The Michigan Department of Transportation (MDOT) recently highlighted research by the Center for Innovative Materials Research at Lawrence Technological University on using carbon-fiber post-tensioned cables to extend the service life of box-beam bridges.
The research project led by Dean of Engineering Nabil Grace was the subject of a new Research Spotlight posted by MDOT: http://www.michigan.gov/documents/mdot/MDOT_Spotlight_CFCC_469162_7.pdf?20140919150943
MDOT and local road departments in Michigan often rely on side-by-side box-beam designs because they are low-cost and relatively easy to construct quickly. One drawback is that such bridges are hard to inspect, making it hard to detect potential defects. The new design developed at LTU reduces the inspection problems.
The Research Spotlight report concludes that the new approach could as much as double the service life of box-beam bridges. MDOT has built several bridges with the new design and will continue to gradually expand its use while evaluating its performance.