(Solved): A box beam is fabricated from two plywood webs that are secured to dimension ...

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A box beam is fabricated from two plywood webs that are secured to dimension lumber boards at its top and bottom flanges. The beam supports a concentrated load of \( P=3700 \mathrm{lb} \) at the center of a 14 -ft span. Bolts (3/8-in. diameter) connect the plywood webs and the lumber flanges at a spacing of \( \mathrm{s} \) \( =10 \) in. along the span. Supports \( A \) and \( C \) can be idealized as a pin and a roller, respectively. [ \( w=4 \) in., \( b=0.25 \) in., \( t=5 \) in., \( h=17 \) in.] What is the first moment of area (Q) that is needed for the calculation of shear flow in the bolts? \[ \begin{array}{l} 782 \text { in. }^{3} \\ 220 \text { in. }^{3} \\ 731 \text { in. }^{3} \\ 675 \text { in. }^{3} \\ 708 \text { in. }^{3} \end{array} \]