Answer Happy

A council intends to build a fire station in Geelong, Victoria.
Figure 2b shows the timber frame of the fire station. The diagonals
in the main truss are 5m long, have a cross-section of 190x45mm and
are seasoned softwood of grade F11. The connection at the ends of
the diagonals is through two (2) M12 bolts in 14mm diameter holes.
The 2 bolts at each end are located at a cross-section
perpendicular to the longitudinal axis of the diagonals.
Structural analysis of the frame, using structural engineering
software, shows that the following unfactored axial tensile loads
are present in the critical diagonals: a permanent load of 30kN and
an imposed action due to people of 40kN considered as “loads of 5
months duration” due to frequent use of the roof area for storage.
It can be assumed that short-term (ψs), long-term
(ψl) and combination factors (ψc) are equal
to zero.
Determine if the diagonals are suitable to carry the applied
loads (22 Marks).
DY Figure 2b