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Columbus native develops more advanced way to test bridges


David Miller



Hundreds, thousands even, drive over bridges in Mississippi every day. 


Often, the integrity of those bridges is tested by one man with a "trained ear," listening for pitch changes as a hammer or chain system creates frequencies. 


A Columbus native hopes to change the seemingly archaic way state and federal agencies test bridge stability. 


Ivy Pinion, a Heritage Academy and Mississippi State University graduate, has revived a technology that for the last 10 years was stuck in neutral.  


The automated chain-drag system is a three-wheeled, walk-behind unit that uses sound waves to test the structural integrity of things made of concrete. The information is processed through a computer to create a detailed map of air pockets or voids in the concrete. 


The system was originally developed at MSU in the late 1990s. MSU has owned the patent since then, but three previous licensing holders never commercialized it.  


Pinion, an engineer with Techvation Incorporated in Huntsville, Ala., first contacted the MSU Office of Entrepreneurship Associate Director Chase Kasper about acquiring licensing rights in November. 


By May, Pinion had secured the licensing rights and started taking the steps to move the lab prototype to the market by early 2012.  


"We''re moving quickly to have it on the market by the first quarter," Pinion said. 


All bridges have voids; older ones have more. However, not all structural voids are internal.  


The Mississippi Department of Transportation inspects bridges throughout the state once every two years. Nearly all inspections are done visually, and at the discretion of the inspector, a chain test could follow if flaws are found on the exterior. 


Current technology uses either a manual chain system or a calibrated hammer to create the frequencies, but someone has to manually listen for pitch changes. This method requires someone with a "trained ear." 


"Through the old school method, it''ll locate the area but won''t tell you the extent of the de-lamination or the air pockets that might be inside," MDOT bridge engineer Keith Carr said. "You''ve got to have someone whose extensively trained to listen for it. Over the years, it''s been a trial and error procedure." 


The automated chain-drag system uses chains to simulate an acoustic signal through the concrete, which is listened to through a microphone and processed with a special algorithm. Through this method, changes in frequency or sound are documented in a detailed map of the entire structure tested.  


Since most of the bridges in the Golden Triangle were built in the 1970s when highway expansion started to increase, bridges in the area are in "good" condition, Carr said.  


According to, 94 percent of bridge decks in Columbus are rated excellent, very good or good.  


Starkville has had 10 of its 33 bridges built since 2000; 65 percent of total bridge decks are rated very good, 25 percent good and 10 percent satisfactory. 


"We don''t have to bring in the chains unless an inspector notices a flaw on the exterior," Carr said. "We don''t have to do it too often. 


Though bridges in the area haven''t shown significant wear, Carr admits the lack of an efficient, cost-effective system to see what can''t be seen limits important data. 


"Not every air pocket warrants repair, but this would definitely be something we''re interested in," Carr said. "It looks promising." 


Wednesday, Pinion and Techvation associates did the first of three prototype verification tests on the University Drive bridge over Highway 12 in Starkville. They were originally scheduled to test for three hours but completed the job in a little more than an hour.  


The next test will be Sept. 19 in Jefferson, Mo. Once prototype testing is complete, Techvation will furnish selected transportation departments with a model for data testing.  


Pinion said Techvation will market the technology to state and federal transportation agencies. Pinion hasn''t settled on a price because he''s still working with a consultant to see what the market dictates. The physical device, which is about the width of a lawnmower, will be easy to replicate. But the software that processes the information and produces a map of the tested structure is the "special sauce," Pinion said. 


"I''ll say this, the goal is to market it from a cost-saving perspective," Pinion said. "This is much more simple and can get jobs completed much quicker. In addition to labor and time savings, it is very repeatable."




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