Proposing a New Model of Hangers in Pedestrian Suspension Bridges to Solve Hangers Slackness Problem
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Abstract
The hangers of suspension bridges can be placed in two forms: vertical or inclined form. Inclined hangers are more liable to fatigue. Vertical hangers are subjected to greater fluctuations of stress resulting from bridge wind loads. To improve aerodynamic stability, inclined hangers can be used instead of vertical ones. Some inclined hangers show considerable signs of distress and some of them show slackness due to their location against loads. In this paper a pedestrian suspension bridge with vertical hangers has been studied as a case study. Then, the same bridge has been studied with inclined hangers. To reduce internal forces, fatigue and slackness in hangers, horizontal cables have been added to inclined hangers. This modification is proposed by the present authors. The added horizontal cables transfer the tensile load from overstressed hangers to adjacent slacked hangers. Three different hanger patterns have been analyzed under nonlinear static analysis for symmetrical and nonsymmetrical live load plus dead load. Results showed that the modified hanger system had been improved considerably in comparison with vertical or inclined hangers and wherever that there is no improvement some solutions have been proposed.
- G. Neils, “Cable Suspension Bridge,” John Wiley and Sons, New York, 2000.
- N. Gimsing; “Cable Supported Bridges: Concept and Design,” John Wiley and Sons, New York, 1997.
- Q. Wu, K. Takahashi and S. Nakamura, “The Effect of Loosening of Cables on Seismic Response of the Ca-ble-Stayed Bridge,” Riron Oyo Rikigaku Koenkai Koen Ron-bunshu Journal, Vol. 50, 2001, pp. 229-230.
- Q. Wu, K. Takahashi, and S. Nakamura, “The Effect of Cable Loosening on Seismic Response of a Prestressed Concrete Cable-Stayed Bridge,” Journal of sound and vibration, Vol. 268, No. 1, No-vember 2003, pp. 71-84.
- Q. Wu, K. Takahashi, and S. Nakamura, “Influence of Cable Loosening on Nonlinear Para-metric Response of Inclined Cables,” NAOSITE: Nagasaki University’s Academic Output Site, Reports of the Faculty of Engineering, Nagasaki University, Vol. 35, No. 65, 2005, pp. 74-81.
- G. C. Sih and X. S. Tang, “Fatigue Crack Growth Rate of Cable-stayed Portion of Runyang Bridge,” Part I—Cable Crack Growth Due to Disproportionate Cable Tigh-tening/Loosening and Traffic Loading, Multiscale Fatigue Crack Initiation and Propagation of Engineering Materials, Springer Science+Business Media, Berlin, 2008, pp. 209-247.
- A. C. Lazer, and P. J. Mckenna; “Large-Amplitude Periodic Oscillations in Suspension Bridges: Some New Connections with Nonlinear Analysis,” Siam Review, Vol. 32, No. 4, December 1990, pp. 537-578. doi:10.1137/1032120
- I. Peterson, “Rock and Roll Bridge: A New Analysis Challenges the Common Explanation of a Famous Collapse,” Science News, Vol. 137, No. 22, 1990, pp. 344- 346. doi:10.2307/3974221
- V. Sepe and G. Augusti, “A Deformable Section Model for the Dynamics of Suspension Bridges, Part I: Model and Linear Response,” Wind and Struc-tures, Vol. 4, No. 1, 2001, pp. 1-18.
- J. Suh and S. P. Change, “Experimental Study on Fatigue Behaviour of Wire Ropes,” International Journal of Fatigue, Vol. 22, No. 4, April 2000, pp. 339-347. doi:10.1016/S0142-1123(00)00003-7
- B. H. Ali, “An In-vestigation into the Static Behavior of the Severn Bridge,” M.Sc. Thesis, UMIST, Manchester, 1984.
- E. V. Chipuru, “Guidelines for the Design and Construction of Suspension Footbridges,” ILO/ASIST, Harare, Zimbabwe, 2001.
- M. A. Al-Khlili, “An Investigation into the Static Behaviour of the Existing Inclined Hanger System on the Severn Suspension Bridge,” M.Sc Thesis, UMIST, Manchester, 1986.