Anchor bolt chairs, also known as anchor chairs or bolt chairs, are devices used to secure anchor bolts in place, ensuring they are properly aligned and anchored to the foundation. These chairs are typically used in construction projects, particularly in the installation of equipment, machinery, and structural steel.
Try to match the thickness of the chair plates with the thickness of the tank shell courses or other widely used plates on the project. This reduces material sourcing costs and minimizes scrap.
(Chair Height): The vertical height of the chair, which dictates the space available for maintenance and bolt clearance. 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.
For decades, this AISI reference has served as the primary guide for designing the stiffened chair assemblies that connect anchor bolts to tank shells. Its prominence is solidified by its incorporation into the American Petroleum Institute's API Standard 650, "Welded Tanks for Oil Storage". Clause 5.12.6 of API 650 explicitly states that an acceptable procedure for anchor chair design is the one outlined in "AISI Steel Plate Engineering Data, Volume 2, Part 5, 'Anchor Bolt Chairs'". While API 650 references Part 5, the design methodology in the referenced AISI data is widely recognized by the industry as the guidance within "Part VII". Anchor bolt chairs, also known as anchor chairs
Using this specific design methodology is considered better for high-performance engineering because it addresses the critical issue of localized stresses that can cause shell failure or bolt bending. Why AISI E-1 Part VII Chairs are Better Minimized Shell Bending
: 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 This reduces material sourcing costs and minimizes scrap
: By using a standardized design, engineers ensure adequate clearance for wrenches and alignment of bolts, which reduces labor costs and installation errors. Key Design Parameters and Components According to AISI Anchor Chair Design Anchor Bolt Chairs Design Considerations , the design focuses on several critical components:
The top plate experiences severe bending forces as the anchor bolt pulls downward against it. AISI provides clear equations to establish the minimum thickness of this plate based on the bolt load and the spacing of the vertical stiffeners. 3. Standardized Stiffener Sizing