In reality, foundations are subjected to moments in addition to the vertical load, and an equivalent force system is considered in the analysis of problems, where the load is considered to be eccentric, that is, at a distance e from the centerline of the footing. Such cases were accounted for by Meyerhof, in the following manner:

where:

B’=B-2eB      (eB is the eccentricity along the width.)

L’=L-2eL      (where eL is the eccentricity along the length.)

A’=B’L’

In the shape factors  F_cs, F_qs, F_gs  equations, effective length and effective width are to be used. The other factors in the equation remain the same. As for the ultimate load equation, it is as follows:

For the case of 2-way eccentricity, a more elaborate approach is proposed, and the equation is the following:

Therefore, the only modification is the use of effective width B’ in the equation.

As for the calculation of ultimate load Q_u, the effective area is used:

where A’=B’L’.

In order to get the effective length and width, 4 cases are considered:

Case I:

 eL/L > 1/6 and eB/B>1/6 then:
 

The effective length is taken as the larger dimension and the effective width is:

 

 

Case II:

eL/L<0.5 and eB/B<1/6 then:

where the magnitudes of L₁ and L₂ are taken from Figure 3:

 

 

Case III:

eL/L<1/6  and 0<eB/B<0.5  then:

 

The magnitudes of B₁ and B₂ are determined from Figure 4.

 

The effective width is equal to:

The effective length is equal to:

 

Case IV:

eL/L<1/6 and eB/B<1/6 then:
 

Values of B₂ are determined from Figure 5, from curves that slope upward. Values of L₂ are determined in a similar fashion from curves that slope downward.

 

The effective width is equal to:

The effective length is equal to: