The Natural Bending Vibration of the Continuous Beam and the Impact Factor of Bridge

Abstract:

The natural frequencies and mode shapes of 2, 3 and 4 spans continuous beam with universal cross section are calculated, and these dynamic parameters of 2 spans continuous beam model are measured. From the analysis and the model test, the locations of the maximum curvatures of the mode shapes are determined, and comparing that with the maximum bending moment of the beam under the action of uniformly distributed load, the selection of the natural frequency of the beam is discussed with the General Code for Design of Highway Bridges and Culverts as the impact factors of the beam is calculated. It is shown from the results of the analysis and the test that, for the impact factor, when the effect of positive bending moment caused by impact force is calculated, the fundamental frequency must be used as shown in the General Code, and the 2^nd or 3^rd frequency must be used when the effect of negative bending moment caused by impact force is calculated. The selection of the frequency should be combined with the mode shape into account for the specific circumstances.

• Periodical: Applied Mechanics and Materials (Volumes 90-93)
• Pages: 1245-1249
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.90-93.1245
• Online since: September 2011
• Authors: Xiang Rong Yuan
• Keywords: Continuous Beam, Impact Factor, Natural Vibration, Vibration Test

References

[1] Department of the transport of P R China: General Code for Design of Highway Bridges and Culverts, Beijing, 2004, China Communications Press.

[2] Liu Xia Ping, Yu Tian Lai and Wang Lan: Bridge Engineering, Beijing, 2005, Science Press.

[3] Song Yi Fan, Dynamics of highway bridge, Beijing, 2000, China Communications press.