Permit Load Model of a Flat Slab Bridge

Alabama Department of Transportation (ALDOT) has an eleven-span flat slab concrete bridge over Jenkins Creek on the northbound side of US Highway 82/231 at milepost 162.56 for which there are no construction drawings or other details that can be used to perform a load rating of the structure. This bridge is approximately 1 mile south of Taylor Road on the south side of Montgomery. The date of construction of the bridge is unknown, but ALDOT's "Bridge Card" for the structure indicates that it was widened by approximately 4 feet in 1930. So, the bridge was built before 1930. Visual inspection of the bridge indicates that the bridge has been widened twice. Details of the bridge widening projects are not available. Currently the bridge carries unrestricted traffic. This is allowed by the American Association of Highway and Transportation Officials (AASHTO's) Manual for Bridge Evaluation (2011) in cases where a reinforced concrete bridge of unknown details has carried unrestricted traffic without developing signs of distress. But, because the structural details of the bridge are unknown, ALDOT cannot perform an analysis to justify issuing a permit to any overweight, non-standard trucks. So, overweight, non-standard trucks are detoured around this bridge. ALDOT would like to have the ability to consider requests for permits on this heavily traveled route.