State Highway Administration officials have identified six bridges in Maryland that were built using a similar technique to the one highway experts say appeared to have been the cause of the Connecticut Turnpike bridge collapse June 28 in which three people died.
State officials, under orders from the Federal Highway Administration, say they are examining the bridges but that there is no reason to think they are unsafe, because they have more support than the Connecticut bridge.
Highway officials say the Connecticut accident may have been caused by a pin used to link support spans that was found sheared in half.
The pin connection is a technique designed in the 1950s. It was less expensive than existing methods and allowed for more bridge movement in strong winds, said Earle Freedman, assistant chief engineer in charge of bridge development with the Maryland State Highway Administration.
The SHA began its inspection in early July, starting with the Woodrow Wilson Bridge connecting Maryland and Virginia over the Potomac River, Freedman said.
The Maryland bridges being inspected are the 16th Street bridge over B&O Railroad tracks near Silver Spring; U.S. 50 over the Amtrak railroad tracks near Landover Hills; I-81 over the Potomac in Washington County; and, in Anne Arundel County, U.S. 50 over the Severn River and the Baltimore-Washington Parkway over Stony Run Creek.
Freedman stressed that these bridges are not identical to the one in Connecticut. He said the Maryland bridges are much stronger because they have more girders. The Connecticut bridge had two girders, he said, while Maryland bridges have four to eight. He said if one girder failed, a bridge might sag but would not collapse.