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Re: Redistribution of Moments in grid Floor

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Thanks for your response. The ultimate negative moment is 1057kNm
(779.9kip.ft) and 20% redistribution means 211.4kNm (155.9kip.ft) is
redistributed. After redistribution, the design moment is reduced to 881kNm
(649.7kip.ft). The cracking moment Mcr of the member is 130.6 kNm
(96.36kip.ft) as per Indian code. The service load moment is 704.6 kNm
(519.8kip.ft). The Grid floor is covering an area of 14.4mx21.4m (47.2ft x
70.2 ft). Beams are provided at 3.6m (11.8m) spacing. The beam size is
350mmx800mm (13.77in x 31.50 in). Slab thickness is 120mm (4.72in). Prima
facie, I feel member sizes are inadequate.  My major concerns are below.

1.      Since it is grid floor, when the support moment is trying to shed
the moments to the midspan, will the other beams prevent it?. I mean, the
beam is not able to rotate freely to redistribute the moments.

2.      Is there any limit on Ma/Mcr i.e. Mu/cracking moment to avoid
extensive cracking?.

Thanks

Ashraf

On 11 December 2013 00:21, Matthew Stuart <MStuart(--nospam--at)pennoni.com> wrote:

> It is also interesting to note that until 2008 ACI only allowed transfer 
> of negative moment. As of 2008 you can do the same with positive moments.
> 
> And the criteria allows moment transfer for both new design and the
> analysis of existing structures, where it really can come in handy.
> 
> D. Matthew Stuart, P.E., S.E., F.ASCE, F.SEI, SECB, MgtEng
> Structural Division Manager
> Pennoni Associates Inc.
> Office 215-222-3000 x7895
> Mobile 908-309-8657
> http://www.pennoni.com | mstuart(--nospam--at)pennoni.com
> 
> -----Original Message-----
> From: seaint-seaosc(--nospam--at)mail-list.com [mailto:seaint-seaosc(--nospam--at)mail-list.com] On
> Behalf Of Harold Sprague Sent: Tuesday, December 10, 2013 11:23 AM
> To: seaint-seaosc(--nospam--at)mail-list.com
> Subject: RE: [SEAINT-SEAOSC] Redistribution of Moments in grid Floor
> 
> It does not make a difference if it is a grid floor or not.  Moment

Truncated 652 characters in the previous message to save energy.

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