The State Highway Department shall have power to prepare plans for and to rebuild all county bridges, at the expense of the Commonwealth, when such bridges across rivers are located on State Highway routes, or connect two State Highway routes, connect two or more counties, and have been heretofore destroyed by fire.
Any such bridge so destroyed by fire shall be rebuilt by the State Highway Department in accordance with provisions of existing laws providing for the rebuilding by the Commonwealth of county bridges destroyed by fire or wind storm.
36 P.S. § 3111