• Title, Summary, Keyword: suspension bridge

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Investigation on mechanics performance of cable-stayed-suspension hybrid bridges

  • Zhang, Xin-Jun
    • Wind and Structures
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    • v.10 no.6
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    • pp.533-542
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    • 2007
  • The cable-stayed-suspension hybrid bridge is a cooperative system of the cable-stayed bridge and suspension bridge, and takes some advantages and also makes up some deficiencies of both the two bridge systems, and therefore becomes strong in spanning. By taking the cable-stayed-suspension hybrid bridge, suspension bridge and cable-stayed bridge with main span of 1400 m as examples, the mechanics performance including the static and dynamic characteristics, the aerostatic and aerodynamic stability etc is investigated by 3D nonlinear analysis. The results show that as compared to the suspension bridge and cable-stayed bridge, the cable-stayed-suspension hybrid bridge has greater structural stiffness, less internal forces and better wind stability, and is favorable to be used in super long-span bridges.

Investigation on the wind-induced instability of long-span suspension bridges with 3D cable system

  • Zhang, Xin-Jun
    • Wind and Structures
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    • v.14 no.3
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    • pp.209-220
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    • 2011
  • The cable system is generally considered to be a structural solution to increase the spanning capacity of suspension bridges. In this work, based on the Runyang Bridge over the Yangtze River, three case suspension bridges with different 3D cable systems are designed, structural dynamic characteristics, the aerostatic and aerodynamic stability are investigated numerically by 3D nonlinear aerostatic and aerodynamic analysis, and the cable system favorable to improve the wind-induced instability of long-span suspension bridges is also proposed. The results show that as compared to the example bridge with parallel cable system, the suspension bridge with inward-inclined cable system has greater lateral bending and tensional frequencies, and also better aerodynamic stability; as for the suspension bridge with outward-inclined cable system, it has less lateral bending and tensional frequencies, and but better aerostatic stability; however the suspension bridge is more prone to aerodynamic instability, and therefore considering the whole wind-induced instability, the parallel and inward-inclined cable systems are both favorable for long-span suspension bridges.

THE INVESTIGATION OF MULTIPLICATION OF SUSPENSION BRIDGE EQUATION USING LINKING THEORY

  • Nam, Hyewon
    • Korean Journal of Mathematics
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    • v.15 no.1
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    • pp.1-11
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    • 2007
  • It is well known that a suspension bridge may display certain oscillations under external aerodynamic forces. Under the action of a strong wind, in particular, a narrow and very flexible suspension bridge can undergo dangerous oscillations. So it would be very contributive to determine under what conditions a similar situation cannot occur, and find out safe parameters of the bridge construction. In this paper, we investigate relations between the multiplicity of solutions and nonlinear terms in this suspension bridge equation using critical point theorem and linking theorem.

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Aerodynamic flutter analysis of a new suspension bridge with double main spans

  • Zhang, W.M.;Ge, Y.J.;Levitan, M.L.
    • Wind and Structures
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    • v.14 no.3
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    • pp.187-208
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    • 2011
  • Based on the ANSYS, an approach of full-mode aerodynamic flutter analysis for long-span suspension bridges has been presented in this paper, in which the nonlinearities of structure, aerostatic and aerodynamic force due to the deformation under the static wind loading are fully considered. Aerostatic analysis is conducted to predict the equilibrium position of a bridge structure in the beginning, and then flutter analysis of such a deformed bridge structure is performed. A corresponding computer program is developed and used to predict the critical flutter wind velocity and the corresponding flutter frequency of a long-span suspension bridge with double main span. A time-domain analysis of the bridge is also carried out to verify the frequency-domain computational results and the effectiveness of the approach proposed in this paper. Then, the nonlinear effects on aerodynamic behaviors due to aerostatic action are discussed in detail. Finally, the results are compared with those of traditional suspension bridges with single main span. The results show that the aerostatic action has an important influence on the flutter stability of long-span suspension bridges. As for a suspension bridge with double main spans, the flutter mode is the first anti-symmetrical torsional vibration mode, which is also the first torsional vibration mode in natural mode list. Furthermore, a double main-span suspension bridge is better in structural dynamic and aerodynamic performances than a corresponding single main-span structure with the same bridging capacity.

Seismic performance and its favorable structural system of three-tower suspension bridge

  • Zhang, Xin-Jun;Fu, Guo-Ning
    • Structural Engineering and Mechanics
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    • v.50 no.2
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    • pp.215-229
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    • 2014
  • Due to the lack of effective longitudinal constraint for center tower, structural stiffness of three-tower suspension bridge becomes less than that of two-tower suspension bridge, and therefore it becomes more susceptible to the seismic action. By taking a three-tower suspension bridge-the Taizhou Highway Bridge over the Yangtze River with two main spans of 1080 m as example, structural dynamic characteristics and seismic performance of the bridge is investigated, and the effects of cable's sag to span ratio, structural stiffness of the center tower, and longitudinal constraint of the girder on seismic response of the bridge are also investigated, and the favorable structural system is discussed with respect to seismic performance. The results show that structural response under lateral seismic action is more remarkable, especially for the side towers, and therefore more attentions should be paid to the lateral seismic performance and also the side towers. Large cable's sag, flexible center tower and the longitudinal elastic cable between the center tower and the girder are favorable to improve structural seismic performance of long-span three-tower suspension bridges.

Study of seismic performance of cable-stayed-suspension hybrid bridges

  • Zhang, Xin-Jun;Yu, Zhou-Jun
    • Structural Engineering and Mechanics
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    • v.55 no.6
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    • pp.1203-1221
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    • 2015
  • By taking a cable-stayed-suspension hybrid bridge with main span of 1400 m as example, seismic response of the bridge under the horizontal and vertical seismic excitations is investigated numerically by response spectrum analysis and time history analysis, its seismic performance is discussed and compared to the cable-stayed bridge and suspension bridge with the same main span, and considering the aspect of seismic performance, the feasibility of using cable-stayed-suspension hybrid bridge in super long-span bridges is discussed. Under the horizontal seismic action, the effects of structural design parameters including the cable sag to span ratio, the suspension to span ratio, the side span length, the subsidiary piers in side spans, the girder supporting system and the deck form etc on the seismic performance of the bridge are investigated by response spectrum analysis, and the favorable values of these design parameters are proposed.

Analytical Method to Determine the Dynamic Amplification Factor due to Hanger Cable Rupture of Suspension Bridges (현수교 행어 케이블 파단에 의한 동적확대계수의 해석적 결정법)

  • Na, Hyun Ho;Kim, Yuhee;Shin, Soobong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.18 no.6
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    • pp.301-308
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    • 2014
  • A suspension bridge is a type of bridge in which the beam is suspended by load-bearing cables. There are two classifications: the self-anchored suspension bridge has the main cable anchored to the bridge girders, and the earth-anchored suspension bridge has the main cable anchored to a large anchorage. Although a suspension bridge is structurally safe, it is prone to be damaged by various actions such as hurricanes, tsunamis and terrorist incidents because its cables are exposed. If damage to a cable eventually leads to the cable rupture, the bridge may collapse. To avoid these accidents, studies on the dynamic behavior of cable bridges due to the cable rupture have been carried out. Design codes specify that the calculated DAF (dynamic amplification factor) should not exceed a certain value. However, it has been difficult to determine DAFs effectively from dynamic analysis, and thus no systematic approach has been suggested. The current study provides a guideline to determine DAFs reliably from the dynamic analysis results and summarizes the results by applying the method to an earth-anchored suspension bridge. In the study, DAFs were calculated at the location of four structural parts, girders, pylons, main cable and hangers, with variations in the rupture time.

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

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

Study of seismic performance and favorable structural system of suspension bridges

  • Zhang, Xin-Jun;Zhang, Chao
    • Structural Engineering and Mechanics
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    • v.60 no.4
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    • pp.595-614
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    • 2016
  • By taking the Runyang Highway Bridge over the Yangtze River with 1490 m main span as example, structural response of the bridge under the horizontal and vertical seismic excitations is investigated by the response spectrum and time-history analysis of MIDAS/Civil software respectively, the seismic behavior and the influence of structural nonlinearity on the seismic response of the bridge are revealed. Considering the aspect of seismic performance, the suitability of employing the suspension bridge in super long-span bridges is investigated as compared to the cable-stayed bridge and cable-stayed-suspension hybrid bridge with the similar main span. Furthermore, the effects of structural parameters including the span arrangement, the cable sag to span ratio, the side to main span ratio, the girder height, the central buckle and the girder support system etc on the seismic performance of the bridge are investigated by the seismic response spectrum analysis, and the favorable earthquake-resistant structural system of suspension bridges is also discussed.

The Main Stream of Mathematical Modeling of a Suspension Bridge (교량건설방식에 따른 수학적 모델링의 변천과정 기술과 현수교 방정식의 수학적 연구의 흐름)

  • Nam, Hye-Won
    • Journal for History of Mathematics
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    • v.20 no.4
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    • pp.93-104
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    • 2007
  • It is well known that a suspension bridge may display certain oscillations under external aerodynamic forces. Under the action of a strong wind, in particular, a narrow and very flexible suspension bridge can undergo dangerous oscillations. The collapse of the Tacoma Narrows suspension bridge caused by a wind blowing at a speed of 42 miles per hour, is one of the most striking examples. In this paper, we study models describing oscillations in suspension bridges and known results.

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