172
MOLESWORTH’S POCKET-BOOK
Stress Diagrams for Braced Girdbbs. (Dewar.)
On the vertical line A Y set off, with any scale, the units of
load at each apex (= in this case | total load evenly distributed).
Draw, from each point thus set off, lines parallel to the top
and bottom booms ; and diagonal lines parallel to the bracing.
The stresses may be measured off by the scale of units.
STRESS DIAGRAM.
GIBDER DIAGRAM. LOAD DISTBIBVTE».
STRESS DIAGRAM.
Alternative Load.
MAXIMUM STRESS ON EACH DIAGONAL FROM A PARTIAL
TKAVILLINQ LOAD UMLFOKMir DISTBIBUTED. (Dewar.)
Draw BC as before, supposing
the whole girder loaded; and B A at any con-
'** venlent angle. To any convenient scale set out
B1 = 1; 1,2 = 2; 2, 3 = 3; 3,4 = 4, ending at 6, 7 = 7, the
number of loaded apices In the girder. Join 7 C and draw
lines parallel to it through 6,5,4, &c., cuttingB C, and through
the points of intersection draw horizontal lines and zigzag lines
parallel to the diagonals as before. The diagonals represent
the greatest stress from a travelling load. Beyond the centre
D they represent the greatest compression on what would be a
tie if the load were fixed, and tension on what would be a strut.