Short posts of cast iron, with a length in inches not exceeding eight times their least dimension, may be safely loaded with six tons for each square inch of metal in the cross section.

The safe load for longer columns should be computed by means of accepted formulas. These formulas vary for different forms of cross section; they may be found in most books of references. The following table gives the safe loads for hollow cylindrical columns with {-inch shell, and caps and bases cast as described in Section

260. Tables for other thicknesses of shell and for square and rectangular columns are given in the Architects' and Builders' Pocket Book.

Table IV. Safe Loads In Tons For Hollow Cylindrical Cast Iron Columns

Thickness of Shell ¾ Inch.

Length column.

Diameter of column (outside).

6 ins.

7 ins.

8 ins.

9 ins.

10 ins.

11 ins.

12 ins.

13 ins.

Feet.

Tons.

Tons.

Tons.

Tons.

Tons.

Tons.

Tons.

Tons.

6

60.6

78.1

94.0

110.8

128.6

144.9

161.7

180.0

7

55.7

72.2

88.9

106.9

124.2

140.1

156.4

176.0

8

50.7

66.3

83.8

101.1

117.7

135.2

151.1

170.3

9

45.8

61.9

78.7

95.2

113.4

130.4

1458

164.5

10

40.8

56.0

73.5

89.4

106.8

123.2

140.5

158.7

11

37.1

51.5

68.4

83.6

100.1

118.3

135.2

153.0

12

334

47.1

63.3

79.7

95.9

113.5

129.9

147.2

13

30.9

44.2

58.1

739

89.4

106.3

124.6

141.4

14

27.2

39.8

547

70.0

85.0

101. 4

119.2

135.6

15

24.7

36.8

496

64.1

78.5

96.6

114.0

129.9

16

22.3

33.9

46.2

60.3

71.9

91.8

108.7

124.1

18

• •. •

29.0

41.0

52.5

67.6

84.5

103.4

118.3

20

. •. •

24.4

36.0

44.7

63.3

77.2

98.1

112.5

Metal area of cross-section.

sq. ins.

sq. ins.

sq. ins.

sq. ins.

sq. ins.

sq. ins.

sq. ins.

sq. ins.

12.37

14.73

17.10

19.44

21.80

24.15

26.51

28.86

Table V. Safe Loads, In Pounds, For Gas Or Steam Pipe Columns. Computed By Formula

Safe Load = Metal Area x (11,000 - 35 l/r)

Nominal Size.

External Dia.

Thickness.

Weight per foot.

Area of Section.

r

Length in Feet.

8

9

10

12

14

ins.

ins.

ins.

lbs.

lbs.

lbs.

lbs.

lbs.

lbs.

Standard Pipe.

2½

2.875

.204

5.74

1.59

.94

11,810

11,030

10,420

3

3.5

.217

7.54

2.26

1.16

18,290

17,500

16,710

15,050

3½

4.0

.226

9.00

2.59

1.35

22,040

21,330

20,510

18,790

17,250

4

4.5

.237

10.66

3.33

1.50

28,900

28,230

27,300

25,440

23,570

4½

5.0

.247

12.34

3.73

1.68

33,570

32,674

31,760

29,800

27,970

5

5.563

.259

14.50

4.17

1.88

37.530

37.530

36,520

34,630

32,520

6

6.625

.280

18.76

5.57

2.25

50,130

50,130

50,130

48,790

46,640

7

7.625

.301

23.37

7.18

2.59

64,620

64,620

64,620

64,620

62,640

8

8.625

.322

28.18

8.14

2.94

73.260

73.260

73.260

73,260

73,260

XX Strong.

2½

2.875

.56

13.68

4.09

0.82

28,200

26,090

23,722

3

3.5

.608

18.56

5.52

1.02

42,500

40,240

38,080

33,120

3i

4.0

.642

22.75

6.63

1.20

54.360

52,040

49,720

45,o8o

39,78o

4

4.50

.682

27.48

8.33

1.35

70,630

68,300

65,680

60,390

55,140

5

5.563

.75

38.12

11.73

1.70

105,570

102,754

99,880

94,130

88,320

6

6.625

.875

53.11

15.80

2.04

142,200

142,200

141,170

133,980

128,450