Correlation Study on Modal Frequency and Temperature Effects of a Cable-Stayed Bridge Model

Abstract:

In recent years, structural health monitoring has been paid more and more attention in bridge engineering community. Previous researches showed that ambient temperature was one of principal factors affecting structural modal parameters in long-term. In this paper, an experimental study on correlation between dynamic properties of a cable-stayed bridge and its structural temperature was performed under temperature controlled laboratory environment. Using hammer impacting method, a dynamic testing was conducted based on a steel cable-stayed bridge model which had a span layout of 0.9+1.9+0.9m. During the experiment, the first six vertical bending modes under the environmental temperature of 0, 20 and 40°C were identified with the consideration of three kinds of boundary conditions at the deck’s ends as to two degrees of freedom, i.e. the longitudinal translation (UX) and the rotation about the transverse beam (RotZ). The above boundary conditions are UX & RotZ not constrained, UX constrained only and UX & RotZ constrained, attempting to simulate the different conditions of the bridge expansion joints. The efforts were paid to explain the physical mechanism of the results based on the updated FE model. This experimental study indicates a tendency that the frequency of the cable-stayed bridge model decreases with the increase of temperature. And furthermore, the relative difference of frequencies between 0 and 40 °C is affected by boundary conditions; in other words, when the deck is free to expand, the variation of model’s frequencies is smaller than that when the deck is restrained to expand, which is similar to the condition of the bridge’s expansion joints cannot work as normal. This experimental study can give some reference to the research of SHM and damage identification for cable-stayed bridges.

• Periodical: Advanced Materials Research (Volumes 446-449)
• Pages: 3264-3272
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.446-449.3264
• Online since: January 2012
• Authors: Li Min Sun, Yi Zhou, Xue Lian Li
• Keywords: Cable-Stayed Bridge, Experimental Study, Frequency, Structural Health Monitoring (SHM), Temperature

References

[1] L.M. Sun and Z.H. Min: "Temperature Effects on Modal Parameters and Its Experimental Validation", Health Monitoring of Structural and Biological Systems 2010, San Diego, CA, USA, 76502L-13. (2010)

DOI: 10.1117/12.848749

[2] J.F. Liu, Y. Liu and Q.W. Zhang: "Dynamic Properties' Variation of Sutong Bridge under Operational Stage", Proceedings of the 7th International Cable Supported Bridge Operator's Conference, Zhenjiang, China. (2010, In Chinese)

[3] H. GilJong, C. Park and I. Bae: "Upgrading of Structural Health Monitoring System for Cable Supported Bridge in Korea", Proceedings of the 7th International Cable Supported Bridge Operator's Conference, Zhenjiang, China. (2010, In Chinese)

[4] A.Q. Li, Y.L. Ding, Q.G. Fei and C.Q. Miao: Journal of Southeast University (Natural Science Edition), Vol. 37 (2007), p.245. (In Chinese)

[5] K.Q. Fan, Y.Q. Ni and Z.M. Gao: China Journal of Highway and Transport, Vol. 19 (2006), p.67. (In Chinese)

[6] Y. Xia, H. Hao, G. Zanardo and A. Deeks: Engineering Structures, Vol. 28 (2006), p.441.