Work will begin this week on the first two bridges in Butler County that will be replaced as part of the state's Rapid Bridge Replacement program.

The Saxonburg Boulevard bridge over Bull Creek in Clinton Township will close today. The bridge was built in 1929 and averages 2,153 vehicles per day. Traffic will be detoured to Ekastown Road, Lardintown Road, Millerstown-Culmerville Road and back to Saxonburg Boulevard.

The detour will be in place until mid-August.

The West Cruickshank Road bridge over a tributary of Glade Run in Middlesex Township will close Wednesday. That bridge, built in 1987, carries 1,060 vehicles per day.

Traffic will be detoured to Pittsburgh Road, Brownsdale Road and Three Degree Road until mid-August.

These two bridges are the first of four to be replaced in the county this year. Another seven will be replaced in 2016 and 2017.

The bridge replacements are part of the Rapid Bridge Replacement Project, a public-private partnership between the state Department of Transportation and Plenary Walsh Keystone Partners, which will finance, design, replace and maintain the bridges for 25 years.

In other state road project, shoulder work will begin today on Route 28 between the Allegheny and Butler county line and Iron Bridge Road in Armstrong County.

The right lane in both directions will be restricted during work hours.

Traffic on July 6 will shift to the right lane to facilitate milling, patching, and paving of the road.

The $2.1 million resurfacing project is being done by Derry Construction and is expected to be completed in October.