STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

viralcivileng · SEFI Member Joined: 26 Jan 2003 Posts: 9

Hi friends,
this is Viral.
I came across one problem.
Is there any logic to reduce the self weight of the portion of pile which is submerged?
I found in one design that they have calculated submerged weight of pile which is partly under water. I couldn't understand this logic. How this weight will be less than dry condition like that in soil? They had just subtracted unit weight of water from that of concrete and then calculated weight. Is this wright? If yes then why? If no then also why?

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sadish · SEFI Member Joined: 26 Jan 2003 Posts: 14

Buoyant force will be considered for piles in marine environment. This
upward force will be deducted from the pile downward force. But this
deduction doesn't mean the reduction in self weight of the structure.
Buoyant force will be checked for pull out capacity of piles if it
experience both submerge & dry condition. In dry condition buoyant force
is not considered.

Regards

N.Venkatesh Sadish Kumar

-----Original Message-----
Message From viralcivileng[AT]yah... [mailto:viralcivileng[AT]yah...]
Sent: Friday, September 07, 2007 11:08 PM
To: Sadish Kumar, N. Venkatesh SPEL-P2
Subject: pile weight

Hi friends,
this is Viral.
I came across one problem.
Is there any logic to reduce the self weight of the portion of pile
which is submerged?
I found in one design that they have calculated submerged weight of pile
which is partly under water. I couldn't understand this logic. How this
weight will be less than dry condition like that in soil? They had just
subtracted unit weight of water from that of concrete and then
calculated weight. Is this wright? If yes then why? If no then also why?

Get the freedom to save as many mails as you wish. Click here to know
how.

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nishithkshah · SEFI Member Joined: 26 Jan 2003 Posts: 3

hello ,viral

this is correct because ,any thing which is under water would have an upward force which we know has buoyancy .because the half the portion of pile is submerged there is force equal to that of water being pushed due to presence of pile , &will reduce the weight or self weight.

viralcivileng[AT]yah... wrote: Hi friends,
this is Viral.
I came across one problem.
Is there any logic to reduce the self weight of the portion of pile which is submerged?
I found in one design that they have calculated submerged weight of pile which is partly under water. I couldn't understand this logic. How this weight will be less than dry condition like that in soil? They had just subtracted unit weight of water from that of concrete and then calculated weight. Is this wright? If yes then why? If no then also why?

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lele_raj · ... Joined: 26 Jan 2003 Posts: 145

hi virol,

it's very common to deduct unit weight of water in case of submerged footing. it's applied to all sorts of footings, not only piles. example: a "pad and chimney" type footing for a HV transmission tower where water table is likely to rise upto ground level.

Best regards,

Rajendra (Raj) Lele

P Please consider the environment before printing this e-mail or any attachment/s.

----- Original Message ----
Message From "nishithkshah[AT]yah..."
To: lele_raj[AT]yah...
Sent: Sunday, 9 September, 2007 11:14:18 PM
Subject: pile weight

hello ,viral

this is correct because ,any thing which is under water would have an upward force which we know has buoyancy .because the half the portion of pile is submerged there is force equal to that of water being pushed due to presence of pile , &will reduce the weight or self weight.

viralcivileng[AT]yah... wrote: Hi friends,
this is Viral.
I came across one problem.
Is there any logic to reduce the self weight of the portion of pile which is submerged?
I found in one design that they have calculated submerged weight of pile which is partly under water. I couldn't understand this logic. How this weight will be less than dry condition like that in soil? They had just subtracted unit weight of water from that of concrete and then calculated weight. Is this wright? If yes then why? If no then also why?

Get the freedom to save as many mails as you wish. Click here to know how.

Unlimited freedom, unlimited storage. Get it now

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Parth.Vyas · SEFI Member Joined: 26 Jan 2003 Posts: 7

Hi to all,
Agreed what is being said by Mr. Rajendra in case of open
的基础。但在深foundation like pile before subtraction of water
buoyancy affect some body need to check that weather the pile uplift capacity
given by soil investigation report has included the water buoyancy or not.
Generally in soil investigation report as per industrial standard they must
give pile uplift capacity considering water buoyancy affect in presence of
highest ground water table present. In that case there is no need to reduce
water buoyancy effect again.

Parth Vyas
Jacobs Canada Inc.
833 - 4th Ave. S.W.
Calgary, Alberta T2P 3T5

-----Original Message-----
Message From lele_raj[AT]yah... [mailto:lele_raj[AT]yah...]
Sent: Monday, September 10, 2007 5:48 AM
To: Vyas, Parth
Subject: pile weight

hi virol,

it's very common to deduct unit weight of water in case of submerged footing.
it's applied to all sorts of footings, not only piles. example: a "pad and
chimney" type footing for a HV transmission tower where water table is likely
to rise upto ground level.

Best regards,

Rajendra (Raj) Lele

P Please consider the environment before printing this e-mail or any
attachment/s.

----- Original Message ----
Message From "nishithkshah[AT]yah..."
To: lele_raj[AT]yah...
Sent: Sunday, 9 September, 2007 11:14:18 PM
Subject: pile weight

hello ,viral

this is correct because ,any thing which is under water would have an upward
force which we know has buoyancy .because the half the portion of pile is
submerged there is force equal to that of water being pushed due to presence
of pile , &will reduce the weight or self weight.

viralcivileng[AT]yah... wrote: Hi friends,
this is Viral.
I came across one problem.
Is there any logic to reduce the self weight of the portion of pile which is
submerged?
I found in one design that they have calculated submerged weight of pile
which is partly under water. I couldn't understand this logic. How this
weight will be less than dry condition like that in soil? They had just
subtracted unit weight of water from that of concrete and then calculated
weight. Is this wright? If yes then why? If no then also why?

Get the freedom to save as many mails as you wish. Click here to know how.

Unlimited freedom, unlimited storage. Get it now

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Parth.Vyas · SEFI Member Joined: 26 Jan 2003 Posts: 7

Sorry please find the corrected mail as attached below.

Hi to all,
Agreed what is being said by Mr. Rajendra in case of open
的基础。但在深foundation like pile before subtraction of water
buoyancy affect some body need to check that weather the pile uplift capacity
given by soil investigation report has included the water buoyancy or not.(I
mean to say as per soil investigation report the pile uplift capacity for
pile has been already worked out by considering pile submerged weight under
highest water table present at site).

Generally in soil investigation report as per industrial standard they must
give pile uplift capacity considering water buoyancy affect in presence of
highest ground water table present. In that case there is no need to reduce
water buoyancy effect again.

Parth Vyas
Jacobs Canada Inc.
833 - 4th Ave. S.W.
Calgary, Alberta T2P 3T5

Parth Vyas
Jacobs Canada Inc.
833 - 4th Ave. S.W.
Calgary, Alberta T2P 3T5

-----Original Message-----
Message From lele_raj[AT]yah... [mailto:lele_raj[AT]yah...]
Sent: Monday, September 10, 2007 5:48 AM
To: Vyas, Parth
Subject: pile weight

hi virol,

it's very common to deduct unit weight of water in case of submerged footing.
it's applied to all sorts of footings, not only piles. example: a "pad and
chimney" type footing for a HV transmission tower where water table is likely
to rise upto ground level.

Best regards,

Rajendra (Raj) Lele

P Please consider the environment before printing this e-mail or any
attachment/s.

----- Original Message ----
Message From "nishithkshah[AT]yah..."
To: lele_raj[AT]yah...
Sent: Sunday, 9 September, 2007 11:14:18 PM
Subject: pile weight

hello ,viral

this is correct because ,any thing which is under water would have an upward
force which we know has buoyancy .because the half the portion of pile is
submerged there is force equal to that of water being pushed due to presence
of pile , &will reduce the weight or self weight.

viralcivileng[AT]yah... wrote: Hi friends,
this is Viral.
I came across one problem.
Is there any logic to reduce the self weight of the portion of pile which is
submerged?
I found in one design that they have calculated submerged weight of pile
which is partly under water. I couldn't understand this logic. How this
weight will be less than dry condition like that in soil? They had just
subtracted unit weight of water from that of concrete and then calculated
weight. Is this wright? If yes then why? If no then also why?

Get the freedom to save as many mails as you wish. Click here to know how.

Unlimited freedom, unlimited storage. Get it now

___________________________
_______
Sick of deleting your inbox? Yahoo!7 Mail has free unlimited storage.
http://au.docs.yahoo.com/mail/unlimitedstorage.html

This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail.

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