Modelling A shell Element with Compression only properties (i.e Brick wall on a slab)

[ash]

hi friend

I will appreciate if any one enlight me on the subject topic how to achieve a brick wall over slab behaviors with shell elements.(compression only).

Thanks in Advance.

[UmarMakhzumi]

The only way I can think of is very tedious. Model shell elements in layers and introduce compression only links between them. What are you trying to do here- just curious !

Thanks.

[ash]

Hi Umar

Thanks for replying

I am trying to model a pure masonry wall behavior  in 3 story building, the wall will only transfer the gravity loads but wont take any axial tension.

Critical part comes when we have a beam/slab  which is hogging due to adjacent span or any uplift, wall elements takes tension from it and try to hold down the beam/slab. and change the actual behavior of the structure.

I just want to transfer the gravity loads through the modeled walls, but not the tension (as there will be no tension in brick wall elements due to hogging), but ofcourse in sagging case my walls should act as compression element and shall transfer the loads from above as per their material properties.

Trying to simulate a house with brick walls over/under slabs, beams to check the stresses and load concentration in my structure.

 

Thx in advance

 

[Ayesha]

5 hours ago, ash said:

Critical part comes when we have a beam/slab  which is hogging due to adjacent span or any uplift, wall elements takes tension from it and try to hold down the beam/slab. and change the actual behavior of the structure.

This shouldn’t happen as beam is not connected to wall and only resting on wall in real world case - therefore your modelling should represent it. There was also another question on the forum on modelling CRP and I think the same reply would fit here. Contact, gap etc are better modelled in FEM software. Personally you shouldn’t be doing a model for a 3 story building in a FEA software. Keep it simple. If you still want to do it, use compression only springs to connect the beam to wall. That would be simple but I strongly suggest using advanced models for simple things.

[ash]

I agree, such simple structure should not modeled and should be done using classical methods.

The reason i am trying to solve is my curiosity. otherwise I already designed and executed that structure 5 years back with simplified approach, and its still intact 😇.

unfortunately i did not found the answer for my question, and i considered it a good forum to discussed, thats why i raised the question.

Are not we are here for the same reason, Should not give up and try to find the answers which we can't find else were?

Regards
Muhammad

 

[Ayesha]

2 minutes ago, ash said:

Are not we are here for the same reason, Should not give up and try to find the answers which we can't find else were?

You can try links or compression only springs.

[ash]

I am not sure if we can assign sping/links to wall/slab/beams without breaking them in to small segments, can we?

[Ayesha]

You will need to mesh the wall and then add links at those nodes.

 

[Nustian371]

Incase you model the wall for gravity only loads the modelling in the FEA analysis will still show you the hogging moments under certain load cases as it will take that as a deflection. You can try another simple approach in which you model the equivalent concrete beam element for the masonry above your beam slab similar to equivalent steel or concrete n=Es/Ec, This will provide the additional depth to the beam/slab below which will reduce the hogging moments. The issue i always found with the links and springs is the definition of there properties and the force capacity as it is very difficult to determine for the plastered walls or block masonry.