[Adopted 9-27-1937 by Ord. No. 55]
A. 
Forms shall be of lumber two inches thick or of steel of equal strength, except on curves, where flexible strips may be used.
B. 
They shall be held rigidly in place by stakes or braces with top edges at true line and grade given by the Engineer. Ends of the adjoining forms shall be flush.
C. 
The forms shall be set to give the walk a slope toward the curb of 1/4 inch per foot of width.
A. 
Where division plates are used, they shall be of one-eighth-inch steel, as wide as the depth of the slab and as long as the width of the walk.
B. 
Forms and division plates shall be thoroughly cleaned and oiled each time before they are used.
A. 
That portion of the ground surface directly beneath the slab shall be called the "subgrade."
B. 
All soft and spongy material in the subgrade shall be removed and replaced with suitable material. Fills shall be compacted in layers, not exceeding six inches. The whole subgrade shall be thoroughly and uniformly compacted to a firm surface having as nearly as possible a uniform bearing power.
C. 
A template, resting upon the side forms and having its lower edge at the exact elevation of the subgrade, shall be drawn along the forms before any concrete is laid. Any high places in the subgrade shall be removed so that the template will pass over without being raised off the side forms or being tipped at an angle to the sidewalk surface.
D. 
The subgrade shall be damp but not muddy when concrete is placed upon it.
Where, in the opinion of the Engineer, it is considered necessary to save the walk from damage by frost action, drains of four-inch tile shall be laid to the lines and grades given by the Engineer.
A. 
The sidewalk, in residential areas, shall consist of one four-inch course of concrete in the proportion of one part portland cement, two and 1/2 parts of fine aggregate and four parts of coarse aggregate. All materials shall be accurately measured in a manner approved by the Engineer.
B. 
All sidewalks shall be at least four feet wide.
C. 
Sidewalks in areas designated or zoned as business property shall be at least five inches thick, of the above-mentioned proportions.
A. 
The ingredients of the concrete shall be thoroughly mixed until each particle of fine aggregate is coated with cement and each particle of coarse aggregate is coated with mortar.
B. 
Where a mechanical mixer is used it shall be of an approved batch type. Each batch shall be mixed at least one minute from the time all the materials, including water, are in the drum, until the beginning of the discharge.
C. 
Consistency of the mixed concrete shall be such that no separation of the ingredients takes place and some tamping is necessary to bring the mortar to the surface.
A. 
The freshly mixed concrete shall be placed immediately on the prepared subgrade. It shall then be struck off and tamped with a straightedge template, resting upon the side forms and advanced with a crosswise sawing motion.
B. 
It shall then be rolled with a light sheet-iron roller, weighing approximately one pound per linear inch of surface contact, and floated with a wooden float until the surface has a true contour and the concrete is thoroughly compacted.
C. 
The placing of concrete shall not be suspended for 45 minutes or longer except at the end of a slab.
D. 
No concrete shall be placed on a frozen subgrade or when the temperature is, or is liable to be within 24 hours, below 35º F., except with the written permission of the Engineer or Commissioner of Public Works.
A. 
The walk shall be cut into separate rectangular slabs. No plain concrete slab shall be longer than six feet on any one side.
B. 
Where division plates have been used, they shall be removed after the concrete has hardened sufficiently to avoid breaking the edges or corners of the slabs.
C. 
Where the division plates have not been used, the partially set concrete shall be cut through the subgrade. Care shall be taken to make the cut at right angles to the surface of the sidewalk.
D. 
The surface edges of each slab shall be rounded to a radius of about 1/4 inch. Markings shall be exactly at cuts between slabs.
Expansion joints shall be extended from the surface to the subgrade and be truly at right angles to the sidewalk surface. They shall be placed as follows:
A. 
At or near all places where the sidewalk line intersects a curbline or other sidewalk, a one-inch expansion joint shall be made at right angles to the center line of the walk.
B. 
A one-half-inch expansion joint shall be made across the walk at approximately fifty-foot intervals.
A. 
As soon as the concrete has set sufficiently, it shall be sprinkled and kept moist for 48 hours.
B. 
The contractor shall protect the concrete from damage by rain, pedestrians and animals, with suitable covers and barricades and by red lights at night.[1]
[1]
Editor's Note: For additional regulations on street obstructions, see Art. VII of this chapter.
C. 
The foregoing specifications concerning terms, materials, forms, subgrade, draining, subbase, mixing, placing, finishing, jointing and curbing shall govern the construction of two-course sidewalks, except as noted below.
A. 
Two-course sidewalks, in residential areas, shall consist of a base 3 1/4 inches thick, composed of concrete in the proportions of one part portland cement, three parts fine aggregate and five parts coarse aggregate and a topcoat 3/4 of an inch thick, composed of mortar in the proportions of one part portland cement and two parts fine aggregate. All sidewalks shall be at least four feet wide.
B. 
Sidewalk in areas designated or zoned as business property shall be at least five inches thick and shall consist of a four-inch base with a one-inch top as mentioned above.
The base shall be deposited on the subgrade and thoroughly compacted by tamping. It shall then be struck off by a template which shall leave it nowhere less than 3/4 of an inch below the finished surface.
Before the initial set of the bottom course has taken place, it shall be covered by the mortar for the top coat.