DOVER, Del. — Delaware's transportation secretary ordered immediate inspections of major bridges in the state on Thursday to see if they might have any problems similar to an interstate bypass that had to close in Wilmington.
Delaware Department of Transportation Secretary Shailen Bhatt also told The Associated Press that his agency was checking under the bridges to make sure the state's property is properly marked.
The action comes after the Interstate 495 bridge was closed because of tilting support columns. The bridge, a bypass that helps alleviate congestion on I-95 and normally carries about 90,000 vehicles daily, has been closed since Monday, snarling traffic on the crucial north-south artery. It will be at least several weeks before it is reopened.
Officials suspect that a large mound of dirt dumped next to the bridge over several years shifted the ground underneath the span and caused the columns to tilt. Bhatt said at least part of the pile was on the state's property.
He said inspectors will first look at bridges of similar design in similar soils.
"I want eyes on all those bridges immediately," he told the AP. "We've literally got folks going out today. This is something that folks will be working around the clock."
In all, there are 1,600 bridges in Delaware, including 91 that are on interstate highways. Bhatt said he couldn't immediately say exactly how many bridges would be inspected or how long it would take.
The disappearance of a fence that cordoned off the state's property underneath the I-495 bridge has exposed a possible gap in the state's inspection program, he said.
"We need to get an inventory of all of our bridges and make sure right of way fencing is intact, and it needs to be part of our two-year inspections. If it isn't, it needs to be," he said.
The Federal Highway Administration does not ask states to examine government property around bridges as part of its guidelines for inspections every two years, an agency spokesman said.
Bhatt said he doesn't know what happened to the fence. The agency so far has not contacted law enforcement.
"We're going to determine when and who took it down," he said.
In light of the Delaware trouble, Maine transportation department officials said regional offices were alerted to keeping an eye out for dumping near bridges, but there were no plans for extra inspections. About a half-dozen other states also said they did not plan special checks.
Tripp Shenton, who chairs the Department of Civil and Environmental Engineering at the University of Delaware, said that while it's rare for bridges to be damaged by debris on the ground, inspectors probably should be instructed to note anything unusual. In 1996, a large pile of tires caught fire beneath a bridge on I-95 in Philadelphia, damaging the span and closing it briefly.
Gov. Jack Markell, who planned to visit the Delaware bridge later Thursday, praised the engineer who first reported the potential problem to state officials last week. The engineer, an employee of a private company on the site for an unrelated project, saw cracking in the soil around the dirt pile and then spotted the leaning columns.
"He was highly observant that something didn't look quite right," Markell said.
The contractor who dumped the dirt is working with state officials to remove it. He was allowed to use the site under an arrangement with a company that leases land next to the bridge.
Officials have said a system to shore up and brace the bridge will have to be designed, which will take weeks. State officials do not have an estimated price tag for the repairs.