This is said to have been the first dam upon the construction of which a cableway was employed. A 2-in. cable weighing 7 lb. per ft. was stretched between towers 667 ft. apart. It was at first given a sag of 20 ft. which increased 3 ft. to 5 ft. under load. It parted under a load of 6 tons while in service and a new cable was installed; the towers being raised 10 ft. to permit a greater sag. (As at present installed cableways are given a sag equal to 5 per cent, of the span.) Cost of cableway installed was $3750.

Fig. 43. Section of Sodom dam, New York; built 1888 to 1893 of rubble masonry; length, 500 ft.; max. height, 98 ft.; contains 35,88; cu. yd.

For river diversion a crib dam was built across the river 80 ft. upstream from the masonry. A canal 26 ft. wide X about 15 ft. deep was built along one hillside returning to the river about 500 ft. below the dam. Maximum flood during the construction period 4166 cu. ft. sec.

Quantities of principal items, and the contract prices:

Earth excavation................................

5,986 cu. yd.

$0.35

Rock excavation....

12,260 cu. yd.

1.50

Deep rock excavation.....

3,600 cu. yd.

2.00

Rubble masonry in 1-2 American cement mortar....

300 cu. yd.

3.75

Rubble masonry in 1-2 Portland cement mortar.....

23,280 cu. yd.

4.50

Rubble masonry in 1-3 Portland cement mortar.....

6,260 cu. yd.

4.25

Brick masonary....

530 cu. yd.

10.25

Granite dimension, stone masonary....

776 cu. yd.

35.73

Facing stone masonary.....

4,287 cu. yd.

10.75

Sand pit 1 mile from dam, quarry 1 1/4 miles-from dam.

Maximum progress on masonry 3000 cu. yd for a month, with twelve masons and three derricks. Average progress 1700 cu. yd. Total cost of dam, $366,499.

Costs to contractor:

. Rubble stone $1.97 per cu. yd. including 5 cents royalty. Facing stone $9.75 per cu. yd. including 15 cents royalty. Facing stone set per cu. yd., $10.97.

Dimension masonry (including dressing) $30.08 per cu. yd. Cement in shed at dam, American $1.00 1/2, Portland $2.31 1/2$ and $2.51 1/2. Laborers paid $1.25 and stone masons $3.50 per day. Double teams hauled stone, 1 to 1 1/2 cu. yd, per trip, six to eight trips per day.

Titicus Dam

(Fig. 44).

The quantities of the principal items of work and the contract prices were as follows:

Earth excavation and disposal in embankments, 500,000 cu. yd at

• • • • $0.25

Other items of earth excavation, 6000 cu. yd. at................

$0.25 to 0.40

Rock excavation, 33,000 cu. yd. at...........................

... 2.25

Permanent timber work, 175 M ft. B.M. at....................

$30 and 32

Concrete, 1500 cu. yd. at....

$4 and 4.50

Brick masonary 500 cu. yd. at....

.... 12.00

Rubble masonry in 1-2 American cement mortar, 140,000 cu. yd. a

... 3.40

Additional price for substituting in above:

1 - 1 American cement mortar...

....................0.70

1 - 1 Portland cement mortar....

............................2.50

1 - 2 Portland cement mortar..

......... 1.75

1-3 Portland cement mortar........................

............... 1.00

Granite dimension stone masonry, 1100 cu. yd. at.........

......... 20.00

Facing stone masonary, 5000 cu. yd. at..................

.........................12.00

About 200 tons of pipe and special castings at..................

$38.00 and 100.00

Other items as face work of masonry, paving, rip-rap, valves, etc. brought total to..............

......... $933,065

Section of Titicus dam, New York.

Fig. 44. Section of Titicus dam, New York; built 1890 to 1895; length, 534 ft.; max. height, 109 ft; contains about 149,000 cu. yd.; contract price, $933,065.

The face masonry was laid with beds perpendicular to face. Six derricks and thirty-six masons averaged 3240 cu. yd. per month. Maximum progress 5700 cu. yd. per month.

New Croton Dam

(Fig. 45, Also See Fig. 17).

As first conceived and designed this dam was known as the Quaker Bridge dam. Opposition to the first proposed location caused it to be moved upstream 1 1/8 miles where it was first known as the Cornell dam, changed later to the New Croton. In both design and construction this dam was a notable advance upon anything previously undertaken and there was very little precedent for many of the problems involved. At the time this was undertaken cable-ways, self-swinging derricks, as well as other features of plant had not been developed and were not appreciated as at present. During the early stages of the work several assignments of contract and reorganizations of forces operated to load the job up with much ill-considered or unnecessary plant. The dam as originally designed and largely built consisted of a masonry wall about 500 ft. long in the center of the valley, to be continued on the north side by a masonry waste weir, and on the south side by an earth dam having a masonry core wall founded on rock. The maximum height of the earth dam was to be 120 ft. above the original surface. When these plans were well along toward completion they were reconsidered, and finally no ft. of the earth and core wall section was replaced by extending the original masonry section, thus reducing the maximum height of the earth dam to 50 ft. The delay caused by the reconsideration and change amounted to two or three years.

Fig. 45. Section of New Croton dam, New York; built 1892 to 1906; part rubble masonry; part cydopean masonry; length, 1200 ft.; max. height, 338 ft.; contains 855,000 cu. yd.

The principal items of the original contract and the prices of the accepted bid were as follows:

Earth excavation, 550,000 cu. yd. at...

.... $0.61

Earth excavation, 35,000 cu. yd. at............................

.... 0.95

Rock excavation, 300,000 cu.yd. at...............

1.95

Refill and embankment, 900,000 cu. yd. at....

----- 0.25

Permanent timber work, 320 M. ft. B.M.......................

$40 and $45

Crib work, 8000 cu. yd. at...........

----- 3.00

Rubble masonry (American cement 2-1), 470,000 cu. yd. at.......

----- 4.05

Rubble masonry (Portland cement 2-1), 30,000 cu. yd. at .......

5.346

Rubble masonry (Portland cement 3-1), 50,000 cu. yd. at .......

4.941

Dry rubble, 12,000 cu. yd. at...

----- 2.50

Rip-rap, 5000 cu. yd. at....

... 1.75

Broken stone, 10,000 cu. yd. at....

----- 1.50

Block stone, 25,00 cu. yd. at...

... 15.00

Dimensions stone masonary 3200. cu. yd. at....

... 35.00

Facing stone masonary, 24,000 cu.yd. at..........

... 13.50

Brick masonary, 2000 cu. yd. at....

10.00

Concrete Portland cement, 3000 cu. yd. at....

...6.006

Concrete American cement 10,000 cu. yd. at..............

••• 4.55

Miscellaneous items, face dressing, sodding, etc., makes total....

. $4,150,573

Owing to the many changes made in the plans the actual cost of the dam, not including engineering, land, and legal expenses, was $6,886,872.

The quantities of the main items involved in the dam as finally built were

Earth excavation....

1,821,400 cu. yd.

Rock excavation...

400,250 cu. yd.

Refill ...

900,000 cu. yd.

Masonary, all kinds....

855,000 cu. yd.

The principal items of plant, and their value, have been given as follows, without, however, any statement as to whether value included freight and erection.

56 Hoisting engines, 15 to 25 h.p.............

$33,600

3 10-ton, 1400 ft. cableways, 75-h.p. engines....................

30,000

10 10-20 ton locomotives......................................

30,000

75 5-7 ton derricks...

75,000

8 pumps....

8,000

5 Rock drills................................................

4,500

2 pile drivers, 3000-lb. hammers..............

1,000

8 Concrete mixers,3 1/2 and 5 cu. yd.............

8,000

3 Stone crusher....

7,000

3 Electric light dynamos............

2,000

80 Flat cars..............

12,000

100 Dump cars.........

10,000

750 Tons steel rails.............................................

30,000

36 Boilers, 10 to 100 h.p....

14,000

3 Steam shovels............

15,000

1 Dredge.....

5,000

75 Teams, with wagons, carts, rollers, scrapers....................

40,000

27 Steam engines, 10 to 60 h.p..................................

5,000

Machine shop.....

7,000

Saw mill....

1,000

Sand and gravel screening plant.....

1,000

8 Derrick swing swing attachments..........

1,200

6 Steam derrick swings.........

1,800

50 Dump buckets...........

3,000

6 3-yd.skips.........

600

200 2yd.skips...

4,000

Duplicate parts for repairs........

5,000

Miscellaneous tools and equipment......

20,000

$374,7000

The cost of laying rubble masonry during 1898 and 1899 when average conditions prevailed, and ten hours constituted a day's work, was about as follows:

Quarrying..................$0.841

Based on labor prices

Sand pits.......................0.073

Cleaning stones... 0. 079

Motar1.....

Masonry......1.118

Quarrymen. $1.50-$1.75

Rigging.......... 0.046

Masons........3.00

Pumping.....................0.103

Hioisting engineers. 2.00

Plant............ 0.200

Stone cutters.........3.00

Insurance...............0.021

Labor...........1.50

Office.........................0.081

Total........ $3.208

1 For 1-2 American cement mortar; for 1-2 Portland cement mortar substitute $1.71 and for 1-3 Portland cement mortar substitute $1,357. For further cost figures see pages 34-36, 80, 92, 142.

The maximum force employed was 475 men on the dam, and 376 men in the quarry. The largest month's work on rubble masonry was during June, 1898, when 17,186 cu. yd. were laid. On Cyclopean masonry the largest month's work was during August, 1904, 17,000 cu. yd.

Acknowledgment is made of the principal sources of information "The Design and Construction of Dams," by Edward Wegmann.

"The Construction of the New Croton Dam," by Edward Wegmann and J. B. Goldsborough in the Journal of the American Society of Engineering Contractors, November, 1910.

The Foundations of the New Croton Dam, by Chas. S. Gowen, Transactions American Society Civil Engineers, June, 1900.

The Changes at the New Croton Dam, by Chas. S. Gowen, Transactions American Society Civil Engineers, June, 1906.

Various issues of Engineering News, Engineering Record, Engineering Contracting.