Question $2(10$ marks$)$

The beam above is made from D$.$ Fir$-$L $24$f$-$E glulam and is subjected to two equally spaced point

loads as shown. Each load imparts $30kN$ of dead load and $16kN$ of snow load. The beam is fully

laterally restrained along its top face. Deflections for the beam must be kept to $\frac{L}{240}$ for snow

load and $\frac{L}{180}$ for total load. For this beam:

a$)$ Determine a trial size using heuristics and the sizes in the selection tables. With

this trial size, estimate the self$-$weight of the beam.

b$)$ Determine the minimum acceptable depth for the beam, considering self weight.

c$)$ Imagine the beam is part of a roof for which a $60-$minute fire resistance rating is

required. Does the beam need to change depth to meet this requirement?