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TonyC

Foundation footings and connecting beams

TonyC 2016-04-18 10:18:19


Here's another interesting topic that I wanted to share with our users.

QUESTION
I'm defining a foundation with footings/plinths on poles.
I now need to define the connecting beams between these foundation elements. How do I proceed to inserting them correctly?

ANSWER
The proper modelling of the connecting beams assumes that the nodes to the foot of the pillars, to which the plinths are connected, are connected by these beams.
This allows you to hold the differential settlements and avoid mutual displacements between plinths.

This condition is met by drawing an "Elevation" beam between the plinths connecting the column bases.
View an example showing the correct modelling: Correct Modelling_1.

Avoid drawing the connecting beams with a beam span equal to the distance between the plinths in order to avoid lability problems.
View an example showing this kind of modelling error: Wrong Modelling_1.

If you want that the connecting beams also contribute to the bearing capacity of the foundation (for example in the case in which these beams are resting on curtain wall panels), you'll need to model these beams defining them as "Foundations", and placing them between the plinths connecting them by means of generic elevation sections.
View an example of a correct modelling alternative: Correct Modelling_2.

In these cases it is necessary to prevent that beams defined as "Foundation" connection beams are drawn from column to column. The simultaneous presence of foundation beams and plinths at the base of a pillar is now allowed.
View an example of this modelling error: Wrong Modelling_2.