Section 14.. The Total Cost of Concrete on Section 15 Was As Follows:

The total cost of concrete on Section 15 was as follows:

Per cu. yd. Labor quarrying, crushing and mixing $0.991 Explosives 0.083 Utica cement, at $0.60 per bbl. 0.930 Portland cement, at $2.25 per bbl. 0.180 Sand, at $1.35 per cu. yd. 0.476 ------ Total $2,660 First cost of plant $0.567

It is not strictly correct to charge the full first cost of the plant to the work as it possessed considerable salvage value at the end.

Comparison.--For the purpose of comparing Sections 14 and 15 the following summary is given of the cost per cubic yard of concrete:

Sec. 14. Sec. 15. General force $0.078 $0.082 Wall force 0.108 0.116 Mixing force 0.121 0.250 Timbering force 0.150 0.140 Hauling force 0.142 0.081 Crushing force 0.073 0.128 Quarry force 0.303 0.275 Cement, natural 0.863 0.930 Cement, Portland 0.305 0.180 Sand 0.465 0.476 Plant (full cost) 0.407 0.567 ------ ------- Total $3.015 $3.225

It should be remembered that on Section 14 there was no drilling and blasting of the rock, but that the "quarry force" not only loaded but hauled the stone to the crusher. The cost of mixing on Section 15 is higher than on Section 14 because the materials were dumped on platforms and shoveled into the mixer, instead of being discharged from bins into the mixer as on Section 14.

~GRAND CENTRAL TERMINAL, NEW YORK, N. Y.~--In building a retaining wall of the cross-section, shown in Fig. 108, a traveling tower moving on tracks parallel to the wall contained the concrete mixing plant. The construction of the tower is shown in Fig. 109. The tower had two platforms, one at the top carrying two 10-cu. yd. bins for sand and stone and the other directly below carrying 40 cu. ft. (4 cu. ft. cement, 12 cu. ft. sand and 24 cu. ft. stone) Ransome mixer driven by a 30 H.P. motor and a Lidgerwood motor hoist. The elevator tower carried two 40-cu. ft. Ransome dumping buckets traveling in guides and dumping automatically into the bins. These buckets were operated by the Lidgerwood motor hoist on the mixer platform. Sand and broken stone on flat cars were brought alongside the tower. The sand was shoveled direct from the car into the sand bucket, but the broken stone was shoveled into wheelbarrows which were wheeled over a light bridging from car to bucket and dumped. Wheelbarrows were used for handling the stone chiefly because the capacity of the plant was so great that enough men could not be worked in the limited space around the bucket to keep up the supply by shoveling. The wheelbarrow work added materially to the cost. Cement was carried from the cars to the sand bucket, hoisted and stored on the mixer platform which provided storage room for 100 bags. A 1-3-6 mixture was used; the sand and stone were chuted directly from the bins to the charging hopper and the cement was charged by hand. The mixed concrete was delivered to two 1 cu. yd. dump cars running on a 2-ft. gage track laid in sections on the cross pieces connecting the uprights of the forms. The track had no switches, so that one car had to wait for the other. Four men were required to push each car and two more men assisted in dumping the car and kept the track clear. The wall was built in sections 51 ft. long, each containing 250 cu. yds. One of these sections was filled in 8 hours with ease and by a little hustling a section was filled in 6¾ hours, which is at the rate of 37 cu. yds. of concrete per hour. Working 8 hours per day the cost of mixing, transporting and placing concrete with this mixing plant, with wages for common labor of $1.50 per day, was as follows:

Total. Per cu. yd. 2 men carrying cement $ 3.00 $0.012 6 men shoveling sand 9.00 0.036 17 men shoveling stone 25.00 0.100 11 men wheeling stone 16.00 0.064 2 men at stone and sand bins 3.00 0.012 2 men opening cement bags 3.00 0.012 1 man dumping hopper 1.50 0.006 1 man dumping mixer 1.50 0.006 1 man cleaning chute, mixer, etc. 1.50 0.006 1 motorman or engineer 3.00 0.012 ------- ------- Total labor mixing $66.50 $0.266 8 men pushing 2 cars 12.00 0.048 2 men cleaning track, etc. 3.00 0.012 7 men spading concrete 10.50 0.042 ------- ------- Total labor transporting, placing $ 25.50 $0.102 1 foreman 5.00 0.020 Electricity estimated 7.00 0.028 ------- ------- Total general $ 12.00 $0.048 Grand total $104.00 $0.416

It will be noted that the cost of shoveling and wheeling the broken stone amounts to 16.4 cts. per cu. yd., or nearly 40 per cent. of the total cost of mixing and placing. The cost of spading the concrete is also high for a sloppy mixture, but is probably accounted for by the fact that the concrete had to be spaded so as to have 2 or 3 ins. of clear mortar next the forms. The forms used in constructing the wall are shown by Figs. 110 and 111. They were made in panels 51 ft. long and a locomotive crane was used to shift the panels. This crane worked handling forms only a small part of the time, but a form gang of 10 carpenters was kept busy all of the time moving and reassembling. Assuming the work of the crane to amount to $5 per day and the wages of the carpenter gang to amount to $25, we get a cost of 12 cts. per cubic yard of concrete for shifting forms. It should be noted carefully that the costs given for this work do not include cost of materials, interest on plant, superintendence and other items.

~WALL FOR RAILWAY YARD.~--For building a retaining wall 7 ft. high, forms were made and placed by a carpenter and helper at $8 per M., wages being 35 cts. and 20 cts. an hour, respectively. Concrete materials were dumped from wagons alongside the mixing board. Ramming was unusually thorough. Foreman expense was high, due to small number in gang; 2 cu. yds. were laid per hour by the gang.

Per day. Per cu. yd. 7 mixers, 15 cts. per hour $10.50 $0.53 2 rammers, 15 cts. per hour 3.00 0.15 1 foreman 30 cts. per hr., 1 waterboy 5 cts. 3.50 0.17 ------- ------ Total labor $17.00 $0.85

The total cost was as follows per cubic yard:

Per cu. yd. 0.8 bbls. Portland cement, at $2 $1.60 Sand 0.30 Gravel 0.70 Labor mixing and placing 0.85 Lumber for forms, at $16 per M. 0.56 Labor on forms, at $8 per M. 0.28 ------ Total, per cubic yard $4.29

The sheathing plank for the forms was 2-in. hemlock.

~CONCRETE FOOTING FOR RUBBLE MASONRY RETAINING WALL.~--In constructing a footing for a retaining wall at Grand Rapids, Mich., a 1-2½-5 natural cement concrete was used. It was found that 1 cu. yd. of concrete was equivalent to 29.8 cu. ft. of material composed of 3.6 cu. ft. or 1.1 bbls. of cement, 8.4 cu. ft. or 2.7 bbls. of sand and 17.8 cu. ft. or 5.5 bbl. of broken stone. The labor cost of 15.5 cu. yds. of concrete was as follows:

Item. Total. Per cu. yd. Foreman, 14 hours at 40 cts. $ 5.60 $0.3613 Foreman, 20 hours at 22.5 cts. 4.50 0.2903 Laborers, 49 hours at 12.5 cts. 6.11 0.3942 Mason, 2 hours at 35 cts. 0.70 0.0451 ------ -------- Total labor $16.91 $1.0909

All material was furnished by the railway company, the contractor furnishing labor only; his contract price for this was $1 per cu. yd.

~TRACK ELEVATION, ALLEGHENY, PA.~--The wall was 6,100 ft. long and 75 per cent. was on curves. The first wall built had a top width of 2½ ft. and a bottom width of 0.4 the height with the back on a smooth batter. Later the back was stepped and last the wall was proportioned as follows: Calling the height from top of foundation to under coping, then width of base was 0.45 (h + 3), the top measuring 2½ ft. The back was arranged in steps 24 ins., 30 ins. and 36 ins. high, and the thickness of wall at each step was, calling h equal to height of step from base, 0.45 (h + 3). Several forms of expansion joints were tried. The first was tarred paper extending through the wall every 50 ft.; the second was ½-in. boards running through the wall every 50 ft.; the third was ½-in. board extending 2 ft. into the wall, with a ¼-in. cove at the angles, every 25 ft. The third construction gave perfect satisfaction.

A 1-2-5 natural cement and a 1-3-6 Portland cement concrete mixed fairly wet were used. The concrete was laid in 8-in. courses and faced with a 1-2 mortar. The forms were 2-in. white pine faced and jack planed on the edges; upon removal of the forms board marks and other defects were removed and a wash of neat cement was applied. One contractor used hand mixing. The sand and gravel were measured in wheelbarrows and wheeled onto the platform; the sand and cement were spread in thin layers, one over the other, and thoroughly mixed dry; the gravel was then spread over the mixture, the whole was shoveled into barrows or the pit again shoveled into place and rammed. The other contractor used a cubical mixer. A charging box holding 1¼ cu. yds. and graduated to show the correct proportions of sand and gravel was filled by shoveling; cement was placed on top and the box hoisted and dumped into the mixer. A barrel holding the correct amount of water was emptied into the mixer which was turned 10 or 15 times and discharged into cars. The costs of mixing by hand and by machine were as follows:

Hand mixing. Total. Per cu. yd. ½ foreman at $3 $ 1.50 $0.025 3 men wheeling barrows at $1.50 4.50 0.075 10 men wheeling materials at $1.50 15.00 0.250 3 men mixing sand and gravel at $1.50 4.50 0.075 6 men mixing concrete at $1.50 9.00 0.150 1 man sprinkling at $1.50 1.50 0.025 ------ ------ Total $36.00 $0.600

The output of the hand mixing gang was 60 cu. yds. per day.

Machine mixing. Total. Per cu. yd. 1 foreman at $3.50 $ 3.50 $0.035 1 stationary engineer at $3 3.00 0.030 ½ foreman at $1.75 0.87 0.009 15 men loading charging bucket at $1.50 22.50 0.225 2 men dumping charging bucket at $1.75 3.50 0.035 2 tagmen at $2, ½ time 2.00 0.020 1 man at trap at $2, ½ time 1.00 0.010 ------ ------ Total $36.37 $0.364

The output of the cubical mixer was 100 cu. yds. per day.

The costs of placing concrete in the forms above the foundation by hand below 12 ft., and by cars and derricks any height, were as follows:

By hand (barrows) below 12 ft. Total. Per cu. yd. 4 men loading concrete at $1.50 $ 6.00 $0.100 1 foreman ½ time at $3 1.50 0.025 10 men wheeling at $1.50 15.00 0.250 1 man scraping barrows at $1.50 1.50 0.025 2 men placing concrete at $1.50 3.00 0.050 1 man placing mortar face at $1.50 1.50 0.025 2 men mixing and carrying mortar at $1.50 3.00 0.050 ------ ------ Total $31.50 $0.525

By cars and derricks-- 1 horse and driver at $3 $ 3.00 $0.030 2 men dumping concrete ½ time at $1.50 1.50 0.015 1 fireman ½ time at $1.75 0.88 0.009 3 tagmen at $1.50 4.50 0.045 8 men placing and ramming conc. at $1.50 12.00 0.120 2 men mixing mortar at $1.50 3.00 0.030 2 men placing mortar at $1.50 3.00 0.030 2 men carrying mortar at $1.50 3.00 0.030 1 foreman at $3 3.00 0.030 1 stationary engineer at $3 3.00 0.030 2 men attending hook at $1.50 3.00 0.030 ------ ------ Total $39.88 $0.399

The costs of placing concrete in the foundations were as follows:

By hand-- Total. Per cu. yd. 1 foreman ½ time at $3 $ 1.50 $0.025 4 men shoveling concrete at $1.50 6.00 0.100 1 man placing concrete at $1.50 1.50 0.025 1 man ramming concrete at $1.50 1.50 0.025 ------ ------ Total $10.50 $0.175

By machine-- 1 horse and driver at $3 $ 3.00 $0.030 3 men pushing and unloading car at $1.50 4.50 0.045 5 men placing and ramming at $1.50 7.50 0.075 1 foreman at $3 3.00 0.030 2 men dumping mixer at $1.50 3.00 0.030 ------ ------ Total $21.00 $0.210

~COST OF RETAINING WALL.~--The following figures of the cost of a concrete retaining wall are given by C. C. Williams:

Cost of Material. Unit Kind and amount of material-- Price. Cost. Stone, 441 tons $ .70 $308.70 Sand, 182.5 yds. .55 100.37 Cement, 536 bbls. .85 453.60 ------- Total $862.67

Lumber ¾ value $205.33 Wheelbarrows, ¾ value, 6 at $3.50 15.75 ------- Total $221.08

Excavation-- Labor, 4,002 hours at 15 cts. $600.30 Carts, 800 hours at 12½ cts. 100.00 Foreman, 460 hours at 35 cts. 171.00 Waterboy, 240 hours at 10 cts. 24.00 ------- Total $895.30

Concrete-- Labor, 2,398 hours at 15 cts. $359.70 Foreman, 224 hours at 35 cts. 77.40 ------- Total $437.10

Handling material-- Unloading cars, 380 hours at 15 cts. $ 57.00 Foreman, 40 hours at 35 cts. 14.00 -------

Total $ 71.00

Forms-- Carpenters, 997 hours at 22½ cts. $224.33

Work to support bridge-- Carpenters, 542 hours at 22½ cts. $121.95 Labor, 458 hours at 15 cts. 68.70 -------

Total $190.65

Superintendence and office-- Superintendent, 30 hours at 50 cts. $15.00 Office 20.00 -------- Total $35.00 -------- Grand total $2,937.13

Proportional costs-- Cost Per Per Cent. Yard of of Total Item. Cost. Concrete. Cost. Concrete materials $ 862.67 $2.02 46.7 Laying concrete 437.10 1.03 23.4 Lumber 205.33 .48 11.3 Building forms 224.33 .53 12.3 Handling material 71.00 .17 03.8 Wheelbarrows 15.75 .04 01.0 Supt., etc. 35.00 .07 01.5 --------- ----- ------ Total $1,851.18 $4.34 100.00 Work on bridge 190.65 Excavation 895.30 --------- $2,937.13