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someshwar ganti
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Joined: 06 Feb 2010
Posts: 85
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 Posted: Fri Jun 13, 2025 11:18 am Post subject: |
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Thank you sir,
Just out of the box thinking since the truss less Roof is not in my scope,
what if I give a Pipe like member (perhaps a parallel truss) connecting the 2 columns on either ends will that work to prevent the Horizontal sway, there by reducing the size of the column and also the footings
| vikram.jeet wrote: | IF YOUR ROLE IS ONLY LIMITED TO COLUMN DESIGN,, ( AND NOT ARCH DESIGN) ,,
THEN IS OBLIGATORY ON PART TO DESIGN COLUMNS FOR FULL MOMENTS BASED ON ACTUAL MODEL WITH COLUMN TAKING FULL HORIZONTAL FORCE AT TIP.
IF BOTH COLUMNS AND ARCH ARE IN YR SCOPE - THEN ONLY YOU CAN ADOPT REDISTRIBUTION FACILITY - SINCE TWO ITEMS OF STRUCTURE CAN NOT BE SEEN IN ISOLATION. AS BOTH ARE INTERDEPENDENT IN CASE ADVANTAGE OF REDISTRIBUTION IS TAKEN. |
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vikram.jeet
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Joined: 26 Jan 2003
Posts: 3962
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| Posted: Fri Jun 13, 2025 4:56 pm Post subject: |
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Do not know the Hall dimensions
Span as revealed by you is 22.5 m
How much Hall size in other dir.
If longitudinal direction dim of Hall is say = L
There is need to design A heavy longitudinal beam for horizontal forces at each frame ( column tip) point as Concentrated horz loads for LATERAL BENDING OF LONGITUDINAL BEAM SPANNING FULL DIMENSION OF HALL AND ENTIRE HORZ FORCE REACTION TO BE TAKEN BY GABLE END BEAM AT EACH END.
GABLE BEAM WILL BE SUBJECT TO DIRECT TENSION AS RESULT OF REACTION Transferred FROM LONG BEAM SPANNING HORIZONTAL END TO END.
THESE BEAMS WILL ALSO SUBJECT TO VERTICAL BENDING BETWEEN COLUMNS BUT HORIZONTAL BENDING IS FOR SPAN AS EQUAL TO FULL HALL LENGTH L
COLUMNS IN THIS CASE WILL BE SPARED FROM SWAY . BUT STILL A MINIMUM OF BASE MOMENT TO BE CONSIDERED TAKING COLUMNS TO BE PROPPED CANTILEVERS
| someshwar ganti wrote: | Thank you sir,
Just out of the box thinking since the truss less Roof is not in my scope,
what if I give a Pipe like member (perhaps a parallel truss) connecting the 2 columns on either ends will that work to prevent the Horizontal sway, there by reducing the size of the column and also the footings
| vikram.jeet wrote: | IF YOUR ROLE IS ONLY LIMITED TO COLUMN DESIGN,, ( AND NOT ARCH DESIGN) ,,
THEN IS OBLIGATORY ON PART TO DESIGN COLUMNS FOR FULL MOMENTS BASED ON ACTUAL MODEL WITH COLUMN TAKING FULL HORIZONTAL FORCE AT TIP.
IF BOTH COLUMNS AND ARCH ARE IN YR SCOPE - THEN ONLY YOU CAN ADOPT REDISTRIBUTION FACILITY - SINCE TWO ITEMS OF STRUCTURE CAN NOT BE SEEN IN ISOLATION. AS BOTH ARE INTERDEPENDENT IN CASE ADVANTAGE OF REDISTRIBUTION IS TAKEN. |
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vikram.jeet
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Joined: 26 Jan 2003
Posts: 3962
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| Posted: Sat Jun 14, 2025 3:03 am Post subject: |
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In preceding post,, idea regarding HORIZONTAL SPANNING BEAM TO TAKE ALL HORIZONTAL FORCES FROM COLUMN TIPS,, BUT THIS IS FEASIBLE ONLY IF, LONGITUDINAL HALL LENGTH IS LIMITED,,
MOST PROBABLY YOU WILL END UP IN VERY ALARMING HORZ. BM AND MAY NOT FIND FEASIBILITY,,
THEREFORE PLEASE DESIGN COLUMNS FOR HORIZONTAL FORCE AND FULL BM AT BASE AND FOUNDATION MUST BE STABLE AND SAFE TO TAKE THE MOMENT Transferred.
IN CASE OF ANY DEFICIENCY IN COLUMN DESIGN - YOU WILL BE ANSWERABLE .
HENCE STICH IN TIME SAVES NINE,, ESPECIALLY IN THIS CASE,, WHERE YOUR SCOPE IS ONLY Limited TO COLUMN AND FOUNDATIONS DESIGN.
IN STRUCTURE DO NOT GO FIR SHORT CUTS,, |
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glnp12
SEFI Member
Joined: 31 Jan 2009
Posts: 8
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| Posted: Mon Jun 16, 2025 5:41 am Post subject: Re: TRUSS-LESS roof Modeling |
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| someshwar ganti wrote: | Dear All
I have a Truss Less Roof, for which I need to do a supporting RCC Framed structure,
I have Modeled the shed in 3D, the RCC columns are failing perhaps due to Horizontal load on the Roof beam due to the CURVED roof.
If someone can help me to correct the STAAD input file ( I have commented all the other Loads in order to correct this issue first) I would really be thankful.
If anybody can help me solve this issue for me,
I will give 6 months Free usage of my software "ARC BDS", that can be used to extract
1. RCC Column, Beams Ast, from a STAAD output file with click of a button, besides generating Great quality Beam L.S drawing directly from STAAD output file
Sorry for putting the above reward, but I need to put that issue to rest as it has been tormenting me for long. |
Please share Staad file to me directly, at, glnp123@gmail.com. I will go through and let you know. |
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glnp12
SEFI Member
Joined: 31 Jan 2009
Posts: 8
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| Posted: Mon Jun 16, 2025 6:12 am Post subject: |
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| vikram.jeet wrote: | In preceding post,, idea regarding HORIZONTAL SPANNING BEAM TO TAKE ALL HORIZONTAL FORCES FROM COLUMN TIPS,, BUT THIS IS FEASIBLE ONLY IF, LONGITUDINAL HALL LENGTH IS LIMITED,,
MOST PROBABLY YOU WILL END UP IN VERY ALARMING HORZ. BM AND MAY NOT FIND FEASIBILITY,,
THEREFORE PLEASE DESIGN COLUMNS FOR HORIZONTAL FORCE AND FULL BM AT BASE AND FOUNDATION MUST BE STABLE AND SAFE TO TAKE THE MOMENT Transferred.
IN CASE OF ANY DEFICIENCY IN COLUMN DESIGN - YOU WILL BE ANSWERABLE .
HENCE STICH IN TIME SAVES NINE,, ESPECIALLY IN THIS CASE,, WHERE YOUR SCOPE IS ONLY Limited TO COLUMN AND FOUNDATIONS DESIGN.
IN STRUCTURE DO NOT GO FIR SHORT CUTS,, |
= = = = =
Is the issue resolved finally or still under discussion to design the columns ? I find hte columns are of 2.0 meters depth, seems to be too large.
Curved roof need not transfer any horizontal load to the supporting structure. One should design the supporting system in that manner. Else, difficult to design the columns. Please check again. |
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vikram.jeet
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Joined: 26 Jan 2003
Posts: 3962
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| Posted: Mon Jun 16, 2025 2:06 pm Post subject: |
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I think, IF A PURELY SEMICIRCULAR ROOF IS SUPPORTED ON COLUMNS,, IT WILL NOT TRANSFER ANY HORIZONTAL FORCE AS RESULT OF GRAVITY LOADING.
HOWEVER IF ROOF ARCH IS SMALLER THAN SEMICIRCLE OR PARABOLIC,, IT MEET COLUMNS AT SOME INCIDENCE - GIVING RISE TO REACTION IN DIRECTION OF INCIDENCE ANGLE - WHICH WILL HAVE HORIZONTAL AND VERTICAL COMPONENTS. HENCE THERE IS NEED TO CONSIDER THIS HORZ FORCE IN COLUMS AT EACH SUPPORT.
Just my view |
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