Olive Bridge Dam

(Fig. 48).

The Olive Bridge dam is a portion of a system of dams and dikes retaining the water in Ashokan Reservoir. (See page 143 for brief description.) Olive Bridge dam itself consists of three sections. The central section of masonry dam proper, is 1000 ft. long. At the south end the masonry section merges, in a distance of 170 ft., into a corewall section, and continues as a corewall and embankment dike for a total length of 1700 ft. Similarly at the north end, the masonry second merges in a distance of 166 ft. into a corewali and embankment section of a total length of 2100 ft. Total length of the three sections 4800 ft. The quantities of the main items for each of the three sections, also the contract prices are given below.

Fig. 48. Section of Olive Bridge dam, New York; built 1908 to 1913; cydo-pean masonry; concrete block faces; length 1,000 ft.; max. height 251 ft.; contains 488,200 cu. yd.

South wing

Masonry dam

North wing

Earth excavation, class A at $r.4o per cu. yd...

$4,000

...

$20,000

Earth excavation, class B at $2.50 per cu. yd...

4,000

...

16,000

Earth excavation, class C at $0.68 per cu. yd...

...

150,000

....

Earth excavation, class D at $0.50 per cu. yd...

20,000

...

40,000

Rock excavation, class A at $3.00 per cu. yd....

5,000

95,000

....

Embankment and refilling various classes at $0.50 and $0.60.

630,000

110,000

1,270,000

Concrete masonry at $4.90 per cu.yd...

25,000

.....

35,000

Cyclopean masonry, class A at $3.40 per cu. yd.

...

432,000l

...

Concrete blocks at $11.50 per cu. yd...

...

56,200

...

Paying at $2.50 per cu. yd....................

8,000

...

12,000

Surface dressing, soil at $3.50 per cu. yd........

20,000

...

40,00.

River control, lump sum....

...

10,000

................0

The above prices did not include cement; the contract price of Portland cement was $1.50 per barrel. Concrete blocks required 1.4 barrels of cement per cu. yd. The 432,000 cu. yd. of cyclopean masonry required 449,000 barrels. Cyclopean masonry = 25.3 per cent, stone, balance concrete. Other items pertaining to the main dam were:

Masonry filling of stream flow opening, 8000 cu. yd. at......

$1.50

Cast-iron pipes and special castings, 75 tons at.............

101.00

Steel castings, 80 tons at....

150.00

Reinforcing steel, 25,000 lb. at...

0.07

Wrought iron, cast iron and steel, 590,000 lb. at............

0.08

Bronze work, 4,000lb. at....

0.50

Small pipe, 2500 lin. ft. at...

0.50

Setting all metal work, 900,000 lb. at............

0.02

The plant employed on the work is described on pages 143 and 144.

Kensico Dam

(See Figs. 22, 23, 32).

Of cyclopean masonry, containing expansion joints and drainage system, with upstream face of concrete blocks and downstream face of stone.

1 Includes some concrete.

The contract includes some work on the reservoir, adjacent highways, bridges, etc.

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

Stream control (lump sum).....

$35,000.00

Excavation, class A, 230,000 cu. yd. at...

0.49

Excavation, class B, 650,000 cu. yd. at...

0.50

Excavation, class C, 380,000 cu. yd. at...

1.40

Excavation, class D, 80,000 cu. yd. at........................

2.00

Excavation, rock, blasting not permitted, 40,000 cu. yd. at......

1.50

(Except for the last item the excavation is classified by location, and not as earth and rock).

Special preparation of rock surface, 40,000 sq. yd. at..............

0.50

Refill:

4-in. layers, 30,000 cu. yd. at..........................

0.50

6-in. layers, 130,000 cu. yd. at..........................

0.65

12-in. layers, 230,000 cu. yd. at..........................

0.20

Covering reservoir bottom, 300,000 cu. yd. at.................

0.55

Deposited in bulk, 650,000 cu. yd. at...........

0.25

Surface dressing, 100,000 cu. yd. at.........

0.50

Portland cement , 900,000 bbl. at.........

1..50

Mass concrete, A, 2500 cu. yd. at..........................

5.75

Mass concrete, B, 35,000 cu. yd. at....

5.25

Cyclopean masonry, 900,000 cu. yd. at.......................

2.65

Facing above, 40,000 sq. yd. at..........

0.15

Concrete blocks, 60,000 cu. yd. at............................

7.50

Reinforced concrete, A, 2500 cu. yd. at.......................

12.50

Reinforced concrete B, 8500 cu. yd. at...............

9.00

Grout, 3000 cu. yd. at..............

5.00

Tool dressing concrete, 75,000 sq. ft. at.......................

0.20

Dimension stone masonry, 14,700 cu. yd. at................

$23.05 to $24.54

Face dressing, stone:

Quarry face, 15,000 sq. ft. at...........

0.13

Bull point 80,000 sq. ft. at...............

0.25

Rough point, 4000 sq. ft. at..............................

0.25

Fine point, 160,000 sq.ft. at....

0.30

4 cut, 150,000 sq. ft. at.................

0.55

6 or 8 cut 1000 sq. ft. at...............

1.00

Straight cast-iron pipe, 350 tons at..........................

60.00

Special cast-iron pipe, 70 tons at.............

100.00

Stone wall, 110,000 lin. ft. at............

0.80

Wooden fence and gaurd rail 25,000 lin. ft. at..............

0.30

Wire fence, 55,000 lin. ft. at...........

0.50

Macadam, 15,000 cu. yd. at................

3.00

Also numerous small items.

Total amount of bid ..............................

$7,953,050.00

In the light of some revision of quantities, and separating those quantities that pertain to the reservoir and the highways, the dam proper will require:

Excavation...

1,200,000 cu. yd.

Embankment.............

2,000,000 cu. yd.

Cyclopean masonry..

800,000 cu. yd.

Concrete blocks..........

60,000 cu. yd.

Dimension stone masonry..............

21,000 cu. yd.

Roughly squared stone masonry....

8,000 cu. yd.

Mass concrete.......

42,000 cu. yd.

Reinforced concrete..........

11,000 cu. yd.

Portland cement......

900,000 barrels

Pipe, valves, and other metal work, value.............

$180,000

Numerous small unlisted items, make the estimated total cost of the dam, including waste weir, waste channel and conduit, drainage system, and grading of grounds, about $6,735,000.

For further information regarding the work and methods, see pages 37, 77, 91, 107, 108, 144, 163.

For illustrated description of crushing plant see Engineering News, February 22, 1912.

The maximum height of 300 ft. is from a point 130 ft. below stream bed and applies to a very short distance. General section is 250 ft. high.

At 300 ft. below crest the thickness is 230 ft.