduction rate of vehicle running on windward side is the control factor for wind-vehicle-bridge system. The unloaded vehicle response is larger than overcrowded vehicle. Due to the wind shielding effect for windward side vehicle, transverse accelerations change suddenly at the beginning and ending of the process for two trains passing each other. 7 tabs, 5 figs, 14 refs.%以某大跨度公轨两用钢桁梁斜拉桥为工程背景,通过车桥组合节段模型风洞试验,测试了不同状态下车辆和桥梁各自的气动力系数,采用自主研发桥梁分析软件BANSYS,分析了不同风速、车速、车载状态下的风一车一桥系统,研究了车辆位置和双车交会对系统响应的影响。计算结果表明:当风速为25m·S-1,车速达到100km·h。时,车辆的轮重减载率超过了行车安全性限值,且当车速达到120km·h-1时,车辆的竖向加速度超过了行车舒适性限值;风速较高时沿迎风侧轨道运行车辆的轮重减载率是系统的控制因素;车辆在空载状态下的各项响应均比在超员状态下的要大;由于迎风侧车的遮风效应,在双车交会开始和结束时车辆横向加速度出现突变。

  20. Effect of cable-stayed bridge's relative height of deck on viscous damper's seismic reduction behavior%斜拉桥面相对高度对粘滞阻尼器减震效果影响研究

    Institute of Scientific and Technical Information of China (English)

    张文学; 黄荐; 王景景

    2015-01-01

    由于地震响应特性对斜拉桥结构影响较大,在塔梁之间合理设置粘滞阻尼器可改善斜拉桥抗震性能。而目前研究多针对具体工程未考虑斜拉桥面相对高度对粘滞阻尼器减震效果影响。以某斜拉桥为模型,通过改变其下塔柱高度改变斜拉桥面相对高度,并系统分析桥面相对高度对斜拉桥粘滞阻尼器减震效果影响。研究表明,桥面相对高度对粘滞阻尼器最优参数及最优减震效果均有较大影响。%Studies show that proper elastic viscous damper between the tower and girder can improve the seismic behavior of cable-stayed bridge.However,conclusions at present are mostly drawn from some specific engineering projects without considering the influence of different relative height of deck on viscous damper's shock reduction effect.By changing the height of lower towers to alter the relative height of deck,the influence of relative height of deck on tower-girder viscous damper's shock reduction effect was analysed based on a certain cable-stayed bridge model.According to the study,it is shown that the relative height of deck of cable-stayed bridge has an outstanding influence on the damper's optimal parameters and the optimum shock reduction effect.

  1. 超大跨度斜拉桥裸塔风致抖振 MTMD 控制研究%Buffeting control of the free-standing tower of a super-long-span cable-stayed bridge using MTMD

    Institute of Scientific and Technical Information of China (English)

    陶天友; 王春峰; 王浩; 李爱群

    2015-01-01

    以主跨1088 m 的苏通大桥为工程背景,根据规范推荐的风谱模型分别模拟了不同风速下裸塔结构的三维脉动风场,基于 ANSYS 进行了裸塔在强风作用下的风致抖振响应及其 MTMD 减振控制研究,重点探讨了 MTMD用于大型斜拉桥裸塔抖振控制的效果及其中的关键影响因素。结果表明:TMD 的数量、MTMD 的质量比、频带宽、阻尼比等参数的变化对其减振效果的影响不尽一致;合理设置 MTMD 参数可大大降低斜拉桥裸塔的抖振位移响应,实现主塔结构抖振的有效控制。分析结果可为大跨度斜拉桥裸塔结构的风致抖振控制提供参考。%With the increase of the height and structural complexity of the long-span cable-stayed bridge tower,the buffeting response of the free-standing tower and its control become one of the key issues in bridge engineering.In this paper,Sutong Bridge,a long-span cable-stayed bridge with a main span of 1088 m is taken as the engineering background.3-dimensional wind turbulence field for the free-standing tower is simulated according to the measured specification spectrum,the buffeting response of the free-standing tower under the action of strong wind and its control using MTMD are studied based on ANSYS.The control effect on buffeting of the free-standing tower of long-span cable-stayed bridge and the key MTMD parameters are investigated. Results show that the influences of the MTMD parameters including the number of TMD,mass ratio,frequency bandwidth and damping ratio are not identical.The MTMD with reasonable pa-rameters can greatly decrease the buffeting displacements for the free-standing tower of the cable-stayed bridge,and therefore effectively control the buffeting of the main tower.Results can pro-vide references for wind-induced buffeting control of the free-standing tower of long-span cable-stayed bridges.

  2. 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.

  3. 厦漳跨海大桥北汊主桥斜拉索外置式阻尼器及其参数分析%Analysis for External Damper for Stayed Cables of Main Bridge in Northern Bay of Xia-zhang Crossing Sea Bridge and Its Parameters

    Institute of Scientific and Technical Information of China (English)

    李军; 杜世界

    2012-01-01

    This paper simply introduces project profile of Xia-zhang Crossing Sea Bridge and expatiates researches on vibration and vibration control of stayed cables at home and abroad. In allusion of features of big flexibility of ultrolong stayed cables, low internal damp, wide distribution of inherent frequency and easy vibration under excitation of wind and rain and displacement of supporting end in northern bay of Xia-zhang Crossing Sea Bridge, the paper conducts analysis for vibration frequency of stayed cables, determination of installing height of damper, selection of viscosity of viscous bodies and calculation for size of damper boxes, etc. , and finally selects viscous shearing damper as external damper for stayed cables to ensure safety of stayed cables.%简要介绍厦漳跨海大桥工程概况,阐述国内外对斜拉索振动及振动控制的研究.针对厦漳跨海大桥北汊主桥超长拉索柔性大、内阻尼低、固有频率分布广,极易在风、风雨和支承端位移等激励下发生振动的特点,从斜拉索振动频率分析、阻尼器安装高度确定、粘性体粘度选择、阻尼器箱体大小计算等几方面进行分析,最终选择粘性剪切型阻尼器作为斜拉索外置式阻尼器来保证斜拉索安全.

  4. 独塔斜拉桥非线性动力特性有限元分析%Finite Element Analysis of Nonlinear Dynamic Characteristics of Single Pylon Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    何军拥

    2012-01-01

      自振频率是评价桥梁动力性能的重要依据。结合某斜拉桥工程设计实例,考虑结构的非线性,采用大型有限元分析程序ANSYS建立三维有限元模型。以等效弹性模量法模拟拉索,利用主从约束模拟塔梁的连接及边墩、辅助墩与主梁的连接;主塔与主梁之间设纵向阻尼器,模拟纵向漂浮体系,对模型进行动力分析,其分析结果为桥梁维修和养护提供参考意见。%  Natural frequencies are critical bases to evaluate the dynamic performance of bridges. This paper takes a large cable-stayed bridge as an example and a finite element computing model is set up for this bridge based on software ANSYS, which is to carry out modal analysis and get relevant modal parameters. The equivalent elastic modulus method is applied to analog cable modulus. The master-slave constraint is used to analog tower and beam connections, the side piers, auxiliary pier and beam connection, and longitudinal damper located between the main beam and the main tower, to simulate vertical float system. The results may be used as reference in bridge inspection etc.

  5. 基于纤维模型的矮塔斜拉桥抗震性能分析%Analysis on the Earthquake Resistant Capability of Low Tower Cable-stayed Bridge by Fiber Model

    Institute of Scientific and Technical Information of China (English)

    张帅

    2011-01-01

    铁路矮塔斜拉桥由于要保证结构刚度,一般不宜采用漂浮体系,而独塔斜拉桥往往采用塔墩粱固结体系,研究此种结构体系在多遇地震尤其在罕遇地震作用下的动力响应、保证结构具有良好的抗震性能是十分必要的;以前的动力弹塑性分析主要集中在公路桥梁和高层结构等方面,铁路桥梁涉及较少,以津保铁路某三线曲线矮塔斜拉桥为工程背景,对其在罕遇地震作用下的动力响应进行非线性时程分析,并通过计算确定桥墩合理配筋,对薄弱环节进行局部加强,以确保结构具有良好的抗震性能,对铁路桥梁的罕遇地震下的动力弹塑性分析有一定的参考作用.%For the stiffness of bridge structure, railway low tower cable-stayed bridge seldom employs floating system while the diagonal single tower bridge often uses the pylon-beam rigid system. It is quite necessary to ensure the earthquake resistant capability and to conduct a research on the dynamic response of this kind of structure system under the influence of frequent earthquakes especially for the rare earthquakes. Since dynamic elasto-plastic analyses mainly focused on road bridges, high-rise structures and seldom on railway bridges, the paper took a three line curved low tower cable-stayed bridge on Tianjin-Baoding railway for example, carried out nonlinear analysis of the dynamic responses of the bridge under the influence of rare earthquakes. Reinforcment of the tower was designed reasonably according to calculations and the weak portions were strengthened to guarantee the earthquake resistant capability. This could be a valuable guide to the dynamic elasto-plastic analysis on structures under rare earthquakes.

  6. 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.

  7. Parametric Study on Nonlinear Viscous Damper of Long-Span Cable stayed Bridge%大跨度斜拉桥非线性粘滞阻尼器参数研究

    Institute of Scientific and Technical Information of China (English)

    严斌

    2013-01-01

    To investigate the influences on longitudinal limit performance of floating-type long-span cable stayed bridge because of the different nonlinear viscous damper parameters under the action of seismic force, by using nonlinear dynamic time-history analysis method, the article carried out the sensitivity analysis for the different damping coefficient C and damping exponent £ of nonlinear viscous damper which was used in a long-span cable stayed bridge. Afterwards, the results of sensitivity analysis were compared with the seismic response without viscous damper in this bridge, and the safety evaluations for both situations were also carried out. Furthermore, the control methods and formulas of selecting the damping coefficient C and damping exponent £ were provided in this article. The results of parametric sensitivity analysis indicate that after setting the nonlinear viscous damper in longitudinal direction of cable stayed bridge, the relative displacements at key positions of the bridge can be reduced effectively by adjusting the parameters of the viscous damper; but important amplification effect on the vertical displacement at the midspan of the bridge occurs when limiting the longitudinal displacement of main girder by nonlinear viscous damper. So, it is significant to reasonably select the damping parameters for the purpose of improving the safety performance of cable stayed bridge under the action of seismic force.%为研究地震作用下非线性粘滞阻尼器参数的不同选取对漂浮式大跨度斜拉桥纵向限位性能的影响.通过非线性动力时程分析法对某大跨度斜拉桥中非线性粘滞阻尼器的阻尼系数C和阻尼指数ξ进行参数敏感性分析,与该桥在未设置粘滞阻尼器状态下的地震响应进行比较分析和安全评价.提出选取阻尼系数C和阻尼指数ξ的控制方法和公式.结果表明:斜拉桥纵桥向设置粘滞阻尼器后,通过调节粘滞阻尼器的参数能有效降低结构

  8. 基于子模型法的斜拉桥塔梁墩固结段局部分析%Analysis on Fixed Tower-Beam-Pier Part of Cable-Stayed Bridge Based on Sub-Model Method

    Institute of Scientific and Technical Information of China (English)

    宋军; 周建庭; 陈增顺

    2013-01-01

    在对大跨径斜拉桥整体结构有限元分析的基础上,应用子模型法对斜拉桥塔梁墩固结位置进行了有限元结构受力分析,计算了4种不同工况下结构的应力应变状态.研究表明:子模型法可以更为精确有效地计算斜拉桥塔梁墩固结处的应力分布情况,计算结果可作为大跨径斜拉桥塔梁墩固结处局部设计和施工的参考依据.%Based on the finite element analysis of the whole structure of the long-span cable-stayed bridge,the sub-model method was applied to do finite element structural stress analysis of the pylon-girder-pier joint,and the stress and strain of the structure were calculated in four different working conditions.The research shows that sub-model method can calculate the stress distribution of the pylon-girder-pier joint more accurately and the calculating results can be considered as the reference to the design and construction of fixed tower-pier-beam part of the long-span cable-stayed bridge.

  9. 大跨径斜拉桥塔墩梁固结处空间受力分析%Analysis of Spatial Mechanical Behavior of Pylon, Girder and Pier Rigid Fixity Structures of Long-span Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    黄力; 刘志权; 石雪飞

    2012-01-01

    The Huaihe and Five Rivers Bridge of Anhui is hybrid girder cable-stayed bridge, with span arrangement (246 +125) m and single tower double cable planes tower pier beam consolidation system. Midas/ Civil is used to establish a space truss model for the overall analysis to determine the most unfavorable parts of the tower-pier-beam loading conditions. With the large general-purpose finite element software ANSYS, three-dimensional solid model tower-pier-beam consolidation is established, which provides scientific and theoretical basis for the design and construction.%安徽五河淮河桥大桥为混合梁斜拉桥,跨径布置为(246+125)m,为独塔双索面塔墩梁固结体系.利用Midas/Civil建立空间杆系模型进行整体静力分析,确定塔墩梁部位四种最不利荷载工况,得到其活载影响线加载位置和荷载大小.再利用大型通用有限元软件ANSYS建立塔墩梁固结处三维实体模型进行受力分析,为设计与施工提供科学理论依据.

  10. 大跨度斜拉桥钢箱梁非对称安装技术%Asymmetric Mounting Technology for Steel Box Girder of Large - span Cable - stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    黄中华

    2012-01-01

    介绍了辽宁滨海公路辽河特大桥斜拉桥钢箱梁非对称悬臂安装技术,通过对本桥方案箱梁非对称悬臂安装方案—边跨钢梁高支架上直接滑移就位连接、主跨钢梁逐段悬臂安装的方案可行性研究与实施,为同类型桥梁施工提供了很好的借鉴作用。%Asymmetric cantilever - type mounting technology of steel box girder of cable - stayed bridge of Li- aohe Bridge across Liaoning Coastal Highway is introduced; through the feasibility study and implementation of asymmetric cantilever - type mounting scheme of steel box girder of the bridge - scheme of direct slip in place con- nection on high bracket of side - span steel girder and section by section cantilever - type mounting of main span steel girder, a good reference is provided for the bridge construction of the same type.

  11. 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.

  12. Maxwell Tension Supports the Water Bridge

    OpenAIRE

    Widom, A.; Srivastava, Y. N.; Swain, J.; Sivasubramanian, S.

    2008-01-01

    A cylindrical flexible cable made up of pure fluid water can be experimentally spanned across a spatial gap with cable endpoints fixed to the top edges of two glass beakers. The cable has been called a water bridge in close analogy to iron cables employed to build ordinary span bridges. A necessary condition for the construction of a water bridge is that a large electric field exists parallel to and located within the water cable. Presently, there is no accepted detailed theory which quantita...

  13. 斜拉桥肋板式主梁剪力滞效应研究%Research of Shear Lag Effect in Ribbed Plate Beam of Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    朱海峰

    2015-01-01

    大跨度斜拉桥剪力滞效应十分突出,在设计和施工过程中应考虑剪力滞效应的影响。根据能量变分原理,推导出肋板式主梁截面的剪力滞系数简易计算公式。以某460米主跨预应力混凝土斜拉桥为研究对象,采用大型空间有限元分析程序MIDASFEA3.3进行三维实体有限元数值分析,并与通过能量变分法计算得到的剪力滞系数比较发现,宽度较大的肋板式主梁剪力滞效应突出,且跨中处截面剪力滞系数小,而塔根处的截面剪力滞系数大,在设计和施工过程中应采取必要的措施保证结构安全。%The shear lag effect is very conspicuous among cable-stayed bridges with long span ,therefore the influence of shear lag effect should be taken into account in the design and construction of these bridges .Here ,a simple formula for calculating the shear lag coefficient of the ribbed plate beam section is derived from energy variation principle .Based on the research of a prestressed concrete cable-stayed bridge with the main span of 460 m ,the three-dimensional entity finite element numerical analysis was conducted by using large spatial finite element analysis program MIDAS FEA3 .3 .The comparison between the shear lag coefficient obtained from the analysis and that from the formula derived from energy variation method indicate that ribbed plate beams with larger width are subjected to prominent shear lag effect ,with smaller shear lag coefficient at mid-span section ,but larger shear lag coefficient at the root of tower section .Accordingly , necessary measures should be taken into consideration in the design and construction process of these bridges ,in order to ensure the safety of the structures .This research will provide some referential value for the research of similar bridges .

  14. 斜拉桥健康监测信号改进小波相关降噪%Improved Wavelet Correlation De-noising on Cable-Stayed Bridge Health Monitoring Signal

    Institute of Scientific and Technical Information of China (English)

    严鹏; 李乔; 单德山

    2012-01-01

    To enhance the dynamic signal de-noising effects of cable-stayed bridge health monitoring, an improved wavelet correlation de-noising algorithm is proposed in order to deal with defects of traditional one. The improved algorithm uses the main energy periods of wavelet coefficients of each layer as the correlation detection neighborhood sizes, and sets a de-noising threshold on the basis of the characteristics of cable-stayed bridge dynamic response signal. Finally the de-noised signal is obtained by a new algorithm on signal reconstruction. Two algorithms, called the traditional wavelet correlation de-noising and wavelet default threshold de-noising algorithms, are compared with the improved one in series of simulation experiments. The results show that improved wavelet correlation de-noising algorithm has better de-noising effect, thus it can be used in dynamic signal de-noising of cable-stayed bridge health monitoring.%为提高斜拉桥健康监测动态信号的降噪效果,针对传统小波相关降噪算法的缺陷,提出一种改进小波相关降噪算法.该算法将各层小波系数的主要能量周期作为相关检测邻域范围,并根据斜拉桥动态响应信号特征设置降噪阈值,最后采用一种全新的信号重构算法,得到降噪后的信号.将该算法与传统小波相关降噪和小波默认阈值降噪算法进行仿真试验比较,结果表明,改进小波相关降噪算法具有较好的降噪效果,能够应用于斜拉桥健康监测动态响应信号的降噪处理.

  15. 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。

  16. Analysis on Wind-Excited Flutter of Cable-Stayed Bridge with Asymmetric Composite Girder and Single Pylon%非对称混合梁独塔斜拉桥风致颤振分析

    Institute of Scientific and Technical Information of China (English)

    杨从娟

    2012-01-01

    With asymmetric composite girder, single pylon and main bridge span arrangement (310+2x 50+2x40) m, the new Haihe River Bridge is a cable-stayed bridge in double cable plane and semi-floating system. The article established space analysis model by using the finite element method, and analyzed the dynamic characteristics under the two stages, respectively the stage of hoisting in maximum single-cantilever status during bridge construction and the stage of completion. Afterwards, the article researched into its vibration model features and periods. Further, the article calculated the critical wind speeds respectively for bending-torsion coupling flutter and for separated-flow coupling flutter based on its dynamic features according to classical theory, also calculated the testing wind speed for bending-torsion coupling flutter and for separated-flow coupling flutter according to the standard specification. Finally, the article assessed the wind-excited flutter of this bridge. The assessment results show that the self-excited flutter of the steel box girder of this bridge can all be restrained under the whole process of assembling of cantilevered method and under the operation process of the completed bridge; the stability index of the completed bridge is bigger than 2. 5 while smaller than 4. 0; so it is suggested that the wind tunnel test for the segment models should be implemented.%新建海河大桥为独塔双索面半漂浮体系的斜拉桥,该桥为非对称混合梁斜拉桥,主桥孔径布置为310m+2x50m+2×40m.利用有限元建立空间分析模型,对该桥施工过程中吊装最大单悬臂状态和成桥状态的2种状态进行动力特性分析,研究其振型特征和周期,根据其动力特性按经典理论计算弯扭耦合颤振和分离流耦合颤振临界风速,并根据规范计算弯扭耦合颤振和分离流耦合颤振检验风速,对该桥风致颤振进行评估;通过评估,该桥钢箱梁悬臂拼装全过程和成桥运营状

  17. 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.

  18. Automated wireless monitoring system for cable tension using smart sensors

    Science.gov (United States)

    Sim, Sung-Han; Li, Jian; Jo, Hongki; Park, Jongwoong; Cho, Soojin; Spencer, Billie F.; Yun, Chung-Bang

    2013-04-01

    Cables are critical load carrying members of cable-stayed bridges; monitoring tension forces of the cables provides valuable information for SHM of the cable-stayed bridges. Monitoring systems for the cable tension can be efficiently realized using wireless smart sensors in conjunction with vibration-based cable tension estimation approaches. This study develops an automated cable tension monitoring system using MEMSIC's Imote2 smart sensors. An embedded data processing strategy is implemented on the Imote2-based wireless sensor network to calculate cable tensions using a vibration-based method, significantly reducing the wireless data transmission and associated power consumption. The autonomous operation of the monitoring system is achieved by AutoMonitor, a high-level coordinator application provided by the Illinois SHM Project Services Toolsuite. The monitoring system also features power harvesting enabled by solar panels attached to each sensor node and AutoMonitor for charging control. The proposed wireless system has been deployed on the Jindo Bridge, a cable-stayed bridge located in South Korea. Tension forces are autonomously monitored for 12 cables in the east, land side of the bridge, proving the validity and potential of the presented tension monitoring system for real-world applications.

  19. 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).

  20. 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.

  1. Cable manufacture

    Science.gov (United States)

    Gamble, P.

    1972-01-01

    A survey is presented of flat electrical cable manufacturing, with particular reference to patented processes. The economics of manufacture based on an analysis of material and operating costs is considered for the various methods. Attention is given to the competitive advantages of the several processes and their resulting products. The historical area of flat cable manufacture is presented to give a frame of reference for the survey.

  2. 空间四索面联体独塔斜拉桥塔梁固结段应力分布规律及合理构造研究%Research on Stress Distribution Rule and Reasonable Structure at Consolidation Section between Tower and Girder of Conjoined Single-tower Cable Stayed Bridge with Four Spatial Cable Planes

    Institute of Scientific and Technical Information of China (English)

    苏小波; 于长皓; 杜细春

    2013-01-01

    On the basis of establishing a local multi-scale analysis model of consolidation section between tower and girder of some single-tower cable-stayed bridge with four spatial cable planes,this paper obtains local stress level and distribution rule in this area via accurate simulation for boundary conditions of load and displacement,and determines the causes of excessive major tensile force at arc section of upper pylon junction through further study.Based on 2 factors,i.e.detail construction and internal force balance,the paper lays down three optimized schemes and compares the optimized results and proposes the recommended scheme.%针对某空间四索面独塔斜拉桥建立塔梁固结段的多尺度局部分析模型,通过对荷载及位移边界条件的准确模拟,得到该区域的局部应力水平及分布规律,并通过进一步研究,确定上塔柱交接处圆弧段主拉应力偏大的产生原因.基于细部构造及内力平衡2个因素拟定3种优化方案,并对优化效果进行对比,提出推荐方案.

  3. 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.

  4. 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.

  5. Surveying Technique in Steel Box Girders Construction of Long- span Steel Pylon Cable- stayed Bridge%大跨径钢索塔斜拉桥钢箱梁施工测量技术

    Institute of Scientific and Technical Information of China (English)

    孙景领; 赵显富; 王新志

    2012-01-01

    Nanjing Third Yangzi River Bridge with its orthotropic plate streamlined fiat steel girder box is the first supergiant cable - stayed bridge in china whose main tower is of steel structure. This paper introduces the accuracy requirement of the steel box girder installation and the way to establish construction control network step by step. It also elaborates on the methods and techniques adopted in the construction and measurement of different sections of the girders. The result shows that the line type of steel box girder accords with the requirement of design.%南京长江三桥是我国首座主塔采用钢结构形式的特大型斜拉桥,主梁为正交异性板流线型扁平式钢箱梁。文章介绍了钢箱粱安装的精度要求,以及分步骤建立施工控制网的方法,并详细阐述了不同梁段施工测量的技术和方法,结果表明成桥后的钢箱梁线型符合设计要求。

  6. Active Opposite Transverse Bracing Technology in Cable-stayed Bridge with Large Angle Tower Column%斜拉桥大倾角斜塔柱对顶横撑施工技术

    Institute of Scientific and Technical Information of China (English)

    童林鸿; 胡军

    2014-01-01

    The design height of the main tower of large span cable-stayed bridge is large. The construction of the inclined pylon with large dip angle is the difficulty and key. Based on the construction of main tower in Fuzhou railway Tongling Yangtze River Bridge, this paper introduces the tower construction by setting the active opposite transverse bracing to ensure construction safety and alignment of the tower structure.%大跨度斜拉桥主塔设计高度较大,其大倾角斜塔柱的施工是难点及重点所在。本文以合福铁路铜陵长江大桥主塔施工为依托,重点介绍了其中塔柱施工时通过设置主动对顶横撑保证塔柱结构安全及线形的施工技术。

  7. 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.

  8. 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

  9. Slanted Pylon Construction Technology of a Cable Stayed Bridge with Box Girder of Corrugated Steel Webs and Without Back Stays%波形钢腹板箱梁无背索斜拉桥斜塔施工技术

    Institute of Scientific and Technical Information of China (English)

    贾贯乾

    2015-01-01

    The original structural single tower cable stayed bridge without back stays is used in the main bridge on Zhens-hui Road in Xinmi City.The main girder is box girder with corrugated steel webs.Pier,tower and girder of the main bridge are consolidated together.The dip angle of the main tower is 59 degrees.Construction of the main girder is very difficult. Based on the design,segmental division is made of the main tower construction.To overcome the difficulties of construc-tion,comparison and study were made on the construction scheme which was explained in details.%新密市溱水路大桥主桥采用新型的钢-混组合结构梁独塔无背索斜拉桥桥型,主梁主塔为波形钢腹板混凝土箱梁。主桥为墩塔梁固结体系,塔身倾斜,斜塔倾角59°,主塔施工难度非常大,质量控制困难。依据设计特点,对斜塔施工进行了合理的节段划分,为克服斜塔实心混凝土结构施工困难,对施工方案进行详细的比选和研究,并对方案实施进行了详细阐述。

  10. Influence of Pile-soil-structure Interaction on Seismic Response of Long Span Cable Stayed Bridge%桩-土-结构相互作用对大跨度斜拉桥地震响应的影响

    Institute of Scientific and Technical Information of China (English)

    段浪; 金波

    2011-01-01

    土层条件对结构在地震作用下的破坏有很大影响.本文旨在对考虑桩-土-结构动力相互作用(PSSI)对大跨度斜拉桥地震响应造成的影响进行评估.文中将桩-土相互作用理想化为采用连续分布的水平弹簧和粘滞阻尼器的Penzien模型,并用ANSYS有限元分析软件对苏通大桥整体模型进行地震响应时程分析来研究PSSI的影响.可以看出,PSSI对苏通大桥地震响应有显著影响,如果忽略PSSI效应,大部分响应将被低估.%Soil conditions have a great deal to do with damage to structures during earthquakes. This paper attempts to assess the influence of dynamic pile-soil-structure interaction (PSSI) on the seismic behavior of long span cable stayed bridge. In the present approach, the soil-pile interaction was idealized as Penzien model using continuously distributed springs and viscous dampers placed in parallel. The effects of PSSI on integral model of SUTONG Bridge were investigated by performing seismic analysis in time domain using ANSYS FEM software. It is observed that the PSSI has significant effects on the seismic response of SUTONG Bridge and a majority of responses may be underestimated if the PSSI effects are ignored.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Nonlinear Time-domain Buffeting Analysis of Cable-stayed Bridge%斜拉桥抖振响应非线性时程分析

    Institute of Scientific and Technical Information of China (English)

    卢伟; 强士中; 周述华

    2001-01-01

    在大跨桥梁抖振响应分析中,时程分析具有其独有的优势。本文利用一系列幅值加权的空间余弦波迭加(WAWS)模拟随机风场,进而计算出抖振力,而自激力则表示为脉冲响应函数与桥梁运动的卷积形式。文中采用含增量动力平衡迭代格式的Newmark-β法进行非线性时程分析,并以南京长江二桥为例进行了数值计算。%Time-domain method plays an important role in buffeting analysis of long-span bridge. In this paper, buffeting forces are based on the wind field simulation of a series of spaced cosine waves with weighted amplitude and self-excited forces are expressed in the convolution form of impulse response functions and bridge motions. A Newmark-β method described in incremental dynamic equilibrium iteration equation is applied in nonlinear calculation. The buffeting response histories of Second Bridge in Nanjing over Yangtze river are calculated by the method described.

  16. Cable Stability

    CERN Document Server

    Bottura, L

    2014-01-01

    Superconductor stability is at the core of the design of any successful cable and magnet application. This chapter reviews the initial understanding of the stability mechanism, and reviews matters of importance for stability such as the nature and magnitude of the perturbation spectrum and the cooling mechanisms. Various stability strategies are studied, providing criteria that depend on the desired design and operating conditions.

  17. Comparative Analysis of Synchronous and Asynchronous Construction of Tower and girder of Yongjiang Railway Cable Stayed Bridge%甬江铁路斜拉桥索塔塔梁同异步施工方法对比分析

    Institute of Scientific and Technical Information of China (English)

    胡晓东; 陈平

    2016-01-01

    The extra-long bridge of Yongjiang River is a domestic first large-span railway cable-stayed bridge with hybrid girder and 177.91 m diamond-type tower. In order to analyze the impact of synchronous and asynchronous constructions of tower and girder on the stress state and linearity of the tower, a finite element model is established to simulate the entire construction process. The comparative analysis reveals that the stress and line of the tower resulted from the two construction methods are of some difference, and both methods meet design requirement, but the asynchronous construction method can save much time. According to the comparative analysis and the actual lagging of the south cable-tower, the south tower and the north tower employ synchronous and asynchronous construction methods respectively, and as a consequence, the synchronization of progress and good economic and social benefits are obtained.%甬江特大桥为国内首座铁路大跨度钢箱混合梁斜拉桥,钻石形索塔高177.91 m。通过建立索塔与下横梁同、异步施工有限元模型,模拟分析同、异步施工对索塔受力状态及线形的影响。对比分析表明,同、异步施工的索塔受力及线形略有差异,均能满足设计要求,而异步施工较同步在工期上有较大优势。根据对比分析及南岸索塔工期滞后的实际情况,甬江特大桥南北岸索塔分别采用了塔梁异步与塔梁同步的施工方法,最后实现工期的同步,收到了良好的经济与社会效益。

  18. Anti-seismic performance analysis of cable-stayed bridge with different bearing constraint system%不同支座约束方式下的斜拉桥抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    周叶波; 徐秀丽; 刘伟庆; 田国伟

    2012-01-01

    为确定某一独塔双索面斜拉桥合理的抗震约束体系,运用有限元软件Sap,结合该桥的特点,建立了索塔纵向、过渡墩纵横向均自由和索塔纵横向、过渡墩横向均约束两种不同约束的体系下桥梁的有限元模型,这两种约束体系分别视为方案1和方案2,并对其分别进行自振特性以及的地震响应分析.结果表明,方案2和方案1相比,主塔支座处的剪力、塔柱的内力以及过渡墩和主塔支座处的位移都降低了很多,索塔约束可降低主塔的内力,从而提高主塔的安全度,因此推荐采用索塔纵横向、过渡墩横向均约束的方案.%In order to find out the appropriate seismic constraint system for single pylons and double cable planes cable-stayed bridge, the space finite element model of the bridge with different constraint system was established by using the software Sap program: tower is free in longitudinal direction and transition piers is free in longitudinal and lateral directions; tower is constrained in longitudinal and lateral directions and transition piers is constrained in lat eral direction. The two kinds of constraint system are regarded as Scheme 1 and Scheme 2. The analysis of the structural natural vibration characteristic and response under earthquake wave were carried out. The results of calculation indicate that, comparing with Scheme 1, the shear at the tower bearing, the force of tower, the displacement at tran sition piers and tower bearing of scheme 2 are all reduced,and the safety of tower of scheme 2 is enhanced. So Scheme 2 is adopted in the paper.

  19. 双斜塔钢箱梁斜拉桥抗风性能试验研究%Experimental investigation on wind-resistant behavior of double pylon cable stayed bridge with steel box beam

    Institute of Scientific and Technical Information of China (English)

    马存明; 陈勉; 王玉柱; 高伟

    2011-01-01

    In order to evaluate wind-resistant behavior of a double pylon cable stayed bridge with steel box beam, dynamic response characteristics of the bridge were analyzed. The aerostatic force coefficient, the critical wind velocity of vibration and vortex-induced vibration response were measured using the combined method of numerical analysis and wind tunnel test, to assess wind-resistant behavior of the bridge. The results showed that the aerodynamic and flutter stability characteristics were good, but there were two obvious vertical vortex-induced resonance regions, and the peak excursion was much larger than the allowable value. Therefore, the bridge needs an aerodynamic shape optimization to reduce or control vortex-induced vibration. By comparing a variety of optimization solutions given by vortex-induced vibration experiments, the most optimized measure for vortex-induced vibration control was to add a fair water fin of 1m wide and 30° incline to the bottom slab.%为了评价某拟建大跨度双斜塔钢箱梁斜拉桥的抗风安全性能,通过数值分析与风洞试验相结合的方法研究其结构动力特性,测定静力三分力系数、颤振临界风速和涡激振动响应,据此分析评估该桥的抗风性能.结果表明,该桥具有较好的气动和颤振稳定性,但存在两个明显的竖向涡激共振区,且最大振幅远超过规定容许值.因此,该桥需要通过气动外形优化,以减小或控制涡激振动.经多种主梁涡激振动性能优化方案对比试验得出其最优措施为轨道内侧增加一条宽1m、与底板夹角成30°的导流板.

  20. On Determining Instability Conditions for Stay Cables Subjected to Parametric Resonance

    OpenAIRE

    Leon, Armando; Ahlin, Kjell; Kao-Walter, Sharon

    2009-01-01

    Parametric Resonance Vibration in cables of cable-stayed bridges is mainly studied when the excitation frequency is close to or twice the cable natural frequency. It is, however, important to consider other cases for this frequency relationship, since among other factors, cable-parametric resonance vibrations are strongly depending on the displacement amplitude at the cable supports. Consequently, the present research work is focused on determining, by experimental and numerical analysis, the...

  1. Research on Working Procedure of Lag Pouring of Wet-joint in Bridge Deck Concrete Slab on Composite Girder of Cable-stayed Bridge%叠合梁斜拉桥混凝土桥面板滞后浇筑湿接缝的工序研究

    Institute of Scientific and Technical Information of China (English)

    胡俊; 曾一峰; 贾俊峰

    2016-01-01

    Construction procedure is complicated for cable-stayed bridge using composite beam. Final state of bridge depends on construction greatly. In the article,a large span cable-stayed bridge was studied. The bridge 3D finite element model was established to analyze the effect of working procedure during construction and at completion. Three working procedures were studied: no lag pouring,one lag pouring and twice lag pouring of wet-joint of concrete slab. The analysis results indicate that tensile stress in concrete slab is small for one/twice lag pouring. But, as lag times increase,compression stress in steel girders increases significantly. One lag pouring is best for structure stress in the construction process and operation stage,and the construction period is short.%叠合梁斜拉桥施工工序繁多,最终的成桥状态与施工过程密切相关.以一大跨度叠合梁斜拉桥为对象,采用空间有限元软件建立精细化力学模型,对比分析了混凝土桥面板湿接缝不滞后、滞后1次及滞后2次这3种施工工序对桥梁结构在施工过程及成桥的受力影响.结果表明,滞后1次及滞后2次的工序下桥面板几乎不出现拉应力,而随着桥面板滞后次数的增加,钢主梁的压应力显著增大,选择桥面板滞后1次的施工工序,结构在施工过程中及成桥运营阶段的受力最佳,同时工期也较短.

  2. 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

  3. Control Technique of Steel Concrete Section of Long -span Cable-stayed Bridge Main-tower Construction%大跨径斜拉桥主塔钢混结合段施工测控技术

    Institute of Scientific and Technical Information of China (English)

    孙景领; 魏浩瀚

    2012-01-01

    南京长江三桥是我国首座主塔采用钢结构形式的特大型斜拉桥.钢混结合段的安装定位精度对钢索塔的成塔线形起着决定性的作用.该文介绍了钢混结合段的安装工艺流程和技术要求及精度估算;对钢混结合段施工专用控制网的建立方法进行了探讨;研究了逐步归化的测控方法在定位过程中的应用,结果表明构件的定位精度符合设计要求.%Nanjing Yangzi river third bridge is the first cable -stayed bridge in China, which main tower is the steel structure form. The installation positioning accuracy of steel concrete composite section plays a decisive role in the linear of steel pylon which would be built.The installation and technical requirements of steel concrete composite section and precision estimation are introduced; the way of the special control network building for the construction of steel concrete composite section is discussed; the measurement and control method of gradual naturalization process in the application of positioning is studied, the results show that the location accuracy of component is accorded with the requirement of design.

  4. 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.

  5. 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 .

  6. 港珠澳大桥东人工岛结合部非通航孔桥管线槽侧板预制工艺%Technology for prefabrication of side panels for cable grooves over non- navigable span of bridge at east artificial island for Hongkong-Zhuhai-Macao Bridge

    Institute of Scientific and Technical Information of China (English)

    曾庆喜; 游川; 王鼎献

    2016-01-01

    The side panels for cable grooves over non-navigable span of bridge at east artificial island for Hongkong-Zhuhai-Macao Bridge are the first small precast components with fair-faced concrete, demanding high quality and showing good appearance. The paper discusses in detail the fine construction technology of steel processing, mold assembly, pouring concrete vibrators, product protection, lifting and so on. It achieved good results.%港珠澳大桥东人工岛结合部非通航孔桥管线槽侧板是第一批采用清水混凝土的小型预制构件,质量要求高,以展示出良好的外观特性。文章详细论述了钢筋加工、模具装配、混凝土浇筑振捣、成品防护与吊装等各环节的精细化施工工艺,取得了良好效果。

  7. Seismic resistance capacity of cable-stayed bridge with three pylons based on plastic hinge model%基于塑性铰模型的三塔斜拉桥抗震能力时程分析

    Institute of Scientific and Technical Information of China (English)

    王龙飞; 王仙芝

    2012-01-01

    采用非线性塑性铰考虑结构构件的混凝土开裂、钢筋屈服和材料滞回效应,利用APDL语言编制二分法程序使计算机进行自动计算和减少计算量,从而建立通过不断增大地震时程作用来计算斜拉桥结构抗震能力的方法,并以该方法分析研究了一座在建的三塔结合梁斜拉桥的抗震能力和地震反应特性.研究结果表明:在抗震能力状态,三塔斜拉桥中塔底内力响应要远大于边塔,但由地震引起的塔顶位移却相差很小,所以提高中塔抗震能力可以较快地提高整体结构的抗震能力;有塑性铰模型要比无塑性铰模型具有更高的计算抗震能力;采用二分法循环计算程序,不仅可以降低人工试算的烦琐程度而且能大幅减少循环计算次数,使大型结构的抗震能力分析较为简便.%Considering the effects of concrete crack, reinforcement yielding and hysteresis of structural components after adopting nonlinear plastic hinges, and using the language of APDL to write a bisection method program for automatic analysis and time reduction, a method of analyzing seismic resistance capacity of cable-stayed bridge was established, in which the seismic load is acted increasingly step by step. The seismic resistance capacity and responses of a composite girder cable-stayed bridge with three pylons under construction was investigated. The results show that the force responses at bottom of the middle pylon are much greater than at that of side pylons, but the deflection responses in the top of pylons caused by the seismic action are very close. So, increasing the capacity of the middle pylon to resist earthquake can improve the seismic resistance capacity of the whole bridge. The calculating seismic resistance capacity of the model with plastic hinges is higher than that with no plastic hinges. The bisection method program for loop calculation can reduce the trivial manual operation work and decrease the times of loop

  8. 桁宽对大跨度铁路斜拉桥车-桥耦合振动性能的影响研究%Study of Influence of Truss Width on Train-Bridge Coupling Vibration of Long Span Railway Steel Truss Girder Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    张强; 李永乐; 邓江涛; 向活跃

    2012-01-01

    为考虑桁宽对大跨度铁路斜拉桥动力特性及车辆走行性的影响,以某主跨580 m双塔斜拉桥为背景,分别建立了3种不同桁宽(15,24,30 m)桥梁的有限元模型,对比其固有频率的差异,并通过车-桥耦合振动分析,比较了3种桁宽情况下桥梁、列车的动态响应.分析结果表明,桥梁横向振动和扭转振动的频率随桁宽的增加而明显增大,竖向振动频率随桁宽的增加而略有减小;主梁的横向位移随桁宽的增加而明显变小,桁宽15 m出现了规律性的横向振动;3种桁宽情况下车辆响应变化不明显,桁宽15m时动车和拖车的响应(特别是轮轴横向力及减载率)总体上较其他2种桁宽的响应略大,车辆的响应对桁架的宽度变化不敏感.%To investigate the influence of truss width on the dynamic and train traveling per-formance of long span railway steel truss girder cable-stayed bridge, a double-pylon cable-stayed bridge of such type with a main span 580 m was cited as an example, the finite element models for the bridge having three kinds of different truss width (15 m, 24 m and 30 m) were respectively built, the differences of natural vibration frequencies of the models were compared and after anal-ysis of the train-bridge coupling vibration, the dynamic responses of the bridge and train under the three kinds of the truss width were acquired. The results of the analysis show that the lateral and torsional vibration frequencies of the bridge significantly increase while the vertical vibration frequency slightly decreases with the increase of the truss width and the lateral displacement of the main girder becomes significantly less with the increase of the truss width. When the trusswidth is 15 m, the regular lateral vibration occurs and the changes of the train responses under the three kinds of the truss width are not significant. When the truss width is 15 m, the respon-ses of the motorized car and trailer (particularly the

  9. 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.

  10. The Research of Application of the Looped Prestressed Tendons with Large Tonnage and Small Radius in the Anchorage Zone of Cable-stayed Bridge Tower%大吨位小半径环向预应力在斜拉桥索塔锚固区中的应用研究

    Institute of Scientific and Technical Information of China (English)

    陈建阳; 徐国平; 刘丽; 朱正群

    2001-01-01

    Nowadays the large tonnage and small radius annular prestress system are applied in the anchorage region of large span cable-stayed bridge construction in our country. The application of this system has been a breakthrough of the Design Specification of Highway Bridge and Culvert. In this article, the application of this system applied in the anchorage region of cable-stayed bridge tower has been probed in close connection with the full-scale model test of the anchorage zone of the Wuhan Junshan Changjiang River Bridge.%目前我国大跨径斜拉桥索塔锚固区开始采用大吨位小半径环向预应力体系,该体系突破了现行《公路桥涵设计规范》的规定。结合武汉军山长江公路大桥索塔锚固区足尺模型试验及张拉工艺模型试验对该预应力体系在斜拉桥索塔锚固区中的应用作了深入的探讨。

  11. 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.

  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 submarine cable installation project. Waiting for a comment period to run would prevent the Coast... and Purpose The submarine cable installation project in the vicinity of the Madison Street Bridge...

  13. Investigation on numerical simulation of 2D vortex-induced vibration of a stay cable in cable-stayed bridge using a RANS method%斜拉桥斜拉索二维涡激振动的数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    季小勇; 陈文礼

    2012-01-01

    采用基于RANS方法的SST湍流模型对斜拉桥斜拉索二维(2D)模型涡致振动进行了数值模拟.2D模型建立和网格划分通过专业前处理软件ICEM-CFD来实现.保持2D模型的频率不变,通过改变风速的方法来研究2D模型涡致振动的特性.研究了2D模型涡致振动的幅值,阻力系数以及锁定区域随约减阻尼变化的规律.研究结果表明斜拉索2D模型发生涡致振动时其幅值随着约减阻尼减小而增大,直至稳定到一个常数,同时通过比较发现数值模拟得到的2D模型幅值与试验结果比较接近;锁定区域随约减风速减小而增大;同样2D模型的平均阻力系数在锁定区域随着约减风速减小而增大.%2D vortex-induced vibration of a stay cable in cable-stayed bridge was numerically simulated by using the SST turbulent model that is based on a RANS method. The 2D model foundation and grid partition were achieved in the special pre-processor software ICEM-CFD. The characteristics of vortex-induced vibration were researched through changing the velocity of fluid and keeping the frequency of the 2D model constant. The amplitude, the drag coefficient and the lock-in region of the 2D model changing as the reduced damping was researched in the paper. The results indicate that the amplitude of the 2D model increases with the reduced damping decreasing, up to a constant; what's more, the results of numerical simulations are close to the experiments. The lock-in region widens as the reduced damping decreasing. In the lock-in region the average drag coefficient increases with the reduced damping decreasing.

  14. Stress Analysis of Pier-tower-girder Fixed Region of Cable-stayed Bridge with Trough Girder%槽型断面梁斜拉桥塔梁墩固结区受力特性研究

    Institute of Scientific and Technical Information of China (English)

    戴公连; 粟淼; 刘文硕; 闫斌

    2014-01-01

    In order to increase the structural longitudinal stiffness and facilitate the swing method,the side girders of trough section of the cable-stayed bridge on the Kunming-Shanghai passenger line were in-serted into the pylon so as to form the pier-tower-girder fixed region.For the (32+80+112)m single tower cable-stayed bridge,the structure and force of the fixed region are very complicated.The large gen-eral-purpose finite element software ANSYS was used to establish the pier-tower-girder fixed region model to study the stress distribution of the fixed region.The correctness of this model was verified.Based on this region model,the force transmission and stress distribution of the fixed region were investigated,and the effect of the local structural details on the fixed region stress was studied.The analysis results show that the global stress level of the fixed region is lower than the girder and tower,but there are stress con-centration phenomena in the fixed region,such as the intersection point between the floor of the trough girder and upper tower,and the corner of the human tunnel in the fixed region.The degree of the stress concentration was relieved significantly by improving the structural details.%为增大桥梁纵向刚度、便于转体施工,沪昆客运专线上某(32+80+112)m 槽型截面独塔斜拉桥将槽型梁两边箱插入塔柱中形成塔梁墩固结体系,其构造和受力情况极为复杂。为研究该桥塔梁墩固结区域的应力分布情况,采用大型通用有限元软件 ANSYS建立塔梁墩固结区局部模型并验证模型正确性。在此基础上,分析固结区域结构传力路径和应力分布规律,探讨局部设计细节对固结区应力的影响。研究表明:塔梁墩固结区内整体应力水平低于固结区范围以外截面,但在槽型梁过渡至固结区内部的交接角以及固结区内部过人洞折角等处存在应力集中现象。通过改进结构设计细节可有效缓解各处的应力集中现象。

  15. 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.

  16. 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.

  17. 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......The newly proposed Femern fixed link between Denmark and Germany will push the limits in engineering design. The selection of a cable-stayed or suspension bridge will lead to one of the longest bridges of its type in the world. The challenges of designing a bridge are many and the prospects...

  18. 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.

  19. 考虑土-结构相互作用的大跨度斜拉桥长周期地震反应分析%Analysis of Long-period Seismic Response of Long-span Cable-stayed Bridge Considering Soil-structure Interaction

    Institute of Scientific and Technical Information of China (English)

    段浪; 赵荣欣

    2012-01-01

    为分析处于软土地基上的大跨度斜拉桥在长周期地震动下的反应,通过ANSYS有限元软件和SHAKE土层地震反应分析程序等辅助软件,基于Penzien模型建立了某大跨度斜拉桥的整体有限元模型.选取一条长周期地震波和一条普通地震波比较分析了自由场地的地震反应,并在此基础上对考虑土一结构相互作用的斜拉桥地震响应进行了研究.结果表明,长周期地震动对软弱土层产生的不利影响要远远大于普通地震动,部分土层产生液化并丧失承载能力,同时,软土地基上的大跨度斜拉桥对长周期地震动十分敏感,结构的地震响应要明显大于普通地震动作用下的响应.%In order to analyze the long-period seismic response of long-span cable-stayed bridge on soft foundation, an integral finite element model of a long-span cable-stayed bridge based on Penzien model was built by using some assistant softwares just like ANSYS software and SHAKE soil stratum seismic response analysis program. The seismic response of free field was comparatively analyzed by choosing a long-period seismic wave and a normal seismic wave. Based on this, the seismic response of cable-stayed bridge in consideration of soil-structure interaction was investigated. It is observed that (1 ) the adverse effect of long-period seismic ground motion on soft foundation is far more greater than that of normal seismic ground motion, and certain soil layer was liquefied and lost bearing capacity; (2) the long-span cable-stayed bridge on soft foundation is quite sensitive to long-period seismic ground motion, and the seismic response of the structure to this seismic ground motion is much greater than that to normal seismic ground motion.

  20. 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

  1. 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

  2. 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.

  3. Damping Estimation from Free Decay Responses of Cables with MR Dampers.

    Science.gov (United States)

    Weber, Felix; Distl, Hans

    2015-01-01

    This paper discusses the damping measurements on cables with real-time controlled MR dampers that were performed on a laboratory scale single strand cable and on cables of the Sutong Bridge, China. The control approach aims at producing amplitude and frequency independent cable damping which is confirmed by the tests. The experimentally obtained cable damping in comparison to the theoretical value due to optimal linear viscous damping reveals that support conditions of the cable anchors, force tracking errors in the actual MR damper force, energy spillover to higher modes, and excitation and sensor cables hanging on the stay cable must be taken into consideration for the interpretation of the identified cable damping values. PMID:26167537

  4. Damping Estimation from Free Decay Responses of Cables with MR Dampers

    Directory of Open Access Journals (Sweden)

    Felix Weber

    2015-01-01

    Full Text Available This paper discusses the damping measurements on cables with real-time controlled MR dampers that were performed on a laboratory scale single strand cable and on cables of the Sutong Bridge, China. The control approach aims at producing amplitude and frequency independent cable damping which is confirmed by the tests. The experimentally obtained cable damping in comparison to the theoretical value due to optimal linear viscous damping reveals that support conditions of the cable anchors, force tracking errors in the actual MR damper force, energy spillover to higher modes, and excitation and sensor cables hanging on the stay cable must be taken into consideration for the interpretation of the identified cable damping values.

  5. Experimental Research on Stress Behavior of Stud Shear Connector in Tower Anchorage Area of Cable-stayed Bridge%斜拉桥锚固区栓钉剪力键力学特性研究

    Institute of Scientific and Technical Information of China (English)

    吴秀发; 张小亭

    2014-01-01

    针对栓钉剪力键用于斜拉桥索塔锚固区连接部位时的应力应变特性,以中部横梁均匀加载为思路,建立局部试验模型,以栓钉剪力键的极限承载力为依据,设计加载方案,通过试验获取栓钉的应变随荷载变化的基本特征,并分析了破坏机理。结果表明:中部加载使模型两侧剪力键受力均匀,设计更为合理;栓钉剪力键的剪应力以加载梁为中心向两侧逐渐降低;高度方向,第7排栓钉受力最大,长度方向,单钉根部受到的剪力最大,应作为控制截面;破坏时,栓钉弯曲变形,根部发生45°剪切破坏,混凝土局部产生裂缝或压碎破坏。%This article mainly studied the stud shear connector for anchorage zone of pylon cable-stayed bridge connecting parts when subject to stress-strain characteristics.Taking central uniform load for ideas established local test model.Loading program was designed which based on the ultimate bearing ca-pacity of stud shear connector.It has acquired the basic characteristics of stud strain with load variation and analyzed the failure mechanism.The results showed that:The model adopts central loaded design is more reasonable because it makes shear connector force uniform on both sides of the model.The shear stress of stud shear connector decreased gradually from the center to both ends of the load beam.In the height direction,the 7th rows of pegs subject the maximum shear stress.In the longitudinal direction,sin-gle nail roots subject the maximum shear stress.It should be used as the control section.When the stud destruction,the stud bending deformation occurs,peg roots shear failure in direction of 45 °,the partial concrete will produce cracks or be crushed.

  6. 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...

  7. 承台结构形式变化对大跨斜拉桥抗震性能的影响分析%Effects of Pile-cap Structure Form on Seismic Performance of Long-span Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    邓育林; 雷凡; 何雄君

    2013-01-01

    以一座大跨斜拉桥为工程背景,基于sap2000有限元软件,建立了考虑群桩-土动力相互作用的三维有限元模型,分别计算了分离式承台与哑铃型承台两种承台形式下大跨斜拉桥的振动特性与地震响应,探讨了主塔基础承台形式对大跨斜拉桥抗震性能的影响.分析结果表明:主塔基础承台形式的变化对结构纵桥向抗震性能的影响不大,而对结构横桥向抗震性能影响较大;对于本桥而言,主塔基础承台形式采用分离式承台时对主塔结构的抗震性能有利,而采用哑铃型承台时对主塔基础的抗震性能有利,因此,应综合考虑并予以选择承台形式.%In combination with a long-span cable-stayed bridge,based on sap2000 program,the threedimensional finite element mode which can consider pile-soil dynamic interaction was developed.Vibration characteristics and seismic response of the long span cable stayed bridge using separation type pile-cap or dumbbell type pile-cap were analyzed.And effects of main-tower's pile-cap structure form on seismic performance of the long-span cable-stayed bridge was discussed.The conclusion of the study shows that the change of main-tower's pile-cap structure form has little influence on the longitudinal seismic response,but has significant influence on the transverse seismic response.For this bridge,when using the separation type pile-cap,the transverse seismic response of the bottom of the pylon will be reduced obviously,but when using the dumbbell type pile-cap,the seismic capacity demand ratio of pile foundation will be improved and so it is of benefit to seismic performance of the bridge foundation.Therefore,it should be taken comprehensive consideration to choose the suitable form of main-tower's pile-cap structure.

  8. 基于多尺度模型修正的结合梁斜拉桥损伤识别方法%Damage identification method of composite cable-stayed bridge based on multi-scale model updating

    Institute of Scientific and Technical Information of China (English)

    钟儒勉; 宗周红; 秦中远; 郑沛娟

    2014-01-01

    The damage identification method based on a multi-scale finite element (FE)model up-dating for a composite cable-stayed bridge is presented with respect to the Guanhe Bridge.First, based on ambient vibration testing and the two-stage response surface method,the FE model upda-ting is conducted,and the updated model is chosen as the undamaged state.Secondly,a multi-scale FE model updating method is used to diagnose the structural damage at different positions and in dif-ferent degrees,and the sensitivity of damage indices including model curvature index (MCI)and modal strain energy index (MSEI)on different structure scale units is discussed.The analysis results show that without considering noise effects,the MCI and MSEI are sensitive to minimal damage (1%)of small scale units,and the locations of cracking damages can be identified,but they are in-sensitive to the big scale units;considering noise effects,the anti-noise ability of the small scale units is better than that of the big scale units in the damage identification,and the anti-noise ability of MSEI is superior to that of the MCI.The results support the idea that the proposed damage identi-fication method based on the multi-scale finite element model updating has great potential in the dam-age identification of practical engineering structures,and it lays a solid foundation for the damage prognosis (DP)of large span structures.%以灌河大桥为工程背景,提出了基于多尺度有限元模型修正的结合梁斜拉桥损伤识别方法。首先基于现场环境振动试验结果和两阶段响应面方法对初始多尺度模型进行修正,并将修正后模型定为原始未损伤状态;进而,利用多尺度模型修正方法对结构不同部位不同程度的损伤进行识别,并探讨了模态曲率损伤指标和单元模态应变能损伤指标对不同结构尺度损伤的敏感性。分析结果表明:在不考虑噪声干扰情况下,模态曲率和单元模态应变能指标

  9. UtilityTelecom_CABLE2007

    Data.gov (United States)

    Vermont Center for Geographic Information — The VT Cable System dataset (CABLE2007) includes lines depicting the extent of Vermont's cable system as of 12/31/2007. Numerous cable companies provide service in...

  10. 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...

  11. A wireless smart sensor network for automated monitoring of cable tension

    International Nuclear Information System (INIS)

    As cables are primary load carrying members in cable-stayed bridges, monitoring the tension forces of the cables provides valuable information regarding structural soundness. Incorporating wireless smart sensors with vibration-based tension estimation methods provides an efficient means of autonomous long-term monitoring of cable tensions. This study develops a wireless cable tension monitoring system using MEMSIC’s Imote2 smart sensors. The monitoring system features autonomous operation, sustainable energy harvesting and power consumption, and remote access using the internet. To obtain the tension force, an in-network data processing strategy associated with the vibration-based tension estimation method is implemented on the Imote2-based sensor network, significantly reducing the wireless data transmission and the power consumption. The proposed monitoring system has been deployed and validated on the Jindo Bridge, a cable-stayed bridge located in South Korea. (paper)

  12. A wireless smart sensor network for automated monitoring of cable tension

    Science.gov (United States)

    Sim, Sung-Han; Li, Jian; Jo, Hongki; Park, Jong-Woong; Cho, Soojin; Spencer, Billie F., Jr.; Jung, Hyung-Jo

    2014-02-01

    As cables are primary load carrying members in cable-stayed bridges, monitoring the tension forces of the cables provides valuable information regarding structural soundness. Incorporating wireless smart sensors with vibration-based tension estimation methods provides an efficient means of autonomous long-term monitoring of cable tensions. This study develops a wireless cable tension monitoring system using MEMSIC’s Imote2 smart sensors. The monitoring system features autonomous operation, sustainable energy harvesting and power consumption, and remote access using the internet. To obtain the tension force, an in-network data processing strategy associated with the vibration-based tension estimation method is implemented on the Imote2-based sensor network, significantly reducing the wireless data transmission and the power consumption. The proposed monitoring system has been deployed and validated on the Jindo Bridge, a cable-stayed bridge located in South Korea.

  13. Analysis on Impact of Viscous Damper on Longitudinal Vibration Response of Steel Truss Girder Cable-stayed Bridge%粘滞阻尼器对钢桁梁斜拉桥纵向振动响应的影响分析

    Institute of Scientific and Technical Information of China (English)

    袁立平; 许智焰

    2015-01-01

    Guiping Yujiang River super major bridge is one of the key projects of Nanning Guangzhou railway, located in Guigang-Guiping reach of Xijiang shipping route. The main bridge crossing Yujiang River is a (36 +96 +228 +96 +36) m five span continuous steel trussed cable-stayed bridge. It’s a ballasted double track bridge with the design speed of 250 km/h. As the longitudinal unconstrained floating system is used between the girder and bridge tower of Yujiang steel truss cable-stayed bridge, train braking and earthquake will cause large longitudinal vibration displacement of gird-er and larger longitudinal bending moment of tower root, which shall have influence on normal operation and safety of the bridge. This paper takes Guiping Yujiang steel trussed cable-stayed bridge as an example, under the action of train bra-king force and earthquake, the influence of viscous damper on the structural vibration response is analyzed in detail, the results show that the viscous damper can markedly reduce the pylon top displacement and the girder displacement, hav-ing better damping effect;preferably control the internal force at joint of tower and girder, especially improve the ben-ding moment and shearing force of control section of the main tower, ensure the normal operation and safety of the bridge.%桂平郁江特大桥是南宁至广州铁路的重点工程之一,位于西江航运干线贵港至桂平河段,跨郁江主桥为(36+96+228+96+36)m五跨连续钢桁斜拉桥。设计速度250 km/h,为有砟轨道双线桥梁。由于桂平郁江钢桁斜拉桥的主梁和桥塔间采用纵向无约束的漂浮体系,列车制动及地震会引起主梁纵向较大的振动位移和桥塔根部较大的纵向弯矩,影响桥梁的正常使用和安全。文章以桂平郁江钢桁斜拉桥为例,对钢桁梁斜拉桥在列车制动力和地震作用下,粘滞阻尼器对结构振动响应的影响进行了详细的分析,结果表明:粘滞阻尼器能显著减小

  14. Modeling vibration response and damping of cables and cabled structures

    Science.gov (United States)

    Spak, Kaitlin S.; Agnes, Gregory S.; Inman, Daniel J.

    2015-02-01

    In an effort to model the vibration response of cabled structures, the distributed transfer function method is developed to model cables and a simple cabled structure. The model includes shear effects, tension, and hysteretic damping for modeling of helical stranded cables, and includes a method for modeling cable attachment points using both linear and rotational damping and stiffness. The damped cable model shows agreement with experimental data for four types of stranded cables, and the damped cabled beam model shows agreement with experimental data for the cables attached to a beam structure, as well as improvement over the distributed mass method for cabled structure modeling.

  15. Research on Damage Identification for the Girders of Cable-stayed Bridges Based on Particle Swarm Optimization-support Vector Machine(PSO-SVM)%基于粒子群优化支持向量机的斜拉桥主梁损伤识别研究

    Institute of Scientific and Technical Information of China (English)

    赵世英; 李延强

    2015-01-01

    A new method of damage detection based on particle swarm optimization-support vector machine (PSO-SVM) is proposed in this paper in order to identify the girder damage of the cable-stayed bridge more ac-curately.The best kernel parameters for support vector machine(SVM) are obtained by particle swarm optimiza-tion(PSO) and the testing model of SVM is established.Taking the most sensitivity cable tension indexes as in-puts of SVM for both training and testing, damage locations of the main girder for cable-stayed bridge are indica-ted by the outputs of SVM.A numerical example for a test model of a single-tower cable-stayed bridge is provid-ed to verify the feasibility of the method.It is shown that the automatic optimization of the parameters for SVM can be realized by PSO algorithm and different kinds of damage of the girder for cable-stayed bridge can be de-tected and the identification efficiency is high.%为了能够更加准确地判断结构损伤位置和程度,本文提出了基于粒子群优化支持向量机(PSO-SVM)方法对斜拉桥主梁进行损伤识别的新方法。该方法以最敏感索张力指标作为损伤识别指标,利用粒子群(PSO)算法寻找支持向量机(SVM)最优参数,建立 SVM 预测模型,以不同位置、不同损伤程度下最敏感索的张力指标作为 SVM 的训练和测试输入,由 SVM 的输出确定损伤位置。通过对实验室的模型斜拉桥的主梁损伤进行了仿真验证,结果表明:采用 PSO 算法很好地解决了采用 SVM 方法进行损伤识别时的参数选择随机性难题,实现了对 SVM 模型参数的自动优化,基于 PSO-SVM 的损伤识别方法对斜拉桥主梁不同程度的损伤均有很高的识别率。

  16. 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......-degrees-of-freedom system with one modal coordinate for the in-plane displacement and one for the out-of-plane displacement. At first harmonic varying chord elongation at excitation frequencies close to the corresponding eigenfrequencies of the cable is considered in order to identify stable modes of vibration. Depending...... on the initial conditions the system may enter one of two states of vibration in the static equilibrium plane with the out-of-plane displacement equal to zero, or a whirling state with the out-of-plane displacement different from zero. Possible solutions are found both analytically and numerically. Next...

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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...

  2. 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

  3. 桥梁半平行钢丝索对称断丝的力学特性分析%Mechanical Properties Analysis of Semi Parallel Wire Cables for Bridges with Symmetric Wire Breaks

    Institute of Scientific and Technical Information of China (English)

    彭崇梅; 张启伟; 李元兵

    2013-01-01

    Strands model or parallel model based on the assumption of parallel wire is helpless to semi parallel wire cable for its helical characteristics and complex structure.Based on the theory of Love's curved bar, the mechanical model for multilayered semi parallel wire cables with symmetric wire breaks is updated with a consideration of the effects of the Poisson's ratio and contact deflection between wires, inter-wire contact force and friction.Axial force distribution of wires, magnification factors of axial force and axial stiffness of the cable are discussed by numerical calculation.Numerical examples show that the contact deformation aggravates axial force nonuniform distribution of wires and that the axial stiffness of cables falls much after the wire breaks.%桥梁用半平行钢丝索由于外层钢丝的螺旋外形和本身构造的特殊性,不能直接应用基于平行钢丝假定的并联模型或钢绞线模型进行力学分析.基于Love曲杆理论,考虑泊松效应、钢丝间接触变形以及钢丝间的接触力和摩擦力的影响,对多层半平行钢丝索的对称断丝模型进行了修正,通过数值计算讨论了拉索截面钢丝拉力分布规律、钢丝拉力增长系数和拉索轴向刚度及其影响因素.计算表明,考虑接触变形后,截面内钢丝拉力分布不均匀,拉索轴向刚度较单根钢丝有较大幅度的下降.

  4. 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.

  5. 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.

  6. 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...

  7. 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

  8. 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

  9. Responses of Long-span Highway and Railway Cable-stayed Bridge Induced by Train Braking Forces%大跨度公铁两用斜拉桥列车制动力作用下结构响应研究

    Institute of Scientific and Technical Information of China (English)

    吕龙; 李建中

    2014-01-01

    以某一正在设计的大跨度公铁两用斜拉桥为背景,利用非线性动力时程分析方法,分析了塔梁间设置黏滞阻尼器时,在列车制动力作用下结构动力响应,并与未设置黏滞阻尼器情况下的结构响应进行比较。分析结果表明,在塔梁间设置黏滞阻尼器能有效地降低在列车制动力作用下梁端及塔梁相对位移,结构受力也有所改善。%Based on a highway and railway cable-stayed bridge under design, dynamic responses of the struc-ture were analyzed under train braking forces by the nonlinear dynamic time-history analysis method. Viscous dampers were installed between the tower and girders for this bridge. Results were compared for models with viscous dampers and without viscous dampers. It is indicated that the displacements on the beam end and rela-tive displacements between tower and beam were reduced effectively by installing dampers between tower and beam.

  10. 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...

  11. 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...... measurements on cable conductor models are presented....

  12. 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...

  13. Nondestructive evaluation techniques for enhanced bridge inspection

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.; Benson, S.; Durbin, P.; Del Grande, N.; Haskins, J.; Brown, A.; Schneberk, D.

    1993-10-01

    Nondestructive evaluation of bridges is a critical aspect in the US aging infrastructure problem. For example in California there are 26,000 bridges, 3000 are made of steel, and of the steel bridges, 1000 are fracture critical. California Department of Transportation (Caltrans), Federal Highway Administration, and Lawrence Livermore National Laboratory (LLNL) are collaborating to develop and field NDE techniques to improve bridge inspections. We have demonstrated our NDE technologies on several bridge inspection applications. An early collaboration was to ultrasonically evaluate the steel pins in the E-9 pier on the San Francisco Bay Bridge. Following the Loma-Prieta earthquake in 1989 and the road way collapse at the E-9 pier, a complete nondestructive evaluation was conducted by Caltrans inspectors and several ultrasonic indications were noted. LLNL worked with Caltrans to help identify the source of these reflections. Another project was to digitally enhance high energy radiographs of bridge components such as cable end caps. We demonstrated our ability to improve the detection of corrosion and fiber breakage inside the end cap. An extension of this technology is limited view computer tomography (CT). We implemented our limited view CT software and produced cross-sectional views of bridge cables from digitized radiographic films. Most recently, we are developing dual band infrared imaging techniques to assess bridge decks for delaminations. We have demonstrated the potential of our NDE technology for enhancing the inspection of the country`s aging bridges.

  14. 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.

  15. Infiniband Based Cable Comparison

    Energy Technology Data Exchange (ETDEWEB)

    Minich, Makia [ORNL

    2007-07-01

    As Infiniband continues to be more broadly adopted in High Performance Computing (HPC) and datacenter applications, one major challenge still plagues implementation: cabling. With the transition to DDR (double data rate) from SDR (single datarate), currently available Infiniband implementations such as standard CX4/IB4x style copper cables severely constrain system design (10m maximum length for DDR copper cables, thermal management due to poor airflow, etc.). This paper will examine some of the options available and compare performance with the newly released Intel Connects Cables. In addition, we will take a glance at Intel's dual-core and quad-core systems to see if core counts have noticeable effect on expected IO patterns.

  16. Magnet cable manufacturing

    International Nuclear Information System (INIS)

    The superconducting magnets used in the construction of particle accelerators are mostly built from flat, multistrand cables with rectangular or keystoned cross sections. The superconducting strands are mostly circular but a design of a cable made of preflattened wires was proposed a few years ago under the name of Berkeley flat; such cable shows some interesting characteristics. Another design consists of a few smaller precabled wires (e.g. 6 around 1). This configuration allows smaller filaments and a better transposition of the current elements. The Superconducting Super Collider project involves the largest amount of superconducting cable ever envisaged for a single machine. Furthermore, the design calls for exceptional accuracy and improved characteristics of the cable. A part of the SSC research and development program is focused on these important questions. In this paper we emphasize the difference between the conventional cabling and wires with superconducting. A new concept for the tooling will be introduced as well as the necessary characteristics of a specialized cabler. 5 figs

  17. 基于Newmark-β显式直接积分法的三塔斜拉桥非线性地震响应分析%Nonlinear Earthquake Response Analysis on Three-tower Cable-stayed Bridge Based on Newmark-β Explicit Scheme Direct Integration Method

    Institute of Scientific and Technical Information of China (English)

    喻明秋; 祝兵; 张斗龙

    2012-01-01

    Cable-stayed bridge with three towers and single cable plane has uniqueness on dynamic behavior in space. In this paper, the Jianbang Yellow River Highway Bridge in Jinan is taken, as example, using finite element method to build spatial dynamic numerical analysis model of the bridge, and to form a structural characteristic equation, the space dynamic characteristics of the structure is obtained with frequency range of 1 600~0 cps and frequency shift 1 cps by using lanc-zos methods for the solution of the equation. The mathematical relationship between pseudo rela-tive velocity response spectrum Sv and pseudo absolute acceleration response spectrum SA is used to select the spectra with basically same characteristic site period in a large number of seismic re-cords, whose peak acceleration and duration are adjusted to directly be input to the dynamic nu-merical analysis model. Using mass and stiffness factor method in calculation on damping ratio of every vibration type, taking stressed state of the structure under dead load as the initial state, Newmark-β explicit scheme direct integration method with γ≧0. 5 and β≧γ/2 which make the method being no-conditional stable is used to the solution of the structure dynamic differential e-quations. Considering the second order effect from dead load in the structure during an earth-quake, the numerical solution of nonlinear seismic response is obtained. Furthermore, general laws on seismic response of such bridge type is concluded to provide a feasible basis for seismic design of such bridge type.%三塔单索面斜拉桥在空间动力行为方面有其独特之处.以济南建邦黄河公路大桥为例,运用有限元方法建立桥梁的空间动力数值分析模型,构建结构特征方程,在频率范围1 600~0 cps,频移为1 cps基础上运用lanczos法解此方程获得结构空间动力特性;进而利用拟相对速度反应谱SV和拟绝对加速度反应谱SA之间的数学关系,在大量地震

  18. 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...

  19. 三维体系斜拉索桥张拉施工技术应用%Application of Three-dimension System Cable-stayed Bridge Stretching Construction Technology

    Institute of Scientific and Technical Information of China (English)

    赵文艺; 薛长迁; 刘斌

    2009-01-01

    该文以天津市新三条石桥为例,介绍了三维斜拉索体系的分级对称张拉工艺及施工操作要点,可供类似工程参考.%Taking Tianjin Xinsantiao Stone Bridge as an example, the article introduces the grade symmetrical stretching technology and the construction operating gist, which can provide the reference for the similar projects.

  20. Active control of vibrations in pedestrian bridges

    OpenAIRE

    Álvaro Cunha; Carlos Moutinho

    1999-01-01

    This paper, apart from making a brief general reference to vibration problems in pedestrian bridges, as well as to the form of modelling of dynamic pedestrian loads, presents the use of a predictive control strategy for the numerical simulation of the dynamic response of actively controlled structures of this type. The consideration of this control strategy permitted the development of a computational model, which was applied to the study of a pedestrian cable-stayed bridge, in order to show ...

  1. Research on earthquake response of highway and railway shared cable-stayed bridge with 532 m-main span and vibration-reducing effect of damper%主跨532 m公铁两用斜拉桥的地震响应及阻尼器减震效果研究

    Institute of Scientific and Technical Information of China (English)

    郭辉; 李永强; 胡所亭; 班新林

    2015-01-01

    以我国首座跨海公铁两用钢桁斜拉桥———元洪航道桥(主跨532 m)为研究对象,采用空间板梁单元法建立有限元模型,对该桥地震响应特征及阻尼器减震效果等进行了研究。结果表明:大跨度斜拉桥动力特性分析除应考虑拉索垂度效应外,也应同时考虑梁—柱效应;动力特性分析时宜优先采用多重Ritz向量法,以使振型参与质量更快达到抗震计算要求;不同地震水平下,边墩和辅助墩的墩底、主塔塔底和下横梁附近截面将承受较大弯矩,为地震易损部位;N4#塔梁间设置纵向黏滞阻尼器后,罕遇地震作用下 N3#主塔(支座纵向固定)顺桥向弯矩、结构纵向位移均明显减小,最大减幅分别达40.6%和44.8%,减震效果明显。%T he Yuanhong C hannel Bridge in Pingtan Railw ay is the first and the largest highw ay and railw ay shared cable-stayed steel bridge crossing the strait in China with the main span of 532 m. The seismic response and seismic mitigation effect of dampers of this bridge was studied based on a spatial plate-beam finite element model. Both sag effect and beam-column effect shall be considered for the analysis of the dynamic characteristics of the large-span cable-stayed bridge. Ritz method was suggested,satisfying the requirement for the faster seismic calculation. It's prone to damage at the bottom of the side and auxiliary pier,the tower's root region and its lower transverse beam under different seismic level. After installing the viscous damper in the longitudinal direction between the N4# pylon and girder,the decrease of longitudinal bending moment of the N3# pylon( with bearings fixed in longitudinal direction) and that of the longitudinal displacement were significant under rarely occurred earthquake,with the maximum decrease rate of 40. 6% and 44. 8% respectively,indicating good effect of seismic mitigation.

  2. Actin Filament Cables in Drosophila Nurse Cells Are Composed of Modules That Slide Passively Past One Another during Dumping

    OpenAIRE

    Guild, Gregory M.; Connelly, Patricia S.; Shaw, Michael K.; Tilney, Lewis G.

    1997-01-01

    At a late stage in Drosophila oogenesis, nurse cells rapidly expel their cytoplasm into the oocyte via intracellular bridges by a process called nurse cell dumping. Before dumping, numerous cables composed of actin filaments appear in the cytoplasm and extend inward from the plasma membrane toward the nucleus. This actin cage prevents the nucleus, which becomes highly lobed, from physically blocking the intracellular bridges during dumping. Each cable is composed of a linear series of modules...

  3. Correction coil cable

    Science.gov (United States)

    Wang, Sou-Tien

    1994-11-01

    A wire cable assembly (10, 310) adapted for the winding of electrical coils is taught. A primary intended use is for use in particle tube assemblies (532) for the superconducting super collider. The correction coil cables (10, 310) have wires (14, 314) collected in wire arrays (12, 312) with a center rib (16, 316) sandwiched therebetween to form a core assembly (18, 318 ). The core assembly (18, 318) is surrounded by an assembly housing (20, 320) having an inner spiral wrap (22, 322) and a counter wound outer spiral wrap (24, 324). An alternate embodiment (410) of the invention is rolled into a keystoned shape to improve radial alignment of the correction coil cable (410) on a particle tube (733) in a particle tube assembly (732).

  4. 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.

  5. 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.

  6. 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.

  7. 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...

  8. Analysis of Impact of Steel-Concrete Joint Section Disengagement on Railway Cable-Stayed Bridge%铁路斜拉桥钢-混结合段脱空影响分析

    Institute of Scientific and Technical Information of China (English)

    叶翰松; 张细敏; 朱亚林; 李端洲

    2015-01-01

    为研究铁路斜拉桥钢-混结合段脱空对结构的影响,以甬江左线特大桥主桥———铁路钢-混混合梁斜拉桥为背景,采用ANSYS软件建立该桥1/2钢-混结合段模型,利用有限单元生死关系杀死钢板底层混凝土单元,模拟脱空破坏,计算在施工阶段或运营初期、长期运营阶段脱空前后结合段结构的应力和位移。结果表明:在施工阶段或运营初期,脱空后局部应力及变形变化明显,局部脱空区域钢板与混凝土之间的隆起距离相对较大,整体应力水平无明显变化,结构安全;在长期运营阶段,脱空后局部主拉应力水平有所增大,整体应力分布规律一致,竖向位移受脱空影响相对较大,钢板与混凝土之间的隆起距离比较小,结构安全。%To study the impact of disengagement of steel‐concrete joint section on the railway cable‐stayed bridge structure ,the left main bridge of the Yongjiang River Bridge ,a railway steel‐concrete hybrid girder cable‐stayed bridge ,was taken as the study background .The ANSYS soft‐ware was used to establish the model of the 1/2 of the steel‐concrete joint section .The technique of birth and death of elements developed in the finite element method was used to destruct the con‐crete elements in the base of the steel plates ,simulate the disengagement destruction and calculate the stress and displacement of the joint section before and after the disengagement in different sta‐ges ,such as construction stage or initial operation stage ,long‐term operation stage .T he results of the study indicate that during the construction stage or initial operation stage ,the stress and de‐formation after the disengagement exhibits distinct variation in some parts of the structure ,in the disengagement area ,the bulging distance between the steel plate and concrete is relatively large , the overall stress level show s no obvious change and the

  9. System reliability assessment of long-span cable-stayed bridges using an updating support vector algorithm%基于更新支持向量的大跨度斜拉桥体系可靠度分析

    Institute of Scientific and Technical Information of China (English)

    刘扬; 鲁乃唯; 殷新锋

    2015-01-01

    A new system reliability assessment method is proposed based on updating support vector method ,considering the characteristic of cable‐stayed bridges with explicit performance functions and multiple failure modes .The traditional Support Vector Machine (SVM ) is developed and applied to sys‐tem reliability analysis of cable‐stayed bridges .T here are four main steps in this algorithm :firstly ,the main failure sequences should be rectified according to the sensitivity analysis of components ;secondly , Least Squares Support Vector Machine (LS‐SVM ) is used to approximate the structural responses ,and then reliability indices of components are obtained using Monte‐Carlo simulation method .Thirdly ,the support vectors in LS‐SVM model are updated on the basis of updated finite element models ,and then the conditional reliability indices of the rest components is calculated based on the updated support vector model;finally ,the failure tree of structural system and series parallel method are used to estimate the system reliability index .The numerical analysis of a concrete cable‐stayed bridge with 420m span has shown the effectiveness and applicability of the proposed algorithm .At the same time ,the main failure sequences and the main failure components of the concrete bridge are given .%针对斜拉桥静力体系可靠度分析中隐式功能函数重构和繁杂失效路径的特点,提出了一种基于更新支持向量的体系可靠度分析方法,将传统的用于构件可靠度分析的支持向量机(SVM )改进并应用于斜拉桥体系可靠度分析。该方法主要有4个步骤:首先通过构件的敏感分析识别斜拉桥的主要失效路径;其次采用最小二乘支持向量机(LS‐SVM )对斜拉桥的隐式功能函数进行重构,并通过Monte‐Carlo抽样得出构件的可靠指标;然后根据已经更新的有限元模型对支持向量进行更新,得出相关构件失效后的剩余构件的

  10. Application of Improved Hierarchic Genetic Algorithm to Damage Detection of the Main Girder for Cable-stayed Bridge%改进分层遗传算法在斜拉桥主梁损伤识别中的应用

    Institute of Scientific and Technical Information of China (English)

    李延强; 张阳

    2014-01-01

    标准遗传算法在解决像斜拉桥这类复杂结构的损伤识别问题时会出现提前收敛,即所谓“早熟”的现象。为了避免此现象的发生,提高损伤识别的效率与精度,提出一种基于改进分层遗传算法的斜拉桥主梁损伤识别方法。采用索力变化作为优化目标函数,将3种具有不同遗传算子的标准遗传算法与变量微调和灾变策略相结合,形成了一种具有灾变特性的分层遗传算法,以实验室独塔斜拉桥模型作为研究对象进行了数值仿真,结果表明:改进的分层遗传算法成功的避免了标准遗传算法“早熟”现象的发生,能快速有效的完成斜拉桥主梁各种损伤的识别;同时对此方法进行抗噪性分析发现,该方法具有良好的抗噪能力。%In the process of damage identification for high‐order nonlinear structure such as cable‐stayed bridges by the standard genetic algorithm ,premature convergence would appear .In order to avoid this ,an improved hierarchic genetic algorithm was proposed . The cable force change was used to establish the optimization function and threetypes of standard genetic algorithm were combined with variable fine‐tuning and hierarchic strategy .To establish a hierarchical genetic algorithm with catastrophe characteristics A single‐tower cable‐stayed bridge model was used in the numerical simulation and the result showed that the probability of premature convergence was reduced in the improved hierarchic genetic algorithm and and the cable‐stayed bridge damage was identified effectively .The anti‐noise performance was better .

  11. Stress Analysis of Asynchronous Construction of Pylon and Bottom End Rail of Hybrid Girder Cable-stayed Bridge%混合梁斜拉桥索塔与下横梁异步施工控制分析

    Institute of Scientific and Technical Information of China (English)

    陈月萍; 张建飞; 胡强圣

    2015-01-01

    A bridge is used with the diamond type concrete pylon, and its total height is 177.91 m.In the intersection position of the Middle-Pylon and the Down-Pylon is the bottom end rail.The construction method of the pylon and bottom end rail are asynchronous constructed, which is we put the middle-pylon into the second construction segment, and then go on the bottom end rail.During the peri-od, pylon will appear cantilever state, so the weak section prone to tensile stress;it is to be avoided in the bridge construction.The pur-pose of this paper is to simulate asynchronous process, to analyze the influence to the tower, and to give the corresponding construction measures.%某特大桥索塔采用钻石型混凝土索塔,索塔总高度为177.91 m,在下塔柱与中塔柱相交位置设置一道下横梁。施工中塔柱与下横梁采用异步施工,即先将中塔柱施工到第二节段再进行下横梁施工。期间,索塔会出现悬臂状态,故索塔的薄弱截面易出现拉应力,这在桥梁施工中是要避免的,为此,先通过模拟分析异步施工过程对索塔的影响,给出相应的施工控制措施。

  12. 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.

  13. 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

  14. Analysis and Verification of Local Stress on Pier-Tower-Girder Fixed Segment of High-Speed Railway Low-pylon Cable-stayed Bridge%高速铁路矮塔斜拉桥墩塔梁固结段局部应力分析与验证

    Institute of Scientific and Technical Information of China (English)

    邓江涛

    2016-01-01

    Local analysis is an important method often used in bridge design and also an indispensable part of the design. The solid finite element model is used to reflect in detail the local stress of structures, playing a guiding role in investigating real stress state of important structures and in the design of reinforcement. In order to investigate real stress state of the pier-tower-girder fixed segment of the prestressed concrete low-pylon cable-stayed bridge and verify the accuracy of local boundary condition analysis, a refined space solid finite element model is established and the accuracy of local boundary condition analysis is verified with reference to a (115+95)m unballasted double line prestressed concrete low-pylon cable-stayed bridge on Beijing-Shenyang dedicated passenger line. The analysis shows that the pier-tower-girder fixed segment experiences a stress concentration at the hole, where reinforcement should be strengthened appropriately, and the stress on the remaining parts meets the requirement. The accuracy of resulted stress is guaranteed by validation of the local model’s internal force transmission and support reactions, and structural safety is ensured. Finally, a typical local analysis method is concluded, which may provide some references for other local stress analysis.%局部分析是桥梁设计中常采用的重要手段,也是设计中不可或缺的重要环节,利用实体有限元模型能反应出结构细部的受力状况,对考察结构重要部位的真实应力状态、结构设计配筋有着指导性作用。为了解高速铁路矮塔斜拉桥墩塔梁固结段的真实应力状态及验证局部分析中边界条件表达的准确性,以京沈客运专线(115+95) m双线无砟轨道预应力混凝土矮塔斜拉桥为工程背景,利用Ansys有限元建立细化的空间实体有限元模型,并对局部模型的边界条件模拟的正确性进行验证,分析表明,墩塔梁固结段进人洞角点处应

  15. 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.

  16. Excitation of Arch and Suspension Bridges by Subwires

    Directory of Open Access Journals (Sweden)

    Noriaki Hiwatashi

    1993-01-01

    Full Text Available A force generation method using a subwire for arch and suspension bridges is proposed. The subwire is connected to the arch or the cable of the bridge through rollers. The uniform force produced by pulling and releasing the pretensioned subwires acts on the bridge as an externalforce. A new device called “the resonance force generator” is also developed to excite the bridges by applying a small force. To verify the proposed concept, a stress ribbon bridge was excited with the resonance force generator.

  17. Excitation of Arch and Suspension Bridges by Subwires

    OpenAIRE

    Noriaki Hiwatashi; Yoji Mizuta; Yutaka Ishihara; Itio Hirai

    1993-01-01

    A force generation method using a subwire for arch and suspension bridges is proposed. The subwire is connected to the arch or the cable of the bridge through rollers. The uniform force produced by pulling and releasing the pretensioned subwires acts on the bridge as an externalforce. A new device called “the resonance force generator” is also developed to excite the bridges by applying a small force. To verify the proposed concept, a stress ribbon bridge was excited with the resonance force ...

  18. 铁路箱形混合梁斜拉桥钢-混结合段有限元分析%Finite Element Analysis of Steel and Concrete Joint Section of Railway Hybrid Box Girder Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    姚亚东; 杨永清; 刘振标; 蒲黔辉; 施洲

    2015-01-01

    To investigate the force characteristics and force transfer mechanism of the steel and concrete joint section of railway hybrid box girder cable‐stayed bridge ,the Yongjiang River Bridge on the North Ring Link of Ningbo Railway Terminal was taken as an example .The soft‐ware ANSYS was used to establish the three‐dimensional finite element model for the steel and concrete joint section of the bridge ,the force conditions and axial force distribution proportions of the steel shell and concrete in the joint section w ere analyzed .T he results of the analysis demon‐strate that under the action of the calculated load ,the structural longitudinal force‐bearing plates are all in the compression state and the structural stress levels are low .With the exception that the forces in the bearing plate change abruptly ,the changing of the forces in other parts is gentle . The stress levels of the different sections of the concrete are low and certain out‐of‐plane deforma‐tion of the sections occurs .The function of the bearing plate in the force transfer is significant . About 54% axial force of the joint section transfers via the bearing plate while the rest of the axi‐al force transfers via the PBL connectors and shear studs . The proportions of the axial force transfer of the connectors present the saddle‐shape distribution that is large at both ends and small in the middle .%为研究铁路钢箱混合梁斜拉桥钢-混结合段的受力特征及传力机理,以宁波铁路枢纽北环线甬江特大桥为背景,采用ANSYS有限元软件建立该桥钢-混结合段的三维有限元模型,分析钢-混结合段中钢壳体和混凝土的受力及轴力分配比例。结果表明:在计算荷载作用下,结构纵向受力板件均处于受压状态,应力水平较低;除承压板处发生突变外,其他部位变化平缓;混凝土各截面应力水平较低,截面发生一定的面外变形;承压板传

  19. 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。

  20. 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...... of the bridge cables. For the wet tests, the twin cable surfaces were treated in order to obtain uniform upper and lower water rivulets. The interaction between water rivulets, surface properties and the flow was found to govern the activation of the RWIV mechanism. The resulting aerodynamic damping from wet...

  1. 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.

  2. 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.

  3. 基于随机地震响应的斜拉桥粘滞阻尼器参数优化%Parameter Optimization of Viscous Damper for Cable-Stayed Bridge Based on Stochastic Seismic Responses

    Institute of Scientific and Technical Information of China (English)

    王波; 马长飞; 刘鹏飞; 汪正兴

    2016-01-01

    In the light of the deficiencies of the existing parameter optimization methods for the viscous damper ,a new parameter optimization method for the damper was proposed based on the stochastic seismic responses of a cable‐stayed bridge .In the new method ,the pseudo excitation method was used to calculate the structural seismic responses at a series of the sample points .The function expression for the parameters of the damper in relation to the structural seismic responses was fitted according to the response surface method and the parameter optimization values of the damper were calculated by the nonlinear programming method by way of taking the damping force of the damper that was minimal as the target function and the relative drift of the damper and the moment in the pylon footing that were less than the specified limit values as the constraint condi‐tions .A semi‐floating system hybrid girder cable‐stayed bridge with double pylons was selected as an example and the parameters of the damper were optimized by the new method .The results dem‐onstrate that the new method can avoid the uncertainty due to the determination of the parameters of the viscous damper that simply relies on the experiences and the consideration of the stochastic nature of the ground motion can make good adaptability of the optimization results .In creating the response surface function ,the application of the high‐order polynomial expression can increase the accuracy of the calculation results .%针对现有阻尼器参数优化方法的缺陷,基于斜拉桥的随机地震响应,提出一种粘滞阻尼器参数优化的方法。该方法利用虚拟激励法计算在一系列样本点处结构的地震响应,根据响应面法拟合结构地震响应关于粘滞阻尼器参数的函数表达式,最终以粘滞阻尼器的阻尼力最小为目标函数、阻尼器相对位移及桥塔塔底弯矩小于规定的限值为约束条件,采用非线性规划法

  4. 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.

  5. 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.

  6. Analysis of the Wind-induced Buffeting Response of Steel Arch Pylon of Single Tower Cable-stayed Bridge During Vertical Rotation Construction%独塔斜拉桥钢拱塔竖转施工风致抖振响应分析

    Institute of Scientific and Technical Information of China (English)

    王向阳; 夏小勇; 韩丽丽

    2016-01-01

    Taking the single tower cable‐stayed bridge on Gaoxin 2nd Road in Wuhan as the research background ,this paper studies the wind‐induced vibration problem during the vertical rotation con‐struction of steel arch pylon of single tower cable‐stayed bridge and analyzes the wind‐induced respon‐ses of steel arch pylon waiting for installation of cables using the finite element analysis software AN‐SYS .Firstly ,the static force coefficients of the arch section for different wind attach angles are calcu‐lated by the combined use of ICEMCFD and FLUENT .By using MATLAB ,linear filtering method is adopted to simulate the fluctuatng wind to calculate the fluctuating wind matrix of key nodes of the steel arch pylon and the time series of wind speed are graphed .The buffeting forces are computed based on the time series of wind speed and then transformed into the time domain .Finally ,wind loads are applied to the FEM model in ANSYS and the wind‐induced vibrations of the steel arch pylon are obtained by the time domain analysis of buffeting using the transient state analysis method .The re‐sults shows that the stability and security of steel arch pylon under wind load can be guaranteed for the one month wating period for the installation of cables .%针对独塔斜拉桥钢拱塔竖转过程中由风荷载引起的振动问题,以武汉市高新二路独塔斜拉桥竖转施工为研究背景,利用有限元分析软件ANSYS对等待挂索的钢拱塔进行风致响应分析。首先运用ICEMCFD和FLUENT结合的方式模拟计算钢拱塔截面在多个风攻角下的静力三分力系数;接着选择线性滤波法进行脉动风模拟,通过MATLAB计算得到钢拱塔关键节点的脉动风速矩阵,并绘制风速时程曲线。根据脉动风速时程曲线计算抖振力的大小并进行时域化处理,在有限元模型上施加风荷载,用瞬态分析法对钢拱塔进行抖振时域分析,获得钢拱塔的振动响应。计算

  7. 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

  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. 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...

  10. Analysis and test research on mechanical performance for steel-concrete composite anchor structure of cable- stayed bridge pylon%斜拉桥索塔钢混组合锚固结构力学性能分析和试验研究

    Institute of Scientific and Technical Information of China (English)

    俞先林; 张奇志

    2009-01-01

    采用自平衡式加载反力架对苏通大桥索塔钢混组合锚固结构进行足尺模型试验,观测模型的应力、裂缝分布和变形情况.采用ANSYS有限元软件对模型进行数值分析.试验和分析结果表明:索孔出口面上方的混凝土表面最易出现裂缝;钢混结合面表现为弯剪共同作用的特性,顶推荷载水平分力主要由钢锚箱结构承担,混凝土亦承担一小部分,竖向分力可全部由剪力钉传递给混凝土承受;单节段模型的有限元计算结果比多节段模型的计算结果偏大,用单节段模型试验结果代表实桥受力状况偏于安全.%Full-scale model test on steel-concrete composite anchor structure for pylon of sutong bridge was done by a self-balanced loading reaction frame to observe the stress,crack distribution and deformation of the model. Also numerical simulation was conducted by the finite element software ANSYS. The results of analysis and test show that cracks most easily occur on concrete surface at upperpart of cable anchor duct export. The steel-concrete contacting surface undertakes mutual action of bending moment and shear. Most horizontal component of pushing load is balanced by steel anchor box and only a small part by concrete,while vertical component of pushing load is all transferred to concrete by shear studs. Since numerical simulation data from single segment model test is larger than that from multi-segmental model test,it's conservative to adopt single segment mode test data instead of actual bridge stress status.

  11. 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...

  12. 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.

  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. 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.

  15. 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

    The aerodynamics of circular cylinders featuring geometric imperfections, such as bridge cables, has received much attention in recent years due to the recognition that such imperfections can be the cause of large amplitude vibrations. Bridge cables are usually made of strands or wires protected...... 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...

  16. 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.

  17. 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,

  18. Superconducting flat tape cable magnet

    Energy Technology Data Exchange (ETDEWEB)

    Takayasu, Makoto

    2015-08-11

    A method for winding a coil magnet with the stacked tape cables, and a coil so wound. The winding process is controlled and various shape coils can be wound by twisting about the longitudinal axis of the cable and bending following the easy bend direction during winding, so that sharp local bending can be obtained by adjusting the twist pitch. Stack-tape cable is twisted while being wound, instead of being twisted in a straight configuration and then wound. In certain embodiments, the straight length should be half of the cable twist-pitch or a multiple of it.

  19. 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.

  20. 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 cables, the rise to span ratio, the height of the filling, and the height of the Super-Light Decks. We find that Pearl-Chain Bridges can be adjusted to resist specific moment loads by changing the normal force in the arch cross section by altering the above parameters. It is also found that the negative...

  1. 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...

  2. Snap loads and torsional oscillations of the original Tacoma Narrows Bridge

    Science.gov (United States)

    Plaut, R. H.

    2008-01-01

    In 1940, the original Tacoma Narrows Bridge was completed on June 10 and opened to traffic on July 1. On November 7, the deck collapsed. Before that day, significant vertical oscillations had occurred, but no torsion. The bridge as built was stable with respect to torsional motion under the winds of November 7 and previous winds with higher speeds. However, snap loads in the diagonal ties attached to the north midspan cable band helped to loosen the band, and the frictional resistance between the band and the north suspension cable passing through it was overcome. The cable began to slip through the band. For this new structural system, with longitudinal motion of the north cable, the wind speed was higher than the critical speed for torsional flutter, and torsional motion was initiated. Approximately 700 cycles of torsional oscillations occurred during the hour prior to the collapse. In the present study, the snap loads on the cable band are discussed first. Then a continuum model of the central span (deck, cables, and hangers) is formulated. The longitudinal motions of the cables are included, so that the slippage can be incorporated. Known information from the observed steady-state torsional motion is utilized with assumed forms of the vertical cable displacements, and the governing equations provide the horizontal cable displacements, the dynamic tensions in the cables, the vertical and torsional motions of the deck, and the resultant lift force and pitching moment (including damping) acting on the deck during its final hour.

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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.......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....

  9. Programmevaluierung Bridge

    OpenAIRE

    Warta, Katharina; Good, Barbara; Geyer, Anton

    2009-01-01

    BRIDGE is an initiative funded by the Ministry for Transport, Innovation and Technology (BMVIT) that aims to close the “funding gap” between basic and applied research in stand-alone projects with the primary objective of jointly developing the potential of basic and applied research. BRIDGE acts as an  umbrella structure under which the Austrian Science Fund (FWF) and the  Austrian Research Promotion Agency (FFG) coordinate two thematically open funding programmes: The ...

  10. 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.

  11. 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…

  12. 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...

  13. 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...

  14. 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,...

  15. Research on the video detection device in the invisible part of stay cable anchorage system

    Science.gov (United States)

    Cai, Lin; Deng, Nianchun; Xiao, Zexin

    2012-11-01

    The cables in anchorage zone of cable-stayed bridge are hidden within the embedded pipe, which leads to the difficulty for detecting the damage of the cables with visual inspection. We have built a detection device based on high-resolution video capture, realized the distance observing of invisible segment of stay cable and damage detection of outer surface of cable in the small volume. The system mainly consists of optical stents and precision mechanical support device, optical imaging system, lighting source, drived motor control and IP camera video capture system. The principal innovations of the device are ⑴A set of telescope objectives with three different focal lengths are designed and used in different distances of the monitors by means of converter. ⑵Lens system is far separated with lighting system, so that the imaging optical path could effectively avoid the harsh environment which would be in the invisible part of cables. The practice shows that the device not only can collect the clear surveillance video images of outer surface of cable effectively, but also has a broad application prospect in security warning of prestressed structures.

  16. 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

  17. Finite element simulations of low-mass readout cables for the CBM Silicon Tracking System using RAPHAEL

    Science.gov (United States)

    Singla, M.; Chatterji, S.; Müller, W. F. J.; Kleipa, V.; Heuser, J. M.

    2014-01-01

    The first three-dimensional simulation study of thin multi-line readout cables using finite element simulation tool RAPHAEL is being reported. The application is the Silicon Tracking System (STS) of the fixed-target heavy-ion experiment Compressed Baryonic Matter (CBM), under design at the forthcoming accelerator center FAIR in Germany. RAPHAEL has been used to design low-mass analog readout cables with minimum possible Equivalent Noise Charge (ENC). Various trace geometries and trace materials have been explored in detail for this optimization study. These cables will bridge the distance between the microstrip detectors and the signal processing electronics placed at the periphery of the silicon tracking stations. SPICE modeling has been implemented in Sentaurus Device to study the transmission loss (dB loss) in cables and simulation has been validated with measurements. An optimized design having minimum possible ENC, material budget and transmission loss for the readout cables has been proposed.

  18. An energy harvesting system using the wind-induced vibration of a stay cable for powering a wireless sensor node

    International Nuclear Information System (INIS)

    This paper proposes an electromagnetic energy harvesting system, which utilizes the wind-induced vibration of a stay cable, and investigates its feasibility for powering a wireless sensor node on the cable through numerical simulations as well as experimental tests. To this end, the ambient acceleration responses of a stay cable installed in an in-service cable-stayed bridge are measured, and then they are used as input excitations in cases of both numerical simulations and experimental tests to evaluate the performance of the proposed energy harvesting system. The results of the feasibility test demonstrate that the proposed system generates sufficient electricity for operation of a wireless sensor node attached on the cable under the moderate wind conditions

  19. ELECTROSTATIC PROCESSES IN POWER CABLES

    Directory of Open Access Journals (Sweden)

    G.V. Bezprozvannych

    2013-09-01

    Full Text Available Observation of contact electrification of power cable samples is made. It is revealed that the contact potential difference and the capacity formed under separation of free charges on the surfaces of the contacting materials depend on cable design, applied materials, and inspection schemes. Time series of capacity drift and dielectric loss tangent caused by instability of triboelectric charging of the contacting surfaces are presented.

  20. 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...

  1. 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.

  2. 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...

  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. Flat conductor cable design, manufacture, and installation

    Science.gov (United States)

    Angele, W.; Hankins, J. D.

    1973-01-01

    Pertinent information for hardware selection, design, manufacture, and quality control necessary for flat conductor cable interconnecting harness application is presented. Comparisons are made between round wire cable and flat conductor cable. The flat conductor cable interconnecting harness systems show major cost, weight, and space savings, plus increased system performance and reliability. The design application section includes electrical characteristics, harness design and development, and a full treatise on EMC considerations. Manufacturing and quality control sections pertain primarily to the developed conductor-contact connector system and special flat conductor cable to round wire cable transitions.

  5. 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.

  6. 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.

  7. 高铁槽形梁斜拉桥塔梁固接结构试验研究及数值分析%Experimental Study and Numerical Analysis on Pylon-Girder Rigid Fixity Structure of a Trough Girder Cable-stayed Bridge in High-speed Railway

    Institute of Scientific and Technical Information of China (English)

    戴公连; 粟淼

    2015-01-01

    Based on a single-tower cable-stayed bridge with trough girder in Shanghai-Kunming high speed rail-way,the design method of test model,stress state,ultimate bend-carrying capacity and load transfer path of the pylon-girder rigid fixity structure is investigated through model test and numerical simulation.The results indicate that the stress level of pylon-girder rigid fixity zone is low under the dead and live load in operational stage,where the longitudinal and vertical normal stress is within 6 .5 MPa,providing sufficient safety capacity in the rigid fixity zone.Under the ultimate bending load,the section of the main span girder close to the rigid fixity zone failed first,indicating stronger bending strength of the pylon-girder rigid fixity zone than the girder section.The force transmission features in the side box girder and the deck slab are similar with the main gird-er and pylon-girder rigid fixity zone,which indicates that the side box is the main force bearing component. Compared with the rigid fixity zone,the deck slab of the girder demonstrates a more evident shear lag effect.%以沪昆高铁某独塔斜拉桥为研究对象,模型试验与数值模拟相结合,研究槽形截面斜拉桥的塔梁固接结构模型的试验方法、受力状态、极限承载能力以及传力机理等。研究表明:运营阶段荷载作用下,斜拉桥塔梁固接区的应力水平较低,纵向和竖向正应力在6.5 MP a以内,塔梁结合部具有较强的安全储备;在梁体抗弯强度极限荷载下,靠近固接区主跨侧槽形梁断面最先破坏,固接区截面抗弯强度大于主梁断面;槽形截面边箱梁和桥面板传力特征在主梁和塔梁固接区基本一致,边箱梁为主要受力构件;较之于塔梁固接区,主梁内的桥面板剪力滞效应更为明显。

  8. 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.

  9. Electromagnetic Transients in Power Cables

    DEFF Research Database (Denmark)

    Silva, Filipe Faria Da; Bak, Claus Leth

    as the shunt admittance matrix of a cable in function of the frequency. The chapter also introduces the different modes of a cable, how to calculate their impedance and velocity, as well as their frequency dependence. The knowledge of modal theory is of utmost importance when working in transient in cables....... It is true that in many cases, software is used to run simulations, and the reader may be tempted to think that only those designing the software need to know how to use modal theory. However, several phenomena require at least a minimum knowledge of the topic and for that reason, the book provides...... more powerful, the analyses started to expand for the more complex phenomena. Being old phenomena, electromagnetic transients are covered in many publications, and classic books such as the 40-year-old Greenwood’s ‘‘Electric Transients in Power Systems’’ are still used to this day. However...

  10. Development of the communication cable suspending robot. Automation of cable suspending works; Tsushin cable tsurika robot no kaihatsu. Cable tsurika sagyo no jidoka

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, T. [Kansai Electaric Power Co. Inc., Osaka (Japan)

    2000-04-01

    The automatic communication cable suspending robot was developed. For disuse of dangerous stringers and improvement of suspending workability, adoption of the new mechanical high-speed labor-saving cable laying method was decided regardless of current communication cable laying methods. This robot can deal with automatic removal works of existing cable hangers which has been thought to be extremely difficult, and thus integration works of many cables by a cable hanger in cable additional installation work. For easy handling of the robot, the robot body is composed of 6 separated parts such as driving part, power source part, cable draw-in part, hanger attaching part, hanger removing part and hanger recovering part according to each function. For avoiding troubles with telephone lines and CATV lines in city areas, the size and mass of the robot were considered enough. After this, some verification tests on the robot effectiveness including performance test, workability test on dummy poles, and field test are scheduled. (NEDO)

  11. Health monitoring of Binzhou Yellow River highway bridge using fiber Bragg gratings

    Science.gov (United States)

    Ou, Jinping; Zhao, Xuefeng; Li, Hui; Zhou, Zhi; Zhang, Zhichun; Wang, Chuan

    2005-05-01

    Binzhou yellow river Highway Bridge with 300 meter span and 768 meter length is located in the Shandong province of China and is the first cable stayed bridge with three towers along the yellow river, one of the biggest rivers in China. In order to monitoring the strain and temperature of the bridge and evaluate the health condition, one fiber Bragg grating sensing network consists of about one hundred and thirty FBG sensors mounted in 31 monitoring sections respectively, had been built during three years time. Signal cables of sensors were led to central control room located near the main tower. One four-channel FBG interrogator was used to read the wavelengths from all the sensors, associated with four computer-controlled optic switches connected to each channel. One program was written to control the interrogator and optic switches simultaneously, and ensure signal input precisely. The progress of the monitoring can be controlled through the internet. The sensors embedded were mainly used to monitor the strain and temperature of the steel cable and reinforced concrete beam. PE jacket opening embedding technique of steel cable had been developed to embed FBG sensors safely, and ensure the reliability of the steel cable opened at the same time. Data obtained during the load test can show the strain and temperature status of elements were in good condition. The data obtained via internet since the bridge's opening to traffic shown the bridge under various load such as traffic load, wind load were in good condition.

  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. 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...

  14. 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.

  15. Equalization of data transmission cable

    Science.gov (United States)

    Zobrist, G. W.

    1975-01-01

    The paper describes an equalization approach utilizing a simple RLC network which can obtain a maximum slope of -12dB/octave for reshaping the frequency characteristics of a data transmission cable, so that data may be generated and detected at the receiver. An experimental procedure for determining equalizer design specifications using distortion analysis is presented. It was found that for lengths of 16 PEV-L cable of up to 5 miles and data transmission rates of up to 1 Mbs, the equalization scheme proposed here is sufficient for generation of the data with acceptable error rates.

  16. 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.

  17. 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.

  18. Cable Voltage Measurement using OKITAI and OLU Submarine Cables for Monitoring Ocean Transport

    OpenAIRE

    Koga, Momoki; Liu, Cho-Teng; Villanoy, Cesar; Taira, Keisuke; 小賀, 百樹

    2005-01-01

    The OKITAI and OLU submarine cables cross the Kuroshio near the entrance into the East China Sea. They are old type co-axial copper cables and were retired from their commercial service in May 1997. For the scientific reuse of the cables, our cable voltage measurement was restarted in June 1998, after the settlement of the cable end facilities at the cable landing station, to monitor the variability of the ocean transport. This paper mainly describes the OKITAI and OLU cable facilities, the c...

  19. 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...

  20. 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.

  1. 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…

  2. Using Cable Television for Library Data Transmission.

    Science.gov (United States)

    Whitaker, Douglas A.

    1985-01-01

    Discusses information gained from a test of cable data circuits on a Geac bibliographic control system at the Wayne Oakland Library Federation (WOLF) (Michigan). Highlights include an introduction to cable, hardware profile, the WOLF experience, and key questions that will affect the future use of cable for data transmission. (EJS)

  3. EMP coupling to multiconductor shielded cables

    International Nuclear Information System (INIS)

    A method is presented for calculating EMP coupling to multiconductor shielded cables by electromagnetic pulse. The induced voltage of inner conductor of the SYV-50-7 cable and SYVZ-9 cable placed on the ground are computed. The computed results agree with those measured

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. What Do We Know about the Audience for Cable Television? A Uses and Gratifications Analysis of Cable Decliners, Basic Cable Subscribers, and Pay Cable Subscribers.

    Science.gov (United States)

    Bradbury, David E., Jr.; Felsenthal, Norman A.

    How do cable television subscribers differ from those who choose not to subscribe to cable? A study employed the uses and gratification paradigm to construct a questionnaire that solicited data from 600 television households in the Dayton, Ohio market. The sample was stratified to assure that one-third of the households had cable available but…

  10. Design of Main Bridge of Shuangyudao Bridge in Zhangzhou Development Zone%漳州开发区双鱼岛大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    陶小兰; 李涛; 姚建军

    2013-01-01

    Main bridge of Shuangyudao Bridge in Fujian Zhangzhou Development Zone is a 36m +2×66m +36m cable-stayed bridge with single pylon and double cable planes, and its girders are fish-belly prestressed concrete continuous box girders, cable pylon is twin-dolphin gate-typed steel tower, piers are in elliptic shape and bored pile foundation is adopted. This paper introduces design of all major structures, analyzes stresses on girder, cable pylon, stayed cable and steel anchor box of the bridge by establishing finite-element integral and local computational models and introduces its construction scheme.%福建省漳州开发区双鱼岛大桥主桥为36 m+2×66 m+36 m独塔双索面斜拉桥,主梁采用鱼腹式预应力混凝土连续箱梁,索塔为双鱼门型钢塔,桥墩为椭圆造型,采用钻孔灌注桩基础.介绍该桥各主要结构的设计,通过建立有限元整体计算模型及局部计算模型对该桥主梁、索塔、斜拉索、钢锚箱的受力进行分析并对其施工方案进行介绍.

  11. 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.

  12. 我国桥梁结构分析%Analysis on domestic bridge structure

    Institute of Scientific and Technical Information of China (English)

    苏国天

    2012-01-01

    This article introduces various bridge structures including plate,type bridge, beam-type bridge, cable-stayed bridge, and suspension bridge and so on, respectively illustrates the characteristics, advantages and structure of bridge structures, and points out the future bridge development trend of "the longer, the larger, the softer", which will be taken bridge aesthetics and environment protection into consideration.%针对国内板式桥、梁式桥、斜拉桥、悬索桥等多种桥梁结构进行了介绍,分别阐述了各种桥梁结构的特点、优点及结构组成,指出未来桥梁发展趋势是"更长、更大、更柔",并更加注重桥梁美学及环境保护。

  13. 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.

  14. Development of modular cable mesh deployable antenna

    Science.gov (United States)

    Meguro, Akira; Mitsugi, Jin; Andou, Kazuhide

    1993-03-01

    This report describes a concept and key technologies for the modular mesh deployable antenna. The antenna reflector composed of independently manufactured and tested modules is presented. Each module consists of a mesh surface, a cable network, and a deployable truss structure. The cable network comprises three kinds of cables, surface, tie, and back cables. Adjustment of tie cable lengths improves the surface accuracy. Synchronous deployment truss structures are considered as a supporting structure. Their design method, BBM's (Bread Board Model) and deployment analysis are also explained.

  15. Aeolic vibration of aerial electricity transmission cables

    Science.gov (United States)

    Avila, A.; Rodriguez-Vera, Ramon; Rayas, Juan A.; Barrientos, Bernardino

    2005-02-01

    A feasibility study for amplitude and frequency vibration measurement in aerial electricity transmission cable has been made. This study was carried out incorporating a fringe projection method for the experimental part and horizontal taut string model for theoretical one. However, this kind of model ignores some inherent properties such as cable sag and cable inclination. Then, this work reports advances on aeolic vibration considering real cables. Catenary and sag are considered in our theoretical model in such a way that an optical theodolite for measuring has been used. Preliminary measurements of the catenary as well as numerical simulation of a sagged cable vibration are given.

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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)

  2. Study on the effects of cable sliding motion on the seismic response of cable tray

    International Nuclear Information System (INIS)

    In various industrial plants such as thermal power plants, nuclear power plants or chemical plants, many cable trays are generally used for supporting cables by which control signals will be transmitted. Cable trays are generally made by thin steel plates both sides of which are folded in the vertical direction, while cables are simply placed on the tray. Thus, cables begin to slides when the response acceleration of trays exceeds some amount of value. Consequently, seismic responses of cable tray will also depend on the occurrence of sliding motion of cables. Therefore, cable trays are seen as highly nonlinear structural systems. In this study, seismic responses of the cable tray are investigated analytically considering the cable sliding motions. A cable tray is modeled by a two-degree-of-freedom system. Response acceleration and displacement of the tray and the cable are evaluated for seismic inputs. It is confirmed that the sliding motion of the cable has very large influences on the seismic responses of the cable tray. (author)

  3. 大连长山大桥主桥合拢段施工方案%Construction Program of the Main Bridge Closure Section of Dalian Changshan Bridge

    Institute of Scientific and Technical Information of China (English)

    潘宇

    2015-01-01

    The main bridge of Changshan Bridge is twin towers and double cable planes three-span prestressed concrete extradosed cable-stayed bridge, whose main span is 260m, so it has the largest span in the same type of bridge. The main beam uses the prestressed concrete single box three rooms streamlined flat box girder. This paper briefly introduces the construction of main beam closure section.%长山大桥工程主桥为双塔双索面三跨预应力混凝土矮塔斜拉桥,主跨260m,为国内同类型桥梁最大跨径。主梁采用预应力混凝土单箱三室流线型扁平箱梁。文章就主梁合拢段施工作简要介绍。

  4. 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

  5. Running Safety of Trains under Vessel-Bridge Collision

    Directory of Open Access Journals (Sweden)

    Yongle Li

    2015-01-01

    Full Text Available To optimize the sensor placement of the health monitoring system, the dynamic behavior of the train-bridge system subjected to vessel-collision should be studied in detail firstly. This study thus focuses on the characteristics of a train-bridge system under vessel-bridge collision. The process of the vessel-bridge collision is simulated numerically with a reliable finite element model (FEM. The dynamic responses of a single car and a train crossing a cable-stayed bridge are calculated. It is shown that the collision causes significant increase of the train’s lateral acceleration, lateral wheelset force, wheel unloading rate, and derailment coefficient. The effect of the collision on the train’s vertical acceleration is much smaller. In addition, parametric studies with various train’s positions, ship tonnage, and train speed are performed. If the train is closer to the vessel-bridge collision position or the ship tonnage is larger, the train will be more dangerous. There is a relatively high probability of running danger at a low speed, resulting from longer stay of the train on the bridge. The train’s position, the ship tonnage, and the train speed must be considered when determining the most adverse conditions for the trains running on bridges under vessel-bridge collision.

  6. 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。

  7. 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.

  8. Reduce Nb3Sn Strand Deformation when Fabricating High Jc Rutherford Cables

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Xuan Peng

    2012-12-17

    During Phase I, our efforts were to reduce subelements deformation when fabricating Nb3Sn Rutherford cables. Our first focus is on 217-sublement tube type strand. We successfully made a few billets in ¾” OD tube with different Cu spacing between subelements, and supplied the strands to Fermi Lab for cabling. Through the rolling test characterization, these types of strands did not have enough bonding between subelements to withstand the deformation. We saw copper cracking between subelements in the deformed strands. We scaled up the billet from ¾” OD to 1.5” OD, and made two billets. This greatly improves the bonding. There is no copper cracking in the deformed strands when we scaled up the diameter of the billets. Fermi Lab successfully made cables using one of this improved strands. In their cables, no Cu cracking and no filament bridging occurred. We also successfully made a couple of billets with hex OD and round ID subelements for 61-subelement restack. Due to the lack of bonding, we could not judge its cabling property properly. But we know through this experiment, we could keep the Nb round, once we select the proper Cu spacing.

  9. Discrete wavelet transform to improve guided-wave-based health monitoring of tendons and cables

    Science.gov (United States)

    Rizzo, Piervincenzo; Lanza di Scalea, Francesco

    2004-07-01

    Multi-wire steel strands are used in civil structures as pre-stressing tendons in prestressed concrete and as stay-cables in cable-stayed and suspension bridges. Monitoring the structural performance of these components is important to ensure the proper functioning and safety of the entire structure. Among the various NDE techniques that are under investigation for monitoring tendons and cables, the use of ultrasonic guided waves shows good promises. The main advantage of this approach is the possibility for the simultaneous monitoring of loads and detection of defects, such as corrosion and broken wires, by using the same ultrasonic setup. Load monitoring is achieved by measuring the travel time of the wave across a given length of the cable. Defect detection is achieved by measuring the reflections of the wave from the geometrical discontinuities. The new contributions of the current paper are two-fold. First, the study identifies those ultrasonic frequencies propagating with low attenuation for long-range defect detection. Second, the technique is substantially improved by implementing the Discrete Wavelet Transform (DWT) as a data post-processing tool. The data de-noising and data compression abilities of the DWT allow for greater sensitivity, larger ranges and higher monitoring speed. It is shown that the implementation of the DWT in the ultrasonic guided-wave technique becomes necessary for monitoring tendons and cables in the field.

  10. 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

  11. 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

  12. 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...

  13. 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.

  14. Occupational Asthma in a Cable Manufacturing Company

    OpenAIRE

    Attarchi, Mirsaeed; Dehghan, Faezeh; Yazdanparast, Taraneh; Mohammadi, Saber; Golchin, Mahdie; Sadeghi, Zargham; Moafi, Masoud; Seyed Mehdi, Seyed Mohammad

    2014-01-01

    Background: During the past decade, incidence of asthma has increased, which might have been due to environmental exposures. Objectives: Considering the expansion of cable manufacturing industry in Iran, the present study was conducted to evaluate the prevalence of occupational asthma in a cable manufacturing company in Iran as well as its related factors. Patients and Methods: This study was conducted on employees of a cable manufacturing company in Yazd, Iran, in 2012. The workers were divi...

  15. Review of high voltage direct current cables

    OpenAIRE

    Chen, George; Miao, Hao; Z. Xu; A. S. Vaughan; Cao, Junzheng; Wang, Haitian

    2015-01-01

    Increased renewable energy integration and international power trades have led to the construction and development of new HVDC transmission systems. HVDC cables, in particular, play an important role in undersea power transmission and offshore renewable energy integration having lower losses and higher reliability. In this paper, the current commercial feasibility of HVDC cables and the development of different types of HVDC cables and accessories are reviewed. The non-uniform electric field ...

  16. 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.

  17. Vincennes University: Pioneer in Cable TV

    Science.gov (United States)

    Beckes, Isaac K.

    1972-01-01

    The development of cable educational television at Vincennes University (Indiana) is discussed in terms of the financing, securing of franchises, educational goals and plans for future expansion. (RN)

  18. 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...

  19. Bridge SHM system based on fiber optical sensing technology

    Science.gov (United States)

    Li, Sheng; Fan, Dian; Fu, Jiang-hua; Huang, Xing; Jiang, De-sheng

    2015-09-01

    The latest progress of our lab in recent 10 years on the area of bridge structural health monitoring (SHM) based on optical fiber sensing technology is introduced. Firstly, in the part of sensing technology, optical fiber force test-ring, optical fiber vibration sensor, optical fiber smart cable, optical fiber prestressing loss monitoring method and optical fiber continuous curve mode inspection system are developed, which not only rich the sensor types, but also provides new monitoring means that are needed for the bridge health monitoring system. Secondly, in the optical fiber sensing network and computer system platform, the monitoring system architecture model is designed to effectively meet the integration scale and effect requirement of engineering application, especially the bridge expert system proposed integration of sensing information and informatization manual inspection to realize the mode of multi index intelligence and practical monitoring, diagnosis and evaluation. Finally, the Jingyue bridge monitoring system as the representative, the research on the technology of engineering applications are given.

  20. 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 cy...

  1. 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.

  2. Innovative configurations for long-span suspension bridges

    OpenAIRE

    Bartoli, G.; P. D’Asdia; S. Febo; C. Mannini; S. Noè; L. Procino

    2009-01-01

    This paper reports the results of a piece of research about long-span suspension bridges with multiple-box girder steel deck characterized by low drag coefficient and high aeroelastic stability. For this type of bridges, by increasing the span length, the contribution to the stiffness of the suspension cables becomes dominant with respect to that of the deck, so that the ratio of the frequency of the first torsional mode to the frequency of the first vertical bending mode approaches unity, wh...

  3. 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...... Subspace Identification (SSI) methods. The modal estimates obtained using these alternative approaches are compared, taking also into account the estimates previously obtained with the conventional Peak Picking technique from the free vibration test of the bridge, performed at the end of construction....

  4. 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.

  5. 7 CFR 1755.870 - RUS specification for terminating cables.

    Science.gov (United States)

    2010-01-01

    ... what constitutes a design change. (4) Materials, manufacturing techniques, or cable designs not... modified materials, manufacturing techniques, or cable designs shall be provided to substantiate product... (Reapproved 1989), Standard Methods of Testing Thermoplastic Insulations and Jackets for Wire and Cable;...

  6. 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.

  7. 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.

  8. Local Government Uses of Cable Television.

    Science.gov (United States)

    Cable Television Information Center, Washington, DC.

    The local government cable access channel is essentially a television station completely controlled by the local government. It differs from a local broadcast television station by being able to reach only those places which are connected to the cable system, having much less programming distribution costs, and having the capacity to deliver…

  9. Assessment of sodium conductor distribution cable

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-06-01

    The study assesses the barriers and incentives for using sodium conductor distribution cable. The assessment considers environmental, safety, energy conservation, electrical performance and economic factors. Along with all of these factors considered in the assessment, the sodium distribution cable system is compared to the present day alternative - an aluminum conductor system. (TFD)

  10. 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...

  11. Cable Television: Its Urban Context and Programming.

    Science.gov (United States)

    Warthman, Forrest

    Cable television's future in urban settings is discussed in the context of alternative media capable of serving similar markets with similar programing. In addition to cable television, other transmission networks such as the telephone network, radio and television broadcasting, microwave networks, domestic satellites, and recording media are…

  12. 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.

  13. Electrohydrodynamic pumping in cable pipes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Crowley, J.M.; Chato, J.C.

    1983-02-01

    Many oil-insulated electric power cables are limited by heat buildup caused in part by the low thermal conductivity of the oil. Circulation of the oil is known to reduce the cable temperature, but can lead to excessive pressure buildup on long cables when using conventional pumping methods. An alternate pumping method using distributed electric fields to avoid this pressure buildup is described. Electrohydrodynamic (EHD) pumping was studied both theoretically and experimentally for possible application in underground cable cooling. Theoretical studies included both analytical and finite-element analysis of the flow patterns driven by travelling electric fields. Experimentally, flow rates in a cable-pipe model were measured under a wide variety of operating conditions. Theory and experiment are in agreement for velocities below 10 cm/s, but higher velocities could not be reached in the experiment, due to increased electroconvection and, possibly, turbulence.

  14. Frequency Dependent Losses in Transmission Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdóttir, Unnur Stella

    2011-01-01

    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......, such as thermal conditions in and around the cable, as well as the heat generated in conductors, screens, armours etc., taking into account proximity and skin effects. The work performed and presented in this paper is concerned with an improved determination of the losses generated in the conductor, by means...... 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...

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Non-cable vehicle guidance

    Energy Technology Data Exchange (ETDEWEB)

    Daugela, G.C.; Willott, A.M.; Chopiuk, R.G.; Thornton, S.E.

    1988-06-01

    The purpose is to determine the most promising driverless mine vehicle guidance systems that are not dependent on buried cables, and to plan their development. The project is presented in two phases: a preliminary study and literature review to determine whether suitable technologies exist to justify further work; and an in-depth assessment and selection of technologies for vehicle guidance. A large number of guidance elements are involved in a completely automated vehicle. The technologies that hold the best potential for development of guidance systems for mine vehicles are ultrasonics, radar, lasers, dead reckoning, and guidance algorithms. The best approach to adaptation of these technologies is on a step by step basis. Guidance modules that are complete in themselves and are designed to be integrated with other modules can provide short term benefits. Two modules are selected for development: the dragline operations monitor and automated machine control for optimized mining (AMCOM). 99 refs., 20 figs., 40 tabs.

  1. Cable Television 1980: Status and Prospect for Higher Education.

    Science.gov (United States)

    Baus, F., Ed.

    Baseline information for the would-be cable television educational programer is provided by two papers, one an overview of the state of the cable television industry, and the other a report on a marketing study conducted to determine consumer attitudes toward cable TV as an educational medium. In "The Promise and Reality of Cable Television,"…

  2. Basic cable routing guidelines for a fast reactor plant

    International Nuclear Information System (INIS)

    In this paper the guidelines evolved for cable routing in 500 MWe Prototype Fast Breeder Reactor (PFBR) are presented. Safety related redundant system cables in a nuclear plant shall not become unavailable due to cable fire. This is ensured by proper cable routing in the plant in addition to the other general fire protection measures

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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 cable and other material used in the construction of such plant. Subsidiary record categories,...

  8. 46 CFR 183.340 - Cable and wiring requirements.

    Science.gov (United States)

    2010-10-01

    ... insulation resistance of the remainder of the cable is measured, and it is determined that the condition of the insulation is unimpaired. (n) All material in a cable splice must be chemically compatible with... reference; see 46 CFR 175.600) except that asbestos insulated cable and dry location cables may not be...

  9. Characteristics of friction between cable and saddle%缆索与鞍座间的摩擦特性

    Institute of Scientific and Technical Information of China (English)

    周凌远; 李乔

    2011-01-01

    The reliability of anti-sliding between saddle and main cable is the key to insure the safety of suspension bridges. Model test was carried on for determining friction factor between main cable and saddle. In the process of the test, the influence of actual contact stress between them on friction factor was taken into consideration. The friction factor between single-strand cable and the saddle and that between multi-strand cable and saddle of the Taizhou Yangtze bridge were obtained with the model test. The main origins of influence factor on these friction factors and their deviation from actual value on this bridge were explored. The real friction factor between cable and saddle on this bridge was evaluated according to theoretical analysis. The result of test and theoretical analysis showed that the friction factor between saddle and multi-strand cable was obviously larger than that between saddle and single-strand cable.%缆索与主鞍座间抗滑移稳定是保障大跨度悬索桥安全的关键,对主缆与鞍座间摩擦系数进行模型试验.在试验中,考虑实桥在使用阶段索股的主缆与鞍座间的实际接触应力对摩擦系数的影响,试验得到泰州长江大桥单索股与鞍座、多索股与鞍座间的摩擦系数.对影响缆索与鞍座间摩擦系数的主要原因以及模型试验测试值与实桥摩擦系数之间的关系开展探讨,通过理论分析并计算出实桥鞍座与主缆间存在的实际摩擦系数值.试验测试和理论分析结果显示,鞍座与多索股间的摩擦系数值明显大于与单索股的摩擦系数值.

  10. 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.

  11. 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.

  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. 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.

  14. 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.

  15. 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.

  16. 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.

  17. High frequency characteristics of medium voltage XLPE power cables

    OpenAIRE

    Mugala, Gavita

    2005-01-01

    The response of a cable can be used to analyze the variation of the material characteristics along its length. For diagnosis of possible ageing, it is necessary to know how cable design, material properties and cable insulation ageing affects the wave propagation. A cable model has therefore been worked out based upon the high frequency properties of the cable insulation and conductor systems. The high frequency characteristics of the semi-conducting screens, new and water-tree aged cross-lin...

  18. 3-D Numerical Simulations of Twisted Stacked Tape Cables

    OpenAIRE

    Krüger, Philipp A. C.; Zermeño, Victor M. R.; Takayasu, Makoto; Grilli, Francesco

    2014-01-01

    Different magnet applications require compact high current cables. Among the proposed solutions, the Twisted Stacked Tape Cable (TSTC) is easy to manufacture and has very high tape length usage efficiency. In this kind of cables the tapes are closely packed, so that their electromagnetic interaction is very strong and determines the overall performance of the cable. Numerical models are necessary tools to precisely evaluate this interaction and to predict the cable's behavior, e.g. in terms o...

  19. 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...

  20. 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.

  1. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  2. Wind Resistant Design of Bridges in Japan Developments and Practices

    CERN Document Server

    Fujino, Yozo; Tanaka, Hiroshi

    2012-01-01

    For long-span bridges, wind action is a dominant factor in their safety and serviceability. A large number of long-span bridges have been built in Japan over the past 30 years, and tremendous amounts of research and technical development have been accomplished in wind resistant design. This book is a compilation of the results of active research and development. Wind resistant design standards generated in Japan are described in the first few chapters. Then comes information such as design wind speed, structural damping, wind tunnel tests, and analyses, which provide the basis of the design standards. Wind-induced vibrations and their control of girders, towers, cables, and other features are explained with examples of field measurements. Comprehensive listings of Japanese experience in vibration control are also presented. Because achieving particularly dynamic safety against wind is still not an easy task, these data and information will be valuable assets for the wind-engineering and bridge-engineering com...

  3. 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.

  4. 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 lowest...... circular eigenfrequencies for in-plane and out-of-plane eigenvibrations, ω and ω, are closely separated. The dynamic analysis is performed by a two-degree-of-freedom modal decomposition in the lowest in-plane and out-of-plane eigenmodes. Modal parameters are evaluated based on the eigenmodes...... for the parabolic approximation to the equilibrium suspension....

  5. System for effecting underwater coupling of optical fiber cables characterized by a novel V-probe cable capture mechanism

    Science.gov (United States)

    Hillenbrand, Christopher F.; Barron, Thomas D.; Nugent, David M.

    1995-03-01

    A submarine trails one fiber optic cable and an undersea vehicle is controlled by this first cable. A missile/torpedo trails a second cable that is to be coupled to the first cable. The second cable has a segment suspended vertically underwater between a buoyant pod and a sea anchor type buoy. The undersea vehicle, or Autonomous Undersea Vehicle, (AUV) hunts for the pod by conventional homing means. A forked cable pickup device in the nose of the AUV captures the suspended cable segment directing it into a slot so a male socket in the underside of the pod mates with a female socket in the slot.

  6. 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.

  7. 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.

  8. Research on key technologies in design of middle pylon of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Ji Lin

    2012-01-01

    At the middle pylon of a three-pylon two-span suspension bridge, the effect of unbalanced loads on the adjacent spans may result in a series of technical bottlenecks in design, such as stability and anti-slippage between saddles and main cables. This article presents the researches conducted on structure selection and behavior characteristics of middle pylon, interaction mechanism between main cables and saddles and their anti-slippage safety performance, elastic and plastic stability analysis and safety assessment of steel middle pylon, and fatigue design load and method for steel pylon of Taizhou Bridge. According to the research results, a longitudinal inverted Y shape steel middle pylon is used in design, effectively solving many technical difficulties, and this type of pylon has become a suitable middle pylon structural form for many three-ovlon two-soan susoension bridges.

  9. Real-time visualization of bridge structural response through wireless MEMS sensors

    Science.gov (United States)

    Chung, Hung-Chi; Enomoto, Tomoyuki; Loh, Kenneth; Shinozuka, Masanobu

    2004-07-01

    This study investigates the reliability and accuracy of wireless micro-electromechanical-system (MEMS)-type sensors in application of bridge structural vibration monitoring. With wireless capabilities added onto the developed sensors, it becomes unnecessary for engineers to connect enormous lengths of cables in order to measure vibration on bridges for instance. We investigated two types of MEMS accelerometers: the ADXL 202E and the Silicon Design 2210. To prove the validity of measuring acceleration by using these devices with wireless communication, we succeeded on measuring a pedestrian bridge's vibration under excitation loads in the center of span. The result had been compared with the traditional cabled sensor, PCB 393C. The wireless sensors were showed to be effective and much affordable to carry out the monitoring missions in situ.

  10. Rural Electric Network Alteration Spurs Cable Production

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>Most aluminum cable enterprises in Yunnan and Zhejiang focus their production capacity on overhead cables needed in rural electric network alteration. During the 12th Five-Year Plan period, China launched the rural electric network alteration & upgrade project. As of the middle of 2011, the budget of the central government for the rural electric network alteration & upgrade project planned by the National Development and Reform Commission has reached up to RMB 64.96 billion.

  11. Cable system transients theory, modeling and simulation

    CERN Document Server

    Ametani, Akihiro; Nagaoka, Naoto

    2015-01-01

    A systematic and comprehensive introduction to electromagnetic transient in cable systems, written by the internationally renowned pioneer in this field Presents a systematic and comprehensive introduction to electromagnetic transient in cable systems Written by the internationally renowned pioneer in the field Thorough coverage of the state of the art on the topic, presented in a well-organized, logical style, from fundamentals and practical applications A companion website is available

  12. Ecology: Electrical Cable Bacteria Save Marine Life

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter

    2016-01-01

    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.......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....

  13. 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.

  14. 大跨度公铁两用钢桁梁斜拉桥结构地震响应特征研究%Study of Structural Seismic Response Characteristics of Long Span Rail-cum-Road Steel Truss Girder Cable-Stayed Bridges

    Institute of Scientific and Technical Information of China (English)

    阮怀圣; 屈爱平; 何友娣; 苗润池; 李龙安

    2015-01-01

    大跨度公铁两用钢桁梁斜拉桥是一种技术复杂的特殊桥梁,为系统地把握该类型桥梁结构在地震作用下的动力响应规律,总结该类桥梁的总体结构特征,统计分析5座公铁两用大桥的结构动力特性值,利用有限元数值仿真方法分析不同结构抗震约束体系的地震响应特点,统计粘滞阻尼器的减震效果并解释效果差异的原因。研究表明:大跨度公铁两用斜拉桥的竖向刚度与公路斜拉桥相比有明显差异,前者的竖弯基频比后者平均高20%左右;在多种结构抗震约束体系中,具有耗能显著特点的液体粘滞阻尼器体系是一种较为理想的结构抗震支承体系;采用粘滞阻尼器后,6座大桥桥塔的弯矩减震率呈现20%左右与60%以上两种不同表现结果,该现象主要与地震动输入的长周期成分取值有关;由于剪力比弯矩的阶次低,导致桥塔剪力比弯矩的减震效果低;粘滞阻尼器对梁端位移的减震效果显著,可达到60%~80%。%T he long span rail‐cum‐road steel truss girder cable‐stayed bridge is a type of the special bridge of technical complexity . To systematically understand the structural dynamic re‐sponse law s of such type of the bridges under the action of earthquake ,the general structural char‐acteristics of the bridges were summed up and the structural dynamic characteristic values of 5 long span rail‐cum‐road steel truss girder cable‐stayed bridges were statistically analyzed .The seismic response characteristics of the different structural seismic restraint systems were analyzed ,using the finite element numerical simulation ,the damping effect of the fluid viscous dampers was statis‐tically collected and the differences of the damping effect were illustrated .The results of the analy‐sis demonstrate that the vertical stiffness of a long span rail‐cum‐road steel truss girder cable‐stayed bridge is

  15. An integrated FBG sensing system for bridge health monitoring

    Science.gov (United States)

    Sun, Ru-Jiao; Sun, Zhi; Dan, Dan-Hui; Sun, Li-Min

    2006-03-01

    Thanking to its distinguishing advantages including wavelength multiplexing capability, miniature size, high sensitivity, immunity from electro-magnetic interference and etc, the fiber Bragg grating (FBG) sensing technologies are regarded as a competent candidate for the bridge long-term health monitoring. According to the shifted Bragg wavelength of the light reflected by a fiber grating, the FBG sensors can accurately measure various physical properties such as strain, temperature, displacement, acceleration and corrosion. One special advantage of the FBG sensing technology is that only one demodulation device is required to acquire various physical properties simultaneously. Compared with the bridge health monitoring system using conventional sensors, this advantage makes the quasi-distributed sensing possible and data transmission more convenient because many FBG sensors can be connected in series by a single fiber. In this paper, an integrated FBG sensing system is presented for monitoring the physical state of a real bridge, the main-navigation channel cable-stayed bridge of the Donghai Bridge. The strain variation of two selected sections in the construction stage and during the load trial test are continuously monitored. The results of this study will supply a good guidance for the use of FBG sensors on the health monitoring of real bridges. Finally, the paper present the design and fabrication of an accelerometer based on the FBG technology for structure vibration monitoring.

  16. Environmental assessment of submarine power cables

    International Nuclear Information System (INIS)

    Extensive analyses conducted by the European Community revealed that offshore wind energy have relatively benign effects on the marine environment by comparison to other forms of electric power generation [1]. However, the materials employed in offshore wind power farms suffer major changes to be confined to the marine environment at extreme conditions: saline medium, hydrostatic pressure... which can produce an important corrosion effect. This phenomenon can affect on the one hand, to the material from the structural viewpoint and on the other hand, to the marine environment. In this sense, to better understand the environmental impacts of generating electricity from offshore wind energy, this study evaluated the life cycle assessment for some new designs of submarine power cables developed by General Cable. To achieve this goal, three approaches have been carried out: leaching tests, eco-toxicity tests and Life Cycle Assessment (LCA) methodologies. All of them are aimed to obtaining quantitative data for environmental assessment of selected submarine cables. LCA is a method used to assess environmental aspects and potential impacts of a product or activity. LCA does not include financial and social factors, which means that the results of an LCA cannot exclusively form the basis for assessment of a product's sustainability. Leaching tests results allowed to conclude that pH of seawater did not significantly changed by the presence of submarine three-core cables. Although, it was slightly higher in case of broken cable, pH values were nearly equals. Concerning to the heavy metals which could migrate to the aquatic medium, there were significant differences in both scenarios. The leaching of zinc is the major environmental concern during undersea operation of undamaged cables whereas the fully sectioned three-core cable produced the migration of significant quantities of copper and iron apart from the zinc migrated from the galvanized steel. Thus, the tar

  17. Environmental assessment of submarine power cables

    Energy Technology Data Exchange (ETDEWEB)

    Isus, Daniel; Martinez, Juan D. [Grupo General Cable Sistemas, S.A., 08560-Manlleu, Barcelona (Spain); Arteche, Amaya; Del Rio, Carmen; Madina, Virginia [Tecnalia Research and Innovation, 20009 San Sebastian (Spain)

    2011-03-15

    Extensive analyses conducted by the European Community revealed that offshore wind energy have relatively benign effects on the marine environment by comparison to other forms of electric power generation [1]. However, the materials employed in offshore wind power farms suffer major changes to be confined to the marine environment at extreme conditions: saline medium, hydrostatic pressure... which can produce an important corrosion effect. This phenomenon can affect on the one hand, to the material from the structural viewpoint and on the other hand, to the marine environment. In this sense, to better understand the environmental impacts of generating electricity from offshore wind energy, this study evaluated the life cycle assessment for some new designs of submarine power cables developed by General Cable. To achieve this goal, three approaches have been carried out: leaching tests, eco-toxicity tests and Life Cycle Assessment (LCA) methodologies. All of them are aimed to obtaining quantitative data for environmental assessment of selected submarine cables. LCA is a method used to assess environmental aspects and potential impacts of a product or activity. LCA does not include financial and social factors, which means that the results of an LCA cannot exclusively form the basis for assessment of a product's sustainability. Leaching tests results allowed to conclude that pH of seawater did not significantly changed by the presence of submarine three-core cables. Although, it was slightly higher in case of broken cable, pH values were nearly equals. Concerning to the heavy metals which could migrate to the aquatic medium, there were significant differences in both scenarios. The leaching of zinc is the major environmental concern during undersea operation of undamaged cables whereas the fully sectioned three-core cable produced the migration of significant quantities of copper and iron apart from the zinc migrated from the galvanized steel. Thus, the tar

  18. Ship nuclear power device of cable aging management

    International Nuclear Information System (INIS)

    Cable for marine nuclear power plant continuous delivery of electrical energy. Cable is mostly in the high temperature and strong radiation and harsh working environment, and can not be replaced in the lifetime This should be the cable aging management methods through research, maintenance and repair program to provide a scientific basis. Cable aging management approach for a number of different levels of cable management at different levels, relying on computers and other modern tools, the use of information management database software maintenance of the cable through the science of aging control. Cable Aging Management including the scope of cable aging management, classification management basis and used for different levels of management supervision and implementation of means testing approach. Application of the ship that has the operational management science, both planned maintenance to improve the science, but also improves the efficiency of aging management. This management method can be extended to nuclear power plants of cable aging management. (authors)

  19. Test of two prototype high-temperature superconducting transmission cables

    Energy Technology Data Exchange (ETDEWEB)

    Lue, J.W.; Lubell, M.S.; Kroeger, D.M.; Martin, P.M. [Oak Ridge National Lab., TN (United States); Demko, J.A.; Jones, E.C. [Oak Ridge Associated Universities, Inc., TN (United States); Sinha, U.; Hughey, R.L. [Southwire Co., Carrollton, GA (United States)

    1996-10-01

    Two 500-A class prototype high-temperature superconducting cables have been constructed by Southwire Company and tested at Oak Ridge National Laboratory (ORNL). In the first cable, no insulation was used to separate the individual HTS tapes. In the second cable, Kapton tape was used to insulate the HTS tapes between successive layers for the study of AC loss and current distribution. The cables were tested with both DC and AC currents in liquid nitrogen from 77 to 69 K. Both cables achieved DC critical current, I{sub c} greater than 500 A. A calorimetric technique that measures the cable temperature rise under ac currents was used to measure the ac loss of the cables. The un-insulated cable showed a cryoresistive behavior under the 60 Hz AC currents. The insulated cable started to show measurable loss at current where there was corresponding resistive loss.

  20. Results from the Danish high temperature superconducting power cable project

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Østergaard, Jacob

    2002-01-01

    For the first time, a high temperature superconducting (HTS) demonstration cable system has been installed in a utility network supplying electricity to consumers. The cable is a 30-m long, 30kVrms, 2, 000Arms cable, installed in the network of Copenhagen Energy at a substation supplying...... approximately 50, 000 customers. The purpose of the cable installation is to obtain installation and operating experience with this type of cable. The cable system has been in operation since May 28th 2001, and the first operating experiences of the cable have been satisfactory. The cable has been in operation...... for more than one year, and the cable has during the first year supplied 101, 000MWh of energy to the customers....

  1. Full-scale fire experiments on vertical horizontal cable trays

    Energy Technology Data Exchange (ETDEWEB)

    Mangs, J.; Keski-Rahkonen, O. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

    1997-10-01

    Two full-scale fire experiments on PVC cables used in nuclear power plants were carried out, one with cables in vertical position and one with cables in horizontal position. The vertical cable bundle, 3 m high, 300 mm wide and 30 mm thick, was attached to a steel cable ladder. The vertical bundle experiment was carried out in nearly free space with three walls near the cable ladder guiding air flow in order to stabilise flames. The horizontal cable experiment was carried out in a small room with five cable bundles attached to steel cable ladders. Three of the 2 m long cable bundles were located in an array, equally spaced above each other near one long side of the room and two correspondingly near the opposite long side. The vertical cable bundle was ignited with a small propane gas burner beneath the lower edge of the bundle. The horizontal cable bundles were ignited with a small propane burner beneath the lowest bundle in an array of three bundles. Rate of heat release by means of oxygen consumption calorimetry, mass change, CO{sub 2}, CO and smoke production rate and gas, wall and cable surface temperatures were measured as a function of time, as well as time to sprinkler operation and failure of test voltage in cables. Additionally, the minimum rate of heat release needed to ignite the bundle was determined. This paper concentrates on describing and recording the experimental set-up and the data obtained. (orig.)

  2. Force Analysis and Experimental Study of Steel Anchor Box in Girder of Railway Hybrid Girder Cable-Stayed Bridge%铁路混合梁斜拉桥索梁钢锚箱受力分析与试验研究

    Institute of Scientific and Technical Information of China (English)

    刘振标; 施洲; 罗世东; 么超逸; 曾甲华

    2015-01-01

    The Yongjiang River Bridge on the North Ring Link of the Ningbo Railway Termi‐nal is a hybrid girder cable‐stayed bridge with a main span of 468 m .In view of the characteristics of the heavy double‐track railway live load and narrow deck on the bridge and the strict require‐ments for the train traveling safety and passenger riding comfort ,a new type of the double‐cantile‐ver steel anchor box in girder has been developed .Integrating both the functions of the structure itself and the wind fairings ,the new steel anchor box has advantages of great bending ,torsional stiffness and good fatigue performance as compared to the traditional single‐cantilever steel anchor box .To systematically analyze the force characteristics of the new type of the anchor box ,the fi‐nite element model was established and the force and force transfer characteristics of the anchor box were analyzed .The local model in full scale of 1∶1 for the anchor box was fabricated and the fatigue checking test of 2 million time cycling and the fatigue failure test of 1 million time cycling were carried out .The results of the tests show that the stress and load of the new anchor box ex‐hibit linear relationship and no cracks are found in the model ,verifying that the structural design of the anchor box is rational and safe and the anchor box is the rational steel anchor box type in girder that is applicable to long span double‐track railw ay cable‐stayed bridges .%宁波铁路枢纽北环线甬江特大桥为主跨468 m的混合梁斜拉桥,基于双线铁路活载重、桥面窄、列车运营安全性和旅客乘坐舒适度要求高,研究采用了一种新型双挑式索梁钢锚箱,集结构功能与风嘴功能于一体,相比传统单挑式锚箱具有抗弯抗扭刚度大、疲劳性能优良的特点。为系统分析新锚箱结构受力特性,通过建立有限元模型,分析索梁钢锚箱的受力特点与传力特性,并制作1∶1足尺

  3. Innovation in Cable Outgoing Pattern of LV Cabinets%低压柜电缆出线方式创新

    Institute of Scientific and Technical Information of China (English)

    申景阳

    2015-01-01

    老山自行车馆工程低压柜为上出线方式,低压柜的出线电缆放置在两层1 000 mm × 200 mm的桥架中, 由于出线回路复杂, 上下层桥架中的电缆存在进入同一面低压柜的情况, 特别是1AA1~1AA7, 2AA1~2AA7两列低压柜中集中了场馆近90%的用电负荷, 共需配出百余条供电电缆. 两层配电桥架的设计不可能合理安装上下交错的电缆. 通过自主创新和方案策划, 设计并实施了柜顶配线箱, 有效地解决了低压柜上出线的各种问题, 保证了安装质量和观感效果.%The LV cabinets of Laoshan Velodrome Project are characterized by upper cables outgoing, which are arranged between two layers of 1 000 mm × 200 mm bridging structure. The loop of the outgoing cables is complex, the cable in the upper layer of the bridging structure and that in the lower layer enter the same LV cabinet, and especially 90 % of the electrical loads of Laoshan Velodrome is concentrated in 1AA1~1AA7 and 2AA1~2AA7 LV cabinets, so hundreds of power supply cables are required. The design of two-layer power distribution bridging structure is unable to realize reasonable installation of the cables staggered up and down. Through independent innovation and program planning, a cable distribution box is designed to arrange on the cabinet top to effectively solve various problems caused by upper cables outgoing of LV cabinets and guarantee the installation quality and appearance effect.

  4. Applying Diagnostics to Enhance Cable System Reliability (Cable Diagnostic Focused Initiative, Phase II)

    Energy Technology Data Exchange (ETDEWEB)

    Hartlein, Rick [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Hampton, Nigel [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Perkel, Josh [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Hernandez, JC [Univ. de Los Andes, Merida (Venezuela); Elledge, Stacy [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); del Valle, Yamille [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Grimaldo, Jose [Georgia Inst. of Technology, Atlanta, GA (United States). School of Electrical and Computer Engineering; Deku, Kodzo [Georgia Inst. of Technology, Atlanta, GA (United States). George W. Woodruff School of Mechanical Engineering

    2016-02-01

    The Cable Diagnostic Focused Initiative (CDFI) played a significant and powerful role in clarifying the concerns and understanding the benefits of performing diagnostic tests on underground power cable systems. This project focused on the medium and high voltage cable systems used in utility transmission and distribution (T&D) systems. While many of the analysis techniques and interpretations are applicable to diagnostics and cable systems outside of T&D, areas such as generating stations (nuclear, coal, wind, etc.) and other industrial environments were not the focus. Many large utilities in North America now deploy diagnostics or have changed their diagnostic testing approach as a result of this project. Previous to the CDFI, different diagnostic technology providers individually promoted their approach as the “the best” or “the only” means of detecting cable system defects.

  5. Concrete bridge prioritization system

    OpenAIRE

    Kesselring, Debbie Anne

    1995-01-01

    An alternative method of prioritization for concrete bridge maintenance, repair, and rehabilitation activities is required due to the inability of the current system to manage the increasing nmnber of aging concrete bridges. The Concrete Bridge Prioritization System was proposed because of its ability to address the critical technical parameters of safety and cost benefit in prioritization of funding and work allocation. The analysis includes four parts, service life assessment, s...

  6. Evaluation of cable ageing in Nuclear Power Plants; Evaluacion del envejecimiento de cables en centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Vergara, T. [Empresarios Agrupados, A. I. E. Madrid (Spain); Alonso Chicote, J. [TECNATOM, S. A. (Spain); Burnay, S. [AEA Technology (UK)

    2000-07-01

    The majority of power, control and instrumentation cables in nuclear power plants use polymers as their basic material for insulation and jacket. In many cases, these cables form part of safety-related circuits and should therefore be capable of operating correctly under both normal and accident conditions. Since polymeric materials are degraded by the long term action of the radiation and thermal environments found in the plant, it is important to be able to establish the cable condition during the plant lifetime. Nowadays there are a number of different methods to evaluate the remaining lifetime of cables. In the case of new plants, or new cables in old plants, accelerated ageing tests and predictive models can be used to establish the behaviour of the cable materials under operating conditions. There are verified techniques and considerable experience in the definition of predictive models. This type of approach is best carried out during the commissioning stage or in the early stages of operation. In older plants, particularly where there is a wide range of cable types in use, it is more appropriate to use condition monitoring methods to establish the state of degradation of cables in-plant. Over the last 10 years there have been considerable developments in methods for condition monitoring of cables and a tool-box of practical techniques are now available. There is no single technique which is suitable for all cable materials but the range of methods covers nearly all of the types currently in use, at present, the most established methods are the indented, thermal analysis (OIT, OITP and TGA) and dielectric loss measurements, All of these are either non-destructive methods or require only micro-samples of material. (Author) 15 refs.

  7. Bulk Electrical Cable Non-Destructive Examination Methods for Nuclear Power Plant Cable Aging Management Programs

    Energy Technology Data Exchange (ETDEWEB)

    Glass, Samuel W.; Jones, Anthony M.; Fifield, Leonard S.; Hartman, Trenton S.

    2016-09-13

    This Pacific Northwest National Laboratory milestone report describes progress to date on the investigation of nondestructive test methods focusing particularly on bulk electrical test methods that provide key indicators of cable aging and damage. The work includes a review of relevant literature as well as hands-on experimental verification of inspection capabilities. As nuclear power plants consider applying for second, or subsequent, license renewal to extend their operating period from 60 years to 80 years, it is important to understand how the materials installed in plant systems and components will age during that time and develop aging management programs to assure continued safe operation under normal and design basis events (DBE). Normal component and system tests typically confirm the cables can perform their normal operational function. The focus of the cable test program, however, is directed toward the more demanding challenge of assuring the cable function under accident or DBE. The industry has adopted 50% elongation at break (EAB) relative to the un-aged cable condition as the acceptability standard. All tests are benchmarked against the cable EAB test. EAB, however, is a destructive test so the test programs must apply an array of other nondestructive examination (NDE) tests to assure or infer the overall set of cable’s system integrity. Assessment of cable integrity is further complicated in many cases by vendor’s use of dissimilar material for jacket and insulation. Frequently the jacket will degrade more rapidly than the underlying insulation. Although this can serve as an early alert to cable damage, direct test of the cable insulation without violating the protective jacket becomes problematic. This report addresses the range of bulk electrical NDE cable tests that are or could be practically implemented in a field-test situation with a particular focus on frequency domain reflectometry (FDR). The FDR test method offers numerous advantages

  8. Bulk Electrical Cable Non-Destructive Examination Methods for Nuclear Power Plant Cable Aging Management Programs

    Energy Technology Data Exchange (ETDEWEB)

    Glass, Samuel W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Anthony M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hartman, Trenton S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-01

    This Pacific Northwest National Laboratory milestone report describes progress to date on the investigation of nondestructive test methods focusing particularly on bulk electrical test methods that provide key indicators of cable aging and damage. The work includes a review of relevant literature as well as hands-on experimental verification of inspection capabilities. As nuclear power plants consider applying for second, or subsequent, license renewal to extend their operating period from 60 years to 80 years, it is important to understand how the materials installed in plant systems and components will age during that time and develop aging management programs to assure continued safe operation under normal and design basis events (DBE). Normal component and system tests typically confirm the cables can perform their normal operational function. The focus of the cable test program, however, is directed toward the more demanding challenge of assuring the cable function under accident or DBE. The industry has adopted 50% elongation at break (EAB) relative to the un-aged cable condition as the acceptability standard. All tests are benchmarked against the cable EAB test. EAB, however, is a destructive test so the test programs must apply an array of other nondestructive examination (NDE) tests to assure or infer the overall set of cable’s system integrity. Assessment of cable integrity is further complicated in many cases by vendor’s use of dissimilar material for jacket and insulation. Frequently the jacket will degrade more rapidly than the underlying insulation. Although this can serve as an early alert to cable damage, direct test of the cable insulation without violating the protective jacket becomes problematic. This report addresses the range of bulk electrical NDE cable tests that are or could be practically implemented in a field-test situation with a particular focus on frequency domain reflectometry (FDR). The FDR test method offers numerous advantages

  9. CSNS control cable information management system based on web

    International Nuclear Information System (INIS)

    This paper presents an approach to data modeling a great number of control devices and cables with complicated relations of CSNS (China Spallation Neutron Source). The CSNS accelerator control cable database was created using MySQL, and the control cable information management system based on Web was further built. During the development of the database, the design idea of IRMIS database was studied. and the actual situation of CSNS accelerator control cables was investigated. The control cable database model fitting the requirements was designed. This system is of great convenience to manage and maintain CSNS control devices and cables in the future. (authors)

  10. Quality control testing of cables for accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Garber, M.; Sampson, W.B. (Brookhaven National Lab., Upton, NY (USA))

    1989-01-01

    A large number of cables have been tested for the CBA, HERA, and SSC Projects. The short sample test procedures and apparatus are reviewed. A simple rule for estimating cable performance from measurements on strands taken from the cable is described. By using this rule of thumb'' cable vendors can make reliable estimates without having to invest in the substantial equipment required for full cable testing. Extracted strand tests should be checked periodically by full scale tests on complete cables. 9 refs., 5 figs., 1 tab.

  11. Measurements for validation of high voltage underground cable modelling

    DEFF Research Database (Denmark)

    Bak, Claus Leth; Gudmundsdottir, Unnur Stella; Wiechowski, Wojciech Tomasz;

    2009-01-01

    This paper discusses studies concerning cable modelling for long high voltage AC cable lines. In investigating the possibilities of using long cables instead of overhead lines, the simulation results must be trustworthy. Therefore a model validation is of great importance. This paper describes...... field test setups and measurements on an already installed cable line with several cross bonding points. These measurements are to be used for cable model validation, which are prepared using simulations. The proposed field tests should be used to validate the cable model for overvoltage problems...

  12. Bridging the Gap

    DEFF Research Database (Denmark)

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska;

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

  13. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures. Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ve...

  14. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  15. 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

  16. HTS twisted stacked-tape cable conductor

    International Nuclear Information System (INIS)

    The feasibility of high field magnet applications of the twisted stacked-tape cabling method with 2G YBCO tapes has been investigated. An analysis of torsional twist strains of a thin HTS tape has been carried out taking into account the internal shortening compressive strains accompanied with the lengthening tensile strains due to the torsional twist. The model is benchmarked against experimental tests using YBCO tapes. The critical current degradation and current distribution of a four-tape conductor was evaluated by taking account of the twist strain, the self-field and the termination resistances. The critical current degradation for the tested YBCO cables can be explained by the perpendicular self-field effect. It is shown that the critical current of a twisted stacked-tape conductor with a four-tape cable does not degrade with a twist pitch length as short as 120 mm. Current distribution among tapes and hysteresis losses are also investigated. A compact joint termination method for a 2G YBCO tape cable has been developed. The twisted stacked-tape conductor method may be an attractive means for the fabrication of highly compact, high current cables from multiple flat HTS tapes.

  17. 47 CFR 36.341 - Cable and wire facilities expenses-Account 6410 (Class B telephone companies); Accounts 6411...

    Science.gov (United States)

    2010-10-01

    ... structures, aerial cable, underground cable, buried cable, submarine cable, deep sea cable, intrabuilding... 47 Telecommunication 2 2010-10-01 2010-10-01 false Cable and wire facilities expenses-Account 6410... Operating Expenses and Taxes Cable and Wire Facilities Expenses § 36.341 Cable and wire facilities...

  18. 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.

  19. Distance and Cable Length Measurement System

    Science.gov (United States)

    Hernández, Sergio Elias; Acosta, Leopoldo; Toledo, Jonay

    2009-01-01

    A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement. PMID:22303169

  20. Distance and Cable Length Measurement System

    Directory of Open Access Journals (Sweden)

    Jonay Toledo

    2009-12-01

    Full Text Available A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement.