Calculation methods for sound pressure level behind a building facing an arterial road

摘要

The revised environmental quality standards for noise have adopted L{sub}(Aeq) as an evaluation index in place of L{sub}50 which has been used for a long time. The new standards divide the 'areas facing roads' into the ones adjacent to arterialroads and the others, and give different target values to each of them. Therefore calculating L{sub}(Aeq) of road traffic noise at the positions behind a building becomes increasingly important. This paper presents simple methods for calculating soundpressure level at all the receivers behind a building of rectangular cross-section directly facing the arterial road. The methods which apply the Maekawa's chart to calculation of sound attenuation by a virtual thin barrier take account of both sounddiffraction and reflection, meet the reciprocity and secure the continuity of calculated values in all the combinations of positions of sound sources and receivers. The sound pressure levels at the receivers are calculated by summing the contributionsfrom the paths propagating over the top and the sides of the building. The validity of the methods presented here is verified by comparing the values by the methods with those calculated on a basis of wave acoustics and with those measured through modelexperiments.