708 
MR. FAIRBAIRN’S EXPERIMENTAL INQUIRY 
span, in the ratio of 6 : 5 in favour of the first position with the rib downwards. For 
plans and sections of these beams see Plate LVIII. fig, 18. 
Table XVIII. Experiments on Wrought-iron Beams (continued). 
No. 
of 
exp. 
Description and form of the beam. 
Weight 
laid on 
middle. 
Deflections 
with these 
weights. 
Breaking 
weight of 
the beam 
of 7 feet 
between 
the sup- 
ports. 
Weight of 
the beam 
of 7 feet 
6 inches 
long. 
Oak beams. 
Remarks. 
Side of 
square of 
oak beams 
of equal 
strength 
with the 
iron one. 
Weight of 
such beams 
of 7 feet 
6 inches 
long and 
specific 
gravity 900. 
7. 
Solid ttTOi 
2 inches long 
upon props 
rib upwards. 
Form and c 
I 
ctr 
r 
a 
jght-iron beam, 4 feet 
weighing 23 lbs., placed 
4 feet asunder; vertical 
imension of section. 
1 Thickness at 
3 a = -24 
? i = -29 
I c = -41 
II d ^ = "36 
AB=2-50 
3 CD =2-85 
lbs. 
1394 
1932 
2470 
2739 
3008 
•135 
•24 
•59 
•90 
1-35 
lbs. 
1790 
lbs. 
41-4 
inches. 
2*9461 
lbs. 
25-43 
With 3008 lbs. the elas- 
ticity was entirely destroy- 
ed, and a like additional 
weight would have de- 
stroyed the form of the 
beam. 
8. 
Same beam rendered straight, and 
turned with its rib downwards “p. 
1394 
1932 
2470 
2739 
3008 
3142 
•17 
•25 
•66 
1-22 
2-20 
sunk 
1870 
41-4 
2-9894 
26-18 
9. 
Solid bean 
length 5 feet 
Distance betv 
upwards thus. 
A 
1 
13 
, same form as before ; 
■| inch ; weight 25^ lbs. 
feen supports 4 feet ; rib 
See fig. to experiment 7. 
Thickness at 
a = -23 
h = -30 
c = -40 
^ d = 
AB = 2-05 
CD =2-95 
1394 
1932 
1526 
2201 
2335 I 
in a few 
minutes J 
•30 
•86 
119 
1-59 
204 
213 
1334 
37-6 
2-671 
20-90 
After bearing the weight, 
2335 lbs., it had taken a 
permanent set, or flexure 
= 1-71 inch, and would 
have sunk more if it had 
not been unloaded. 
10. 
Same beam rendered straight and 
turned upside down thus “p. Distance 
between supports 4 feet. 
1394 
1932 
2201 
23351 
in ami- 
nute J 
2469 
•27 
•51 
101 
1- 57 
1-60 
2- 50 
1411 
37'6 
2-7215 
21-70 
After bearing 2469 lbs. 
it was unloaded, as a little 
additional weight would 
have destroyed its form. 
The experiments in this Table were made on solid T iron, and indicate nearly the 
same proportions, as respects their strength, as the beams composed of a plate and 
double angle-iron riveted together. The whole of these beams appear to be defective 
in form, and are therefore not calculated to sustain a severe transverse strain. To 
attain the section of greatest strength, it is probable a dilferent form would be re- 
quired, as well as a dilferent proportion of the parts, such as in the annexed figure with 
a double flange^. 
* Since the experiments herein recorded were made, others have been instituted on some deck-heams by 
Mr. Kennedy of Messrs. Bury, Curtis and Kennedy, Liverpool, the particulars of which are inserted in the 
Appendix. 
