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Pyramid roof without ridge beam

 
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jeeb
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PostPosted: Sat Mar 21, 2020 7:23 am    Post subject: Pyramid roof without ridge beam Reply with quote

Hi, I hava 500x200 peripheral beams supporting a concrete pyramid slab without ridge beams as shown. I would like to ask how to:
1.design the pyramid slab ?
2.determine the vertical and lateral reactions on the 500x200 peripheral beams ?



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es_jayakumar
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PostPosted: Sat Mar 21, 2020 1:41 pm    Post subject: Reply with quote

Er. Jeeb,
Similar to this, one example is worked out in the book "Structural design of multi-storeyed buildings" by U H Varyani. But, in that example, there are ridge beams provided. By the way, what is the height of the sloped roof and how are the peripheral beams supported, on columns or load bearing masonry ? Can you post a detailed sketch ?

E S Jayakumar
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jeeb
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PostPosted: Sat Mar 21, 2020 3:25 pm    Post subject: Pyramid roof without ridge beam Reply with quote

Dear Jayakumar, the height of the roof is 2m and the peripheral beams are supported on columns as shown. I did make reference to U H Varyani but there is no example without ridge beams. I wish to know how to:
1.design the pyramid in this case, what internal forces the slab need to resist e.g bending thrust?
2. what are the vertical and horizontal reactions on the 500x200 beams?



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es_jayakumar
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PostPosted: Sun Mar 22, 2020 6:40 am    Post subject: Reply with quote

A tentative design attempted by me using STAAD Pro. is enclosed. This is for illustration / guidance purpose only. You can thoroughly verify the design and make your own detailing. It is advisable to provide closely spaced reinforcement mesh or weld mesh at the ridge corners J & H, to take care of complex stresses likely to arise there.

E S Jayakumar



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jeeb
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PostPosted: Sun Mar 22, 2020 12:38 pm    Post subject: Pyramid roof without ridge beam Reply with quote

Dear Jayakumar, thank you so much for your help. I currently don't have StaadPro but I'll download the software and have a look at it.
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Dr. N. Subramanian
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PostPosted: Sun Mar 22, 2020 8:02 pm    Post subject: Re: Pyramid roof without ridge beam Reply with quote

Dear Er.

You need to buy the STAAD Pro software.

Best wishes
Subramanian

jeeb wrote:
Dear Jayakumar, thank you so much for your help. I currently don't have StaadPro but I'll download the software and have a look at it.
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thirumalaichettiar
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PostPosted: Wed Apr 08, 2020 12:55 am    Post subject: Reply with quote

Dear Er.Jeeb,
You can refer a book (old ) on Pyramidal roof by Terrington for analysis of it. Also think about the botom hopper of a Silo where the reverse action applies to the roof.
More over since the Ly=15m & Lx=6m for rough guidance you can assume as an ONE way slab for maximum BM.
As Er.Jeyakumar said you can refer the book by Er,U,H Varyani but at ridges you can have the HIDEN beams.
STADDPRO is good if you use the plate element and some other sofeware like NisaDesign studio, Ram element and of course ETAB can be used for cross checking the outcome of STAADPRO.
Detailing  you have to careful and refer the detailing notes which was long ago I posted in the forum and go through the sticky topic in the forum.

Thanks,
T.RangaRajan.
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jeeb
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PostPosted: Sat Apr 11, 2020 8:12 am    Post subject: Reply with quote

Dear Er. Thirumalaichettiar,

Thank you so much. If possible, could you direct me to thepost regarding the detailing?
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