Stimulation of allowable bearing pressure of square footing from the Plaxis 2D analysis

Hi all, 

In order to find the allowable bearing capacity of the footing, we can use prescribed displacement (25mm) and fins as shown below. 

But here it represents the strip footing as length inside the model is infinite. Based on the pressure bulb, the extension of pressure for square footing less (we normally considered 0.2q as limit) when compare to the strip footing.

So please is any correlation to convert the obtained bearing pressure to square or rectangular footing? (I'm using only Plaxis 2D).

Thanks.