Chapter II

give the amounts of materials per cubic yard of these mixtures; the product of these quantities and the cost of the materials on the ground gives the cost. The labor cost of mixing and placing, including the form work, will run from 10 to 14 cts. per foot. In round figures curb and gutter of the section shown in the accompanying illustrations may be estimated to cost in the neighborhood of 40 cts. per lineal foot. The following sections give records of cost of individual jobs of curb and gutter construction.

~Cost at Ottawa, Canada.~--The method and cost of constructing 1,326 ft. of concrete curb and gutter at Ottawa, Ont., are given in some detail by Mr. G. H. Richardson, Assistant City Engineer, in the annual report of the City Engineer for 1905. We have remodeled the description and rearranged the figures of cost in the following paragraphs.

The concrete curb was built before doing any work on the roadway, and the first task was the excavation of a trench 2½ ft. wide and averaging 1 ft. 8 ins. in depth through light red sand. On the bottom of this trench there was placed a foundation of stone spalls 8 ins. thick; in width this foundation reached from 3 ins. back of the curb to 6 ins. beyond the front of the water table. The curb was made 5 ins. thick and ran from 10 ins. to 5½ ins. in height, and the water table was 14 ins. wide and 4 ins. thick, with a fall of 1¼ ins. from front to back. The concrete used was a mixture of 1 Portland cement, 3 sand, 3 5/8-in. screened limestone, and 4 2-in. stone. It was deposited in forms and tamped to bring the water to the face and then smoothed with a light troweling of stiff mortar.

The forms were constructed by first setting pickets and nailing to them a back board 2 ins. thick and 12 ins. wide and a front board 2 ins. thick and 6 ins. wide. The concrete for the water table was deposited in this form in sections and brought to surface by straight edge riding on wooden strips nailed across the form and properly set to slope, etc. After the water table had been troweled down and brushed a 1×10-in. board was set to mold the front face of the curb. This board was sustained by small "knee frames" made of three pieces of 1×2-in. stuff, one conforming to the slope of the water table and long enough to extend beyond the front of the 2×6-in. front board, a second standing plumb and bearing against the 1×10-in. face board, and the third forming a small corner brace between the two former to hold them in their proper relative positions. The 1×10-in. face board, etc., was separated from the 2×12-in. back board by a 5-in. block at each end, and then braced by the knee frames every 3 or 4 ft. In this way it was possible to bring this 1×10-in. board into perfect line by moving the knee braces in or out, and when correct nailing them to the 2×6-in. front board. The 1×10-in. face board being in position and braced and lined, the curb material was thoroughly tamped in, and when ready was troweled and brushed on the top, a small round being worked onto the top front corner with the trowel.

Expansion joints were provided for by building into the curb every 12 ft., a piece of 3/8-in. boiler plate, which was afterward withdrawn and the joint filled with sand and faced over. As soon as the concrete had set sufficiently the face board was taken down and face of curb finished and brushed, the fillet between curb and water table being finished to 2½ ins. radius. Circular curb and gutter of same construction was built at each corner, ½-in. basswood being used for forms, instead of 2×1-in. lumber.

In addition to the actual construction of curb and gutter the cost given below includes the cleaning up of the street, spreading or removal of all surplus material from excavation, and the extension of all sidewalks out to the curbs at the corners. It was also necessary to maintain a watchman on this work, which duty, under ordinary circumstances, would be done by the general watchman. The total length built was 1,326 ft., of which 1,209 ft. is straight and 117 ft. curved to a 12-ft. radius.

The rates of wages paid were $2 for horse and cart, $1.65 for watchman, and an average of $1.90 per day for labor, including foreman; all for nine hours' work per day. The working force consisted of foreman, finisher, handy man. four concrete men, and three laborers.

The labor cost of the work was as follows:

Per ft. P. C. of Item. Total. cts. total. Excavation and setting boards $ 88.90 6.7 30 Laying stone foundation 43.30 3.3 14 Concreting 61.30 4.6 20 Finishing 45.15 3.4 15 Carting 9.85 0.76 3 Watchman 25.00 1.89 8 Clearing up 13.60 1.04 4 Extras (sidewalk extensions) 17.23 1.31 6 ------- ----- -- Total $304.33 23.00 100

The cost of materials for curb and foundation were as follows:

Per lin. ft. Total. cts. 171.112 tons spalls $102.93 7.76 42 tons 2-in. stone 41.16 3.09 30.8 tons 5/8-in. stone 42.57 3.21 33,000 lbs. cement 161.70 12.19 24 cu. yds. sand 19.20 1.45 ------- ----- Total $367.56 27.70

The cost of supplies and tools was as follows:

1,000 ft. B. M. 2×12 boards charged off $ 9.25 500 ft. B. M. 2×6 boards charged off 4.12 1,000 ft. B. M. 1×10 boards charged off 14.25 ½-in. basswood 4.30 ½ keg 3-in. nails 1.42 ½ keg 4-in. nails 1.43 Pickets 3.25 Tools charged off 3.15 ------ Total $41.17

This total, when divided by 1,326 lin. ft. of curb, gives the cost per lineal foot as about 3 cts. We can now summarize as follows:

Per lin. P. C. of Item. Total. ft. total. Labor $304.33 23 43 Material 367.56 28 51 Supplies 41.17 3 6 ------- ---- --- Total $713.06 $0.54 100

As indicated above, on more extensive work the costs of carting, watchman, cleaning up, and extras would be avoided. They cost on this work 5 cts. and the work could therefore be done for 49 cts. if no such charges were included. On such work also the charge for supplies would be lower per foot and on any future work the labor cost could be materially lowered, this curb having been somewhat of an experiment as to method of construction. It is thought that with no charges for carting, cleaning, watchman, and extras, and with the experience obtained, this curb could be built for about 46 cts. The proportions adopted and the method of construction followed, produce a very strong, dense, homogeneous curb and gutter.

[Illustration: Fig. 125.--Concrete Curb and Gutter at Champaign, Ill.]

~Cost at Champaign, Ill.~--The following costs were recorded by Mr. Charles Apple, and relate to work done at Champaign, Ill., in 1903. The work was done by contract, at 45 cts. per lin. ft. of the curb and gutter shown in Fig. 125.

The concrete curb and gutter was built in a trench as shown in the cut. The earth was removed from this trench with pick and shovel at a rate of 1 cu. yd. per man per hour. The concrete work was built in alternate sections, 7 ft. in length. A continuous line of planks was set on edge to form the front and back of the concrete curb and gutter; and wood

## partitions staked into place, were used. The cost of the work was as

follows:

No. of Total Cost per Item. men. wages. 100 ft. Opening trench, 18×30-in. 2 $3.50 $2.43 Placing and tamping cinders 2 3.50 1.00

Setting forms: Boss setter 1 3.00 ... Assistant setter 1 2.00 ... Laborer 1 1.75 ... -- ----- ----- 3 $6.75 $1.69

Mixing and placing concrete: Clamp man 1 $1.75 ... Wheelers 3 5.25 ... Mixing concrete 4 7.00 ... Mixing finishing coat 2 3.50 ... Tampers 1 1.75 ...

Finishing: Foreman and boss finisher 1 4.00 ... Assistant finisher 1 3.00 ... Water boy 1 .50 ... -- ------ ----- Total making concrete 14 $26.75 $7.64 Total for labor per 100 ft $12.76

Materials for 100 lin. ft.: Quantity. Price. Portland cement 8-1/3 bbls. $1.85 $15.42 Cinders 7.5 yds. .50 3.75 Gravel 2.5 yds. 1.00 2.50 Broken stone 2.5 yds. 1.40 3.50 Sand 1.0 1.00 1.00 Total for material per 100 ft $26.17 Total for material and labor per 100 ft. $38.93

This is the total cost, exclusive of lumber, tools, interest, profits, etc., and it is practically 40 cts. per lin. ft.

In 100 lin. ft. of curb and gutter there were 4.6 cu. yds. of concrete and mortar facing, 4 cu. yds. of which were concrete; hence the 9 men in the concrete gang laid 14 cu. yds. of concrete per day, whereas the 4 men mixing and placing the mortar finishing laid only 2½ cu. yds. of mortar per day, assuming that the mortar finishing averaged just 1 in. thick. Since these 4 men (2 mixers and 2 finishers) received $10.50 a day, it cost more than $4 per cu. yd. to mix and place the 1-2 mortar, as compared with $1.41 per cu. yd. for mixing and placing the concrete. The concrete was built in alternate sections 7 ft. long. The 3 men placing forms averaged 400 lin. ft. a day, so that the cost of placing the forms was $1 per cu. yd. of concrete. The 2 men placing and tamping cinders averaged 16 cu. yds. of cinders per day, or 8 cu. yds. per man. This curb and gutter was built by contract at 45 cts. per lin. ft.

For several jobs, in which a curb and gutter essentially the same as shown in Fig. 125 was built, our records show a general correspondence with the above given data of Mr. Apple. Our work was done with smaller gangs, 1 mason and 2 laborers being the ordinary gang. Such a gang would lay 80 to 100 lin. ft. of curb and gutter per 10-hr. day, at the following cost:

1 mason at $2.50 $2.50 2 laborers at $1.50 3.00 ----- Total $5.50

This made a cost of 5½ to 7 cts. per lin. ft. for labor, and it did not include the cost of digging a trench to receive the curb and gutter.

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