Chapter 1, Problem 1.9.17P

A sign of weight W is supported at its base by four bolls anchored in a concrete footing. Wind pressure P acts normal to the surface of the sign; the resultant of the uniform wind pressure is force fat the center of pressure (C.P). The wind force is assumed to create equal shear forces F/4 in the y direction at each boll (see figure parts a and c). The overturning effect of the wind force also causes an uplift force R at bolts A and C

and a downward force (— R) al bolts B and D (see figure part b). The resulting effects of the wind and the associated ultimate stresses for each stress condition are normal stress in each boll ( h — 60 ksi); shear through the base plate (t _h = 17 ksi); horizontal shear and bearing on each bolt ( t _{f u r} = 25 ksi and cr^ = 75 ksi): and bearing on the bottom washer at B (or D) (a _{b o r} = 50 ksi).