All sidewalks within the city shall be constructed in accordance with the following specifications.
(A) All walks must be at least four feet in width unless a different width is approved by the Superintendent.
(B) On all clay soil the trench shall be excavated to a depth of eight inches below the established grade and then filled with gravel or good filling dirt, free from clay, to a depth of four inches. Where the top soil is not clay, the trench shall be excavated to a depth of four inches below the established grade and no foundation shall be required.
(C) Forms shall be of wood or metal, straight and free from warp and of sufficient strength to resist springing. Forms shall be used to the full depth of the concrete and shall be so installed as to provide a transverse slope to one-quarter inch per foot toward the street.
(D) In all new construction, where practicable, the sidewalk grade shall be established at not less than three inches nor more than six inches above the grade of the top of the curb.
(E) Sidewalks shall be constructed of thoroughly mixed concrete of a minimum thickness of four inches at all points except for driveways where the minimum thickness shall be six inches. All concrete used shall consist of one part cement to two parts very clean, sharp sand and two and one-half parts clean, hard gravel or crushed stone, well graded from one-quarter inch to one inch in size or transit mix of a mixture approved by the Superintendent.
(F) All surfaces shall be finished to a true contour and granular surface.
(G) One-half inch expansion joints shall be provided at intervals of approximately 25 feet and wherever the walk abuts a curb or another walk or building. Joining materials shall extend from the surface of the subgrade, shall be at right angles to the sidewalk surface and shall extend the full width of the walk. Surface edges of each slab shall be rounded to a one-quarter inch radius. Markings shall be exactly at cuts between slabs.
(1979 Code, § 4.44)