Anchor bolt chairs are structural assemblies welded to the base of shells (such as storage tanks, silos, or tubular columns) to transfer uplift loads from anchor bolts into the shell. They are essential because they prevent the shell from buckling or overstressing at the base plate connection.
Chairs are often omitted from corrosion protection specs, leading to rust at the bolt–concrete interface.
AISI E1 Volume II, Part VII Compliance: The Role of Better Chairs aisi e 1 volume ii part vii anchor bolt chairs better
Moving beyond rudimentary, site-fabricated methods to specialized, pre-engineered anchor bolt chairs offers several key advantages that satisfy the stringent requirements outlined in advanced structural guidelines: 1. Superior Precision and Positioning (Accuracy)
), multiplied by the appropriate safety or resistance factor. Step 3: Evaluate Shell Stresses Anchor bolt chairs are structural assemblies welded to
A very specific topic!
: These chairs provide rigid support and precise alignment for anchor bolts, which prevents bolt bending during high-load events like wind or seismic activity and reduces the risk of concrete cracking. Key Design Elements According to the AISI guidelines , a high-quality anchor bolt chair typically includes: AISI E1 Volume II, Part VII Compliance: The
: It defines exact requirements for all chair parts, including: Top Plate : Must have a minimum thickness ( ) and specific width/length to handle the bolt load.
Engineers who specify chairs using rational analysis, detailed fabrication notes, and quality assurance will see fewer field problems, faster erection, and safer load paths. In CFS construction, the chair is small but mighty — treat it that way.
The anchor bolt is centered in the CFS column’s web hole, but the line of action for tension is offset from the column’s centroid → prying action.