Fig. 75.—Forms for Regular Lock Walls, Illinois & Mississippi Canal.

Lock No. 37.—The character of the forms used in constructing the lock walls is shown by Fig. 75. The walls were built in sections and work was continuous with three 8-hour shifts composed about as specified for the guard lock work except that one or two men were added in several places making the total number 58 men. The average output per shift was 65 batches of concrete and 31 batches of facing mortar. The cost of the work, comprising 3,767 cu. yds., was as follows:

Item.Total.Per Cu. Yd.
4,564 bbls. Portland cement$14,181$3.764
2,460 cu. yds. crushed stone4,5211.200
250 cu. yds. pebbles3250.086
1,750 cu. yds. gravel2,3350.619
450 cu. yds. sand4500.119
180,000 ft. B. M. lumber (¼th cost)9900.236
Fuel, light, repairs, etc.1,1710.311
Carpenter work2,5260.671
Pumping2700.071
Mixing and placing concrete6,1701.632
20% cost of plant7300.193
——————
Total$33,669$8.902

Lock No. 36.—The forms used were of the construction shown by Fig. 75. Three shifts were worked, each composed as specified for the guard lock, except that the number of tampers and spreaders was doubled, bringing the gang up to 65 men. The average output per gang per shift was 76 batches of concrete and 35 batches of facing mortar. The cost of 2,141 cu. yds. of concrete in this lock was as follows:

Item.Total.Per Cu. Yd.
3,010 bbls. Portland cement$9,057$4.23
1,377 cu. yds. broken stone1,9220.90
393 cu. yds. pebbles3540.17
459 cu. yds. gravel3100.15
500 cu. yds. sand8890.42
150,000 ft. B. M. lumber (¼th cost)6000.28
Fuel, light, repairs, etc.2530.68
Carpenter work1,4720.11
Mixing and placing concrete3,8971.82
20% cost of plant6500.30
—————
Total$19,404$9.06

The preceding data, made public by Mr. Woermann in 1894, are supplemented by the following information prepared for the authors:

"If any criticism was to be made of the concrete masonry erected in 1893 and 1894, it would probably be to the effect that it was too expensive. The cost of the masonry erected during those two seasons was $8 to $9 per cu. yd. Our records showed that about 45 per cent. of this cost was for Portland cement alone, and moreover, that 40 per cent. of the total cement used at a lock was placed in the 8-in. facing and 5-in. coping. So in the seven locks erected in 1895 on the eastern section, the facing was reduced to 3 ins. and the proportions changed from 1-2 to 1-2½.

"In 1898 this cost received another severe cut, and Major Marshall's instructions stated that the facing should not exceed 1½ ins. in thickness nor be less than ¾-in., while the layer of fine material on top of the coping was to be only sufficient to cover the stone and gravel. The amount of sand was again increased so that the proportions were 1-3.

"The cost of the Portland cement concrete was likewise cheapened by increasing the amount of aggregates. On the earlier work the proportions were 1-2-2-3, while on the work in 1898 the proportions were 1-4-4. The cost of the walls was further cheapened by using Utica cement in the lower steps of the wall, with 2 ft. of Portland cement concrete on the face. The proportions used in the Utica cement concrete were 1-2½-2½. This lower step is one-third of the height, or about 7 ft.