DONALDSONVILLE — Louisiana highway officials closed a major route over the Mississippi River on Friday, and said it would remain shuttered indefinitely, after a barge-mounted crane crashed into the span and severely damaged a load-bearing beam.

It wasn't known when the Sunshine Bridge might reopen. The Louisiana Department of Transportation and Development said it had a contractor standing by to start repairs but was still evaluating the damage Friday afternoon. Drones flew along and beneath the span to scan for trouble spots.

“Safety is our No.1 concern and we have to ensure the bridge can safely handle traffic before it’s reopened," said Shawn D. Wilson, secretary of the state Department of Transportation and Development.

With the bridge out-of-service, a 90-second drive between the east and west banks of the river became a nearly hourlong journey. Highway officials suggested that motorists use a bridge at Gramercy, 20 miles south, or the ferry at Plaquemine, 28 miles north. The next closest bridge is at Baton Rouge, a 33-mile one-way drive to the north.

The 1.5-mile long span connects communities throughout the state's industrial corridor. Chemical plant workers use the four-lane bridge to reach plants lining the banks of the Mississippi River while other commuters take the bridge to shorten drives among Donaldsonville, Gonzales and Baton Rouge.  

Rodney Mallett, a DOTD spokesman, said that one possibility for reopening the bridge could include having only some lanes operating until full repairs could be made. 

From public school workers and students who live, work or attend school on opposites of the river, to plant workers and Donaldsonville residents, the bridge is a key link in the daily lives of tens of thousands.

The bridge, which is in St. James Parish, provides the quickest link between Donaldsonville in Ascension Parish, on the west side of the river, and Baton Rouge and Gonzales on the east. It carried nearly 23,000 vehicles a day in 2015, according to the most recent data available from DOTD. 

Residents were uncomfortable with the uncertainty. 

Willie Joseph, 72, of Donaldsonville, was talking with other men at lunch Friday at the Popingo's gas station on La. 70 at the foot of the bridge about the closure and the loss in recent years of other state-run ferries on the river. Joseph said it would be difficult to remain on the west bank for all his day-to-day needs while the bridge remains closed.

"A lot of stuff we had in Donaldsonville moved over on that side," Joseph said.  

"Yep," added Bobby Bell, 56, also of Donaldsonville. "Moved it from the west and moved to the east bank side. Everything you need, you got to go to the east bank side."

The closure also is happening as the annual sugar cane harvest is cranking into gear, when 18-wheelers haul trailers carrying large metal, mesh baskets laden with cut sugar cane to the mill.

Jim Simon, manager of the American Sugar Cane League, said the closure will affect sugarcane deliveries during the harvest.

"Growers on the east bank of the Mississippi River, especially in the Sorrento area, will have a longer route for cane delivery," Simon said in a statement. 

He said the league and the sugar cane mills would be working with DOTD to minimize the impact of the closure. 

Marquette Transportation, based in Kentucky, operated the towboat that ran the crane barge into the bridge Friday. Marquette is the same company that was operating the towboat that crashed barges into Mardi Gras World in New Orleans this year, an accident that is still being investigated by federal officials. 

Marquette Transportation President Damon Judd said in a statement Friday afternoon that the collision happened shortly before 2 a.m. He said there were no injuries and "no impact to the environment." 

"We are taking this matter very seriously and are actively working with the Coast Guard and the LA DOT to complete the investigation and assess the damage to the bridge and required repairs," he said. 

St. James Parish Sheriff Willy Martin Jr. said Friday morning a crane on a barge was in the "up" position when it hit the bridge.

The boat, which DOTD officials said was moving upriver when it hit the bridge, appeared to have been wedged under the bridge, but was removed Friday morning. 

DOTD's Mallett said the damage was limited to the southwest side of the bridge, or downstream side on the bridge's western side.

Photos supplied by DOTD showed a major horizontal beam along the side of the bridge that had been crumpled, with its bottom plate dangling over the river. Additional photos taken by The Advocate at the scene Friday appear also to show a diagonal crossbeam beneath the bridge also showing signs of damage.

The Sunshine Bridge was dedicated 54 years ago Friday in a ceremony attended by highway officials, congressmen and then-Gov. Jimmie Davis, who more than two decades earlier had recorded the song "You Are My Sunshine." A bridge management plan at the highway department's website says Davis' support for the bridge was so strong that the span came to be known as the Sunshine Bridge.

At the time the Sunshine Bridge opened, it was the only bridge over the Mississippi River between Baton Rouge and the New Orleans area.

Start times for all five Donaldsonville public schools in Ascension Parish were delayed one hour Friday morning due to the bridge closure to allow extra time for staff to get to work, the school system said.

Jackie Tisdell, spokeswoman for the system, said the delayed started help the schools get through Friday.

Tisdell said many teachers and staff who work on the west bank live on the east bank while many west bank students participate in school choice and other programs on the east bank.

The system has fall break Monday and Tuesday, but she said school officials would be monitoring updates on the bridge and planning for the possibility of a more extended closure, if one is needed.

Advocate staff writer Sam Karlin contributed to this report.

Follow David J. Mitchell on Twitter, @NewsieDave.