Investigation of the structural failure of plywood noise barriers

Abstract

This project aims to provide improvements to ply wood noise barriers as well as other types of barriers by evaluating air-borne vibrations from traffic and its effects on the structure and propose ways to minimize it. The objective of the study was to determine what could cause instability in noise barrier structure, as well as the comparison on the effects of different noise barriers. This investigation was carried out using certified acoustics equipment, and variety of locations. Testing of plywood, steel and concrete barriers were conducted at different locations. Results for plywood indicate that most vibration or acceleration recorded in the whole barrier were recorded at the top panel with less acceleration recorded in middle panel and smallest amount recorded near the ground. All results had very significant fluctuations of amplitude. Autospectrum analysis conducted on the results indicated that most of the fluctuations of the panel happened within low frequency noise range. Steel barrier results indicate as with plywood that most vibration or acceleration recorded in the whole barrier were recorded at the top panel with less acceleration recorded in middle panel and smallest amount recorded near the ground. All results had very significant fluctuations of amplitude. Autospectrum analysis conducted on the results indicated that higher frequency noise has also very significant effect on barrier fluctuations as well as low frequency range. Concrete barrier results on other hand indicate that most vibration or acceleration recorded in the whole barrier were recorded at the top panel with less acceleration recorded in middle panel and significant amount recorded near the ground. Compared to other barriers fluctuations are much smaller. Autospectrum analysis conducted on the results indicated that low frequency noise range has predominant effect on the barrier fluctuations. It was found that different types of noise barriers behave differently under continues low frequency noise application. In order to investigate and fully comprehend structural instability in noise barriers these tests are vital to the design and construction. However, further investigations were highly recommended and should be carried out to understand more structural properties of noise barriers.