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Adding storeys to an Exisiting Building
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sarif_n
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Joined: 29 Dec 2012
Posts: 6

PostPosted: Sat Dec 29, 2012 2:21 am    Post subject: Adding storeys to an Exisiting Building Reply with quote

Hi ,
one of my client came with a proposal of adding 2 more storeys to his existing 2 story office building. Friends kindly give me guidance on how to check whether the existing building is suitable for the project.
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syed_A
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Joined: 22 Oct 2011
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PostPosted: Sat Dec 29, 2012 4:32 am    Post subject: Reply with quote

Hello

Collect all the structural design/drawings from your client of an existing building including the geotech report, To check the already designed structure for number of floors , this  I feel basic requirements.

regards
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sarif_n
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PostPosted: Sat Dec 29, 2012 4:44 am    Post subject: Reply with quote

saptabs wrote:
Hello

Collect all the structural design/drawings from your client of an existing building including the geotech report, To check the already designed structure for number of floors , this  I feel basic requirements.

regards




Hi,
Thanks for your response . We are planning for a site investigation . And yes we have the structural details and drawings . Is it enough that we check the existing building and fondation for the extra load from the proposed upper storeys?
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VPandya
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Joined: 09 Nov 2009
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PostPosted: Sat Dec 29, 2012 5:18 am    Post subject: Do Strength Evaluation of Existing Building (ACI 437-03). Reply with quote

Dear Er. sarif_n,
If your firm is not the original company designed this Existing Building, then for the sake of PUBLIC-SAFETY and LIABILITY ISSUES, your firm has to do the following:

a) Check the existing building design against current applicable codes.
Like IS 875, IS 456-2000 or IS 800-2007.

b) In USA we use " Strength Evaluation of Existing Concrete Buildings
ACI 437R-03 and also if required " ASCE 31-03: Seismic Evaluation of Existing Buildings. Some more  references on Strength Evaluation of Existing Buildings:


SEI/ASCE 11-99 Guideline for Structural Condition Assessment of Existing Buildings

562-12 Code Requirements for Evaluation, Repair, and Rehabilitation of Concrete Buildings (an ACI Provisional Standard)
Year of Publication: 2012;

c) Once you are convinced that Existing Building Design meet current Code requirements , then check against taking addtional  loads and what modification are required if any including any Strengthening of Foundations if required, which are very expensive to do.

d) You would be surprised that in some cases cost of strengthening an existing building if required is more than building a new structures of the same size.


Regards.

Vasudeo Pandya P.E. ; S.E.

Structural Engineer.




Last edited by VPandya on Sat Dec 29, 2012 9:45 pm; edited 8 times in total
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rajancivildesign@gmail.co
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Joined: 26 Jan 2011
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PostPosted: Sat Dec 29, 2012 5:26 am    Post subject: Checking the adequacy of existing building Reply with quote

Dear Sir,
Based on the existing two storey building, you calculate loads for additional two storeys to check the adequacy for foundation based on SBC of soil and the foundation size provided in the drawing . Normally, if the building is constructed very long back, you can cosider more SBC, as the buildng is well consolidated and settled. (Overburden pressure to be added to SBC). If there is any inadequacy in loads, you can think of using light cladding materials like HQ concrete block whick is having only 1/3 of normal conventional brick masonry (size 2'x8"x8") density about 600kg/m3. Also you have to check the existing roof slab load  for floor load and the thickness is adequate or not. Similarly, whether the beam will withstand the wall load for proposed future storey also.

V.M.RAJAN.
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syed_A
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Joined: 22 Oct 2011
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PostPosted: Sat Dec 29, 2012 5:42 pm    Post subject: Reply with quote

Dear All
In some cases it may happen that some structures are done for residential purpose
later on due to one or more reason it will be let out for commercial purpose
But the design is done considering live load for residential purpose, So it is not  a bad idea to refer the final str drawings of an existing building so also for how many floors it has been done and what SBC considered
yes Mr Rajan Sir is right, One must know when it was constructed
So please share your opinion on this

regards
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rajancivildesign@gmail.co
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PostPosted: Sun Dec 30, 2012 6:27 am    Post subject: Constructing two more floor to an existing building Reply with quote

Dear Safian,
My friend has constructed a individual building with Ground floor alone in 1980 with a footing of size 3'x3'. The actual column spacing is 16' 9"on one side and 14' 9"on other side. The actual SBC to be adopted is 10t/m2 in that area. When he started construction for one more floor to existing building, the mason refused to take up the construction work because, the size of footing is  inadequate. After that I have visited the site. After taking in to consideration of  increase SBC by adding surcharge load and adopting light weight material as HQ concrete block, I actually design the foundation by considering some wall load in ground floor will be transmitted to ground through grade beam. The building has been constructed, as such there is no crack  in the building. The design is art where the Engineer has applied in his mind by using his own theory in adopting  economy in the design. We should apply the theory with our own experience in the design.
V.M.RAJAN.
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syed_A
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Joined: 22 Oct 2011
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PostPosted: Sun Dec 30, 2012 10:59 am    Post subject: Reply with quote

Dear Rajan Sir
Yes Design is an art so also confidence and exposure,
I would like to know from you and other experts here what concept/Procedure must be adopted in case if some clients ask for modification, alteration of existing structures like removing some columns, introducing new one with large spans
to make space, or some ask to provide lift etc
hence request you to share your experience  as general procedure

Thanks and best regards
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sahilmujawar
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Joined: 17 Mar 2012
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PostPosted: Thu Apr 11, 2013 3:17 am    Post subject: Reply with quote

Dear Rajan sir,
Is their any thumb rule or so from which we can estimate increase in Bearing Capacity of soil due to cosolidation.Please throw some light on this issue.

Sahil Mujawar
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sefmosnge
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Joined: 09 Jun 2013
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PostPosted: Sun Jun 09, 2013 3:55 am    Post subject: Reply with quote

I actually design the foundation by considering some wall load in ground floor will be transmitted to ground through grade beam.
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