The clamp shown in the figure is used to support a load hanging from the lower flange of a steel beam. The clamp consists of two arms (A and B) joined by a pin at C. The pin has diameter d = 12 mm. Because arm B straddles arm A, the pin is in double shear.
Line 1 in the figure defines the line of action of the resultant horizontal force H acting between the lower flange of the beam and arm B. The vertical distance from this line to the pin is h = 250 mm. Line 2 defines the line of action of the resultant vertical force V acting between the flange and arm B. The horizontal distance from this line to the centerline of the beam is c = 100 mm. The force conditions between arm A and the lower flange are symmetrical with those given for arm B.
Determine the average shear stress in the pin at C when the load P = 18 kN.

Line 2 Arm A Arm B -line l Arm A