Length of bearing in feet.

Depth 10 in.

Depth 11 in.

Depth 12 in.

Depth 13 in.

Depth 14 in.

Depth 15 in.

Depth 16 in.

Depth 17 in.

Depth 18 in.

breadth, inches.

breadth, inches.

breadth, inches.

breadth inches.

breadth, inches.

breadth, inches.

breadth, inches.

breadth, inches.

breadth, inches.

10

7 1/2

5 1/2

4

3 1/2

2 3/4

2 1/4

12

1 1/2

1 1/4

11

9

6 3/4

5

4 1/4

3 1/4

2 3/4

2 1/4

2

1 3/4

12

10 1/2

8

52

5

3 3/4

3 1/4

2 3/4

2 1/4

2

13

12 1/2

9 1/2

6 3/4

5 3/4

4 1/2

3 3/4

3

2 1/2

2 1/4

14

14 1/2

10 3/4

7 3/4

6 3/4

5 1/4

4 1/2

3 1/2

3

2 1/2

15

16 1/2

12 1/2

9

7 3/4

6

5

4

3 1/2

3

16

18 3/4

14

10 1/4

8 3/4

7

5 3/4

4 3/4

4

3 1/4

17

_______

16

11 1/2

9 3/4

8

6 1/4

5 1/4

4 1/2

3 3/4

18

..

17 3/4

13

11

8 3/4

7 1/4

6

5

4

19

..

19 3/4

14 1/2

12

9 3/4

8

6 1/2

5 1/2

4 3/4

20

..

_______

16

13 1/2

10 3/4

9

7 1/4

6

5 1/4

21

...

..

17 1/2

15

12

9 3/4

8

6 3/4

5 3/4

22

...

..

19 1/2

16 1/2

13

10 3/4

8 3/4

7 1/2

6 1/4

23

...

...

___

18

14 1/4

11 1/2

9 1/2

8

6 3/4

24

..

...

..

19 1/2

15 1/2

12 3/4

10 1/2

82

7 1/2

25

16 3/4

13 3/4

11 1/4

9 1/2

8

26

Depth 19 in.

Depth 20 in.

Depth 21 in.

18 1/4

15

12 1/4

10 1/4

8 1/2

27

19 3/4

16

13

11

9 1/4

28

Breadth, inches.

Breadth, inches.

Breadth, inches.

___

17 1/4

14 1/4

11 3/4

10

29

18 1/2

15 1/4

12 3/4

10 3/4

30

9 3/4

8 1/2

7 1/2

19 3/4

16 1/4

13 1/2

11 1/2

31

10 1/4

9.

7 3/4

17 1/4

14 1/2

12 1/4

32

11

9 1/2

8 1/4

18 1/2

15 1/2

13

33

11 3/4

10

8 3/4

19 3/4

16 1/2

14

34

12 1/2

10 3/4

9 1/2

17 1/2

14 3/4

35

13 1/4

11 1/2

10

18 1/2

15 3/4

36

14

12

10 1/2

19 1/2

16 1/2

Example. - The scantling for a girder of 20 feet bearing may be 16 inches in breadth and 12 inches deep; or the breadth may be 13* inches, and the depth 13 inches, and so on; but where there is space to admit of a deep girder it requires 1ess timber.

This Table is calculated by the equation 74l2/d3 = b; where l is the length in feet, and b and d the breadth and depth in inches. The bearing is the distance between the centres of the supporting wall-plates; and the scantlings the least that will answer the purpose.

* Pinus sylxestris, see Art. 515.

No. II. Table Of The Scantlings Of Binding Joists, Of Baltic Pink, For Different Bearings, From 5 To 20 Feet, When The Distance From Middle To Middle Is 6 Feet. See Sect, III., Arts. 209 And 210

length of bearing in feet.

Depth 6 in.

Depth 7 in.

Depth

8 in.

Depth 9 in.

Depth 10 in.

Depth 11 in.

Depth 12 in.

Length of bearing in feet.

breadth, inches.

breadth, inches.

breadth, inches.

breadth, inches.

breadth, inches.

breadth, inches.

breadth, inches.

5

4f

3

2

5

6

6 3/4

4

3

2

6

7

________

5 1/2

4

2 3/4

2

7

8

..

7

5 1/4

3 3/4

2 3/4

2

8

9

..

______

6 1/2

4 1/2

3 1/2

2 1/2

9

10

..

..

8

5 1/2

4

3

2 1/2

10

11

Depth 13 in.

Depth 14 in.

Depth 15 in.

6 3/4

5

3 3/4

3

11

12

8

6

4 1/2

3 1/2

12

13

Breadth, inches.

Breadth, inches.

Breadth, inches.

______

7

5 1/4

4

13

14

8

5 3/4

4 1/2

14

15

4

3 1/2

2 3/4

9

6 3/4

5 1/4

15

16

4 1/2

3 3/4

3 1/4

10 1/4

7 3/4

6

16

17

5 1/4

4 1/2

3 1/2

_______

8 3/4

6 3/4

17

18

5 3/4

4 3/4

4

10

7 1/2

18

19

6 1/2

5 1/2

4 1/4

8 1/4

19

20

7 1/4

6

4 3/4

9 1/2

20

Example. - If it be required to find the scantling for a binding joist for a 10 feet bearing, assume 9 inches to be the depth suited to the floor; then, opposite 10 feet, in one of the side columns, and under 9 inches at the head of one of the middle columns, we find 5 1/2 inches, the breadth required. If 8 inches had been fixed upon for the depth, it would have required 8 inches in breadth to be equally as stiff as one 9 by 5 1/2. If the bearing be 19 feet, and 13 inches should be of convenient depth, then opposite 19 in the side columns, and under depth 13 inches, we find 6 1/2 inches, the breadth required.

This Table is calculated by the rule 402 /d3= b; where l is the length in feet; and d the depth, and 6 the breadth, each in inches.