sentences:  The decision was made to extend I-95 north from the New Hampshire Turnpike at Portsmouth and south from the Maine Turnpike in Kittery, and join the roads with a high-speed fixed span over the Piscataqua.Work on the bridge began in 1968 and was completed in 1971, with the I-95 extension to it in Maine completed the following year.Tragedy struck the site about midway through construction.