Part 19 (1/2)

1,780 bbls. natural cement at $1.068 $1,901.04 $1.545 963 cu. yds. stone at $1.619 1,559.91 1.267 53 cu. yds. screenings at $0.392 20.97 0.017 485.6 cu. yds. sand at $0.392 190.36 0.154 Miscellaneous materials 78.15 0.063 --------- ------ Totals $3,750.43 $3.046

Labor Mixing-- 254 hrs. master laborer at $0.21-7/8 $ 55.56 $0.045 4,470 hrs. labor at $0.175 782.42 0.635 Superintendence 18.20 0.015 -------- ------ Total labor mixing $ 856.18 $0.695

Labor Transporting and Placing-- 35 days overseer at $2.33-1/3 $ 81.67 $0.066 1,949 hrs. labor at $0.175 342.07 0.277 Superintendence 34.98 0.028 ------- ------ Total labor transporting and placing $ 458.72 $0.371 Grand total, labor $1,314.90 1.066 Total labor and materials $5,065.33 4.112

No charge is made under materials for rubble stone as the only cost for this was cost of handling and this is included in transporting and placing.

~BREAKWATER, BUFFALO, N. Y.~--The following methods and costs of mixing and placing some 2,561 cu. yds. of concrete are given by Mr. Emile Low, for 10 parapet wall sections and 17 parapet deck sections for a breakwater at Buffalo, N. Y.

The concrete used was a 1 cement, 1 gravel, 1 sand grit and 4 unscreened broken stone. One bag of cement was a.s.sumed to measure 0.9 cu. ft. The voids in the sand grit and gravel were 27 per cent. and in the unscreened stone 39 per cent. The hardened concrete weighed 152 lbs. per cu. ft.

[Ill.u.s.tration: Fig. 80.--Sketch Plan of Concrete Mixing Plant for Buffalo Breakwater.]

Figure 80 shows the arrangement of the mixing plant. The mixer was a 5-ft. cube mixer holding 125 cu. ft., mounted on a trestle and operated by a 912-in. horizontal engine taking steam from a 410-ft. locomotive boiler, also supplying steam to two derrick engines. The material scow contained two pockets for sand, one for gravel and one housed over for cement. Two inside cement men pa.s.sed out the bags in lots of six to one outside cement man who cut and emptied them into the charging bucket.

Three sand shovelers each loaded a 3.6 cu. ft. barrow and wheeled them tandem to the bucket, and two gravel men each loaded a 2.7 cu. ft.

barrow and wheeled them tandem to the bucket. The broken stone was loaded by eight shovelers into another bucket, also containing 21.6 cu.

ft. The two buckets were alternately hoisted and emptied into the mixer hopper, there being a dump man on the mixer who dumped the buckets and attended to the water supply. A charger put the mixer in operation and when the charge was mixed the car men dumped it into a skip resting on a small car which was then run out on the track under the mixer to the derrick which handled the skip to the work. Derrick A handled the materials from the scows and derrick B handled the mixed concrete. The force on the derricks consisted of two enginemen, four tagmen and the fireman.

The ten parapet wall sections containing 841 cu. yds. were built in 46 hours, making 17 batches of 1.07 cu. yds., or 18.2 cu. yds. placed per hour. The 17 parapet deck sections containing 1,720 cu. yds. were built in 88 hours, making 18.8 batches of 1.08 cu. yds., or 19.5 cu. yds.

placed per hour. For the parapet deck work the force was increased by 2 men handling materials and 1 man on the mixer. The labor cost of mixing and placing the concrete was as follows:

Per Per Loading Gang-- day. cu. yd.

1 a.s.sistant foreman 2.00 $0.011 3 cement handlers 5.25 0.029 3 sand shovelers 5.25 0.029 2 gravel shovelers 3.50 0.020 8 stone shovelers 14.00 0.076 1 hooker on 1.75 0.010 ------ ------ Totals $31.75 $0.175

Mixer Gang-- 1 dumpman $ 1.75 $0.010 1 charging man 1.75 0.010 2 car men 3.50 0.020 2 enginemen at $3.25 6.50 0.035 4 tagmen at $2 8.00 0.044 1 fireman 2.00 0.011 ------ ------ Totals $23.50 $0.130

Wall Gang-- 1 Signalman $ 1.75 $0.010 1 dumper 1.75 0.010 6 shovelers at $2 12.00 0.065 4 rammers 7.00 0.038 1 foreman 4.00 0.022 ------ ----- Totals $26.50 $0.145 Grand totals $81.75 $0.450

[Ill.u.s.tration: Fig. 81.--Concrete Blocks for Pier at Port Colborne Harbor.]

[Ill.u.s.tration: Fig. 82.--Forms for Molding Blocks, Port Colborne Harbor Pier.]

[Ill.u.s.tration: Fig. 83.--Device for Handling Blocks, Port Colborne Harbor Pier.]

~PIER CONSTRUCTION, PORT COLBORNE, ONT.~--In constructing the new harbor at Port Colborne, Ont., on Lake Erie, the piers consisted of parallel rows of timber cribs set the width of the pier apart and filled in and between with stone blasted and dredged from the lake bottom in deepening the harbor. The tops of the cribs terminated below water level and were surmounted by concrete walls set on the outer edges. These walls were filled between with stone and the top of the filling was floored part way or entirely across, as the case might be, with a thick concrete slab. The footings of the walls to just above the water level were made of concrete blocks 447 ft., constructed as shown by Fig. 81. The wall above the footing course and the floor slab were of concrete molded in place. The concrete work consisted of molding and setting concrete blocks and of molding concrete wall and slab in place.

The blocks were molded on sh.o.r.e, s.h.i.+pped to the work on scows and set in place by a derrick. Figure 82 shows the construction of the forms for molding the blocks; the bottom tie rods pa.s.sed through the part.i.tions forming the ends of the molds. The sides were removed in 48 hours and used over again. Figure 83 shows the hooks used for handling the molded blocks. Considerable trouble was had in setting these blocks level and close jointed, owing to the difficulty of leveling up the stone filling under water.

[Ill.u.s.tration: Fig. 84.--Scow Plant for Mixing and Placing Concrete, Port Colborne Harbor Pier.]

The ma.s.s concrete was mixed and placed by the scow plant, shown by Fig.

84. The scow was loaded with sufficient sand and cement for a day's work and towed to and moored alongside the pier. Forms were set for the wall on top of the block footing. These forms were placed in lengths of 60 to 75 ft. of wall and resembled the block forms with part.i.tions omitted.

The bottoms of the rear uprights were held by being wedged into the grooves in the blocks, and the bottoms of the front uprights were held by bolts resting on top of the blocks. The tops of the uprights were held together across the wall by tie bolts. The forms being placed, the mode of procedure was as follows:

The crusher fed directly into a measuring box. After some 6 ins. of stone had run into the box the door of the crusher spout was closed. A wheelbarrow load of sand was spread over the stone in the box and over this were emptied and spread two or three bags of cement. Another layer of stone and then of sand and of cement were put in and these operations repeated until the box was full. The box was then hoisted and dumped into the hopper of a gravity mixer of the trough type which ran along a track on the scow and fed directly into the forms. The gang worked consisted of 1 foreman, 1 derrickman and 18 common laborers. This gang placed from 65 to 75 cu. yds. of concrete per day at a labor cost of 50 cts. per cu. yd.

[Ill.u.s.tration: Fig. 85.--Cross-Section of Concrete Pier, Superior, Wis.]

~CONCRETE BLOCK PIER, SUPERIOR ENTRY, WIS.~--The methods and cost of constructing a concrete pier 3,023 ft. long and of the cross-section shown by Fig. 85 at Superior entry, Wisconsin, are given in the following paragraphs.