Bedding stress

Hello everybody,
How do you get bedding stress in foundations for eartquake combination in Sofistik 2022?

Thank you all

Hello Marina

This depends on the method you used to calculate the seismic action. If you used the response spectrum analysis, you have to keep in mind that after this calculation the sign of the load value is lost. So the calculation does not give you a representative distribution of the bedding stresses in the floor slab from earthquakes. All other combinations are of no use here either.

So what could you do?
I assume you need the bedding stresses to analyse if the foundation lifts. You get this information from the nodal displacements. If the nodes of the floor plate are moving upwards, you get a gap under the plate. Now you can reduce the bedding in these areas by using attribute areas without any bedding.

Another workaround for displaying bedding stresses is to use spring elements. Spring elements can be created with an attached SOFiMSHA run.

+prog sofimsha urs:3
syst rest
ctrl rest 2
spri QGRP NA 5 CP 20000 CT 10000

I hope these explanations will help you.

Best regards
Frederik Höller
Your SOFiSTiK Support Team