全部 标题 作者
关键词 摘要

OALib Journal期刊
ISSN: 2333-9721
费用:99美元

查看量下载量

相关文章

更多...

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

DOI: 10.1155/2012/463134

Full-Text   Cite this paper   Add to My Lib

Abstract:

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. 1. Introduction The pretensioned cables in a typical cable-stayed bridge of medium size [1], as they are very long with a length of magnitude order 100?m, and a pretension axial force of magnitude order 1000?kN, exhibit, perpendicularly to their axis, a very small geometric stiffness, corresponding to their fundamental vibration mode, of a magnitude order only 50?kN/m. Also perpendicularly to their axis, they exhibit a very small intrinsic damping, due to their material internal friction. For the previous reasons, they are often subjected to large amplitude vibrations. And, if the external excitation is approximately periodic, with a period close to a natural period of the cable, for example, the fundamental one, then resonance may happen, and vibration amplitudes increase excessively and are maintained, with no significant reduction for a long time, unless special measures are taken. Two usual reasons for the previous cable vibrations of cable-stayed bridges are the following.(1)A pretensioned cable exhibits a sag under its self-weight. Because of traffic, the ends of the cable, on pylon and deck, are subject to a variation of their displacements; thus the elongation and axial force of the cable vary, which implies variation of its geometric stiffness, too, as well as variation of the sag of the cable. This vibration, due to variation of

References

[1]  R. Walther, B. Houriet, W. Isler, P. Moia, and J. F. Klein, Cable-Stayed Bridges, Th. Telford, London, UK, 2nd edition, 1999.
[2]  E. Caetano, “Cable vibrations in cable-stayed bridges,” IABSE-Structural Engineering Documents, 2007.
[3]  L. Caracoglia and D. Zuo, “Effectiveness of cable networks of various configurations in suppressing stay-cable vibration,” Engineering Structures, vol. 31, no. 12, pp. 2851–2864, 2009.
[4]  L. Caracoglia and N. P. Jones, “Passive hybrid technique for the vibration mitigation of systems of interconnected stays,” Journal of Sound and Vibration, vol. 307, no. 3–5, pp. 849–864, 2007.
[5]  L. Caracoglia and N. P. Jones, “In-plane dynamic behavior of cable networks. Part 1: formulation and basic solutions,” Journal of Sound and Vibration, vol. 279, no. 3–5, pp. 969–991, 2005.
[6]  L. Caracoglia and N. P. Jones, “In-plane dynamic behavior of cable networks. Part 2: prototype prediction and validation,” Journal of Sound and Vibration, vol. 279, no. 3–5, pp. 993–1014, 2005.
[7]  P. G. Papadopoulos, A. Diamantopoulos, P. Lazaridis, H. Xenidis, and C. Karayiannis, “Simplified numerical experiments on the effect of hysteretic damping of cross-ties on cable oscillations,” in 9th International Conference on Computational Structures Technology, Athens, Greece, September 2008.
[8]  P. G. Papadopoulos, J. Arethas, P. Lazaridis, E. Mitsopoulou, and J. Tegos, “A simple method using a truss model for in-plane nonlinear static analysis of a cable-stayed bridge with a plate deck section,” Engineering Structures, vol. 30, no. 1, pp. 42–53, 2008.
[9]  P. G. Papadopoulos, “A simple algorithm for the nonlinear dynamic analysis of networks,” Computers and Structures, vol. 18, no. 1, pp. 1–8, 1984.

Full-Text

Contact Us

service@oalib.com

QQ:3279437679

WhatsApp +8615387084133