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Show Pipe Arch Bridge. An engineering curiosity, said to be-unique be-unique to this country and t have-only have-only one parallel In Europe, is tlie- pipe arch bridge over the Sudbiirs-riTer Sudbiirs-riTer which carries Boston's water-supply. water-supply. The span is eighty feet, and the steel pipe, seven and one-half feet In diameter rises five and one-half one-half feet above the horizontal at the center. The pressure on the abutments abut-ments when the ipipe is filld Willi water is grrnt and is resisted by a mass of concrete forty feet thick behind be-hind each abutment. Across the-curved the-curved tops runs a hand-railed fait bridge. The steel of the pipe In the-arched the-arched portion is five-eighths of am inch in thickness. |