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TonyC

Foundation with connecting plinths/plinths on piles and beams

TonyC 2019-09-16 11:39:21


I want to share a request for assistance.

Question
I am defining a foundation with plinths/plinths on piles. I have to insert the connecting beams between these foundation elements. How can I insert them correctly?

Answer
The correct modelling of the connecting beams presupposes that the nodes at the foot of the pillars, to which the plinths are applied, are connected by these beams. This allows the containment of differential settlement and the avoidance of mutual displacements between plinths.
This condition is satisfied, drawing between two plinths, a beam of "Elevation" that connects the bases of the pillars.
View an example of correct modeling: Correct Modeling_1

It is necessary to avoid drawing the connecting beams with a light equal to the clear distance between the plinths in order to avoid problems of lability.
View an example of this incorrect modeling: Incorrect Modeling_1

If you want the connecting beams to also contribute to the bearing capacity of the foundation (for example, if the infill panels rest on these beams), it is advisable to model these beams and define them as "Foundation", insert them between the plinths and connect them to the pillars using segments of "Elevation" beam (perhaps defined as sections for generic material).
View an example of correct alternative modeling: Correct Modeling_2

In general, it is necessary to prevent the connecting beams defined by "Foundation" from being drawn from a pillar, as the simultaneous presence, at the base of a pillar, of beams and plinths of foundation.
View an example related to this incorrect modeling: Incorrect Modeling_2