1997 年 34 巻 p. 307-317
This paper presents practical methods for predicting and evaluating sound diffraction by plural low noise barriers erected with intervals. First of all, two calculating methods for sound diffraction by the plural barriers of finite length are verified by a model test. Secondly, we propose the section-averaged equivalent continuous A-weighted sound pressure level (SA · LAeq) and the section-averaged insertion loss (SA·IL) as evaluation indices and show through mathematical simulations that the SA·IL depends on the opening ratio of the barriers regardless of the position of the openings. Finally, we also propose a simple practical method for calculating the SA·IL by the low noise barriers.