Design a group of four headed bolts spaced as shown to support a 25,000 lb factored tension load and 7500 lb reversible factored shear load resulting from wind load. The connection is located at the base of a column in a corner of the building foundation.

F’c = 4000 psi (normalweight concrete)

Note: OSHA Standard 29 CFR Part 1926.755 requires that the column anchorage use a least four anchors and be able to sustain a minimum eccentric gravity load of 300 lb located 18 in. from the face of the extreme outer face of the column in each direction. The load is to be applied at the top of the column. The intent is that the column be able to sustain an iron worker hanging off the side of the top of the column

1. The solution to this example is found by assuming the size of the anchors, then checking compliance with the design provisions. Try four 3/4 in. ASTM F1554 Grade 55 headed bolts with hef = 11 in. as shown in figure.
   

2. This is a tension/shear interaction problem where values for both the design tensile strength and design shear strength will need to be determined. Design tensile strength is the smallest of the tensile strengths as controlled by steel, concrete breakout, pullout, and side-face blowout. Shear design strength is the smallest of the shear strengths as controlled by steel, concrete breakout, and pryout.

3. Determine the design tensile strength :
   
   Steel strength :
   
   
   
   Per Table 34-1 from ACI318, the ASTM F1554 Grade 55 headed bolt meets the Ductile Steel Element
   definition of D.1. 

We will continue the study by determining shear design strength of the anchors and we will conclude by checking the interaction of shear and tension. These next steps will be updated soon.