PITTSBURGH >> Over two dozen river barges broke loose from their moorings and floated down the Ohio River in Pittsburgh, striking one bridge that had already been preemptively closed and damaging a marina, officials said. The boats eventually were pinned to the riverbank or went over a dam downstream, officials said.

Pittsburgh police, fire and emergency medical services responded around 11:25 p.m. Friday to reports of the barges “floating uncontrolled” down the river, Pittsburgh Public Safety said in a statement. The area had been hit by flooding after heavy rains Thursday.

The Sewickly Bridge was struck by a barge a few minutes before 2 p.m. today, the Pennsylvania Department of Transportation said. It “was closed in advance of the strike and will remain closed until our crews complete an inspection,” spokesperson Steve Cowan said.

Officials in Moon Township, which is connected by the bridge to the community of Sewickly, earlier said the span would be temporarily closed “due to unmanned barge passing through.”

Eleven of the 26 barges that broke free were quickly contained to one side by another towing vessel just downstream, said Cmdr. Justin Jolley of the Coast Guard marine safety unit in Pittsburgh. Nine others were collected at the Emsworth lock and dam downstream.

Five or six barges went through the dam. Four ended up just downstream at a lock and dam, while another ended up on the bank of the river and was stabilized. Marine safety units were searching for one barge unaccounted for, Jolley said.

Pittsburgh public safety officials reported damage to Peggy’s Harbor, a marina on the river. The Pittsburgh Post-Gazette reported that the McKees Rocks Bridge was also closed as a precaution but later reopened following inspection.

Twenty-three of the barges were carrying dry cargo, mostly coal, and at least one was loaded with fertilizer, according to the owner, Jolley said. Three were empty. There were no hazardous materials on any of the vessels, the city said.

The Coast Guard put out a broadcast notice to mariners to inform them about the potential hazard, but high water was preventing traffic on the river, Jolley said.

The barges were owned or operated by Campbell Transportation Co., the city’s statement said. Jolley said Coast Guard officials were working with the owner on a salvage plan. Pennsylvania State Police and other agencies were also alerted.

The vulnerability of bridges to strikes from barges and ships came into stark relief last month when a container ship rammed a support of the major Francis Scott Key Bridge in Baltimore, collapsing the span and leading to the deaths or presumptive deaths of six road workers.