Factor of Safety for Bolt C  
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The figure shows the free body diagram of the beam. The reaction forces at C are C subscript x and C subscript y directed horizontally to the right and vertically upwards respectively. A 75 kilo newton load acts on the beam 2.5 meters from point C. The force along the support rod directed away from the point B is F subscript 1 at an angle of 35 degrees with the horizontal.
The resultant force in bolt C is
C=65.38 kN,
the cross-sectional area of a 16 mm diameter bolt is
Apin=201.062 mm2,
and the limiting stress is 280 MPa.
Compute the shear stress in bolt C, keeping in mind that the bolt is used in a double shear connection:
τc=C2Apin=(65.38 kN)(1,000 N/kN)2(201.062 mm2)   =162.59 MPa
The factor of safety for bolt C is therefore:
FS=280 MPa162.59 MPa=1.72