VERONA – Maine Department of Transportation engineers have discovered more deterioration than anticipated in a section of one of the main cables on the Waldo-Hancock Bridge.
According to DOT’s resident engineer Phil Roberts, a recent inspection of a section of the south-side main cable showed that all of the wires in one section of one of the 37 strands that make up the cable were broken.
The discovery does not change the bridge’s positive safety rating, Roberts said, and will not affect the flow of traffic across the bridge.
“I haven’t seen enough visual damage to say that the safety factor has gone any lower,” he said.
That could change, he said, if further inspections uncover significant deterioration in other sections of the bridge. Suspension bridge experts from Parsons Transportation Group, the successor company to the designers of the bridge, have been called in and are now inspecting that section of bridge.
“If they come up with a lower safety factor, we may want to do something,” Roberts said.
The department will increase efforts to enforce the 500-foot spacing for trucks that the DOT has posted for the bridge, Roberts said. Heavy traffic fatigues cables and can shorten the life of the bridge, but does not affect the overall safety rating of the bridge.
The department called Parsons engineers last fall when they discovered more deterioration than anticipated on the bridge’s north cable. Parsons’ independent study determined that while the bridge remained safe for normal travel, the deterioration in the cables had shortened its useful life to six to eight years.
Parsons’ engineers are already looking at the 25-foot section of the south cable in question, Roberts said.
Each main cable consists of 37 steel strands arranged in a hexagonal spiral. Each strand, in turn, is made of 37 wires, making a total of 1,369 wires in each cable.
The initial visual inspection last week showed that the section of the strand appeared to have 26 broken wires.
“This indicates that the bridge was already essentially nonfunctional at this location, [that it was] not supporting the bridge in any real way,” Roberts said. “Further examination showed that all 37 wires in that strand were broken.”
The DOT has begun a federal process to consider new options for the bridge, including construction of a new bridge near the same location. Initial estimates have indicated that constructing a new bridge could cost between $25 million and $39 million. Those estimates do not include engineering and design costs.
The federal process, guided by the National Environmental Policy Act, requires that the department considers repairing the existing bridge as one of the options, and also requires that local issues be considered. The department plans to meet with local residents to discuss the process this summer.