WASHINGTON TWP., Pa. -

Work to replace a Pennsylvania Turnpike bridge in northern Lehigh County will begin next year, but the job won't be finished until the fall of 2017.

Called the Emerald Bridge, the 56-year-old span carries turnpike traffic over Main Street and Trout Creek in Washington Township.  It is 465 feet long.

The bridge will be replaced with two separate structures. Each new bridge will have three 12-foot travel lanes with 12-foot outside and inside shoulders. The project also involves reconstruction of one mile of roadway.

The Pennsylvania Turnpike Commission has awarded a $34.3 million contract to Trumbull Corp. of Pittsburgh, the low bidder to design and build the new bridge on the Northeast Extension (Interstate 476).

The project will be 100 percent funded by toll dollars, according to the turnpike commission.

The design process, including permitting and right-of-way acquisition, is expected to last about one year with construction to begin in the spring of 2015 and continue through the fall of 2017.

Construction-related activities on I-476 that require lane restrictions and reduced work-zone speeds of 40 mph will  occur only during off-peak hours Mondays through Fridays, weather permitting.

The Emerald Bridge is at milepost A68.53, about  11 miles north of the Lehigh Valley Interchange and seven miles south of the Mahoning Valley Interchange.

The bridge was part of the 73-mile-section of the turnpike's Northeast Extension that opened to traffic on Nov. 7, 1957, between Allentown and Clarks Summit.