Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Redistribution of Moments in grid Floor

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I don't recall what your role is here, but if you have ultimate (no pun 
intended) responsibility for approval of the design and it doesn't make 
sense to you then have them neglect redistribution.

Engineering is equal parts art and science. If it isn't reasonable then 
don't go with it.

W. L. Polhemus, Jr. P.E.


> On Dec 11, 2013, at 2:36 AM, "Ashraf Manjappara" 
> <ashraf.manjappara(--nospam--at)> wrote: 
> 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

Truncated 1058 characters in the previous message to save energy.

Post your message to the list by sending it to: 

The email messages sent to the list will be saved in an archive on the World Wide Web.
These archives are located at:

To contact the list owner, send your message to:

Sponsored By: Pacific Structural & Forensic Engineers Group, Inc. (PSFEG)

To unsubscribe, switch to/from digest, get on/off vacation, or change your email address, click here.