I have this problem i cannot figure out. I dont understand why the first moment of the shaded area with respect to the centroidal axis (Q) includes the upper flange?

Since i am looking for the shear in the bolts i took one of the angles and used that for my Q, therefore the bolt is acting in single sheer (acting longitudially).

I do it in using my method using only 1 angle and i get 265KN not 255KN. So i dont know why they use the top flange and the two angles instead of just using 1 flange.

if anyone is good at this hit me up!



Jason NYC