What is the minimum anchor bolt size for seismic category E?

• A. #5
• B. 1/2 Inch
• C. 3/4 Inch
• D. 5/8 Inch

Answer: (A)

The key idea is that seismic category E requires a minimum size for hold-down anchor bolts to ensure enough strength against earthquake forces. The standard minimum is a No. 5 bolt, which corresponds to a 5/8 inch diameter. This size provides greater tensile and shear capacity than smaller bolts, reducing the risk of pullout or shear failure under strong shaking. A 1/2 inch bolt would be below the minimum, while a 3/4 inch bolt would be larger than required for the minimum, though it could be used if higher loads are anticipated. Remember, actual capacity also depends on embedment depth, concrete strength, spacing, and edge distances, but the code sets No. 5 (5/8") as the minimum for seismic category E.