Whenever a public bridge has been built or maintained by any borough or township, or both, or by any two townships, and used by the public for travel, the county commissioners may take the same as a county bridge whenever the proper authorities having the maintenance, supervision and control of such bridge shall tender the same to said county commissioners free and without charge therefor. Any bridge so taken shall thereafter be maintained and kept in repair as a county bridge.
16 P.S. § 5758