An annual report presented to the Road Commission for Oakland County (RCOC) Board of Road Commissioners by the Great Lakes Engineering Group, RCOC’s bridge inspection consultant, on Thursday, Oct. 20, revealed that the agency’s bridges are in fairly decent condition.
According to the report, 61 percent of RCOC’s 107 bridges greater than 20 feet in length are in good condition, while 17 percent are fair, 9 percent are poor and 13 percent are critical.
“We’ve been very aggressive about going after available dollars for bridge preventive maintenance work as well as for bridge replacements,” explained RCOC Board Chairman Ron Fowkes. He noted the Road Commission has completely replaced 19 bridges over the last 11 years and performed preventive maintenance work on 8 bridges in the last two years alone.
Fowkes added that while RCOC would like to bring all its bridges to good condition, it is not worried that any of its bridges are at risk of falling down. “That’s because every bridge greater than 20 feet in length receives a detailed inspection every two years,” he explained.
“At the first sign of deterioration, the frequency of inspections is increased, and continues to increase as deterioration advances. Because of this, it’s highly unlikely that a bridge on our system could advance to the point of being at risk of collapse without us closing it well before that.”
Great Lakes Engineering Group specializes in bridge inspections and has some of the most qualified bridge experts in the state. Bridge inspections involve close examination of the critical superstructure, such as bridge beams, that is under the bridge deck and therefore out of sight. They can involve inspectors in scuba diving gear getting in the water under a bridge to examine under-water elements of the substructure.
“When our inspections indicate a bridge has reached a level of deterioration that affects its ability to carry certain weights, we typically reduce the amount of weight that can legally be driven across the bridge in order to slow the rate of deterioration,” Fowkes said. He added that these restrictions typically don’t impact passenger cars but generally effect commercial trucks.
RCOC expects to perform preventative maintenance on two bridges in 2017: both on 12 Mile over the Rouge River in Southfield. In 2018, RCOC expects to replace one bridge (Wixom Road over the Huron River on the Commerce Township/Milford Township border) and conduct preventative maintenance on three additional bridges. Bridges are selected for replacement or preventive maintenance based on the inspection results.
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