Aisi E 1 Volume Ii Part Vii - Anchor Bolt Chairs Better

When anchor bolts pull down tightly on a shell, they can cause localized buckling or "secondary bending". By utilizing chairs, the load is properly distributed over a larger surface area of the shell, reducing stress concentrations. 2. Standardized and Predictable Load Distribution

Large-diameter, flat-bottomed tanks can become unstable under high winds or seismic activity, which can generate significant overturning moments. Anchor chairs are the engineered solution, serving as a robust connection that transfers the overturning load from the tank shell to the embedded anchor bolts in the concrete foundation.

An anchor bolt chair is a specialized structural bracket. It is welded to the base of a cylindrical steel shell or column. aisi e 1 volume ii part vii anchor bolt chairs better

: Must be tall enough (typically between 6 and 33 inches) to distribute loads without overstressing the shell. Weld Strength

Allows for fine-tuning of the bolt's height (Z-axis) and position (X/Y-axes) [2]. When anchor bolts pull down tightly on a

Beyond the formulas, industry experts and peer discussions reveal essential practical considerations for a successful design:

Note: Always verify which generation of the AISI standard is active in your jurisdiction (e.g., AISI S100-16 vs. older E-1). It is welded to the base of a

: The primary benefit of these chairs is their ability to minimize secondary bending in the shell. Without chairs, concentrated loads from anchor bolts can deform thin shells; the AISI design ensures these loads are distributed evenly over a larger area. Controlled Stress Linearization

Making a chair excessively tall increases the bending moment exerted on the tank shell. Keep the chair just tall enough to allow proper tool clearance for bolt tensioning or torquing.

While standard anchor bolt chairs are designed to distribute local loads and minimize secondary bending in the shell, they can sometimes overstress light base rings or shells when spaced too closely. The AISI standard provides specific guidelines for this "better" alternative: The Continuous Top Ring Feature

Understanding why this specific framework yields a better, safer, and more cost-effective design requires a deep dive into its engineering principles, structural mechanics, and practical advantages over alternative methods. The Mechanics of an Anchor Bolt Chair