Two parallel vertical plates welded to both the tank shell and the top plate. They transfer the load from the top plate down into the tank shell.
They are necessary when the anchor bolt circle is larger than the diameter of the column or shell, requiring a bridged connection (a "chair") to connect the anchor bolt load back to the shell. They are common on steel smokestacks, pressure vessels, and large flat-bottom tanks. Key Design Principles for "Better" Anchor Bolt Chairs
All welds should conform strictly to AWS D1.1/D1.1M standards. aisi e 1 volume ii part vii anchor bolt chairs better
Commonly used in Pre-Engineered Buildings (PEBs) and heavy industrial foundations. Why Better Chairs Mean Better Structural Performance
: A unique aspect of this design is that a portion of the shell—specifically within Two parallel vertical plates welded to both the
Next time you detail a moment frame, a heavy column, or even a light industrial rack, remember: The anchor bolt chair is not a cost to be minimized. It is a component to be optimized. And the path to optimization is paved by .
In the engineering of industrial storage tanks, pressure vessels, and tall columns, the transition of high tensile loads from anchor bolts into thin-walled shells is a critical structural challenge. (Steel Plate Engineering Data) provides the industry-standard methodology for designing anchor bolt chairs. They are common on steel smokestacks, pressure vessels,
The AISI E-1 guide uses specific notation for calculating the optimal dimensions of a chair assembly: Top Plate Dimensions : Top-plate width along the shell. : Top-plate length in the radial direction.
are heavily engineered stiffened assemblies welded to structural shells that optimize structural safety, wind resistance, and seismic survival. Published by the American Iron and Steel Institute (AISI) under its authoritative Steel Plate Engineering Data , this specific design methodology provides empirical formulas to safely distribute enormous eccentric tensile loads from anchor bolts into thin-walled vessel or tank shells. Without these properly designed chairs, severe localized secondary bending forces would deform, buckle, or rupture the shell wall under high wind overturning moments or seismic uplift.
Preventing the thin shell of the vessel from buckling under localized tension or compression.