Column Load Distribution in API 650 11th Edition

[LeonEarle]

In paragrapn 5.10.4.7 a. of the new 11th edition, there is language for distribution of column loads. Does anyone know, is it intended that the product load plus the bottom plate load would be deducted from the soil bearing capacity resulting in the load available for the column load distribution?

 

[TankDude]

It is not clearly stated that way but I would consider taking that approach to be conservative.

 

[JStephen]

In an ideal world, the soils report would address this. It is very common to have 2,000 psf of product on soils good for 2,000 psf bearing, which implies zero bearing for the columns. But where you have uniform loading over a wide area, you may be able to have higher concentrated loads within that area- ask the geotech people if in doubt.

 

[JoeTank]

When no geotech info is available, most tank designers would limit the additional bearing loads of the columns to about one-half of the liquid pressure on the soil.

Joe Tank