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ashutosh.jain SEFI Member
Joined: 26 Jan 2003 Posts: 12
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Posted: Tue Apr 06, 2021 8:56 am Post subject: Air Pressure Inside Metro Rail Tunnel for Cable/Pipe Support. |
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Hello Everyone,
I want to design a pipe /cable support inside Metro rail tunnel. My query is how much air pressure to be considered during movement of Train, I plan to consider this air pressure as wind load on support member. Is there any standard value which I can take or any tech reference anybody can provide, I will be grateful.
Regards,
Ashutosh. |
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vikram.jeet General Sponsor
Joined: 26 Jan 2003 Posts: 3839
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Posted: Tue Apr 06, 2021 11:59 am Post subject: |
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Not involved in metro tunnels
Since tunnel is open at both ends there is free flow of air in longitudinal direction. Transversely an air pressure of Cpi= -0.8p
may be taken as internal air pressure based on IS875 (clause 6.2.2.8)on wind loads regarding horizontal cylinders.
But try see specific guidelines in metro literature on net.
vikramjeet |
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pvgraju ...
Joined: 07 Jun 2020 Posts: 66
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Posted: Wed Apr 07, 2021 11:03 am Post subject: AIR PRESSURE INSIDE METRO TUNNEL |
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Dear Sir,
When the train is moving with certain speed it is moving in a fluid called air.Horizontal force will be massxaccleration. Same force will be exerted on the air which will move in oppsoite direction of train movement. For excat reference you can refer some fluid mechanics reference with topic bodies submerged inside fluid.
Regards,
P.V.Gavarraju |
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vikram.jeet General Sponsor
Joined: 26 Jan 2003 Posts: 3839
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Posted: Wed Apr 07, 2021 1:01 pm Post subject: |
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Yes , Dear Er Gavarraju ji ,
When tunnel strech is having no train presence, the space will be occupied by air and Cpi =-0.8p trnseversly in line with Is 875. But when a train enters tunnel there is going to be additional pressure. In absence of any reference , as a logical view Cpi can be further factored by (x-sec area of tunnel) /(Balance tunnel area after deducting train x-sec). As regards inertia force of speeding train , since tunnel ends are allowing passage of air freely without any blockage, air escapes without exerting extra pressure , other than discussed above .
May be some more convincing view from some sefi member come.
Best wishes & rgds
vikramjeet |
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vikram.jeet General Sponsor
Joined: 26 Jan 2003 Posts: 3839
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Posted: Wed Apr 07, 2021 3:45 pm Post subject: |
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I think you are right in enquiring this aspect of aerodynamics in metro tunnel. Request you to spend some time on internet and studies are available on this aspect.
Also see Railway tunnels by ministry of Rlys and transportation tunnels by MORTH. Some metro documents may also to be seen available on Google.
Yr vision is far sighted as a structural designer.
Best wishes
vikramjeet |
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pvgraju ...
Joined: 07 Jun 2020 Posts: 66
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Posted: Thu Apr 08, 2021 9:15 am Post subject: METRO RAIL TUNNELS |
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Dear Sir,
Thank you for your suggestion. Very nice to hear from you.Definitely i will go through the references you provided and study further on this aspect.
Regards,
P.V.Gavarraju |
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ashutosh.jain SEFI Member
Joined: 26 Jan 2003 Posts: 12
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Posted: Fri Apr 09, 2021 7:53 am Post subject: |
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Dear All,
Many thanks for your valuable feedback and suggestions. Will update once I find some references.
Thanks
Ashutosh Jain |
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