PITTSBURGH — Two remaining spans of a nearly 60-year-old bridge that once took the Pennsylvania Turnpike across the Allegheny River will be demolished on Friday.

The main span of the bridge in Harmar Township was imploded July 13 using 200 pounds of explosives.

On Friday, a 268-foot span on the western side of the river will be imploded and fall into a back channel of the river. A 213-foot span on the east side of the river will fall on land.