Tank Anchor Chair

Depending on the height to diameter ratio and wind/seismic forces, some tanks need to be constrained from tipping over, some do not.

Guest - GA. _{short and to the point}

A tank is either anchored or unanchored. Anchor chairs and bolts are one method of anchoring a tank.

The anchor chair or anchor ring or straps or whatever else you are allowed to use by the code to which you are building are all there to stop the tank tipping over, as per post 1 but also to stop it lifting off due to internal pressure etc. The "anchor's" principle point must be to the shell plating and not to the tank bottom (this is what the chair achieves amongst other things).

A tank can be unanchored if the overturning moment from wind loading is not greater than 2/3 of the load resisting it excluding the product contained.

For anchor chair design look at AISI T-192 Volume II part VII.

banu,

The design of an anchor "chair" as used on tanks and vessels is to develop the full strength of the anchor bolt.

A simple anchor bolt going through the floor plate of the tank is limited by the hole strength of the floor plate. It is not as effective as an anchor.