Because the AISI E 1 method offers a higher degree of calculation accuracy, it allows for the optimization of chair geometry. Engineers can confidently reduce the thickness of top plates or the width of side ribs where stress analysis permits, without compromising safety. This leads to lighter, more economical chairs that are easier to weld and install compared to the bulky, block-like chairs produced by conservative, non-analytical methods.
(Top-Plate Length): The length of the plate in the radial direction. (Top-Plate Thickness): The thickness of the top plate.
To get the most out of your anchor bolt chairs, they must be engineered exactly to the specifications outlined in . The standard provides strict guidelines regarding geometric parameters and clearances: Bolt Circle and Clearances
When designing these components, engineers routinely look to the American Iron and Steel Institute (AISI) publications for standardized, reliable formulas. Specifically, provides the industry-standard design procedure for anchor bolt chairs. aisi e 1 volume ii part vii anchor bolt chairs better
Anchor bolt chairs might appear to be small components in the grand scheme of a massive industrial shell or tank, but their impact on structural integrity is massive. They prevent secondary bending, manage eccentric loads, and securely tie your critical infrastructure to the foundation.
Properly designed chairs distribute the load more evenly between the bolt and the foundation reinforcement. They act as a rigid framework, reducing the risk of bolt bending or failure under vertical loads, especially compared to temporary, improvised supports. 3. Increased Efficiency in Construction Time is money in construction.
The distance between the anchor bolt and the shell is the eccentricity ( ). Minimizing this distance reduces the bending moment ( ) on the chair. Because the AISI E 1 method offers a
Without a chair assembly, the base plate acts as a simple cantilever. Under high tensile loads (uplift), the plate can deform, causing the nut to lose contact or the grout to crack. An is essentially a structural assembly—often consisting of a horizontal plate (cap plate), vertical stiffeners (webs), and occasionally side plates—that encases the anchor bolt. It moves the reaction point of the bolt closer to the column flange, drastically reducing the bending moment on the base plate.
Engineers using this manual must calculate several key dimensions to ensure the chair is "better" than a generic attachment: Chair Height (
The American Iron and Steel Institute (AISI) publishes various standards and specifications for the steel industry, including those related to cold-formed steel, hot-rolled steel, and coated steel products. While AISI standards cover a wide range of topics, specific details on anchor bolt chairs might not be directly addressed in their publications but could be referenced in broader construction or engineering standards. (Top-Plate Length): The length of the plate in
By strictly adhering to established safety reduction factors and stress formulas, the risk of chair failure during high winds or seismic events is drastically reduced.
Following the minimum requirements of the code guarantees safety, but designing a better anchor bolt chair requires balancing structural efficiency with manufacturing economy.