Designing anchor bolt chairs according to (published by the American Iron and Steel Institute) is the industry standard for distributing anchor bolt loads into a tank shell or vessel wall while minimizing secondary bending stresses.
By using a top plate and vertical plates welded directly to the shell, these chairs create a rigid structure. Simpler gusset designs often under-estimate peak stresses because they do not form this "box" configuration, which effectively manages the eccentric moment of the bolt.
The “chair” elevates the CFS member slightly above the concrete to prevent moisture wicking and accommodate bolt tolerances.
To ensure that anchor bolt chairs meet the standards outlined in AISI E 1 Volume II Part VII, follow these best practices: aisi e 1 volume ii part vii anchor bolt chairs better
Tightening a nut directly onto a thin column base plate can cause the plate to bend or "dish."
2. Why the AISI E-1 Part VII Framework Outperforms Alternatives
The design and implementation of anchor bolt chairs are governed by the standard. These structural devices are essential for distributing loads from anchor bolts to a shell or column, particularly in high-stress applications like storage tanks and silos. The Necessity of Anchor Bolt Chairs Designing anchor bolt chairs according to (published by
Anchor bolt chairs play a crucial role in ensuring the stability and safety of structures. AISI E 1 Volume II Part VII provides the industry-recognized standard for their design and installation. By following these guidelines, builders and engineers can ensure that anchor bolt chairs are designed and installed to withstand various loads and stresses, enhancing the overall safety and durability of the structure. Whether you're designing a new building or retrofitting an existing one, adhering to AISI E 1 Volume II Part VII guidelines for anchor bolt chairs is essential for optimal structural performance.
Note: Always verify which generation of the AISI standard is active in your jurisdiction (e.g., AISI S100-16 vs. older E-1).
The vertical wall of the storage vessel, which experiences localized stresses from the chair assembly. The “chair” elevates the CFS member slightly above
Two parallel vertical plates welded to both the tank shell and the top plate. They transfer the load from the top plate down into the tank shell.
Anchor bolt chairs are critical structural components used to anchor cylindrical steel structures—such as storage tanks, chimneys, pressure vessels, and towers—to their concrete foundations. These assemblies distribute high concentrated overturning moments and shear forces from wind or seismic loads safely into the foundation. When designing these components, engineers routinely turn to the American Iron and Steel Institute (AISI) standards. Specifically, provides the industry-standard design methodology for anchor bolt chairs.