PROFIS Engineering Base Plate Module

This is an explanation of the calculation of the bending capacity of the baseplate under Pure tension and Flexure. These are the two cases that put the anchors under Tensile loading.

Please note that the calculation of the Neutral Axis (Y) and the distribution of loads to the anchors are not a part of this calculation.

The user is required to use any simultaneous equation solver to figure out the location of the Neutral axis and the forces on the anchors.

The software utilizes the bending lines (m) and (n) as defined by AISC Design Guide 1, 2nd Ed, for the calculation of the bending capacity of the baseplate.

Once (m) and (n) are established, the following logic is used to calculate the capacity of the baseplate per DG1 under a pure tensile or flexure loading.

Furthermore for the Flexure loading case we consider bending of the plate at the tension as well as compression sides.

Explanation for plate Bending under Tension Loading Case in DG1

x(n): This is the perpendicular distance from the centrline of the anchor point to either the nearest (m) or (n) bending line.

T(n): The tension force per anchor. In the case of pure tension we divide the total axial force by the number of anchors.

beff(n): This is the effective bending width as defined in AISC. This is obtained by a 45 degree angle from the centerline of the anchor to the nearest (m) or (n) axes.

From the Mpl equation above, we can see that the more the number of anchor rows perpendicular to (m) or (n), the more terms in the equation. Moment equation should be developed for both (m) and (n) axes and the higher moment applied should be used to compare with the bending capacity of the plate.

Edge distances should be used to develop the expressions for the x(n) and beff(n).

Here is an example on how to calculate these parameters.

Note: Apply a compression loading with or with out column eccentricity when no tensile loads are present in the anchors. The compression stress under the is not necessarily constant.

Verify bending around each bending line M, and N of the column. Calculate the resulting compression load Cr for each compressed area and evaluate the moment by multiplying the Cr with its distance to the bending line xi. Assume the total length of the bending line as the effective width beff resisting the acting moment.

Cr = Resultant compression load x = distance to the bending line (m in case of strong axis bending and n incase of weak axis) beff = Effective width