$4\mathrm{.}6$ An angle $L881$ section is suggested for a shelf angle which is attached to a structural steel frame

system. The Angle spans over $14$ feet $($i$.$e$.,L=14$ feet$).$ The lateral restraints are at ends only. The wall

supported by the angle is $4-$inch brick with a height of $12\mathrm{.}6$ feet.

Use the LRFD method in this problem. The section properties for the angle are $S_x=15\mathrm{.}8i{n}^3,I_x=89\mathrm{.}1i{n}^4.$

For this angle, $F_y=36$ksi.

$($a$)$ Compute the factored moment $M_u$ and end reaction $R_u$ of this angle.

$($b$)$ Compute the moment resistance $M_n$ of the angle.

$($c$)$ Compute the angle deflection in inches.

$($d$)$ Based on your findings in $($a$),($b$)$ and $($c$),$ decide whether the angle is ok$.$

$($e$)$ The connection of this angle to the structural steel is via two A$325$ bolts $($similar to the

example done in class$).$ However, for the welded part, a $4-$inch strip of weld of $\frac{3}{16}$ inches in

size is suggested for the connection of this angle to the structural system $($via a plate bracket$).$

The eccentricity of the reaction $R_u$ with respect to the weld is also $4$ inches and the electrode

type is E$70$xx$.$ Compute the factored shear resistance of the weld using the AISC tables. Based on

your finding and the $R_u$ you computed in Part $($a$),$ decide whether the weld is ok$.$