Related Resources: civil engineering

### Concrete Column Base Plate Design

Base plates are usually used to distribute column loads over a large enough area of supporting concrete construction that the design bearing strength of the concrete is not exceeded.

The nominal bearing strength fp kip/in2 or ksi (MPa) of the concrete is given by: In most cases, the bearing strength, fp is 0.85Fc when the concrete support is slightly larger than the base plate or , 1.7Fc when the support is a spread footing, pile cap, or mat foundation. Therefore, the required area of a base plate for a factored load Pu is: where is the strength reduction factor 0.6. For a wide flange column, A1 should not be less than bf d, where b is the flange width, in (mm), and d  is the depth of column, in (mm).

The length N, in (mm), of a rectangular base plate for a wide-flange column may be taken in the direction of d as: The width B, in (mm), parallel to the flanges, then, is: The thickness of the base plate tp, in (mm), is the largest of the values given by the equations that follow: Where:
m projection of base plate beyond the flange and parallel to the web, in (mm)
(N = 0.95d)/2  