Noise assessment of expansion joints built perpendicularly and angled in the direction of traffic. Measurement method: Case study

Although expansion joints are an essential element of bridge infrastructure, they cause huge noise problems. Expansion joints can be structured differently whilst also being able to be installed differently. This article presents a case study on expansion joints installed perpendicularly and at an angle to the direction of traffic. It appears that the installation method affects the overall level of sound produced. Differences between diagonal and perpendicular constructions in the direction of traffic reach up to 2.9 dB. This value approximately corresponds to a doubling of the level of noise. The paper also presents a Type B uncertainty assessment for a Class I acoustic metre. The separation of upper and lower bounds of uncertainty is a particularly interesting result. In doing so, it was noted that the interval in which the true value of the measurement is located is asymmetrical. In the case of a type B uncertainty analysis, an upper limit on the expanded uncertainty of U_B,95⁺=1.12dB and a lower limit of U_B,95^-=-1.22dB.