The contractor shall notify the city in advance of the time when they is to commence pouring concrete so that provision may be made for inspection by the city, such notice to be in writing, and any sidewalk placed without such prior notice shall be condemned and is condemned, and the contractor shall have no claim against the owner of the abutting property or against the abutting property for payment on account of such condemned work. (1957 code § 8.12.060(c).)