The Ontario Building Code | Steel Beams

9.23.4.3. Steel Beams

(1) The spans for steel beams with laterally supported top flanges shall conform to Table 9.23.4.3. for floors and Tables A-20 to A-29 for roofs and floors.

Table 9.23.4.3.
Maximum Spans for Steel Beams supporting Floors in Dwelling Units

Forming Part of Sentence 9.23.4.3.(1)

Item

Column 1

Column 2

Column 3

Column 4

Column 5

Column 6

Column 7

Column 8

supported Joist Length, m (Half the sum of joist spans on both sides of the beam)

2.4

3.0

3.6

4.2

4.8

5.4

6.0

Section

One Storey supported

1.

W150 × 22

5.5

5.2

4.9

4.8

4.6

4.5

4.3

2.

W200 × 21

6.5

6.2

5.9

5.7

5.4

5.1

4.9

3.

W200 × 27

7.3

6.9

6.6

6.3

6.1

5.9

5.8

4.

W200 × 31

7.8

7.4

7.1

6.8

6.6

6.4

6.2

5.

W250 × 24

8.1

7.6

7.3

7.0

6.6

6.2

5.9

6.

W250 × 33

9.2

8.7

8.3

8.0

7.7

7.5

7.3

7.

W250 × 39

10.0

9.4

9.0

8.6

8.4

8.1

7.9

8.

W310 × 31

10.4

9.8

9.4

8.9

8.4

8.0

7.6

9.

W310 × 39

11.4

10.7

10.2

9.8

9.5

9.2

9.0

Section

Two Storeys supported

10.

W150 × 22

4.9

4.4

4.1

3.8

3.5

3.4

3.2

11.

W200 × 21

5.6

5.1

4.6

4.3

4.1

3.8

3.7

12.

W200 × 27

6.4

6.1

5.6

5.3

4.9

4.7

4.4

13.

W200 × 31

6.9

6.5

6.2

5.8

5.4

5.1

4.9

14.

W250 × 24

6.8

6.1

5.6

5.2

4.9

4.6

4.4

15.

W250 × 33

8.2

7.7

7.0

6.5

6.1

5.8

5.5

16.

W250 × 39

8.8

8.3

7.8

7.2

6.8

6.4

6.1

17.

W310 × 31

8.7

7.8

7.2

6.7

6.2

5.9

5.6

18.

W310 × 39

10.0

9.3

8.5

7.9

7.4

7.0

6.7

(2) Beams described in Sentence (1) shall at least meet the requirements for Grade 350 W steel in CSA G40.21, "General Requirements for Rolled or Welded Structural Quality Steel".

(3) A beam may be considered to be laterally supported if,

(a) the wood joists bear on its top flange at intervals of 610 mm or less over its entire length,

(b) the load being applied to this beam is transmitted through the joists, and

(c) 19 mm by 38 mm wood strips in contact with the top flange are nailed on both sides of the beam to the bottom of the joist supported.