Design Of Novel Noise Barrier For Highways And Study On The Effect Test

Noise barrier is an economical and effective method of mitigating noise impaction that is common use in the highway. In order to take balance between on the technology of noise barrier,expense and environment ,a new type of noise barrier shall be designed to be effective on mitigating noise impaction ,firm in use ,be harmonious with local landscape . This dissertation introduces and discusses acoustic theory ,designing principal and content for noise barriers. Basing on the example of residential area of CHENGANG –XIWAN ,author systematically analyses and designs some issues of the noise barrier about end value of noise attenuation ,location ,length ,height etc. Disuse tyres and other absorption materials are used and developed to become a new type of noise barrier which can mitigate the traffic noise impaction by reverberation and noise absorption. This dissertation discusses measuring method of standing wave tube which measure absorption coefficients of absorption materials .After analyzing the measuring results ,an absorption material is chosen and used for the noise barrier designing . This dissertation also discusses principal and measuring method of reverberation-chamber which can measure the absorption coefficients of tyre composite noise barrier and perforated –panel and fiberglass noise barrier. According the test results ,the test results are analyzed and compared to validate the new type of noise barrier .With computation of a simulating software, the effect of noise attenuation is predicted for the noise barrier after construction . After explaining the sound absorption principal of reverberation structure and discussing computation method of reverberation frequency,three serials of experiments are made to analyze the spectrum of different reverberation noise barriers. Under shocks of hammer ,three types of noise barrier represent different energy density spectrums according frequency. By mapping the results of frequency ,the tyre noise barrier have capability of reverberation under sound such as traffic noise whose main frequency is 500Hz and near 500Hz and mitigating noise impaction by reverberation .