Homework $3$

$1$

Multiple Answer

$50$ points

Shown in the figure below is a sawn lumber beam made of Douglas$-$Fir $4"$x No$1$ & Btr grade. Select the correct option$($s$).$ Multiple options may be correct, and negative scoring is applicable for wrong answers.

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$L=21ft$

The maximum deflection in the beam is $0\mathrm{.}7$ in

Sawn lumber section with nominal size $($bxd$)414$ will work

The maximum deflection in the beam is $0\mathrm{.}5$ in

The minimum section modulus required is $115\mathrm{.}8i{n}^3$

The actual bearing stress in the beam is $180$ psi, assuming bearing length is $3\mathrm{.}5$ in

The maximum bending moment in the beam is $138915$ lb $-$in

The minimum section modulus required is $100i{n}^3$