While chairs are essential, the best chair is sometimes no chair at all. For small tubular columns (less than
The American Iron and Steel Institute (AISI) is a leading authority on steel and its applications. Their publications, including AISI E 1 Volume II Part VII, provide valuable insights and guidelines for various industries. In this article, we will focus on anchor bolt chairs, a crucial component in construction, and explore their significance, types, and benefits.
Anchor bolts are rarely perfectly aligned, and eccentricity (the distance between the bolt's centerline and the shell) is a common challenge. AISI Part VII formulas specifically account for anchor bolt eccentricity, ensuring the chair can handle the twisting forces (moments) caused by this offset. Key Design Considerations under AISI E-1 Part VII
provides the definitive engineering standard for designing efficient, safe, and structurally sound anchor bolt chairs for steel equipment like storage tanks and vessels.
If you are currently working on a or calculating loads , I can help you dive deeper. See the standard welding patterns recommended by AISI? aisi e 1 volume ii part vii anchor bolt chairs better
Chairs are typically fabricated from structural steels such as ASTM A572 Grade 50 Interference:
): The distance from the shell to the bolt centerline. Minimum eccentricity is usually (for heavy hex nuts).
An anchor bolt chair is a fabricated steel bracket, typically made from cold-formed C-sections or angles, that:
on local loading in cylindrical vessels to determine shell stress above the chair. Vertical Side Plates: While chairs are essential, the best chair is
Is using AISI E-1 Volume II Part VII better for your project?
Tightening a nut directly onto a thin column base plate can cause the plate to bend or "dish."
| Feature | Standard Base Plate (No Chair) | AISE Part VII Chair | | :--- | :--- | :--- | | | Bending of base plate | Tension/Shear in stiffeners | | Bolt Capacity | Reduced by prying action | Near full tensile capacity | | Plate Thickness | Must be very thick to resist bending | Can be thinner (stiffeners take the load) | | Grout Pressure | High localized point loads | Distributed pressure | | Cost | Lower material, higher risk | Higher material, lower lifecycle cost |
However, merely meeting minimum code requirements is insufficient for many projects. A approach—focused on rational engineering, fabrication precision, and installation reliability—yields safer, more durable, and more economical structures. In this article, we will focus on anchor
inch larger than the bolt diameter to allow for field misalignments. Focus on Weld Quality
To get the best results when implementing AISI E-1 Volume II Part VII, engineers must pay close attention to several practical variables:
Discuss the difference between (pipe) vs. square column chairs?
If you are looking into , you are diving deep into the mechanics of anchor bolt chairs . This specific section provides the engineering community with the formulas and design methodologies needed to ensure these components safe and effective.