It shall be lawful, and the right is hereby given to the cities of this commonwealth to enter upon, take, use and appropriate private property for the purpose of constructing and maintaining all such piers, abutments, fills, slopes and approaches as shall be found necessary in the erection, construction and maintenance of such bridges as shall be authorized and constructed by such cities, within their corporate limits, over any stream or river which shall separate any parts or portions of such city.
53 P.S. § 2551