Five tests were conducted on the main (213m) span of the cleddau bridge at milford haven. The bridge was excited by the sudden release of a 32.2 ton (32.72mg) weight from a cable attached to the superstructure at the centre of the span. The resulting dynamic response was recorded using gauges fixed at different positions on the superstructure and piers. The decays of vibration were dominated by the fundamental mode at 0.53hz and interactive effects produced by other modes were relatively small. Values of damping, calculated as an averaged form of logarithmic decrement, varied from 0.043 to 0.059. There was relatively little variation between gauges and the main experimental scatter was from test to test. Damping was approximately constant along the decays and was independent of amplitude of deflection for up to plus or minus 13mm. A limited number of measurements were made of vibrations produced by heavy vehicles during normal trafficking. It was found that the biggest movements were at 1.90hz and involved amplitudes of up to 0.635mm. Measurements were made of wind induced vibrations, but there were very few instances of high winds during the period of measurement and the largest amplitude measured was plus or minus 8.1mm at a wind speed of 20 m/s.

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