Question 4
(a) The beam is made from four boards nailed together as shown in Figure Q4 (a). If the beam is
subjected to an internal moment of M = 3.2 kNm, determine the maximum compressive and
tensile stress in the beam
(b) Consider the same beam as in part (a), the internal moment is replaced by the transverse shear
force of 2.4 kN as shown in Figure Q4(b). If each nail can support a shear force of 280N,
determine their required spacing s.
(20 marks)
A
100 mm
25 mm
125 mm
M
75 mm
25 mm
75 mm
75 mm
25 mm
Figure Q4 (a)
2.4 kN
100 mm
A
25 mm
25 mm
S
75 mm
S
S
25 mm
75 mm
-75 mm
25 mm
Figure Q4 (b)