Cladding interfering with analysis

[mgaafar]

Hi, I was modelling a roof slab with cladding in the snow drift zones so I can apply the trapezoidal load distribution.

after reviewing the results, I found that the cladding edge acted as a support to the roof beams while it has no stiffeness!!

the cladding is applied on a one way floor system as well, but i cannot see that this can make any problems.

Any idea why it is doing this?! 

File is attached for reference.

[mgaafar]

Also for some reason, the file I already sent became corrupt and gives weird results, although what i did is only saved it, opened it in repair mode which obviously destroyed it somehow. Rafal/Artur, is it possible that you see what made this file to be corrupt? for it to work again, I had to delete all the wall cladding, change the floor diaphram to partial XY and then save and re-open in repair mode for the file to run properly.

i just need to know what i did wrong to avoid it next time.

Thanks

[Artur.Kosakowski · Accepted solution]

I'd recommend not to define claddings on panels. They are not intended to be used like this (it should be either or) and it is better to use surface load on contour instead. the repair mode issue: I'm not able to tell what happened having only the description but mind that this option is intended as the rescue one for corrupted models rather than e.g. the tool to reduce size of the file. If you want to use you should follow the steps described in this article.

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[mgaafar]

Ok thanks Artur, but if I understand you correctly that I should not  put a cladding on a panel because it will not give correct results as shown on the snap shots?

another thing, I had to re-model the previous building because for some reason it got corrupted and could not trust it anymore, the new model I noticed that the total weight/floor and the total weight of the building is less than what i calculated, so i was playing around and found what was causing this issue.

I modeled the ramp as Curtain wall - one way slab with no stiffening or mesh as i only needed the effect on the ramp wight on the structure, but when I changed the type to meshed one-way slab then I got better results and found that the floor weights are more accurate than before.

I checked the first model (with ramps modeled as curtain wall-one way with no mesh) and found that RSA had properly distributed the load to the supporting wall.

my question now, is it a flaw that we can't use curtain-wall type element with no mesh to model an inclined slab/ramp, or what had made the model to behave like this?

the two models are attached for reference.

http://www.4shared.com/zip/W9Kcz9zXce/ONE_WAY-RAMP-SHELL.html

http://www.4shared.com/zip/vG4qsIT_ce/ONE_WAY-RAMP-NO-SHELL.html

snap shot for model without shelling the ramp:

the model output with shell to ramp

[Artur.Kosakowski]

The equivalent lateral force method calculates itself the self-weight based on properties of objects and for cladding panels it assumes it as 0. To have their self-weight included you should define their load case in a separate load case and convert it into mass.

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[mgaafar]

Artur,

        but this does not match the output, are you talking about the ramps only (inclined panels) or all the cladding panels because ROBOT actually calculated the mass of the Double Tee (DT) horizontal cladding panels while it seems it ignored only the ramps if I did not mesh them.

the DT weight only is about 6840 kips/floor including the ramps and (5615 kips without the ramp) so that gives the difference in effective seismic weight shown previously, so based on your post I should see significant reduction in the effective weight about 11085 kips VS 38445 kips.

Please advise!

[Artur.Kosakowski · Accepted solution]

Only ramps as other are diaphragms rather than cladding./curtain wall types. 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.