| Span. | Rise. | Panel. | Chords. | End braces. | Centre braces. | End rod. | Centre rod. |
|---|---|---|---|---|---|---|---|
| 50 | 10 | 7 | 2—8 × 10 | 72 | 5 × 5 | 2—1⅛ | 2—1 |
| 75 | 12 | 9 | 2—8 × 10 | 82 | 5 × 5 | 2—1½ | 2—1 |
| 100 | 15 | 11 | 3—8 × 10 | 92 | 6 × 6 | 2—1¾ | 2—1 |
| 150 | 20 | 13 | 4—8 × 12 | 102 | 6 × 7 | 3—2 | 3—1 |
| 200 | 25 | 15 | 4—8 × 16 | 122 | 7 × 7 | 5—2 | 5—1 |
PRATT’S BRIDGE.
Fig. 68.
181. Assume the following data for an example:—
| Span | 100 | feet. |
| Rise | 12 | feet. |
| Panel | 10 | feet. |
| Weight per lineal ft. | 2,500 | lbs. |
The tension on the lower, or the compression on the upper chord, will be
250000 × 100
96 = 260,417 lbs.
The manner of dimensioning the chord, and of splicing, is the same as already described for Howe’s.