Ohio Rev. Code § 735.07
The contract referred to by section 735.05 of the Revised Code shall be between the city and the bidder, and the city shall pay the contract price in cash. Where a bonus is offered for completion of a contract prior to a specified date, the department of public service may exact a prorated penalty in like sum for every day of delay beyond a specified date.
When, in the opinion of the director of public service, it becomes necessary, in the prosecution of any work or improvement under contract, to make alterations or modifications in the contract, such alterations or modifications shall only be made upon the order of the director, but such order shall be of no effect until the price to be paid for the work and material or both, under the altered or modified contract, has been agreed upon in writing and signed by the director on behalf of the city and the contractor, and approved by the board of control.
No contractor may recover anything for work or material because of any such alteration or modification unless the contract is made in such manner, nor shall he be allowed or recover for such work and material, or either, more than the agreed price. The law relating to the requiring bids and the awarding of contracts for public buildings, and improvements, so far as it applies, shall remain in full force and effect.
R.C. §735.07