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jeeb SEFI Member
Joined: 23 Dec 2018 Posts: 10
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Posted: Sat Mar 21, 2020 7:23 am Post subject: Pyramid roof without ridge beam |
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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 General Sponsor
Joined: 24 Nov 2011 Posts: 1408 Location: Cochin
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Posted: Sat Mar 21, 2020 1:41 pm Post subject: |
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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 SEFI Member
Joined: 23 Dec 2018 Posts: 10
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Posted: Sat Mar 21, 2020 3:25 pm Post subject: Pyramid roof without ridge beam |
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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 General Sponsor
Joined: 24 Nov 2011 Posts: 1408 Location: Cochin
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Posted: Sun Mar 22, 2020 6:40 am Post subject: |
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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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Pyramidal Roof.rar |
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jeeb SEFI Member
Joined: 23 Dec 2018 Posts: 10
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Posted: Sun Mar 22, 2020 12:38 pm Post subject: Pyramid roof without ridge beam |
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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 General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Sun Mar 22, 2020 8:02 pm Post subject: Re: Pyramid roof without ridge beam |
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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 Silver Sponsor
Joined: 26 Jan 2003 Posts: 3554
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Posted: Wed Apr 08, 2020 12:55 am Post subject: |
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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 SEFI Member
Joined: 23 Dec 2018 Posts: 10
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Posted: Sat Apr 11, 2020 8:12 am Post subject: |
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Dear Er. Thirumalaichettiar,
Thank you so much. If possible, could you direct me to thepost regarding the detailing?
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