www.sefindia.org

STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

 Forum SubscriptionsSubscriptions DigestDigest Preferences   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups  RegisterRegister FAQSecurity Tips FAQDonate
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log in to websiteLog in to websiteLog in to websiteLog in to forum 
Warning: Make sure you scan the downloaded attachment with updated antivirus tools  before opening them. They may contain viruses.
Use online scanners
here and here to upload downloaded attachment to check for safety.

Spreadsheets from members

 
This forum is locked: you cannot post, reply to, or edit topics.This topic is locked: you cannot edit posts or make replies.    www.sefindia.org Forum Index -> Past Discussions Year 2007
View previous topic :: View next topic  
Author Message
amitavabh
SEFI Member
SEFI Member


Joined: 26 Jan 2003
Posts: 19

PostPosted: Wed Sep 26, 2007 1:17 am    Post subject: Spreadsheets from members Reply with quote

Dear Friends,

I would like to draw attention of our forum members. I have seen that now-a-days nobody is contributing their spreadsheets/programs to our SEFI  forum.

This is not healthy for the forum. I request everybody to upload their spreadsheet/programs to this site and enrich it. The members may arrange some "spreadsheet drive month" for this.

Please let me know your comments.

Regards
Amitava Bhattacharjee
Kolkata, India.

wrote:
-------------------------
Message From  a_bhattacharjee[AT]yah...
Subject: Daily Digest Fri Sep 14 00:00:05 2007
Date: 14/09/07
Time: 10:57:24
-------------------------
Dear Bhavin,

Thank you for your mail. I have some items to discuss further, which are as following.

1. Support: I prefer spring support at nodes of base raft plate elements.

2. During Uplift pressure:

a) To know Stability against uplift a simple hand calculation may be used and at that time effect of spring support shall not be taken.

b) For uplift load case the local bending/forces of the base raft may be obtained from Staad using following idea:

Provide spring support around the edge of the raft, in line with the vertical tank walls to give a near site effect. Use proportionate influence area of raft to calculate each spring support.

When the base raft bends, it will mainly bend within its periphery beneath the heavy walls.

3. Additional Load cases: I had discussed about the loadcases that one shall take to analyse underground tanks. However, another 2 load cases shall be taken into consideration for analysis of underground tanks. They are:

a) Dynamic increment of soil pressure during seismic activity.
b) Sloushing effect of liquid inside the tank during the seismic activity. The liquid will change place during such movement like it does in rivers, ponds and Oceans during seismic activity.

However this kind of analysis is done for very important tank types. Say tanks that will contain radio active material, hazerdous liquids detrimental to underground and over ground environment etc.

Regards

wrote:
-------------------------
Message From  bhavinpatel[AT]vms...
Subject: Underground Tank Design
Date: 13/09/07
Time: 11:11:23
-------------------------
Dear Mr.Bhattacharjee,

When we model Base raft in STAAD, there are two issues regarding
supports.
1. Which kind of support should we provide. Plate Mat
Elastic Mat Spring Support. (I personally feel the plate mat option
gives better results when raft is modeled with plate element.)
2. When central portion of base raft is subjected to uplift
pressure in tank is empty condition, The spring support will resist that
upward deflection according to their stiffness which is not the actual
case with soil.

Regards
Bhavin
_________

a_bhattacharjee[AT]yah... wrote:
Dear Jagjit,

For designing underground tanks you can use following methods:

1. Use plate element and model it in Staad or other software. Provide
soil spring support for base raft.

Calculate soil, water and surcharge pressure on wall. Calculate uplift
due to water on raft. Use tank empty + soil around tank present
condition. Then use full + soil absent around tank during test condition
for worst load cases. If there is chember in the tanks then use
alternate chember filled/empty etc. Then analyse.

Take output forces of plates. Select maximum force of "plate center
stress summery" among the plates of each wall. Add torsional moment to
the moment of both direction seperately. Then Design for this moment of
each wall. Then take out bottom and top slabs. Calculate and check the
crack width of walls/slabs against code values.

Use IS 3370 and IS 456 for refering to codal provision.

2. Calculate forces on tanks as told above. then use Roark's table to
find out moment coefficients and then design for those forces. Check
crack width.

Regards
Amitava Bhattacharjee
Kolkata

Take the Internet to Go: Yahoo!Go puts the Internet in your pocket:
mail, news, photos & more.

Why delete messages? Unlimited storage is just a click away.

Park yourself in front of a world of choices in alternative vehicles.
Visit the Yahoo! Auto Green Center.

-------------------------

Boardwalk for $500? In 2007? Ha!
Play Monopoly Here and Now (it's updated for today's economy) at Yahoo! Games.
-------------------------

-------------------------
Message From  Akshaya.Das[AT]ake...
Subject: Underground Tank Design
Date: 14/09/07
Time: 12:14:07
-------------------------
Bhavin,

Reply to Point No.2

Use compression only spring to simulate soil. In case of uplift
corresponding soil spring will be inactive and will show zero support
reaction.

Regards,

Dr A K Das

-----Original Message-----
Message From  bhavinpatel[AT]vms...
[mailto:bhavinpatel[AT]vms...]
Sent: Thursday, September 13, 2007 4:41 PM
To: Das, Akshaya
Subject: Underground Tank Design

Dear Mr.Bhattacharjee,

When we model Base raft in STAAD, there are two issues regarding
supports.
1. Which kind of support should we provide. Plate Mat
Elastic Mat Spring Support. (I personally feel the plate mat option
gives better results when raft is modeled with plate element.)
2. When central portion of base raft is subjected to uplift
pressure in tank is empty condition, The spring support will resist that
upward deflection according to their stiffness which is not the actual
case with soil.

Regards
Bhavin
_________

a_bhattacharjee[AT]yah... wrote:
Dear Jagjit,

For designing underground tanks you can use following methods:

1. Use plate element and model it in Staad or other software. Provide
soil spring support for base raft.

Calculate soil, water and surcharge pressure on wall. Calculate uplift
due to water on raft. Use tank empty + soil around tank present
condition. Then use full + soil absent around tank during test condition
for worst load cases. If there is chember in the tanks then use
alternate chember filled/empty etc. Then analyse.

Take output forces of plates. Select maximum force of "plate center
stress summery" among the plates of each wall. Add torsional moment to
the moment of both direction seperately. Then Design for this moment of
each wall. Then take out bottom and top slabs. Calculate and check the
crack width of walls/slabs against code values.

Use IS 3370 and IS 456 for refering to codal provision.

2. Calculate forces on tanks as told above. then use Roark's table to
find out moment coefficients and then design for those forces. Check
crack width.

Regards
Amitava Bhattacharjee
Kolkata

Take the Internet to Go: Yahoo!Go puts the Internet in your pocket:
mail, news, photos & more.

Why delete messages? Unlimited storage is just a click away.

Park yourself in front of a world of choices in alternative vehicles.
Visit the Yahoo! Auto Green Center.

Everywhere

This e-mail and any attachment are confidential and may be privileged or otherwise protected from disclosure. It is solely intended for the person(s) named above. If you are not the intended recipient, any reading, use, disclosure, copying or distribution of all or parts of this e-mail or associated attachments is strictly prohibited. If you are not an intended recipient, please notify the sender immediately by replying to this message or by telephone and delete this email and any attachments permanently from your system.

-------------------------

-------------------------
Message From  bhavinpatel[AT]vms...
Subject: Underground Tank Design
Date: 14/09/07
Time: 13:07:57
-------------------------
Dear Dr. A K Das,

I have already tried that option of using compression only spring. I
gave uplift pressure in a separate load case and combine that in load
combinations. Now when I analyzed the model, the uplift load will not be
resisted by supports and hence it will give me large deformations
causing instabilities. Those large deformations when combined in load
combinations will give me very very large moments which is surely
impractical.
The other option is to apply uplift pressure and vertical downward
loads in one load case. This option may be workable but again there are
two issues.
1> For some load combinations we have to design the Structure/Raft for
no water pressure from bottom. In such case it is difficult and
confusing to define separate dead load case and analyze for that.
1> When there is a large raft with different size of panels, the no. of
iterations required for converging the reactions are very large which
cause very long time to analyze. I had analyzed such structure and it
took 24 hours to analyze even at the initial stage.

So compression spring is the best option but with the above issues.

Regards,
Bhavin Patel

-----Original Message-----
Message From  Akshaya.Das[AT]ake... [mailto:Akshaya.Das[AT]ake...]

Sent: 14 September 2007 17:44
To: Bhavin Patel
Subject: Underground
Tank Design

Bhavin,

Reply to Point No.2

Use compression only spring to simulate soil. In case of uplift
corresponding soil spring will be inactive and will show zero support
reaction.

Regards,

Dr A K Das

-----Original Message-----
Message From  bhavinpatel[AT]vms...
[mailto:bhavinpatel[AT]vms...]
Sent: Thursday, September 13, 2007 4:41 PM
To: Das, Akshaya
Subject: Underground Tank Design

Dear Mr.Bhattacharjee,

When we model Base raft in STAAD, there are two issues regarding
supports.
1. Which kind of support should we provide. Plate Mat
Elastic Mat Spring Support. (I personally feel the plate mat option
gives better results when raft is modeled with plate element.)
2. When central portion of base raft is subjected to uplift
pressure in tank is empty condition, The spring support will resist that
upward deflection according to their stiffness which is not the actual
case with soil.

Regards
Bhavin
_________

a_bhattacharjee[AT]yah... wrote:
Dear Jagjit,

For designing underground tanks you can use following methods:

1. Use plate element and model it in Staad or other software. Provide
soil spring support for base raft.

Calculate soil, water and surcharge pressure on wall. Calculate uplift
due to water on raft. Use tank empty + soil around tank present
condition. Then use full + soil absent around tank during test condition
for worst load cases. If there is chember in the tanks then use
alternate chember filled/empty etc. Then analyse.

Take output forces of plates. Select maximum force of "plate center
stress summery" among the plates of each wall. Add torsional moment to
the moment of both direction seperately. Then Design for this moment of
each wall. Then take out bottom and top slabs. Calculate and check the
crack width of walls/slabs against code values.

Use IS 3370 and IS 456 for refering to codal provision.

2. Calculate forces on tanks as told above. then use Roark's table to
find out moment coefficients and then design for those forces. Check
crack width.

Regards
Amitava Bhattacharjee
Kolkata

Take the Internet to Go: Yahoo!Go puts the Internet in your pocket:
mail, news, photos & more.

Why delete messages? Unlimited storage is just a click away.

Park yourself in front of a world of choices in alternative vehicles.
Visit the Yahoo! Auto Green Center.

Everywhere

This e-mail and any attachment are confidential and may be privileged or
otherwise protected from disclosure. It is solely intended for the
person(s) named above. If you are not the intended recipient, any
reading, use, disclosure, copying or distribution of all or parts of
this e-mail or associated attachments is strictly prohibited. If you are
not an intended recipient, please notify the sender immediately by
replying to this message or by telephone and delete this email and any
attachments permanently from your system.

-------------------------

Be a better Heartthrob. Get better relationship answers from someone who knows.
Yahoo! Answers - Check it out.

Posted via Email
Back to top
View user's profile Send private message
er.bhavin
SEFI Member
SEFI Member


Joined: 26 Jan 2003
Posts: 5

PostPosted: Wed Sep 26, 2007 6:05 am    Post subject: Spreadsheets from members Reply with quote

Dear sir,

I appreciate your appeal. I am preparing an excel sheet which gives
the column design results calculated in staad to excel with column no.,
Area of steel required & Area of concrete required. I hope this may be
helpful. As it prepares I will upload for your invaluable comments.

Another thing that I want to discuss with all members is Staad Design
Parameters. Most of the Indian people are using staad for analysis. Some
are using analysis results and design the elements manually. But as we
know we can also design the elements with using staad if we use proper
design parameters. There are Lots of design parameters available in
STAAD. So I think we must discuss them in this forum. And Check the
design made in STAAD with manual design. STAAD design will save lots of
engineering hours.

Thanks.
Bhavin

-----Original Message-----
Message From  a_bhattacharjee[AT]yah... [mailto:a_bhattacharjee[AT]yah...]
Sent: 26 September 2007 12:17
To: Bhavin Patel
Subject: Spreadsheets from members

Dear Friends,

I would like to draw attention of our forum members. I have seen that
now-a-days nobody is contributing their spreadsheets/programs to our
SEFI  forum.

This is not healthy for the forum. I request everybody to upload their
spreadsheet/programs to this site and enrich it. The members may arrange
some "spreadsheet drive month" for this.

Please let me know your comments.

Regards
Amitava Bhattacharjee
Kolkata, India.

wrote:
-------------------------
Message From  a_bhattacharjee[AT]yah...
Subject: Daily Digest Fri Sep 14 00:00:05 2007
Date: 14/09/07
Time: 10:57:24
-------------------------
Dear Bhavin,

Thank you for your mail. I have some items to discuss further, which are
as following.

1. Support: I prefer spring support at nodes of base raft plate
elements.

2. During Uplift pressure:

a) To know Stability against uplift a simple hand calculation may be
used and at that time effect of spring support shall not be taken.

b) For uplift load case the local bending/forces of the base raft may be
obtained from Staad using following idea:

Provide spring support around the edge of the raft, in line with the
vertical tank walls to give a near site effect. Use proportionate
influence area of raft to calculate each spring support.

When the base raft bends, it will mainly bend within its periphery
beneath the heavy walls.

3. Additional Load cases: I had discussed about the loadcases that one
shall take to analyse underground tanks. However, another 2 load cases
shall be taken into consideration for analysis of underground tanks.
They are:

a) Dynamic increment of soil pressure during seismic activity.
b) Sloushing effect of liquid inside the tank during the seismic
activity. The liquid will change place during such movement like it does
in rivers, ponds and Oceans during seismic activity.

However this kind of analysis is done for very important tank types. Say
tanks that will contain radio active material, hazerdous liquids
detrimental to underground and over ground environment etc.

Regards

wrote:
-------------------------
Message From  bhavinpatel[AT]vms...
Subject: Underground Tank Design
Date: 13/09/07
Time: 11:11:23
-------------------------
Dear Mr.Bhattacharjee,

When we model Base raft in STAAD, there are two issues regarding
supports.
1. Which kind of support should we provide. Plate Mat
Elastic Mat Spring Support. (I personally feel the plate mat option
gives better results when raft is modeled with plate element.)
2. When central portion of base raft is subjected to uplift
pressure in tank is empty condition, The spring support will resist that
upward deflection according to their stiffness which is not the actual
case with soil.

Regards
Bhavin
_________

a_bhattacharjee[AT]yah... wrote:
Dear Jagjit,

For designing underground tanks you can use following methods:

1. Use plate element and model it in Staad or other software. Provide
soil spring support for base raft.

Calculate soil, water and surcharge pressure on wall. Calculate uplift
due to water on raft. Use tank empty + soil around tank present
condition. Then use full + soil absent around tank during test condition
for worst load cases. If there is chember in the tanks then use
alternate chember filled/empty etc. Then analyse.

Take output forces of plates. Select maximum force of "plate center
stress summery" among the plates of each wall. Add torsional moment to
the moment of both direction seperately. Then Design for this moment of
each wall. Then take out bottom and top slabs. Calculate and check the
crack width of walls/slabs against code values.

Use IS 3370 and IS 456 for refering to codal provision.

2. Calculate forces on tanks as told above. then use Roark's table to
find out moment coefficients and then design for those forces. Check
crack width.

Regards
Amitava Bhattacharjee
Kolkata

Take the Internet to Go: Yahoo!Go puts the Internet in your pocket:
mail, news, photos & more.

Why delete messages? Unlimited storage is just a click away.

Park yourself in front of a world of choices in alternative vehicles.
Visit the Yahoo! Auto Green Center.

-------------------------

Boardwalk for $500? In 2007? Ha!
Play Monopoly Here and Now (it's updated for today's economy) at Yahoo!
Games.
-------------------------

-------------------------
Message From  Akshaya.Das[AT]ake...
Subject: Underground Tank
Design
Date: 14/09/07
Time: 12:14:07
-------------------------
Bhavin,

Reply to Point No.2

Use compression only spring to simulate soil. In case of uplift
corresponding soil spring will be inactive and will show zero support
reaction.

Regards,

Dr A K Das

-----Original Message-----
Message From  bhavinpatel[AT]vms...
[mailto:bhavinpatel[AT]vms...]
Sent: Thursday, September 13, 2007 4:41 PM
To: Das, Akshaya
Subject: Underground Tank Design

Dear Mr.Bhattacharjee,

When we model Base raft in STAAD, there are two issues regarding
supports.
1. Which kind of support should we provide. Plate Mat
Elastic Mat Spring Support. (I personally feel the plate mat option
gives better results when raft is modeled with plate element.)
2. When central portion of base raft is subjected to uplift
pressure in tank is empty condition, The spring support will resist that
upward deflection according to their stiffness which is not the actual
case with soil.

Regards
Bhavin
_________

a_bhattacharjee[AT]yah... wrote:
Dear Jagjit,

For designing underground tanks you can use following methods:

1. Use plate element and model it in Staad or other software. Provide
soil spring support for base raft.

Calculate soil, water and surcharge pressure on wall. Calculate uplift
due to water on raft. Use tank empty + soil around tank present
condition. Then use full + soil absent around tank during test condition
for worst load cases. If there is chember in the tanks then use
alternate chember filled/empty etc. Then analyse.

Take output forces of plates. Select maximum force of "plate center
stress summery" among the plates of each wall. Add torsional moment to
the moment of both direction seperately. Then Design for this moment of
each wall. Then take out bottom and top slabs. Calculate and check the
crack width of walls/slabs against code values.

Use IS 3370 and IS 456 for refering to codal provision.

2. Calculate forces on tanks as told above. then use Roark's table to
find out moment coefficients and then design for those forces. Check
crack width.

Regards
Amitava Bhattacharjee
Kolkata

Take the Internet to Go: Yahoo!Go puts the Internet in your pocket:
mail, news, photos & more.

Why delete messages? Unlimited storage is just a click away.

Park yourself in front of a world of choices in alternative vehicles.
Visit the Yahoo! Auto Green Center.

Everywhere

This e-mail and any attachment are confidential and may be privileged or
otherwise protected from disclosure. It is solely intended for the
person(s) named above. If you are not the intended recipient, any
reading, use, disclosure, copying or distribution of all or parts of
this e-mail or associated attachments is strictly prohibited. If you are
not an intended recipient, please notify the sender immediately by
replying to this message or by telephone and delete this email and any
attachments permanently from your system.

-------------------------

-------------------------
Message From  bhavinpatel[AT]vms...
Subject: Re: [SEFI]
Underground Tank Design
Date: 14/09/07
Time: 13:07:57
-------------------------
Dear Dr. A K Das,

I have already tried that option of using compression only spring. I
gave uplift pressure in a separate load case and combine that in load
combinations. Now when I analyzed the model, the uplift load will not be
resisted by supports and hence it will give me large deformations
causing instabilities. Those large deformations when combined in load
combinations will give me very very large moments which is surely
impractical.
The other option is to apply uplift pressure and vertical downward
loads in one load case. This option may be workable but again there are
two issues.
1> For some load combinations we have to design the Structure/Raft for
no water pressure from bottom. In such case it is difficult and
confusing to define separate dead load case and analyze for that.
1> When there is a large raft with different size of panels, the no. of
iterations required for converging the reactions are very large which
cause very long time to analyze. I had analyzed such structure and it
took 24 hours to analyze even at the initial stage.

So compression spring is the best option but with the above issues.

Regards,
Bhavin Patel

-----Original Message-----
Message From  Akshaya.Das[AT]ake... [mailto:Akshaya.Das[AT]ake...]

Sent: 14 September 2007 17:44
To: Bhavin Patel
Subject: Underground
Tank Design

Bhavin,

Reply to Point No.2

Use compression only spring to simulate soil. In case of uplift
corresponding soil spring will be inactive and will show zero support
reaction.

Regards,

Dr A K Das

-----Original Message-----
Message From  bhavinpatel[AT]vms...
[mailto:bhavinpatel[AT]vms...]
Sent: Thursday, September 13, 2007 4:41 PM
To: Das, Akshaya
Subject: Underground Tank Design

Dear Mr.Bhattacharjee,

When we model Base raft in STAAD, there are two issues regarding
supports.
1. Which kind of support should we provide. Plate Mat
Elastic Mat Spring Support. (I personally feel the plate mat option
gives better results when raft is modeled with plate element.)
2. When central portion of base raft is subjected to uplift
pressure in tank is empty condition, The spring support will resist that
upward deflection according to their stiffness which is not the actual
case with soil.

Regards
Bhavin
_________

a_bhattacharjee[AT]yah... wrote:
Dear Jagjit,

For designing underground tanks you can use following methods:

1. Use plate element and model it in Staad or other software. Provide
soil spring support for base raft.

Calculate soil, water and surcharge pressure on wall. Calculate uplift
due to water on raft. Use tank empty + soil around tank present
condition. Then use full + soil absent around tank during test condition
for worst load cases. If there is chember in the tanks then use
alternate chember filled/empty etc. Then analyse.

Take output forces of plates. Select maximum force of "plate center
stress summery" among the plates of each wall. Add torsional moment to
the moment of both direction seperately. Then Design for this moment of
each wall. Then take out bottom and top slabs. Calculate and check the
crack width of walls/slabs against code values.

Use IS 3370 and IS 456 for refering to codal provision.

2. Calculate forces on tanks as told above. then use Roark's table to
find out moment coefficients and then design for those forces. Check
crack width.

Regards
Amitava Bhattacharjee
Kolkata

Take the Internet to Go: Yahoo!Go puts the Internet in your pocket:
mail, news, photos & more.

Why delete messages? Unlimited storage is just a click away.

Park yourself in front of a world of choices in alternative vehicles.
Visit the Yahoo! Auto Green Center.

Everywhere

This e-mail and any attachment are confidential and may be privileged or
otherwise protected from disclosure. It is solely intended for the
person(s) named above. If you are not the intended recipient, any
reading, use, disclosure, copying or distribution of all or parts of
this e-mail or associated attachments is strictly prohibited. If you are
not an intended recipient, please notify the sender immediately by
replying to this message or by telephone and delete this email and any
attachments permanently from your system.

-------------------------

Be a better Heartthrob. Get better relationship answers from someone who
knows.
Yahoo! Answers - Check it out.

Posted via Email
Back to top
View user's profile Send private message
Display posts from previous:   
This forum is locked: you cannot post, reply to, or edit topics.This topic is locked: you cannot edit posts or make replies.    www.sefindia.org Forum Index -> Past Discussions Year 2007 All times are GMT
Page 1 of 1

 

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum


© 2003, 2008 SEFINDIA, Indian Domain Registration
Publishing or acceptance of an advertisement is neither a guarantee nor endorsement of the advertiser's product or service. advertisement policy