Result: During a moderate wind uplift event (85 mph), the mezzanine column experienced only 60% of its design load. Yet the anchor bolt chair legs buckled, the weld fractured, and the bolt pulled out of the concrete. The non-compliant chairs had no leg bearing check (Point 1 above) and used mild steel fillet welds too small for the applied load.
AISI E 1 Volume II Part VII requires that the anchor bolt chair material be galvanically compatible with both the anchor bolt (typically ASTM A449 or A193 Gr. B7) and the concrete. This often mandates:
Better anchor bolt chairs are engineered to allow concrete to flow through and around them without trapping air pockets (honeycombing). This ensures a solid, void-free connection between the bolt and the foundation, maintaining the structural integrity required by . 3. Vertical Plumbness Assurance aisi e 1 volume ii part vii anchor bolt chairs better
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.
When evaluating anchor bolt assembly methods, the use of engineered anchor bolt chairs offers substantial improvements in precision, structural load capacity, and installation speed. Following the principles outlined in AISI E1 Volume II, Part VII, adopting superior anchor bolt chair systems ensures that the foundation meets the high-performance requirements of modern structural steel projects. Result: During a moderate wind uplift event (85
In cold-formed steel (CFS) construction, anchor bolt chairs are critical but often overlooked components. They transfer tensile and shear loads from CFS columns or posts to concrete foundations via anchor bolts. AISI E-1 (North American Standard for Cold-Formed Steel Framing – General Provisions), Volume II, Part VII, provides specific prescriptive and performance-based requirements for these chairs.
The top plate, which bears the nut, should have a minimum thickness of ) and a maximum of Clearance: A minimum clearance of AISI E 1 Volume II Part VII requires
However, for engineers looking to optimize both safety and cost, the methodology outlined in regarding Anchor Bolt Chairs offers a distinct advantage over generic or simplified design approaches. Here is why adhering to the AISI E 1 standard results in better, more efficient, and safer designs.
While some chairs are meant to be cast into the concrete, "better" systems are designed to be partly reusable, offering cost savings over the long term. The Cost-Benefit Analysis: Better Chairs Save Money
: By preventing anchor bolt bending and reducing concrete cracking at the foundation, these designs increase the durability of the entire structure.