I just tried solving it by hand and got an X value of -5.65 inches so i know its wrong. do you know of any "safer" means of solving it. Thank you so much for helping check my work.
The next step i took was to sum the for the MOI for all 4 parts:
Iz=\sum(bh^3)/12 + Ad^2 , which resulted in...
To solve for my Ybar i broke the region into 4 parts:
Part_______ Area______Ybar_______Ybar*Area
1:________.75*x_____.75+x/2____.5625x+.375x^2
2:________.75*x_____.75+x/2____.5625x+.375x^2
3:________.75*x_____.75+x/2____.5625x+.375x^2
4:________.75*21______.375________5.90625
Area Total...
okay so here is what i have so far:
the moment cap. of the un-stiffened plate i used Iz=(bh^3)/12= (21)(.75^3)/12= .73828
then knowing \sigmaallow=Mc/Iz i solved for M where c=(3/4)/2 resulting in M equaling roughly 53.15 kip*in.
my next step is finding the centroid of the stiffened base plate...
A ¾” by 21” wide base plate is required to resist an applied moment of 250 in-kips,
(bent about the weak axis). The allowable stress for the plate is 0.75*fy and fy = 36 ksi.
The plate may not work and may require stiffeners. Three stiffeners can be welded onto
the plate and used to increase...