Ohio Rev. Code § 315.08
The county engineer shall perform for the county all duties authorized or declared by law to be done by a registered professional engineer or registered surveyor, except those duties described in sections 307.37 and 307.38 and Chapters 343., 6103., and 6117. of the Revised Code. The engineer shall prepare all plans, specifications, details, estimates of cost, and submit forms of contracts for the construction, maintenance, and repair of all bridges, culverts, roads, drains, ditches, roads on county fairgrounds, and other public improvements, except buildings, constructed under the authority of any board within and for the county. The engineer shall not be required to prepare plans, specifications, details, estimates of costs, or forms of contracts for emergency repairs authorized under section 315.13 of the Revised Code, unless the engineer determines them necessary.
R.C. §315.08