Encyclopaedia Britannica, 11th Edition, "Bréquigny, Louis Georges Oudard Feudrix de" to "Bulgaria" / Volume 4, Part 3

by Various

M = R₁p-∑(W₁p₁+W₂p₂ ...)

where the summation extends to all the loads to the left of a b. If the loads on the right of the section are considered the expressions are similar and give the same results.

If A_t A_c are the cross sections of the tension and compression flanges or chords, and h the distance between their mass centres, then on the assumption that they resist all the direct horizontal forces the total stress on each flange is

H_t = H_c = M/h

and the intensity of stress of tension or compression is

f_t = M/A_th,

f_c = M/A_ch.

If A is the area of the plate web in a vertical section, the intensity of shearing stress is

f_x = S/A

and the intensity on horizontal sections is the same. If the web is a braced web, then the vertical component of the stress in the web bars cut by the section must be equal to S.