53 Pa. Stat. § 2581
Whenever any city of this commonwealth shall be divided or separated in any of its territorial sections or parts by intervening rivers or streams of water it shall be lawful, and the right is given to such city or cities, to purchase, enter upon, take, use, hold and appropriate such bridge or bridges, together with the approaches and appurtenances thereto, lying within the corporate limits of such cities as shall have been erected and now in use over such rivers or streams of water so dividing and separating the sections or parts aforesaid. Whenever the councils of such cities shall determine upon the purchase, appropriation or condemnation of such bridge or bridges, approaches and appurtenances, it shall be so expressed by ordinance or joint resolution of such councils.
53 P.S. § 2581