Whenever a public bridge has been built or maintained by one or more municipal corporations, and it shall afterwards appear to the commissioners that the care, maintenance and responsibility of said bridge is greater than it is reasonable that the said municipal corporations should bear, the commissioners may enter such bridge upon record as a county bridge, and it shall thereafter be a county bridge in the same manner as if it had originally been so entered on record, if the proper local authorities having the maintenance, supervision and control of such bridge shall tender the same to the said county free and without charge.
16 P.S. § 2656