DOVER, Del. — The emergency closure of an interstate bridge in Delaware created heavier-than-normal traffic conditions Tuesday for motorists on Interstate 95, a major East Coast artery.
Morning rush hour on I-95 through Wilmington, Delaware, was slower than usual after the I-495 bridge over the Christina River was closed Monday because four supporting columns were tilting. No major problems were reported, however, and traffic was flowing in both directions.
The I-495 bridge normally carries about 90,000 vehicles a day, carrying traffic around Wilmington and freight trucks to the port of Wilmington. The closing forced more traffic onto I-95, which runs through downtown Wilmington and already is heavily congested during the morning and afternoon rush hours.
State transportation officials, who placed tilt sensors on the bridge columns, planned to provide an update on the bridge closure Tuesday afternoon.
Meanwhile, Delaware officials put up message boards and were working with their counterparts in surrounding states to help get the word out to motorists.
"We're basically letting from Florida to Maine know that this issue is going on in Delaware so that trucking interests can be made aware," Delaware Transportation Secretary Shailen Bhatt said Monday evening.
"You can't take 90,000 vehicles and just shift them onto 95 and not expect to have an impact," Bhatt added. "This is an important artery for the Northeast."
Bhatt suggested that motorists traveling south from New York may want to stay on the New Jersey Turnpike rather than getting on I-95, crossing into Delaware over the Delaware Memorial Bridge south of Wilmington and then getting back on I-95. Similarly, motorists traveling north can stay on I-95 through Wilmington or take I-295 into New Jersey and bypass northern Delaware.
Officials said I-495 will be closed northbound at Terminal Avenue, which leads to the port. Southbound traffic on I-495 would be closed at the Pennsylvania state line, with traffic diverted onto I-95. Southbound port traffic was being directed to I-295 east and then to Delaware 9 north to the port.
Officials said the four columns on the south bank of the river are tilted by as much as 2.4 degrees, or 4 percent, from vertical. The bridge will be closed in both directions until officials can determine what caused the tilt and what must be done to address it.
"The whole bridge will be re-inspected," said Rob McCleary, chief engineer for the Delaware Department of Transportation.
Workers placed sensors on the four columns Monday to help engineers determine whether they are still shifting. Bhatt said officials should have data by Tuesday afternoon that will tell them whether the bridge is still moving. Crews have excavated around some columns and were checking soil beneath the columns.
Delaware transportation officials said the agency got a report late Friday from an engineering firm working on an unrelated project about a possible bridge problem and dispatched an inspection team Monday morning.
"It didn't come to us as like an emergency call," Bhatt said, explaining why a team wasn't sent earlier.
Officials said the main span of the bridge over the water is considered "fracture critical," meaning that failure of one element could result in failure of the entire bridge, which consists of a concrete deck on steel beams supported by 37 reinforced concrete columns. However, the tilting columns in question support a different area of the 38-span bridge.
"The main span is not what's in question here," McCleary said.
Built in 1974, the bridge is scheduled for inspection ever two years and was last inspected in October 2012.