§ 11.16.010. Definitions and specifications

"Permanent sidewalks" means cement concrete sidewalks constructed in accordance with the following:

Standard Specifications for Concrete Sidewalk Construction

City of Centerville, Iowa

(1) Description and dimensions. Portland cement concrete sidewalks shall be composed of Portland cement concrete proportioned, mixed, and constructed on a prepared soil base in accordance with these specifications to a standard thickness of four inches. The standard width shall be not less than four feet but may be increased to greater widths in minimum increments of width of one foot. All walks shall be laid to the grade established therefor by ordinance and with the back line of four walks placed one foot out from the property line and the back line of five-foot and wider walks placed on the property line.

(2) Composition, consistency, and materials. Concrete used shall conform to the following proportions:

	Per Bag	Per Cubic Yard
Cement	1 pound	648 pounds
Sand	220 pounds	1520 pounds
Gravel or  crushed stone	220 pounds	1520 pounds

 

It shall be mixed to a uniform consistency, and with a water content such that the slump shall not exceed four inches when tested by the AASHO Standard Method of "Slump Test for Consistency of Portland Cement Concrete", T 119. Sand shall be natural sand, free within a maximum limitation of one and one-half percent of injurious amounts of silt, shale, coal, organic matter, or other deleterious substances. Gravel or crushed stone shall be washed and screened gravel or crushed limestone obtained from ledges in which at least ninety-five percent of the total shall have a percentage of wear not in excess of forty-five when tested in accordance with the current AASHO Standard Method of "Test for Abrasion of Coarse Aggregate", T 96, Grading B. It shall be free of any unsound material in which disintegration is accompanied by an increase in volume.

(3) Construction Method.

(a) Preparation of subgrade. The foundation for sidewalks shall be prepared by excavation or filling to a depth such that the specified depth will be obtained below the established grade line after compaction of the base as specified herein, If filling be required, it shall be done only with natural soil or crushed limestone corresponding to Class A roadstone (at least fifty percent passing #4 sieve and at least twenty-five percent fines or dust). Sand may not be used. The base and any fill shall be thoroughly compacted by tamping or rolling until a smooth, dense, and hard subgrade is obtained.

(b) Forming. Wood or steel forms shall be used to form a straight edge set true to line and grade. If wood they shall be not less than one and five-eights inches in thickness and of a width of not less than three and five-eights inches. Forms shall be set true to line and grade and held rigidly in place by adequate staking placed outside of the forms.

(c) Placement and finishing. The subbase shall be thoroughly moistened if dry, and concrete then placed in successive batches to the full depth and width of the slab in one operation. It shall be thoroughly spaded along the edge and tamped to eliminate voids. A flat surface shall be generated by operation of a screed across the top of the forms, filling any low places as the screed progresses. After the final surface elevation and flatness have been obtained by the screed and any unavoidable floating, the entire surface shall be steel troweled to obtain a dense, smooth surface. Troweling shall be delayed until the concrete has set long enough to work correctly under the trowel and should be interrupted on any section when excess water has been flushed to the surface, After absorption of the water, troweling can be resumed. When the final steel trowel finish has been obtained, the surface should be brushed lightly to obtain a traction surface. The brush shall be such as to cause a fine ribbed finish and not coarse grooves in the surface. It shall be cleaned frequently, but water shall not be carried back onto the surface of the concrete. Edges shall be rounded with a suitable edging tool and walks shall be cross-divided every four feet by cutting on a straight line with a pointed trowel or by use of a metal divider to form joints. Cuts shall be done late enough or else repeated so that a plane of weakness will result. The finished cut shall be edged.

In no case shall dry cement or dry cement and sand be sprinkled on the surface to absorb surface water, and in no case shall water be added to or sprinkled on the surface for ease in finishing.

A curing medium shall be applied after finishing the walk. This may be an impervious white sprayed-on coating or impervious paper or mats, Burlap or any other method which requires periodic wetting may not be used.

(d) Two course construction. Two course construction is approved provided that the topping course is composed of a mixture having the same sand and cement content as the base course, omitting only coarse aggregate, and that such topping be not less than one-half inch in thickness and be placed not longer than two hours after placement of the basic slab.

(e) Jointing. At intervals not exceeding fifty feet, one-half inch thick expansion joints shall be constructed by insertion of a bituminous or asphaltic joint strip. Such joints shall also be used at the meeting of a walk with any building or structure, at sidewalk intersections, at the intersection of house or parking sidewalks with the sidewalk, and where walks meet curbs or any other fixtures in the surface. When sidewalks are constructed between an adjoining permanent structure on one side and a curbing on the other side, continuous expansion joint material shall be installed adjacent to the curbing. Joint strip material shall be set one-fourth to one-half inch below finish grads.

(4) Driveway entrances. Where driveways, paved entries or alleys, crosswalks, the thickness shall be increased to not less than six inches and such crossings shall be reinforced either by the use of 6 × 6 - 6/6 mesh or three one-half inch reinforcing bars set lengthways. The grade elevation of such crossings may not be depressed below the sidewalk grade but shall be a continuation of it, and no curbing or step is permitted. Such entrances shall terminate at the outside edge of the curbing and shall not lap over the curb. One inch expansion material shall be used between the end of such entrances and the curbing and one-half expansion material shall be used on either side of the sidewalk if the driveway or slab is not constructed as a continuous slab through the sidewalk. The end of entrance slabs shall be thickened to not less than eight inches where such slabs meet pavements.

Under some circumstances, permission will be given to reduce curb height in which case the cut may be smoothed, if desired, by use of asphaltic or other patching materials, but in no case shall the driveway or entrance slab be constructed beyond the outside or back edge of the curb. Such patching shall not extend beyond the face surface of the remaining curbing and the flow line elevation of the gutter shall not be changed by filling of any sort.

(5) Special construction and fixtures. Wherever fixtures such as manholes, crossing plates, access doors, posts or poles are situated in sidewalks, the effect of expansion and contraction shall be anticipated and extra expansion material used as indicated. Telephone or power poles which must be incorporated into the walk shall be isolated from it by encirclement with an expansion joint strip not less than one-half inch in thickness to the full depth of the sidewalk. Should the fixture be such that no bond is desirable, a heavy coating of asphalt or bituminous material shall be applied to the fixture before placement of concrete. Where sidewalk construction causes damage or destruction of existing curbings, they shall be rebuilt to match similar curbing in new condition. Materials and method of construction shall conform to these specifications and forming shall be carefully done; the concrete shall be cured in the same manner as for sidewalks.

(6) Removal of nonconforming construction. Gutter fillets, and sidewalk driveway and entrance slabs not conforming with established line and grade and this specification may be removed from the street by the city and the expense thereof charged to the abutting property owner.

(7) Standard drawing. A drawing illustrating the herein specified details of construction of sidewalks and driveway and entrance slabs is on file with the city clerk and is made a part of this section by reference.

The contractor or walk builder will be required to provide the proper barriers or lights to properly protect the walks built until they shall become thoroughly set.

(Ord. 895 § 2, 1969).