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Chirag_Garg SEFI Member
Joined: 18 Dec 2020 Posts: 3
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Posted: Mon Sep 27, 2021 1:36 pm Post subject: Taking effect of brick masonary walls for earthquake |
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Dear All,
I was recently doing a earthquake analysis for a project and was confused regarding the time period to be used for earthquake analysis. I have been using 0.09h/d^0.5 for my other projects which i guess is the usual practice.
But this time, I thought to analyze the structure by strut action of brick masonry walls as per IS1893-2016. Here are the observations:
1) Time period difference between conventional method and by using struct element is not significant.
2) Column design is over-conservative for earthquake forces if conventional method is used and that is particularly because bending in column with strut is minimal and column act as almost pure axial member.
Request all engineers to add their observations to this if they also have done similar analysis.
Regards
Chirag Garg
IIT Roorkee |
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pvgraju ...
Joined: 07 Jun 2020 Posts: 66
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Posted: Tue Sep 28, 2021 3:37 pm Post subject: Taking effect of brick masonary walls for earthquake |
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Dear sir,
Masonry strut is effective in compression only.So after modeling beam element as a truss at the end region model a compression spring with same stiffness as beam element. Then check the results. Check with also pin end for truss element.
Regards,
P.V.Gavarraju. |
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sakumar79 ...
Joined: 18 Apr 2008 Posts: 713
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Posted: Tue Oct 05, 2021 1:25 am Post subject: |
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DearSir,
Please note my views on the same
1. Brickwork is only capable of acting as a compression strut.
2. Further, it's effects are reduced by presence of openings (which may or may not have been originally planned). Also, once it cracks, it's stiffness will reduce drastically.
3. There are too many unknowns in masonry. We have a lot of different types of blocks and varying thickness of walls. Quality control varies too much between vendors
4. 115 mm thick walls, 100 mm thick walls, etc have very poor capacity as compression strut by default
It is therefore not advisable IMHO to take results of column design from the model with struts. Even in the case of time period, it is better to take a conservative approach in case the strut model results in lower Vb.
Hope that helps
Yours sincerely
S Arunkumar |
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vikram.jeet General Sponsor
Joined: 26 Jan 2003 Posts: 3835
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Posted: Tue Oct 05, 2021 2:26 am Post subject: |
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Very vivid , lucid and candid view /response from Er S Arun kumar .
Put up the scenario of infills in totality.
sakumar79 wrote: | DearSir,
Please note my views on the same
1. Brickwork is only capable of acting as a compression strut.
2. Further, it's effects are reduced by presence of openings (which may or may not have been originally planned). Also, once it cracks, it's stiffness will reduce drastically.
3. There are too many unknowns in masonry. We have a lot of different types of blocks and varying thickness of walls. Quality control varies too much between vendors
4. 115 mm thick walls, 100 mm thick walls, etc have very poor capacity as compression strut by default
It is therefore not advisable IMHO to take results of column design from the model with struts. Even in the case of time period, it is better to take a conservative approach in case the strut model results in lower Vb.
Hope that helps
Yours sincerely
S Arunkumar |
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