Author(s): Pedersen Torben Holm, Finne Per, Hansen Morten Bording
Vehicles driving over expansion joints on bridges generate impulsive noise additional to the ordinary vehicle pass-by noise. Neighbours to bridges have complained about annoyance from the many thousands of impulsive sounds 24/7, yet there is no tradition for taking the impulsive sounds into account when measuring or calculating road traffic noise.\nFor other types of noise – e.g. industrial noise – LAeq is adjusted with a penalty for prominent impulses. This paper describes measurements and analysis of the impulses from the joints according to the impulse prominence method described in Nordtest Acou 112 and British Standard 4142. Measurements were made before and after improvements of the joints and the road surface. Listening tests with 18 assessors on 64 samples of the impulses were also performed. From the measurements and listening tests it is concluded that the method can be used to quantify the impact on the environment of the impulses from the bridge expansion joints. The procedure is sensitive enough to detect the improvement of the expansion joints and there is high correlation between the physical prominence metric, P and the assessments of the prominence in the listening test (R2 = 0.95 for average values).
Name: Mr Per Finne