.972 THE STRENGTH AND ELASTICITY OF IRONBARK TIMBER 
- » therefore equals the intensity of longitudinal shearing s 
at the neutral axis of the beam. If we take the case of 
beams bolted together without transomes, this longitudinal s 
_will have to be resisted by the bolts, otherwise the two beams 
not act as a solid beam of the same depth; there will also 
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considered the neutral layer), the sectional area o 
being determined with reference to the longitudinal shearing § 
longitudinal stress is determined, and it is then only necessary 
know the resistance of the material to shearing stress, both 2a 
and across the grain. 
The following experiments were made on a strutted beam, § 
fig, 10, the load was applied in the centre, and a weight of 50 
was connected with the extremity of the cantilevers to rep 
the effect of the weight of adjacent spans, in the manner al 
eseribed three sets of experiments were made ; first, with a ce 
weight, which was increased to the breaking point which occu 
with 2,850 lb. The beam failed immediately over the poi 
64. 
_ The following tables show loads and deflections :— 
: _ | Delotta, Ww. Beri 
| 
{ 
Tb. inches. tb. inches. 
. 100 0-05 1,300 | 0-47 
A 200 0°10 1,500 0°52 
300 0-12 1,7 | 0°59 
500 0-17 1,900 0°67 
- 700 0-24 2,100 | 0°75 
900 - 0°32 2,300 0°82 
1,100 0-41 2 500 0°S7 
; 2,800 
~The broken timber was then replaced with sound timber, 
the load applied at the points.« a, in order to test the stu 
é 
