HARRISBURG — Eleven bridges in Butler County will be replaced under a new state bridge program.

The state Department of Transportation has finalized its $899 million Rapid Bridge Replacement Project contract that will replace 558 bridges across the state, including the 11 in the county.

“We have a signed contract completed, and the Plenary Walsh Keystone Partners team has already begun preparing for construction of these bridges,” said PennDOT secretary Barry Schoch in a news release. “This is an important milestone in the state’s most ambitious public-private partnership initiative to date.”

Construction will begin this summer, the release said. All the bridges must be replaced within 36 months.

The bridges in the county to be replaced are:

• Zelienople borough bridge carrying Route 68 over Glade Run in Zelienople

• Route 308 bridge near Rider Church Road over a tributary of Stone Run in Center Township

• Freeport Road bridge near Caldwell Drive over a tributary of Thorn Creek in Jefferson Township

• Bonniebrook Road bridge near Ringneck Lane over Bonnie Brook in Summit Township

• Saxonburg Boulevard over Bull Creek in Clinton Township

• McCalmont Road over Connoquenessing Creek in Butler Township

• Brownsdale Road over Glade Run in Forward Township

• Cruikshank Road over a tributary of Glade Run in Middlesex Township

• Seneca School Road over Connoquenessing Creek in Jackson Township

• Thompsontown Road bridge south of Queen Junction Road over B&LE rail tracks in Clay Township

• Route 19 southbound ramp over Route 19 northbound in Jackson Township

PennDOT in October picked Plenary Walsh and its team of 11 subcontractors to lead the project.

The team will manage the bridges’ design, construction and maintenance for 25 years after construction under the public-private partnership contract.

It also is responsible for getting the capital for construction. PennDOT will maintain ownership of the bridges.

The contract will create savings for the state, allow PennDOT to replace the bridges more quickly than under the agency’s traditional model, the news release said.

The average project cost per bridge is $1.6 million. Through PennDOT’s standard process, the cost to build and to maintain a bridge would average more than $2 million, the release said.