Tensile Strengths of Ropes

Manila Rope 3 strands, 3g in. long

Manila Rope 4 strands, 36 in. long

Cast-steel Wire Rope

6 STRANDS

Circumference

Breaking load

Circumference

Breaking load

Circumference

No. of wires in strand

Breaking load

in.

lb.

in.

lb.

in.

  

lb.

1.625

1,750

2.825

4,250

1.062

6

6,285

2.25

3,680

3.375

6,050

1.375

19

11,850

2.375

4,750

3.75

7,700

1.563

19

12,590

2.812

5,400

4.25

11,140

1.595

19

19,500

3.188

6,800

4.825

14,020

1.780

19

19,150

3.625

7,635

5.375

16,550

1.938

19

21,510

4.375

8,980

3.188

7,700

      

4.75

11,870

3.125

7,630

      

5.125

15,100

          

2.562

2,850

          

3.033

4,930

          

4.188

11,650

          

Tile-draining

Number of feet of drain tile required per acre when placed the  specified distances apart (Fippin)

20 feet apart....................    2180 feet

25 feet apart...................    1743 feet

30 feet apart...................    1452 feet

40 feet apart...................    1090 feet

50 feet apart...................      872 feet

100 feet apart...................      436 feet

150 feet apart...................      290 feet

200 feet apart...................      218 feet

Limit of size of drain tile to grade and length (Elliott)

Size of Tile in Inches

Minimum

Grade per

100 Ft. in

Feet

Limit of Length in Feet

2..................

.10

600

3..................

.09

800

4 . . . . ..............

.05

1600

5..................

.05

2000

6..................

.05

2500

7..................

.05

2800

8..................

.05

3000

9 ..................

.05

3500

10 ..................

.04

4000

11 ..................

.04

4500

12 ..................

.04

5300

These limits are based on perfectly laid tile, which is seldom achieved. The lay of the land, the nature of the earth, the occurrence of rocks and trees and other obstructions, the necessity of making detours, and other conditions, all influence the theoretical limits of efficiency.

Conditions that determine the size of the drains, particularly the mains (Elliott) : —

1.  The depth of water to be removed in twenty-four hours over the area of the drainage system.

2.  Rapidity with which the water is brought to the main, that is, the number, size, and fall of the laterals.

3.  The existence of emergency surface drainage.

4.  The texture and physical condition of the soil, that is, whether it is open and porous or dense and retentive.

5.  The grade of the ditch.

Number of acres from which 1/4 inch of water will be removed in 24 hours by outlet tile-drains of different diameters and different lengths with different grades (adapted from Elliott)

Diameter of

Tile in

Inches

Grade in Inches per 100 Feet

1

2

3

6

9

Length of Drain in Feet

1000

2000

1000

2000

1000

2000

1000

2000

1000

2000

 

Acres of Land drained by Different Sizes of Tile

5 .

19.1

15.7

22.1

19.4

25.1

22.7

32.0

30.3

37.7

36.3

6 .

29.9

24.8

34.8

30.5

39.6

35.9

50.5

47.8

59.4

57.3

7 .

44.1

36.4

31.1

44.8

58.0

52.8

74.0

70.1

87.1

84.1

8 .

61.4

50.7

71.2

62.6

80.9

73.6

103.3

98.0

121.4

117.3

9 .

82.2

68.1

95.3

83.8

108.4

89.6

138.1

131.3

162.6

157.1

10 .

106.7

88.5

123.9

108.9

140.6

128.1

179.2

170.5

211.1

204.4

12 .

167.7

139.3

194.6

171.6

221.1

201.8

281.8

268.6

331.8

321.7

14 .

245.3

204.3

284.9

251.7

323.5

296.1

412.9

393.9

485.8

472.1

16 .

341.4

284.6

369.3

350.4

449.9

412.2

573.7

548.8

675.2

657.3

18 .

456.4

381.3

529.1

470.1

601.8

552.5

767.4

733.1

902.3

880.5

20 .

591.5

245.9

686.3

610.5

780.0

718.2

994.5

954.6

1170.0

1144.0