Precast barrier rails may shorten the duration of Iowa road projects in the future

20160426_142513This time of year it’s easy to get a little frustrated by road construction, even if it means the road will be improved once the crews are done. The Iowa Department of Transportation is working on several ways to shorten the time work crews are on a job site to decrease motorists’ frustrations and increase the safety for both motorists and workers alike.

One work zone time-saver under development is precast barrier rails, an element of accelerated bridge construction. In traditional construction, the concrete barriers on a highway are formed and poured onsite, usually closing lanes of traffic for days at a time. Under the leadership of Sri Sritharan, researchers at Iowa State University are developing the precast version. This effort is funded by the Florida International University’s University Transportation Center for Accelerated Bridge Construction. Member partners for UTC-ABC include ISU, Florida International University, and the University of Nevada at Reno.

With the precast technology, the barriers are manufactured in segments at an off-site location and brought to the work zone, set into place and connected together. Jim Nelson of the Iowa DOT’s Office of Bridges and Structures, said the new technology is part of the ongoing Accelerate Bridge Construction or ABC initiative. “ABC projects are going on all over the county. Iowa had led the way in several test projects and we’re one of a few states now working on pre-cast barrier rail.”

20160426_143118Sritharan said, “Overall the testing was very successful. We learned a lot and can help with moving the precast barrier concept forward so that field implementation can be done.”

Nelson says safety is always the key element when determining whether the Iowa DOT will use a new technology on an Iowa highway. “There is still some testing that needs to be done on these precast elements,” he said.

The FHWA requires all new products used on the National Highway System (NHS) to be tested using the AASHTO Manual for Assessing Safety Hardware (MASH) crash test criteria. Nelson said, “The static load testing by ISU is a good first step to determining if the precast system will work. MASH may require actual crash testing before these are finally approved for use.”

Once the precast barriers have been proven safe in a test environment, look for them on a roadway near you, saving time and inconvenience in the work zone.  

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