Precast concrete sound-absorptive walls fix current problems while eliminating future issues.
By the time Dwight D. Eisenhower took office in 1953, momentum for a highway system to connect the entire country was at full steam. In fact, Eisenhower himself favored the plan based on his military experiences.
With the backing of the president, the Interstate Highway System became official in 1956 thanks to the National Interstate and Defense Highways Act. That act, coupled with the ever-increasing reliability of automobiles and Americans’ interest in exploring the country, set the course for a future with more traffic.
What people soon realized is cars and trucks en masse are loud. As a result, sound walls began showing up regularly throughout the ‘60s. Since that time, engineers, manufacturers and designers have developed more effective systems that also bolster aesthetics.
Perhaps the biggest leap in technology, though, has been the use of sound-absorptive walls in place of sound-reflective walls. With reflective walls, sound is simply redirected. As future developments are built, that reflected sound can become an issue. Absorptive walls are porous and eliminate future issues. For a more technical look at the differences, read our articles from the Summer 2014 and Winter 2011 issues of Precast Solutions.
In Madison, Wis., the city and its residents worked together to develop a suitable solution to road noise resulting from significant growth. The need for sound mitigation was particularly great along Verona Road. Together, the Wisconsin Department of Transportation and residents agreed on a precast concrete wall with an architectural finish on both sides featuring a deep-block stone finish with a smooth simulated coping along the top.
Crest Precast, Inc. in La Crescent, Minn., manufactured 33,000 square feet of wall panels. The JBM75® system, created by JBM Solutions Inc., is a proprietary mix design that includes wood fibers to aid in the absorption of unwanted noise. The precast panels achieved a .85 noise reduction coefficient reading in the field.
“Construction of all walls was very straightforward, with little-to-no additional work in the field to fit the panels,” said Dave Gliniecki, P.E., project manager for contractor Zenith Tech, Inc. “The wood fiber textured finish has been shown to be durable to resist damage during transportation or construction handling. (WisDOT) seemed very pleased with the uniform appearance of the finished product.”
Part two of this series will feature projects using sound-absorptive walls in Virginia.