Prior to the performance of any work under a professional, technical or expert services contract awarded by the City, a contractor shall comply with the Workers' Compensation Law, ORS Chapter 656, as it may be amended, and if Workers' Compensation Insurance is required by ORS Chapter 656, shall maintain coverage for all subject workers as defined by ORS Chapter 656, and shall maintain a current, valid certificate of Workers' Compensation Insurance on file with the City Auditor for the entire period during which work is performed under the contract.