Concrete Construction Part 40

_Cost._--The cost of the 1,217 cu. yds. of concrete in the culvert was as follows:

Item. Per cu. yd.

1.08 bbls. cement at $1.72 $1.85 0.47 cu. yd. sand at 30 cts. 0.14 0.25 cu. yd. broken stone at 51 cts. 0.13 0.8 cu. yd. slag at 26 cts. 0.21 Lumber in forms, etc. 0.30 Miscellaneous materials 0.05 Labor, unloading materials 0.11 Labor, mixing and placing concrete 0.42 Labor, building forms 0.55 Labor, not cla.s.sified 0.18 Labor, excavating 40 cts. per cu. yd. 0.28 Labor, back filling and tearing down forms 0.10 ----- Total $4.32

~CULVERTS FOR NEW CONSTRUCTION, WABASH RY.~--The following data relate to culvert work carried out in constructing the Pittsburg extension of the Wabash Ry. in 1903. All the work was done by contract.

_Plant I_: This plant was located on a hillside with the crushing bins above the loading floor or platform which extended over the top of the mixer, so that the crushed stone could be drawn directly from the chutes of the bins and wheeled to the mixer. The sand was hauled up an incline in one-horse carts and dumped on this floor, and was also wheeled in barrows to the mixer. The proportions used were 4 bags of cement, 4 barrows of sand and stone dust and 7 barrows of crushed stone. A 7/8-cu.

yd. mixer was used and it averaged 40 cu. yds. per 10-hour day at the following cost for labor:

Item. Per day. Per cu. yd.

1 foreman $ 3.00 $0.08 3 men charging with barrows 4.50 0.11 1 man attending engine and mixer 2.50 0.06 2 men loading concrete barrows 3.00 0.08 4 men wheeling concrete barrows (100 ft.) 6.00 0.15 4 men ramming concrete 6.00 0.15 4 men wheeling and bedding rubble stones 6.00 0.15 ------ ----- Totals $31.00 $0.78

a.s.suming 1/3 ton of coal per day at $3 per ton, we have 2 cts. more per cubic yard for fuel.

_Plant II._--At this plant a Smith mixer was used with a loading floor 4 ft. above the ground, this low platform being made possible by having a hole or sump in which the skip receiving the concrete was set. A derrick handled the skips between the sump and the work. The batch was made up of 2 bags of cement, 2 barrows of sand and 4 barrows of stone. The output was 50 cu. yds. per day of 10 hours at the following cost:

Item. Per day. Per cu. yd.

1 man feeding mixer $1.50 $0.03 1 mixer runner 2.50 0.05 1 derrick engineman 2.50 0.05 2 tagmen swinging and dumping 3.00 0.06 6 men wheeling materials 9.00 0.18 2 men tamping concrete 3.00 0.06 1 foreman 3.00 0.06 ------ ----- Totals $24.50 $0.49

The cost of fuel would add about 3 cts. per cubic yard to this amount.

~SMALL ARCH CULVERT COSTS, PENNSYLVANIA R. R.~--Mr. Alex. R. Holliday gives the following figures of cost of small concrete culvert work carried out under his direction. The culvert section used is shown in Fig. 171. This section gives a slightly larger waterway than a 36-in.

cast iron pipe. Eight culverts, having an aggregate length of 306 ft.

were built, using a mixture of Portland cement and limestone and screenings. Each culvert had a small spandrel wall at each end.

The work was done by a gang of six men, receiving the following wages:

Foreman, cents per hour 27.5 a.s.sistant " " " 17.5 Laborers " " " 15.0 Teams " " " 35.0

The materials were hauled about 1 mile from railway to site of work.

Cement, including freight and haulage, cost $1.97 per barrel. Limestone and screenings cost 50 cts. per cu. yd. f. o. b. at quarry. No freight charges are included in cost of any of the materials except cement. The cost of the 306 ft. of culvert was as follows:

Item. Total. Per lin. ft. Per cu. yd.

Labor $443.14 $1.45 $3.35 Stone and screenings 78.50 0.25 0.60 Cement 307.53 1.01 2.34 Forms 12.00 0.04 0.09 ------- ----- -----

Total $841.17 $2.75 $6.38

[Ill.u.s.tration: Fig. 171.--Small Culverts, Pennsylvania R. R.]

~26-FT SPAN ARCH CULVERT.~--The culvert was 62 ft. long and 26-ft. span and was built of 1-8 and 1-10 concrete mixed by hand. The wages paid were: General foreman, 40 cts. per hour; foreman, 25 cts. per hour; carpenters, 22 to 25 cts. per hour, and laborers, 15 cts. per hour. The cost of the concrete in place, exclusive of excavation but including wing walls and parapet, was as follows:

Per cu. yd.

0.96 bbl. cement, at $1.60 $1.535 1.03 tons coa.r.s.e gravel, at $0.19 0.195 0.40 tons fine gravel, at $0.21 0.085 0.32 tons sand, at $0.36 0.115 Tools, etc. 0.078 Lumber for forms and centers 0.430 Carpenter work on forms (23 cts. hr.) 0.280 Carpenter work platforms and buildings 0.050 Preparing site and cleaning up 0.210 Changing trestle 0.085 Handling materials 0.037 Mixing and laying, av. 15 cts. per hr. 1.440 ------ Total per cu. yd $4.540

There were 1,493 cu. yds. of concrete in the work. The excavation cost $463 and the total cost was $7,243.

~COST OF RAILWAY CULVERT.~--The culvert was for a single track railway and contained 113 cu. yds. of concrete and required 36 cu. yds. of excavation. The figures are given by C. C. Williams as follows:

Cost of Material.

Kind and Amount of Material. Unit Price. Cost.

Stone, 113.2 tons $.70 $ 79.24 Sand, 46.8 yds. .55 25.74 Cement, 137 bbls. .85 116.45 ------- Total $221.43

Lumber 52.50 Rail and bolts 36.60 ------- Total $ 89.10

Excavation.

Labor, 189 hours at .15 $ 28.35 Foreman, 60 hours at .30 18.00 ------- Total $ 46.35 Concrete.

Labor, 683 hours at .15 $102.45 Foreman, 130 hours at .30 39.00 ------- Total $141.45

Forms.

Carpenters, 313 hours at .225 $ 70.42 Labor, 30 hours at .15 4.50 ------- Total $ 74.92

Handling Materials.

Moving material, 245 hours at .15 $ 36.75 Unloading material, 95 hours at .15 14.25 Foreman, 20 hours at .30 6.00 ------- Total $ 57.00

Superintendence and Office.

Superintendent, 6 hours at .50 $ 3.00 Office 10.00 ------- Total $ 13.00 ------- Grand total $643.25

Proportional Costs.

Per cent.

Cost of Total Per Yard Cost of Item. Cost. Concrete. Concrete.

------ Concrete material $221.43 $1.96 7.1 Laying concrete 141.45 1.25 23.6 Lumber 52.50 .46 08.7 Rail and bolts 36.60 .32 06.1 Building forms 74.92 .67 13.3 Handling material 56.90 .50 09.0 Superintendent and office 13.00 .12 02.2 ----- ------ Total $5.28 100.00 Excavation 46.35 1.28 ------- Total $643.15

Contractor's Receipts.

113 yds. concrete at $5.95 $672.35 36 yds. excavation at .30 10.80 ------- Total $683.15 Total cost 643.15 ------- Profit, 5.9% of contract price $ 40.00

~12-FT. CULVERT, KALAMAZOO, MICH.~--A portion 1,080 ft. long of a new channel built in 1902-3 for a small stream flowing through the city of Kalamazoo, Mich., was constructed as an arch culvert of the form shown by Fig. 172. The concrete section is reinforced on the lines indicated by a double layer of woven steel wire fabric. The concrete was approximately a 1 cement, 6 sand and gravel mixture.

[Ill.u.s.tration: Fig. 172.--Cross-Section of Culvert at Kalamazoo, Mich.]

The centers were built in sections 12 ft. long of the form and construction shown by Fig. 173, and a sufficient number was provided to lay twelve sections of invert and six sections of arch. The arch centers were arranged to be uncoupled at the crown; this with the hinges at the quarter points permitted the two halves to be separated and each half to be folded so that it could be carried from the rear of the work through the forms still in place and erected again for new work. When in place the center ribs rested on the side forms which set on the invert concrete and are braced apart by the hinged cross-strut. This cross-strut was the key that bound the whole structure together; the method of removing this key is indicated by Fig. 174. From his experience with these centers the engineer of the work, Mr. Geo. S.

Pierson, remarks:

"In work of this kind it is very important to have the centering absolutely rigid so it will not spring when concrete is being tamped against it and thus weaken the cohesion of the concrete. It is also important to have the arrangement such that all the centering can be removed without straining or jarring the fresh concrete. The centers were generally removed in about three or four days after the concrete arch was in place."

[Ill.u.s.tration: Fig. 173.--Center for Culvert at Kalamazoo, Mich.]

The invert concrete was brought to form by means of templates, Fig. 173, and straight edges. The side forms were then placed and braced apart by the struts and concreting continued to the skewback plane indicated in Fig. 173. The arch form was then placed; it rested at the edges on the side forms and was further supported by center posts bearing on boards laid on the bottom of the invert. A template, Fig. 175, was used to get the proper thickness and form of arch ring. Outside forms were used to confine the concrete at the haunches but nearer the crown they were not required.

[Ill.u.s.tration: Fig. 174.--Hinged Cross Strut for Center for Culvert at Kalamazoo, Mich.]

Much of the work was done when the thermometer, during working hours, ranged from 12 to 25 above zero. When the temperature was below freezing, hot water was used in mixing the concrete and on a few of the coldest days salt was dissolved in the water. In addition each section of the work was covered with oiled canvas as soon as completed, and the conduit was kept closed so far as was practicable to retain the heat.

Concreting was never stopped on account of cold weather.