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Ashwani Saxena
SEFI Member
Joined: 22 Aug 2020
Posts: 1
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 Posted: Fri Jun 25, 2021 2:21 pm Post subject: Blast Resistant Building |
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Dear All,
Please enlighten me about design requirement of Blast resistant building, I need to design G+1 building in LNG plant (Marine Area) for blast over pressure as 0.2bar with +ve phase duration 1.50 sec. For that do we go for dynamic approach (time history) or static approach in design is needed.
Is there any guideline is available.
Thanking You.
Regards,
Ashwani Saxena
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vikram.jeet
General Sponsor
Joined: 26 Jan 2003
Posts: 3706
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| Posted: Sat Jun 26, 2021 4:21 am Post subject: |
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Dear Er
Pl refer BIS CODE IS 4991 ON BLAST RESISTANT DESIGN OF STRUCTURES FOR EXPLOSION ABOVE GROUND.
All design criteria and guidelines are given in this Code.
Beat wishes
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glnp12
SEFI Member
Joined: 31 Jan 2009
Posts: 4
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| Posted: Mon Jun 28, 2021 10:55 am Post subject: Re: Blast Resistant Building |
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| Ashwani Saxena wrote: | Dear All,
Please enlighten me about design requirement of Blast resistant building, I need to design G+1 building in LNG plant (Marine Area) for blast over pressure as 0.2bar with +ve phase duration 1.50 sec. For that do we go for dynamic approach (time history) or static approach in design is needed.
Is there any guideline is available.
Thanking You.
Regards,
Ashwani Saxena |
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IS 4991 gives pressure calculations. But the method is quite old. Once the pressure of 0.2bar is estimated, one can use 'transient dynamic' analysis (either, linear or non-linear) for time based response. Concrete structures are quite stiff and can tolerate good amount of pressure within small time (pulse load). If the strains / forces are beyond linear range, from the above analysis, use cracked moment of inertia, and non-linear properties for steel (say, elastic-plastic or elastic-strain-hardening model) for checking collapse mechanism. Brick walls may collapse under pressure waves, due to poor bonding between bricks and columns / beams. This is the only critical aspect. For RCC shear-wall structures, this issue can be handled easily.
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vikram.jeet
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Joined: 26 Jan 2003
Posts: 3706
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| Posted: Mon Jun 28, 2021 11:48 am Post subject: |
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Blast resistant wall
I think brick walls with sandwiched RCC wall can also help and shuttering cost is not there , and a thick wall section of about 230 (bk wall outside). + 200 ( sandwiched RCC). + 115 ( bk wall inside) = 545 mm thick wall , will able to take blast load. Both inside and outside bk walls masonry shall also be reinforced after every 4 to 5 courses with light reinforcement. Anchor reinforcement bars of about 550 mm ( the composite wall thickness ) shall also be provided at regular intervals to have bond between bk and sandwiched RCC .
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suraj
General Sponsor
Joined: 17 Apr 2008
Posts: 5579
Location: NCR Faridabad, E mail suraj_engineer@yahoo.co.uk
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| Posted: Tue Jun 29, 2021 11:05 am Post subject: Field Engineering Building+General+Blast |
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Please Refer to posting dated 29.03.2010
https://www.sefindia.org/forum/viewtopic.php?t=7277
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spshaha
SEFI Member
Joined: 07 Apr 2012
Posts: 4
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| Posted: Wed Jun 30, 2021 4:30 am Post subject: Blast Resistant Building |
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dear sir pl find doc for blast design specification
sp shaha
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Blast_load_doc.doc |
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pvgraju
...
Joined: 07 Jun 2020
Posts: 66
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| Posted: Thu Jul 01, 2021 8:20 am Post subject: Blast Resistant Building |
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Dear Sir,
Loading depends upon positive phase plotted against time vs pressure diagram.
if positive phase is smaller than natural period effect of explosion vanishes.
when positive phase is longer than natural period static load.
when positive phase and natural period are in near agreement then dynamic loading.
Regards,
P.V.Gavarraju.
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glnp12
SEFI Member
Joined: 31 Jan 2009
Posts: 4
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| Posted: Mon Dec 26, 2022 10:51 am Post subject: Blast Loads : Difference of Opinion |
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Sorry to differ with some of the answers. Blast / Explosion pressures are of very short duration and cannot be compared to natural time period of structures. However, depending on the charge, pressures increases. This will lead to immediated increase in stresses / strains in structures. If they are beyond tolerable limits, structures tend to yield, and may lead to failure.
One issue with such loads is, cascading failures, which cannot be stopped. This area need detailed understanding, and proper judgement. One can refer any structural dynamics text books, for interaction of pulse load and time period of structures.
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