Masonry structures

Hi,

I would like to ask about masonry structures in Karamba. Description mentions only beam and shells however is that possible to simulate brick walls or reinforcement walls in case of core of a tall building or building perimiter walls until 4-5 storey ? Also If I change dgree of a Beam can be simulated as a vertical column made of steel, brick or reinforced concrete?

Replies to This Discussion

Permalink Reply by Karamba3D on November 4, 2013 at 2:46am

Hi Onrender,

you can use Karamba for the simulation of brick and reinforced concrete walls.

If not reinforced with steel bars both concrete and brick structures show brittle behavior: They are strong in compression but weak in tension. Therefore when analyzing them with Karamba make sure that no tension stresses occur in those structural elements.

In case tension can not be avoided (by e.g. adding dead weight) one has to add reinforcement. The normal procedure when dealing with reinforced concrete structures is to do a linear elastic calculation which does not take account of cracking. The underlying assumption is, that the decrease of stiffness due to cracking is approximately uniform in the structure and thus does not lead to a large scale redistribution of internal forces. After having determined the cross section forces, one does a non-linear cross section design to determine the required amount of reinforcement. This can be done by hand (in case of uniaxial bending) or with programs like Response2000 (see http://www.ecf.utoronto.ca/~bentz/r2k.htm) or INCA2 (see http://www.u-pfeiffer.de/) in case of biaxial bending. Both of the programs can be downloaded for free.

The cross section design procedure in Karamba is based on the Eurocode 3 for steel structures. In case of brick or reinforced concrete structures different design formulas than that in EC3 apply.

Best,

Clemens

Permalink Reply by Ramon Casas on November 18, 2013 at 9:33am

I am working as well on the analysis of brick building structures. You'll find some pictures attached.

I detected the tension problems, because of tractions, but I can't avoid it geometrically nor simplifying the model. So I know there will show errors on my non-reinforced walls.

However, my question is: do you think that if I only pay attention to the reactions on the ground nodes, I can trust the behaviour of the model??

Attachments:

sample_a.JPG, 395 KB
sample_b.JPG, 118 KB
sample_c.jpg, 1.4 MB

Permalink Reply by Karamba3D on November 18, 2013 at 10:30am

Your reaction forces are compressive throughout the foundations so they should be fine in the context of you brick building structure.

I am not a specialist in modeling brick buildings, but as far as I know they perform poorly in the event of earthquakes due to the combination of being very stiff and showing brittle failure if not reinforced properly.

You should also limit the slenderness of your walls to prevent them from buckling.

Best,

Clemens

Permalink Reply by Ramon Casas on November 19, 2013 at 4:55am

Many thaks for your quick response, Clemens.

I've taken into account the slenderness of the walls, by applying a coefficient from our local normative that majorates the resulting tension.

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