Background: The project was undertaken after World War I to maintain clearance for river traffic and to control the elevation of the Allegheny River to prevent flooding. It replaced a suspension bridge that was built in 1884. The Warhol Bridge was the first self-anchored suspension bridge in the United States. It was also the first of the three sister bridges to be constructed.

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The Andy Warhol Bridge will close for more than a year starting next month, adding one more construction zone to an area crowded with orange barrels and traffic backups.

That’s bad news for Bridget Kiener, 20, who commutes daily from her South Side home to her job on the North Shore using the bridge.

“That will be a nightmare,” she said. “I don’t know how else to get home then. I think it’s going to add at least another 30 minutes onto my commute.”

The bridge closure occurs as major PennDOT projects continue to congest roadways in the city’s North Side and routes into Downtown, including Route 65 (Ohio River Boulevard), Liberty Bridge, and starting Monday, the East Ohio Street ramp to northbound Route 28. The city, county and Duquesne Light have traffic-blocking projects under way or starting soon in the area.

Officials said it’s difficult to coordinate road construction projects among the agencies responsible for maintaining the area’s roads.

The Southwestern Pennsylvania Commission, a federally designated metropolitan planning organization, can do only so much, commission spokeswoman Shannon O’Connell said.

“We try to coordinate, but it depends on who owns the infrastructure,” she said.

Allegheny County Department of Public Works spokesman Michael Dillon said the county took other projects into consideration when planning the Andy Warhol Bridge work, but a federal funding time line meant the bridge work couldn’t wait.

Richard Connors, Allegheny County Department of Public Works chief bridge engineer, said it would have been ideal to start earlier in the year.

“In a perfect world, we would want to start in the spring, but we needed approval from different agencies,” he said.

The bridge, at Seventh Street, will close to vehicular and pedestrian traffic starting Aug. 15 for the project, which is expected to last until Nov. 17, 2017. The closure is required for a $25.4 million project, which includes a new concrete deck, structural steel repairs, painting and upgrades to the bridge’s drain system.

The work will affect thousands of motorists and Port Authority of Allegheny County bus riders, likely by increasing traffic on the other two river crossings.

An average of 5,300 vehicles pass over the bridge each day, Dillon said, compared with 7,700 that use the Roberto Clemente Bridge, and the 11,000 vehicles that cross the Rachel Carson Bridge. The Carson Bridge is the recommended detour route for Warhol Bridge users.

Three hundred fifty buses on 12 routes pass over the Andy Warhol Bridge each day, authority spokesman Adam Brandolph said. On weekdays, about 146 inbound buses use the Rachel Carson Bridge. There has been no service on the Roberto Clemente Bridge since 2000 because it always closes during Pirates games, he said.

During the games, a significant flow of traffic leaving the city will need to use the Rachel Carson Bridge. At least that is the plan for the Port Authority, Brandolph said.

“We normally direct all buses over the Rachel Carson Bridge, but there will likely be a secondary detour on a daily or weekly update,” he said. “We’ll have to play it by ear and see how it goes. If everyone is using Ninth Street, we may continue to use it, or we may look for a secondary detour.”

Twenty-three home games will remain on the Pirates’ schedule after the Andy Warhol Bridge closes.

None of those games coincides with Steelers home football games; however, the Pittsburgh Panthers and Pirates will play games on the same days twice in September.

On Sept. 3, the Panthers take on Villanova at 1:30 p.m. at Heinz Field. On Sept. 10, the Panthers face Penn State at noon. The Pirates play at 7:05 p.m. on both days.

Dillon suggests traffic leaving the city should take the David McCullough (16th Street) Bridge or the Fort Duquesne Bridge.

Additional police will be stationed in high-traffic areas Downtown when the bridge first closes, and traffic signals will be retimed, Dillon said.

The bridge closure likely will lead to some traffic backups.

“I imagine the first Pirates game will have a backup, but we’re being proactive,” he said. “We’re also working with the Pirates to see if anything can be changed to close the Roberto Clemente Bridge later to let traffic out.”

Phillip Poupore is a Tribune-Review staff writer. Reach him at 412-320-7820 or ppoupore@tribweb.com.

Renatta Signorini is a Tribune-Review staff reporter. You can contact Renatta at 724-837-5374, rsignorini@tribweb.com or via Twitter .