RUPTURE STRESSES IN BEAMS AND CRANE HOOKS. 



215 



Of the rectangular specimens C and D agree fairly well, but E, which is square, falls 

 short in the induced stress. 



F, G, and H are comparable as a group, and the results in the cases F and Gr are 

 quite satisfactory. H, however, shows a deficiency in the induced stress which is 

 somewhat marked on the 36-inch span, but less so on the 15-inch span. This may 

 be explained by the fact that it is impossible for the web portion of the section as it 

 is laid to be stressed to its full rupture value before the flanges give way. But if we 

 consider this section as made up of the flanges only, as shown by the shaded portions 

 of H, then the results are much nearer agreement, and are given in the table as jH-, 

 and 2H2. Section K was also tested for two lengths of span, the results of which 

 differ somewhat. If the average of the induced stresses be taken, it agrees with the 

 direct tension result. 



Table II. gives the results of these tests. 



Table II. 



Beams. 



Tension Tests. 



Section. 



Area in 

 sq. in. 



Vt + Vc- 



Central 

 Load. 

 Tons. 



Span. 

 Ins. 



Fibre Stress, 



2WL 



torc=— — . 



Myt+ycH 



Tons per sq. in. 



Area in 

 sq. in. 



Total 

 Load. 

 Tons. 



Tensile Stress 



per sq. in. 



Tons. 



A 



•7854 



•425 



•428 



36 



23-08 



•7854 



18-75 



23-87 



B 



•463 



•755 



•485 



36 



24-98 



•463 



11-62 



25-10 



C 



•805 



•805 



•805 



36 



2236 



•805 



18-8 



23-35 



D 



1-8 



•45 



•925 



36 



20-55 



•163 



3-28 



20-1 



E 



•93 



•48 



•477 



36 



1923 



•93 



23-6 



25-34 



F 



•26 



•445 



•135 



36 



21-00 



•123 



309 



25-1 



Gj 



•81 



•39 



•383 



36 



2182 



•161 



375 



23-3 



G 2 



•81 



•39 



1-055 



15 



2504 



•161 



3-75 



233 



Hi 



•448 



•266 



•109 



36 



16-43 



•108 



2-64 



24-46 



H 2 



•448 



•266 



•285 



15 



17-88 



•108 



2-64 



24-46 



iH, 



•285 



•315 



•109 



36 



21-86 



•108 



2-64 



24-46 



2^2 



•285 



•315 



•285 



15 



23-81 



•108 



2-64 



24-46 



Ki 



•67 



1-31 



•87 



36 



17-84 



•137 



2-99 



21-76 



K 2 



•67 



1-31 



2-725 



15 



23-29 



•137 



2-99 



21-76 



II. Bending Moment in Cases of Eccentric Loading, as Hooks, etc. 



Another and important case is where a section is subjected to non-axial loading, 

 as in crane hooks. 



Under such conditions a section as AB of fig. 2 is generally said to experience : — 

 (l) A uniformly varying stress due to the bending moment of a couple of magni- 

 tude WL, the intensity at any point varying directly as the distance of 

 that point from a fixed axis N in the plane of the section known as the 

 neutral axis of stress ; 



