• Title/Summary/Keyword: concrete cable-stayed bridge

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A multi-parameter optimization technique for prestressed concrete cable-stayed bridges considering prestress in girder

  • Gao, Qiong;Yang, Meng-Gang;Qiao, Jian-Dong
    • Structural Engineering and Mechanics
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    • v.64 no.5
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    • pp.567-577
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    • 2017
  • The traditional design procedure of a prestressed concrete (PC) cable-stayed bridge is complex and time-consuming. The designers have to repeatedly modify the configuration of the large number of design parameters to obtain a feasible design scheme which maybe not an economical design. In order to efficiently achieve an optimum design for PC cable-stayed bridges, a multi-parameter optimization technique is proposed. In this optimization technique, the number of prestressing tendons in girder is firstly set as one of design variables, as well as cable forces, cable areas and cross-section sizes of the girders and the towers. The stress and displacement constraints are simultaneously utilized to ensure the safety and serviceability of the structure. The target is to obtain the minimum cost design for a PC cable-stayed bridge. Finally, this optimization technique is carried out by a developed PC cable-stayed bridge optimization program involving the interaction of the parameterized automatically modeling program, the finite element structural analysis program and the optimization algorithm. A low-pylon PC cable-stayed bridge is selected as the example to test the proposed optimization technique. The optimum result verifies the capability and efficiency of the optimization technique, and the significance to optimize the number of prestressing tendons in the girder. The optimum design scheme obtained by the application can achieve a 24.03% reduction in cost, compared with the initial design.

Nonlinear Analysis of Curved Prestressed Concrete Cable-Stayed Bridge due to Large Deflection (대변위를 고려한 곡선 프리스트레스트 콘크리트 사장교의 비선형 해석)

  • Lee, Jae-Seok;Choi, Kyu-Chon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.341-344
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    • 2006
  • A study for the nonlinear analysis of segmentally erected curved PSC(prestressed concrete) cable-stayed bridge considering the effects due to large deflections is presented. Various case studies regarding the effects of the material nonlinearities and the geometric nonlinearities on the behavior of segmentally erected curved PSC cable-stayed bridge are conducted. The numerical results on the bridge which has relatively low stress profile through the bridge deck section like the example herein show that the geometric nonlinearities has more significant effects on the structural behavior than the material nonlinearities.

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Passive control system for seismic protection of a multi-tower cable-stayed bridge

  • Geng, Fangfang;Ding, Youliang;Song, Jianyong;Li, Wanheng;Li, Aiqun
    • Earthquakes and Structures
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    • v.6 no.5
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    • pp.495-514
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    • 2014
  • The performance of passive control system for the seismic protection of a multi-tower cable-stayed bridge with the application of partially longitudinal constraint system is investigated. The seismic responses of the Jiashao Bridge, a six-tower cable-stayed bridge using the partially longitudinal constraint system are studied under real earthquake ground motions. The effects of the passive control devices including the viscous fluid dampers and elastic cables on the seismic responses of the bridge are examined by taking different values of parameters of the devices. Further, the optimization design principle of passive control system using viscous fluid dampers is presented to determine the optimized parameters of the viscous fluid dampers. The results of the investigations show that the control objective of the multi-tower cable-stayed bridge with the partially longitudinal constraint system is to reduce the base shears and moments of bridge towers longitudinally restricted with the bridge deck. The viscous fluid dampers are found to be more effective than elastic cables in controlling the seismic responses. The optimized parameters for the viscous fluid dampers are determined following the principle that the peak displacement at the end of bridge deck reaches to the maximum value, which can yield maximum reductions in the base shears and moments of bridge towers longitudinally restricted with the bridge deck, with slight increases in the base shears and moments of bridge towers longitudinally unrestricted with the bridge deck.

Influence of structural system measures on the dynamic characteristics of a multi-span cable-stayed bridge

  • Geng, Fangfang;Ding, Youliang;Xie, Hongen;Song, Jianyong;Li, Wanheng
    • Structural Engineering and Mechanics
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    • v.52 no.1
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    • pp.51-73
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    • 2014
  • A three-dimensional finite element model for the Jiashao Bridge, the longest multi-span cable-stayed bridge in the world, is established using the commercial software package ANSYS. Dynamic characteristics of the bridge are analyzed and the effects of structural system measures including the rigid hinge, auxiliary piers and longitudinal constraints between the girders and side towers on the dynamic properties including modal frequency, mode shape and effective mass are studied by referring to the Jiashao Bridge. The analysis results reveal that: (i) the installation of the rigid hinge significantly reduces the modal frequency of the first symmetric lateral bending mode of bridge deck. Moreover, the rigid hinge significantly changes the mode shape and effective mass of the first symmetric torsional mode of bridge deck; (ii) the layout of the auxiliary piers in the side-spans has a limited effect on changing the modal frequencies, mode shapes and effective masses of global vibration modes; (iii) the employment of the longitudinal constraints significantly increases the modal frequencies of the vertical bending modes and lateral bending modes of bridge deck and have significant effects on changing the mode shapes of vertical bending modes and lateral bending modes of bridge deck. Moreover, the effective mass of the first anti-symmetric vertical bending of bridge deck in the longitudinal direction of the fully floating system is significantly larger than that of the partially constrained system and fully constrained system. The results obtained indicate that the structural system measures of the multi-span cable-stayed bridge have a great effect on the dynamic properties, which deserves special attention for seismic design and wind-resistant design of the multi-span cable-stayed bridge.

Creep and shrinkage effects in service stresses of concrete cable-stayed bridges

  • Lozano-Galant, Jose Antonio;Turmo, Jose
    • Computers and Concrete
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    • v.13 no.4
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    • pp.483-499
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    • 2014
  • Most of the methods presented in the literature to define the target service stresses (Objective Service Stage, OSS) of cable-stayed bridges rarely include the time-dependent phenomena effects. Nevertheless, especially in concrete structures, this assumption might be on the unsafe side because time-dependent phenomena usually modify service stresses. To fill this gap, this paper studies the time-dependent phenomena effects into service stresses of concrete cable-stayed bridges. After illustrating the important role of these phenomena in an asymmetrical cable-stayed bridge without backstay, a new method to include their effects into the OSS is presented. An important issue to be considered in this method is the target time in which the OSS is defined to be achieved. The application of this method to two different structures showed the convenience of defining the OSS to be achieved at early times because that way the envelope of service stresses is reduced.

Estimation of error factors in concrete cable-stayed bridge considering creep (크리프를 고려한 콘크리트 사장교의 오차 요인 추정)

  • Park, Jong-Bum;Cho, Jae-Yeol;Park, Jung-Il;Chang, Sung-Pil
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.387-388
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    • 2009
  • In concrete cable-stayed bridge, the time-dependent effects of concrete should be taken into account for the optimum cable force adjustment. The method for estimating the creep coefficient with using the deflections and the cable forces in concrete cable-stayed bridge is presented and the effects of the creep coefficient error are analyzed.

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A Study on the Long-Term Behavior of UHPC Pedestrian Cable Stayed Bridge (UHPC 보도사장교의 장기거동에 관한 연구)

  • Chin, Won-Jong;Kim, Young-Jin;Choi, Eun-Suk;Kim, Byung-Suk
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.109-110
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    • 2010
  • A pedestrian UHPC cable-stayed bridge(Super Bridge I) of the KICT was completed as a test bed. A long-term monitoring system has been installed on the UHPC bridge in order to acquire all types of long-term data such as strain, acceleration, tension force, wind direction and speed, temperature, etc. This system will provide valuable database enabling to assess the long-term behavior of the UHPC pedestrian hybrid cable-stayed bridge. This database will be exploited for the evaluation of the mechanical characteristics and serviceability of the UHPC members so as to estimate the behavioral features of long-span hybrid cable stayed bridges.

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Time-dependent effects on dynamic properties of cable-stayed bridges

  • Au, Francis T.K.;Si, X.T.
    • Structural Engineering and Mechanics
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    • v.41 no.1
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    • pp.139-155
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    • 2012
  • Structural health monitoring systems are often installed on bridges to provide assessments of the need for structural maintenance and repair. Damage or deterioration may be detected by observation of changes in bridge characteristics evaluated from measured structural responses. However, construction materials such as concrete and steel cables exhibit certain time-dependent behaviour, which also results in changes in structural characteristics. If these are not accounted for properly, false alarms may arise. This paper proposes a systematic and efficient method to study the time-dependent effects on the dynamic properties of cable-stayed bridges. After establishing the finite element model of a cable-stayed bridge taking into account geometric nonlinearities and time-dependent behaviour, long-term time-dependent analysis is carried out by time integration. Then the dynamic properties of the bridge after a certain period can be obtained. The effects of time-dependent behaviour of construction materials on the dynamic properties of typical cable-stayed bridges are investigated in detail.

Effects of Cable Rupture on Dynamic Responses of a Concrete Cable-stayed Bridge (케이블 파단이 콘크리트사장교 동적거동에 미치는 영향)

  • Kim, Yu Hee;Go, Hyeong Gyu;Kim, Jae Cheon;Shin, Soobong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.3
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    • pp.84-91
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    • 2012
  • This paper aims to investigate the effects of cable rupture on the dynamic responses of concrete cable-stayed bridges in comparison with those of steel composite ones. It examines an adequate analysis method for simulating cable rupture using a time history function and evaluates the design guidelines for dynamic amplification factor (DAF). The computed DAFs from a concrete cable-stayed bridge are compared with those from a steel composite one based on the design guideline. As a conclusion, the current design guidelines for DAF may be reliable in overall but show some unstable cases despite satisfying the design guidelines, especially for concrete cable-stayed bridges.

Nonlinear Analysis of Incheon Bridge Considering Time-Dependent Behavior of Concrete Pylon (콘크리트 주탑의 시간 의존적 거동을 고려한 인천대교의 비선형 해석)

  • Ha, Su-Bok;Kim, Jin-Il;Hwang, Chang-Hee;Shin, Hyun-Mock;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.2
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    • pp.155-162
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    • 2012
  • Recently, building of long span bridge is increasing and cable stayed bridges have large portion in civil projects. As the spans of bridges become longer, steel cable-stayed bridges have been constructed mainly for slim structure. But in many case, pylons are constructed by concrete for the stability of structures and the economy. Concrete is greatly influenced by the long-term behavior like creep and drying shrinkage, so analysis of stress redistribution and structural change in construction is required. In this study, as a cable stayed bridge with concrete pylon, Incheon Bridge is analyzed by nonlinear FEM analysis program RCAHEST. Through this analysis, time dependent effect of concrete pylon to whole cable stayed bridge system is studied.