Urgent help required etabs
Current time: 12-16-2018, 09:58 PM
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Author: king12
Last Post: erimajus
Replies 9
Views 4248

Urgent help required etabs
#1
Hello forum members,
I have encountered a problem in etabs the error is something like this .
***warning ***
the solution lost 9.5 digits of accuracy for dof uz of joint 4299 located at x
also
*warning***
for starting load vector: load = dead
load is applied to one or more massless degrees of freedom,
corresponding ritz modes may be unavailable or inaccurate for dynamics
also
how to check for soft storey in etabs?

Kindly your help and feedback is much awaited.
#2
That happened to me in SAP2000 when in a joint i connected a element of very small stiffness with one a very high stiffness. Sorry for my english.
#3


The loss of digits implies either the case where something very stiff is supported from something very flexible or most commonly it implies a mechanism (loss of stability). Make sure that the particular node is properly connected to a stable substructure and/or that you have not introduced more hinges than the required ones. Check the deflected shape under say selfweight and that should give you guidance as to where the problem is focused. Alternatively you could post the .e2k and someone to have a look.
.
#4

YOU ARE GETTING ERROR BECAUSE AT SOME ORPAN NODES OR CONNECTIVITY OF BEAMS IS NOT PROPER , YOU CAN CHECK SOFT STORY BY GOING TO DIPLAY>SHOW TABLES>STORY SHEAR
REGARD'S
KUMAR007


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#5


I believe that in order to check for soft-storey symptoms the user should investigate whether or not plastic hinges may form in the columns of the same storey. This would have to do with the resistance of all members framing to the column in question and their potential overstrength. I do not think that story shear would indicate such issues. In fact I think that in order to verify the design against such issues in ETABS you need to perform a pushover analysis so as to enable frame elements to yield and hence reveal the collapse mechanism of the structure.


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#6
Etabs model

[Image: info.png]
Dear friends,

Here I am uploading this model your feedback is very essential and comments awaited.



[Image: Download.png]

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#7
cover to column should be 50mm, are you providing shear wall or normal brick wall, if shear wall is provided then you should start from bottom, if normal brick wall then aplly the loading only
#8
hi King12

I pick out some problem possible caused this problem

1)Dynamic Analysis parameters : should only select AccelX and AccelY
2)B150830 you defined as column in its properties but in the model it is going nowhere
3)Try to use merge point for 0.1 tolerance for the whole model
4) In my opinion, to the define the partition wall load, it should define as null element and apply loads on it rather than define as beam with a relative stiffness. Other, convert to surface load for vertical elements design.

Hope this help you
#9
Dear King12,

How can i download your model free?...
I will correcte your model and sent it back to you.

Thanks
Dear King,,

Your Etab Model Seems to be inpractical. Just one question what are those walls in superstructure from first level till roof? are they just a partion wall or as a Support as what is seems to be in your model?... all of your columns stops at level 1. if you intentionally model it as is it then you must be having a transfer slabs or beams at level 1 to carry all those planted walls as shown in your model as your main support.

Using Automesh in the model does not give accurate stresses as numerical erroe will be more.

I think you must remodel it again.
Thanks
#10
Dear King12,

what I always do to minimize the warning after run the analysis in Etabs is to check the model (Analyze - check model) and check all option box, if there error in the model we should fix the model. Thanks.

Regards,
erimajus
[-] The following 1 user says Thank You to erimajus for this post:
  • jaks


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