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surja_gain General Sponsor


Joined: 17 Jul 2009 Posts: 11
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Posted: Sun Jun 05, 2022 5:33 am Post subject: Regarding installtion of steel truss on masonry walls |
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I would like to install steel roof trusses (SHS / RHS tubes) each of span 8.00 m c/c on the roof of my house which is a two storied masonry structure building constructing with 250 mm thick load bearing brick walls.
Is this structurally feasible, considering that the foundation of the building is of adequate capacity and soundness?
Is there a relevant IS Code for this type of design consideration?
I would very grateful if the experts in this forum can help me out in this matter. Thank you very much.
Surja Gain
West Bengal. |
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vikram.jeet General Sponsor

Joined: 26 Jan 2003 Posts: 3432
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Posted: Sun Jun 05, 2022 8:50 am Post subject: |
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Steel roof shed at terrace
As stated in some recent posting , steel shed type roof is light weight structure and can be easily installed on existing roof. But some precautions to be kept in view as under :
(i) If only open shed : ( without walls / cladding )
It will be predominantly subjected to wind uplift force at truss ends and anchoring shed to existing roof slab/ beam is most important in case rcc columns at truss supports do not exist. Brick piers with full height Anchors reinf bars must be welded from truss ends to slab reinf bars . At least two nos 12mm dia bars at face of brick work and concealed in plastering need to be provided.
(ii)If Top floor shed is cladded with sheeting I.e walls are of sheeting :
In this situation regular rcc stub columns with their reinf welded to existing rcc roof beams are to be provided to take care of Wind uplift force from roof PLUS wind moments from wall cladding . Reinf will depend upon c/c columns .
(iii)In case walls and cross walls are available with roofing of sheeting , then Anchors full height as discussed at (i) need to be provided here also. |
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surja_gain General Sponsor


Joined: 17 Jul 2009 Posts: 11
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Posted: Mon Jun 06, 2022 4:39 am Post subject: |
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vikram.jeet wrote: | Steel roof shed at terrace
As stated in some recent posting , steel shed type roof is light weight structure and can be easily installed on existing roof. But some precautions to be kept in view as under :
(i) If only open shed : ( without walls / cladding )
It will be predominantly subjected to wind uplift force at truss ends and anchoring shed to existing roof slab/ beam is most important in case rcc columns at truss supports do not exist. Brick piers with full height Anchors reinf bars must be welded from truss ends to slab reinf bars . At least two nos 12mm dia bars at face of brick work and concealed in plastering need to be provided.
(ii)If Top floor shed is cladded with sheeting I.e walls are of sheeting :
In this situation regular rcc stub columns with their reinf welded to existing rcc roof beams are to be provided to take care of Wind uplift force from roof PLUS wind moments from wall cladding . Reinf will depend upon c/c columns .
(iii)In case walls and cross walls are available with roofing of sheeting , then Anchors full height as discussed at (i) need to be provided here also. |
Thank you sir for the quick help.
For my needs, the shed will be an open shed, to provide shelter from the rain and sun. The slab for the 1st floor roof (which will subsequently become the floor of the open shed) is yet to be cast.
I intend to cast the slab over supporting RCC wall beams / bands resting over all the masonry walls.
Is it possible to cast RCC columns to be used as the truss supports, with column reinforcements embedded and anchored completely inside the wall beams which are resting on the masonry 250 mm thick walls? |
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vikram.jeet General Sponsor

Joined: 26 Jan 2003 Posts: 3432
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Posted: Tue Jun 07, 2022 3:24 am Post subject: |
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[quote="surja_gain"] vikram.jeet wrote: | Steel roof shed at terrace
Thank you sir for the quick help.
For my needs, the shed will be an open shed, to provide shelter from the rain and sun. The slab for the 1st floor roof (which will subsequently become the floor of the open shed) is yet to be cast.
I intend to cast the slab over supporting RCC wall beams / bands resting over all the masonry walls.
Is it possible to cast RCC columns to be used as the truss supports, with column reinforcements embedded and anchored completely inside the wall beams which are resting on the masonry 250 mm thick walls? |
Yes sir ,there won't be any problem. You can raise stub columns may be 250x250 or 250x 350 on rcc beams of rcc roof (to be floor of shed) with at least 4 nos 16mm dia bars or more depending upon design dictate. Since shed str is light wt , it may increase reinf in rcc roof beams/ bands marginally . But most important is check against wind uplift force from stub columns transfered to rcc beams.
Further it may be cautioned that with passage of times , thinking of Dwellers change and seeing stub columns as rcc pillars there become tendency to remove shed and put Pucca rcc roof , THIS WILL BE VERY RISKY AND NEED TO BE ADDRESSED FOR ANY FUTURE MISADVENTURE. |
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surja_gain General Sponsor


Joined: 17 Jul 2009 Posts: 11
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Posted: Tue Jun 07, 2022 3:30 pm Post subject: |
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[quote="vikram.jeet"] surja_gain wrote: | vikram.jeet wrote: | Steel roof shed at terrace
Thank you sir for the quick help.
For my needs, the shed will be an open shed, to provide shelter from the rain and sun. The slab for the 1st floor roof (which will subsequently become the floor of the open shed) is yet to be cast.
I intend to cast the slab over supporting RCC wall beams / bands resting over all the masonry walls.
Is it possible to cast RCC columns to be used as the truss supports, with column reinforcements embedded and anchored completely inside the wall beams which are resting on the masonry 250 mm thick walls? |
Yes sir ,there won't be any problem. You can raise stub columns may be 250x250 or 250x 350 on rcc beams of rcc roof (to be floor of shed) with at least 4 nos 16mm dia bars or more depending upon design dictate. Since shed str is light wt , it may increase reinf in rcc roof beams/ bands marginally . But most important is check against wind uplift force from stub columns transfered to rcc beams.
Further it may be cautioned that with passage of times , thinking of Dwellers change and seeing stub columns as rcc pillars there become tendency to remove shed and put Pucca rcc roof , THIS WILL BE VERY RISKY AND NEED TO BE ADDRESSED FOR ANY FUTURE MISADVENTURE. |
Thank you very much sir, for your extremely valuable guidance. Your learned advice will be very helpful indeed. |
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