EFFECTIVE NOISE BARRIER SOLUTIONS FOR TXDOT: A FIRST-YEAR PROGRESS REPORT

Studies have shown that motor vehicle noise is a significant national problem in many communities. Construction of traffic noise barriers (sound walls) has been the most often used mechanism to mitigate vehicle noise for residents living next to high density roadways or proposed high density roadways. The purpose of this three-phase research project is to develop guidelines and a design guide for analysis, design, and construction of effective noise barrier systems in Texas. This report provides the progress accomplished in Phase I, which was a literature review and review of current noise barrier design and construction practices in Texas. The report provides an excellent acoustical background on how noise barriers work, and summarizes the current noise analysis software. In Texas, each Texas Department of Transportation (TxDOT) district office is responsible for the design of its noise barriers; consequently, many different designs have been successfully used. Designs include small precast concrete panels on precast Jersey large precast panels, reinforced masonry, cast-in-place concrete, and barriers with safety-shaped bases. Details are provided from interviews with district design engineers. Additional research is in progress on the possible use of a random jagged top to noise barriers that laboratory experiments show to have a 3-8 dB improvement in insertion loss. Additional research is in progress on finite-element analysis of barriers that might receive vehicle impact. This research will continue with Phase II to study the noise barrier systems in use by other states, the acoustical effectiveness of absorptive noise barriers, and software for noise analysis and aesthetic evaluation. Phase III will study parallel noise barrier systems and will develop a design guide for use by TxDOT district offices.