911.33. Maintenance.
   The acceptance of any defective material or faulty structure by the City shall not relieve the contractor of the responsibility of replacing at his own expense defective walks or driveways, constructed by the contractor or his subcontractor. All such replacement work shall be started not later than ten days after being so instructed in writing by the Commissioner. Full or partial payment by the City shall not be construed to mean that the work performed is acceptable to the City. Final acceptance by the City of all work performed under this contract shall not extend more than six months beyond final construction operations.
   At the discretion of the Director, a sum of money equivalent to five percent of the total cost of the work performed may be retained by the City until final acceptance of all work performed, which final acceptance may be six months from last construction operation. This money to be retained by the City shall be held as security for the work of the replacement of such defective walk or driveway as is found to be the responsibility of the contractor.
(1952 Code § 7-4-40)