Potential Flaw Is Found in Design of Fallen Bridge

Potential Flaw Is Found in Design of Fallen Bridge - New York Times: "Investigators have found what may be a design flaw in the bridge that collapsed here a week ago, in the steel parts that connect girders, raising safety concerns for other bridges around the country, federal officials said today.... Crews were doing work on the deck of the Interstate 35W bridge when it gave way, hurling rush-hour traffic into the Mississippi River and killing at least five people.... Federal authorities indicated that one added stress on the gusset plates may have been the weight of construction equipment and nearly 100 tons of gravel on the bridge, where maintenance work was proceeding when the collapse occurred. A construction crew had removed part of the deck with 45-pound jack hammers, in preparation for replacing the 2-inch top layer, and that may also have altered the stresses on the bridge, some experts said."