Aisi E 1, Volume Ii, Part Vii Anchor Bolt Chairs
AISI E 1, Volume II, Part VII Anchor Bolt Chairs
An anchor bolt chair is a structural component that supports and distributes the load from an anchor bolt to a shell or a column. Anchor bolt chairs are used when anchor bolts are required at supports for a shell, such as in tanks, silos, or other cylindrical or conical structures. Anchor bolt chairs are made of carbon steel or alloy steel and consist of a top plate, vertical plates, and a bottom or base plate. They are designed to minimize secondary bending in the shell and to avoid interference with the base or bottom plate.
The design of anchor bolt chairs is based on the work of Bjilaard and is presented in Part VII of AISI E 1, Volume II, a manual for the design of steel structures. This manual provides formulas and guidelines for the dimensions, stresses, and welds of anchor bolt chairs. It also includes tables and figures to illustrate the design process and examples of typical chair configurations.
The main factors that affect the design of anchor bolt chairs are:
The design load or the maximum allowable anchor bolt load, which is determined by the external forces acting on the structure and the anchor bolt strength.
The eccentricity of the anchor bolt with respect to the shell or column, which causes bending stress in the vertical direction.
The top plate width and length, which determine the span and the load distribution along the top plate.
The top plate thickness, which affects the bending stress in the horizontal direction.
The chair height, which influences the stress distribution in the shell or column.
The vertical plate thickness and width, which affect the stiffness and strength of the chair.
The bottom or base plate thickness, which provides stability and resistance to buckling.
The weld size and type, which ensure adequate connection between the chair components and the shell or column.
The design of anchor bolt chairs requires careful consideration of these factors and compliance with the applicable codes and standards. AISI E 1, Volume II, Part VII Anchor Bolt Chairs provides a comprehensive and practical guide for engineers and designers who need to design anchor bolt chairs for steel structures.
AISI E 1, Volume II: Design Manual for Steel Structures. American Iron and Steel Institute (AISI), Washington D.C., 1992.