CTR’s Transparent Sound Wall Project Wins TxDOT Award
Each year TxDOT’s Environmental Affairs Division recognizes departmental projects that meet TxDOT’s transportation goals while also protecting the environment by bestowing the Environmental Achievement Awards (EAA). To be eligible for an EAA, the exemplary project must both enhance the natural and human environment and arise from district initiative (rather than from a state mandate). CTR is proud to announce that the 2014 EAA goes to a project in which one of our researchers played an integral part.
Ten years in the making, this project involved installing Texas’s first transparent noise wall along a section of IH 30 in Dallas, preserving the view for residents while also decreasing the noise from the increasingly busy highway.
This truly collaborative project involved engineers from TxDOT’s Dallas District, the Kessler Park Neighborhood Association, TxDOT’s Research and Technology Implementation Office, material vendors, and CTR researcher Dr. Manuel Trevino, a noted pavement expert who contributed his considerable expertise in tire-pavement interaction—a key component to be addressed when looking to decrease traffic noise. Former TxDOT Director Phil Wilson approved this pilot project to assess the life cycle costs of acrylic panels used as lightweight sound barriers.
Many of the Kessler Park Neighborhood homes were constructed over 50 years ago—well before the traffic noise analysis requirements instituted in 1970. The traffic on IH 30 has grown along with the rest of Dallas, affecting the nearby neighborhood and park, which features a popular running trail. To effectively diminish the traffic rumble, the existing 8-foot-high concrete barrier needed to be extended to 18 feet. However, the barrier’s foundation couldn’t support the weight of that much additional concrete (not to mention the unfortunate visual impact for the neighborhood).
To help create the optimal sound design, Dr. Trevino performed a Traffic Noise Model analysis to evaluate the noise impacts for existing and future traffic conditions, providing a year’s worth of ambient noise readings. He also investigated the use of transparent noise walls in other states to identify any practical lessons that would benefit this installation. The project team considered various transparent materials before selecting an acrylic panel that is warrantied for 30 years and has an expected useful life of at least 50 years. Working at night, TxDOT crews completed the installation of this 2,500-foot-long section in only 45 days.
Dr. Trevino took noise measurements at numerous neighborhood locations before and after the wall’s installation and found a significant overall difference in the noise levels. Neighborhood residents were pleased with the noticeable decrease in traffic noise, particularly since the acrylic panels also preserved the view of the park and the Dallas skyline.
In September, the Noise Analysis and Abatement Coordinator for TxDOT’s Dallas District, George Reeves, presented the project at the TxDOT Environmental Affairs Conference in Galveston. A project team member and 26-year TxDOT veteran, Mr. Reeves notes that these panels, at one-tenth the weight of concrete, are ideal for bridge structures where view preservation is important. He reports that the use of these panels has been characterized as “thinking out of the concrete box.” The work completed represents Phase I of the project; Phase II will begin in about three years, after completion of IH-30 Horseshoe project.
The Environmental Affairs Division also named a runner-up and honorable mention for this year’s EAA. The runner-up project involved reconstructing the bridge at CR 340 and the San Saba River in TxDOT’s Brownwood District, which required the relocation of the resident freshwater mussel population. TxDOT worked with the Texas Parks and Wildlife Department and the Texas A&M Institute for Renewable Natural Resources to relocate and monitor the mussels from the project area. The honorable mention went to the Lacy Road 4 Piney Creek Bridge Project, which rehabilitated a Depression-Era masonry bridge in the Davy Crockett National Forest. Lufkin District personnel used innovative techniques to retain the structure’s historic feel while increasing the load rating.
[* UPDATE, January 16,2015: Details about this project are covered under TxDOT Research Project 0-6804 and the first technical report is expected to be published in 2015.]