• Registered: 2011-01-31
  • Posts: 2

Topic: Supports

Dear Sir,

I am trying to model a slab that is supported on some areas on the contour but I wish to allow the corners to uplift.

I have created the first macroelement (no.1) which consists of the slab. Then after, underneath the macroelement no.1, I created 10 new macroelements which represent the elements on which the slab is rested. The 10 macroelements are supported on their inferior surface using surface supports fixed on Zg and free on Xg and Yg. The macroelement no.1 is loaded gravitationally (-Zg).

The contact between macrolement no 1 and the rest of the macroelements should be designed in such a way that it would block displacement on -Zg but allow displacement on +Zg.
Which is the best way to achieve this?

Thank you very much.

Quote Post 1

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Supports

If you are not interested in the deformations/stresses/etc. in the support blocks, the easiest way is to use nonlinear surface springs (e.g., with tensile stiffness about 1/100-1/1000 of the compressive).

Another option is to define an Interface (GAP) material and assign it to the contacts between ME 1 and the support macroelements. Please follow the recommendations in the ATENA 2D User's and Theory Manuals.

dpryl's Website

Quote Post 2

  • Registered: 2011-01-31
  • Posts: 2

Re: Supports

Thank you for the prompt reply.

I think I shall use GAP elements. What should the values of Knn, Ktt, ft, C, friction coefficient be in order to simulate best the situation described in the previous post (fixed -Zg, free +Zg).

Thank you.

Quote Post 3

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Supports

To represent only dry friction and no tensile connection, set the interface tensile strength to 1/4-1/10 of the concrete tensile strength (0 is bad from the numerical point of view) and the cohesion to about 2x the tensile strength.

Please follow the recommendations in the manuals for the other values (initial and residual stiffnesses, ...)
http://www.cervenka.cz/products/atena/k … n-contacts

dpryl's Website

Quote Post 4