This section is from the book "Building Construction And Superintendence", by F. E. Kidder. Also available from Amazon: Building Construction And Superintendence.
One inch thick, supported at both ends.
For other thicknesses, multiply the load in table by the thickness of the beam in inches. For concentrated load at centre divide by two. For permanent loads such as masonry, reduce 10 per cent.
Span In feet. | Depth of Beam in Inches. | |||||||||
4 | 6 | 7 | 8 | 9 | 10 | 12 | 14 | 15 | 16 | |
1 lbs. | lbs. | lbs. | lbs. | lbs. | lbs. | lbs. | lbs. | lbs. | ||
6 | 588 | 1,200 | 1,688 | 2,188 | 2,700 | 3,333 | 4,800 | 6,533 | 7,500 | 8,533 |
8 | 400 | 900 | 1,226 | 1,600 | 2,025 | 2,500 | 3,600 | 4,900 | 5,633 | 6,400 |
10 | 820 | 720 | 980 | 1,280 | 1,620 | 2,000 | 2,880 | 3,920 | 4,500 | 5,120 |
12 | • • • • | 600 | 816 | 1,066 | 1,350 | 1,666 | 2,400 | 3,266 | 3,750 | 4,266 |
14 | • • • • | 514 | 700 | 914 | 1,157 | 1,428 | 2,056 | 2,800 | 3,214 | 3,656 |
15 | ..... | 480 | 658 | 853 | 1,080 | 1,333 | 1,920 | 2,613 | 3,000 | 3,412 |
16 | • • • • | • • • • | 612 | 800 | 1,012 | 1,250 | 1,800 | 2,450 | 2,816 | 3,200 |
17 | • • • • | • • • | • • • | 753 | 953 | 1,176 | 1,694 | 2,306 | 2,653 | 3,012 |
18 | • • • | • • • | • • • • | • • | 900 | 1,111 | 1,600 | 2,177 | 2,500 | 2,844 |
20 | • • • | • • • | • • • | • • • | • • • • | 1,000 | 1,440 | 1,960 | 2,250 | 2,560 |
22 | • • • • | • • • • | • • • | • • • | • • • | • • • | 1,309 | 1,782 | 2,045 | 2,327 |
28 | • • • • | • • • | • • • • | • • • | • • • | • • • | • • • | 1,704 | 1,956 | 2,226 |
24 | • • • • | • • | • • | • • • • | • • • | • • • • | • • • • | 1,633 | 1,875 | 2,133 |
26 | • • • • | • • | • • • | ......• | • • • | * • • | • • • • | 1,568 | 1.800 | 2,048 |
27 | • • | .... | • • | • • • | • • • | • • • | • • • • | 1,451 | 1,666 | 1,896 |
Loads below and to the left of heavy line may crack plastered ceilings.
Tables VI and VII give the safe distributed loads for long leaf yellow pine and spruce beams 1 inch thick, by which the strength of beams of any thickness may be easily obtained.
 
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