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Flat slab under wall loading
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ykalamkar
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Joined: 26 Jan 2003
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Location: Nagpur

PostPosted: Thu Jan 01, 2009 6:50 am    Post subject: Flat slab under wall loading Reply with quote

Sir
In flat slab type building we normally consider equivalent wall load on slab as Uniformly Distributed load over slab. Is there any criteria to calculate equivalent wall load or it is just total load over area? Is it not necessary to strengthen the flat slab due to point load?

Yogesh Kalamkar
M.E. (STRUCT)

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Dr. N. Subramanian
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PostPosted: Fri Jan 02, 2009 4:34 am    Post subject: Flat slab under wall loading Reply with quote

Dear Mr. Yogesh Kalamkar

As per IS code: Load due to partition: Increase the floor load by 33.3% per metre run of partition wall subject to a minimum of 1 kN/m2. The total weight per metre run must be less than 4 kN/m. If the wall is thick it has to be considered as line load. But why do you want to consider thick walls on flat slabs?

Subramanian

Dr.N.Subramanian,Ph.D.,F.ASCE, M.ACI,

Consulting Structural Engineer
Maryland, USA

See my books at: www.multi-science.co.uk/subramanian-book.htm
www.oup.co.in/search_detail.php?id=144559





--- On Thu, 1/1/09, ykalamkar <forum@sefindia.org> wrote:
Quote:
From: ykalamkar <forum@sefindia.org>
Subject: [ECONF] Flat slab under wall loading
To: econf@sefindia.org
Date: Thursday, January 1, 2009, 12:34 PM

Sir
In flat slab type building we normally consider equivalent wall load on slab as Uniformly Distributed load over slab. Is there any criteria to calculate equivalent wall load or it is just total load over area? Is it not necessary to strengthen the flat slab due to point load?

Yogesh Kalamkar
M.E. (STRUCT)
     



     



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parikhhardik4u
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PostPosted: Fri Jan 02, 2009 7:16 am    Post subject: Re: Flat slab under wall loading Reply with quote

[quote="drnsmani"]Dear Mr. Yogesh Kalamkar

As per IS code: Load due to partition: Increase the floor load by 33.3% per metre run of partition wall subject to a minimum of 1 kN/m2. The total weight per metre run must be less than 4 kN/m. If the wall is thick it has to be considered as line load. But why do you want to consider thick walls on flat slabs?

Subramanian

Dr.N.Subramanian,Ph.D.,F.ASCE, M.ACI,

Consulting Structural Engineer
Maryland, USA

See my books at: www.multi-science.co.uk/subramanian-book.htm
www.oup.co.in/search_detail.php?id=144559


Dear Sir,
i have one case where flat slab is 250 thk, having a wall of 5 m height and 200mm thick(light weight material used density@10Kn/M3) and running length is 22 m. i have model in staad using FEM.
For the above case,
1.how to give wall loading?
2.how to check it for shear

Thanks in Advance,

HARDIK
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ykalamkar
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Location: Nagpur

PostPosted: Fri Jan 02, 2009 8:29 am    Post subject: Flat slab under wall loading Reply with quote

Sir,
My column grid is say 8 X 8 M. and there is wall of length say 24m. Even if we consider wall of half brick thk. i.e. 150 mm total including plaster, load of wall per meter for 4 m ht is 0.15X20X4 = 12 kN/m. Total load = 24*12 = 288 kN. Area = 64 m2. Shall I have to apply line load? Or shall I apply equivalent load as 1.33X288/64 = 6 kN/m2 ?
Sir, I would like to know in which IS code it is mentioned?
Thanking you sir for your helpful guidance.
Yogesh  

From: drnsmani [mailto:forum@sefindia.org]
Sent: Friday, January 02, 2009 10:17 AM
To: econf@sefindia.org
Subject: [ECONF] Re: Flat slab under wall loading



Dear Mr. Yogesh Kalamkar

As per IS code: Load due to partition: Increase the floor load by 33.3% per metre run of partition wall subject to a minimum of 1 kN/m2. The total weight per metre run must be less than 4 kN/m. If the wall is thick it has to be considered as line load. But why do you want to consider thick walls on flat slabs?

Subramanian

Dr.N.Subramanian,Ph.D.,F.ASCE, M.ACI,

Consulting Structural Engineer
Maryland, USA

See my books at: www.multi-science.co.uk/subramanian-book.htm
www.oup.co.in/search_detail.php?id=144559





--- On Thu, 1/1/09, ykalamkar wrote:    
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PostPosted: Mon Jan 05, 2009 4:08 am    Post subject: Re: Flat slab under wall loading Reply with quote

Dear Mr. Yogesh Kalamkar,

You can do both. But when the column grid is only 8 x8 m. Why do you want to disperse 24m wall weight in 64 m2. The weight to be taken is only 12 x8/64=1.5 kN/m2 is it not? The provision mentioned by me is in IS 875 Part 2. Since I do not have that code with me here, I am not able to tell the Clause no. I think it is given as a footnote in one table. You may also refer to RC Designers Handbook, by reynolds and Steedman, Table 55-56, to get some app. value of BM due to such concentrated loads.

Best wishes
NS
[quote="ykalamkar"]Sir,
My column grid is say 8 X 8 M. and there is wall of length say 24m. Even if we consider wall of half brick thk. i.e. 150 mm total including plaster, load of wall per meter for 4 m ht is 0.15X20X4 = 12 kN/m. Total load = 24*12 = 288 kN. Area = 64 m2. Shall I have to apply line load? Or shall I apply equivalent load as 1.33X288/64 = 6 kN/m2 ?
Sir, I would like to know in which IS code it is mentioned?
Thanking you sir for your helpful guidance.
Yogesh
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uhvaryani
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PostPosted: Mon Jan 05, 2009 7:08 am    Post subject: flat slab under wall loading Reply with quote

dear mr.kalamkar,
major brick walls should be made to rest on beams.brick partition walls resting directly
on slab are likely to get cracked due to variable deflection of slab panels.4.0 to 5.0m
high patition walls,mentioned in some dispatches are quite unusual in common buildings.
storey heights in buildings are of the order of 3.0 to 3.5m.
with regards,
uhvaryani

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uhvaryani
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PostPosted: Mon Jan 05, 2009 7:27 am    Post subject: failure of flat slab structures Reply with quote

dear sefians,
analysis of flat slab structures is emperical.full scale tests were conducted in U.S.A
to finalise the emperical method given in the code.failure of aflat slab structure was
reported in Worli,Bombay.a telecast was made on Zee TV.it was chaired by late,
respected engineer mr.r.n.raikar.some architects,engineers,contractors and some
survivors of this incidence paticipated in the discussion.with computer methods,based
on finite element,flat slab structures can be properly analysed.analysis of flat slab
structures requires more work.
with regards,
uhvaryani


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Ramachandran. K.S
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PostPosted: Mon Jan 05, 2009 7:56 am    Post subject: Flat slab under wall loading Reply with quote

Dear Dr.Subramanian & Mr.Yogesh Kalmkar,

This is covered in Clause 3.1.2 with the heading "Load due to light partitions" in IS:875 part-2.

Regards,
K.S.Ramachandran
Quote:
----- Original Message -----
From: drnsmani (forum@sefindia.org)
To: econf@sefindia.org (econf@sefindia.org)
Sent: Monday, January 05, 2009 9:38 AM
Subject: [ECONF] Re: Flat slab under wall loading


Dear Mr. Yogesh Kalamkar,

You can do both. But when the column grid is only 8 x8 m. Why do you want to disperse 24m wall weight in 64 m2. The weight to be taken is only 12 x8/64=1.5 kN/m2 is it not? The provision mentioned by me is in IS 875 Part 2. Since I do not have that code with me here, I am not able to tell the Clause no. I think it is given as a footnote in one table. You may also refer to RC Designers Handbook, by reynolds and Steedman, Table 55-56, to get some app. value of BM due to such concentrated loads.

Best wishes
NS
[quote="ykalamkar"]Sir,
My column grid is say 8 X 8 M. and there is wall of length say 24m. Even if we consider wall of half brick thk. i.e. 150 mm total including plaster, load of wall per meter for 4 m ht is 0.15X20X4 = 12 kN/m. Total load = 24*12 = 288 kN. Area = 64 m2. Shall I have to apply line load? Or shall I apply equivalent load as 1.33X288/64 = 6 kN/m2 ?
Sir, I would like to know in which IS code it is mentioned?
Thanking you sir for your helpful guidance.
Yogesh






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sdec.in
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PostPosted: Mon Jan 05, 2009 9:56 am    Post subject: Flat slab under wall loading Reply with quote

But as I understand from his mail, Mr Kalamkar is discussing walls which are other than light partitions; in our country walls are still either 9" or 4 and a half " brick work(or block work) which translates into substantial line loads and need to be carefully handled in flat slabs( in case of beam-slab structures, for example, we do not allow any 9" brick walls on slabs and provide suitable beams underneath them).

Regards
Sangeeta Wij
[quote] ----- Original Message -----
From: Ramachandran. K.S (forum@sefindia.org)
To: econf@sefindia.org (econf@sefindia.org)
Sent: 05 January, 2009 2:32 PM
Subject: [ECONF] Re: Flat slab under wall loading


Dear Dr.Subramanian & Mr.Yogesh Kalmkar,

This is covered in Clause 3.1.2 with the heading "Load due to light partitions" in IS:875 part-2.

Regards,
K.S.Ramachandran
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vikram.jeet
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PostPosted: Mon Jan 05, 2009 11:02 am    Post subject: [ECONF] Re: Flat slab under wall loading Reply with quote

Clause 3.1.2 of IS 875 P-II

" In office and other buildings where actual loads due to light partitions cannot be assessed
at the time of planning,the floorsand the supporting structural members shall be  
designed to carry, inaddition to other loads,uniformly distributed loads per square meter
of not less than 33.33% of weight per meter run of finished partition,subject to minimum
of 1.0kN/m2 provided total weight of partition walls per sqm of wall area does not exceed
1.50kN/m2 and total load per meter length is not greater than 4.0k N/m"

From the clause it is learnt that  

- -- equivalent udL ( on slab) of partition load/sqm can be taken as 1/3rd partition load/meter
--- minimum shall be 100 kg/m2

Limiting loading for partition type : Total Partition load max upto 150Kg/m run per meter height(ie 150Kg/m2)
parttions are applicable
Also partition weight shall not be more than 400 kg/m run


May kindly correct me for the codal interpretation


vikramjeet

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