All sidewalks shall be laid to conform to the established grade of the street and shall slope so as to coincide with the following described line: beginning at the top of the curb at the established grade and extending thence to the fence line or property line at an incline upward from the curb the rate of three-eighths (3/8) of an inch for each foot. At street intersections, sidewalks shall be ramped from normal grade to street to provide for handicapped and bicycle use.