5 ILCS 315/8

The collective bargaining agreement negotiated between the employer and the exclusive representative shall contain a grievance resolution procedure which shall apply to all employees in the bargaining unit and shall provide for final and binding arbitration of disputes concerning the administration or interpretation of the agreement unless mutually agreed otherwise. Any agreement containing a final and binding arbitration provision shall also contain a provision prohibiting strikes for the duration of the agreement. The grievance and arbitration provisions of any collective bargaining agreement shall be subject to the Illinois "Uniform Arbitration Act". The costs of such arbitration shall be borne equally by the employer and the employee organization.