Dynamic Field Tests and Studies on Vibrational Characteristics of Long-Span Suspension Bridges

Abstract

To evaluate the wind resistance of suspension bridge, it would be necessary to know the vibrational characteristics, such as natural frequency, mode shape and structural damping, of actual bridge. Some dynamic field tests using two special vibrators were conducted at the Ohnaruto Bridge, the Ohshima Bridge and the Minami Bisan-Seto Bridge. At the tests, the vibration of large amplitude was excited, and some interesting vibrational properties as regards natural frequencies and damping values were obtained. This paper describes the test results and some studies.

Extracting Bridge Frequencies From the Dynamic Response of a Passing Vehicle

“…The measurement may be conducted with the on-going traffic remaining uninterrupted or partially terminated (McLamore et al 1971;Abdel-Ghaffar et al 1978). For the case where the traffic can be temporarily terminated for experiment or before a bridge is opened to the traffic, either an ambient vibration test with no on-going traffic (Farrar and James III 1997, Fujino et al 2000, Chang et al 2001, an impact test Reid 1982, Huang et al 1999) or a forced vibration test (Okauchi et al 1992, Maragakis et al 1998 can be conducted on the bridge for the purpose of measuring the frequencies of vibration. For structures that are susceptible to wind loads, such as cable-stayed and suspension bridges, field measurements aimed at wind-induced vibrations were also conducted (Brownjohn et al 1994).…”