J. I. HAYCROF'J 



LVII. 



Stresses in the Flanges at points One Metre distant 

 from Centre Lines (Vertical) of each Panel. 





Direct Stress 

 from Horizon- 

 tal Stress at In- 

 flexion Point 

 of Vertical. 



Si 



in 



millim. 



Moment 

 Calculated. 



10 "I, 



V 



in 



kgs. 

 mtrs. 



STRESSES. 



Flange in 

 Panel. 



In kgs. per sq. millim. 



Tons 





Direct. 



Bending. 



Total. 



sq. in. 



j Left 

 1 \ Eight 

 9 \ Left 

 4 } Eight 



Left 

 6 ( Eight 



\ Left 



4 \ Eight 



Left 



5 \ Centre 

 ( Eight 



27,070 



27,070 



74,440 



74,440 



108,270 



108,270 



128,570 



128,570 



135,340 



135,340 



135,340 



19,200 

 19,200 

 19,200 



22,840 

 22,840 

 22,840 

 22,840 

 22,840 

 22,840 

 22,400 

 22,840 



+ 23,200 



-23,200 



+ 17,400 



- 17,400 



+ 11,600 



-11,600 



+ 5,800 



- 5,800 















4,270 



4,270 

 4,270 

 6,200 

 4,200 

 6,200 

 4,200 

 6,200 

 4,200 

 5,600 

 6,200 



1-4 

 1-4 



3-9 

 3-3 

 4-8 

 4-8 

 5-7 

 5-7 

 5-9 

 6-1 

 5-9 



5-4 

 5-4 

 4-1 

 2-8 

 2-8 

 1-9 

 1-4 

 0-9 



o-o 

 o-o 

 o-o 



6-8 

 6-8 

 8-0 

 6-1 

 7-6 

 6-7 

 7-1 

 6-6 

 5-9 

 6-1 

 5-9 



4-3 

 4-3 

 5-1 

 3-9 

 4-8 

 4-2 

 4-5 

 4-2 

 3-7 

 3-9 

 3-7 



From a comparison of tables shewing the results according to 

 rigorous and approximate methods, it will be seen that the only 

 practical discrepancy is in the case of the flange stress at the 

 centre of the longitudinal, where the difference amounts to 

 14 Kilos = 089 tons, but this could be considerably reduced by 

 preserving the same flange area at that point as on either side of 

 it. 



On investigating the case of partial distribution of the live 

 load, it will be found that the greatest increase of total stress due 

 to partial loading on any vertical never exceeds 1 kg. per sq. 

 millim = -6 tons per square inch, so that by making verticals, 3 

 4 and 5 of similar cross sections, this difficulty can be surmounted, 

 and the necessity for complete investigation of partial loading 

 obviated. 



This concludes the investigation of stresses in a girder with 

 parallel flanges, but Professor Vierendeel applies his system to 

 all shapes of truss. The bridge, with parallel flanges of 

 31*5 metres span, was erected in the Park of Terveureu, near 

 Brussells, and tested to destruction under the supervision of two 

 engineers from the Department of Roads and Bridges. It failed, 

 as shown on the photograph, under a distributed load of 404 tons. 



