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.

Punching Shear in Eccentric Footing

 
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> Speak Out Box
View previous topic :: View next topic  
Author Message
sathyace
...
...


Joined: 04 Jun 2011
Posts: 60

PostPosted: Fri Oct 25, 2019 5:10 am    Post subject: Punching Shear in Eccentric Footing Reply with quote

Hi All,

How to calculate the punching shear in eccentric footing(column located at the edge) ?

Please refer the attachment and clarify how the punching shear behaviour in plan-1 & plan-2 footing?

Thank you.

Regards,
Sathya.



Eccentric footing.png
 Description:
 Filesize:  7.91 KB
 Viewed:  44 Time(s)

Eccentric footing.png


Back to top
View user's profile Send private message
es_jayakumar
General Sponsor
General Sponsor


Joined: 24 Nov 2011
Posts: 1246
Location: Cochin

PostPosted: Fri Oct 25, 2019 9:29 am    Post subject: Reply with quote

First of all, edge or corner columns on an isolated footing is theoretically unstable, as soil will develop tension on the farther side. Hence the proposed arrangement is never advisable to adopt.
For academic interest : In the first case, there is a stiffener beam. Hence, there will be no punching action. In the 2nd case, the punching shear will act at d/2 from the face of the column. The attached Work sheet will be handy for calculations in this connection.

E S Jayakumar



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.
Design of Slab Type Raft or Footing for Moment & Shear.xls
 Description:

Download
 Filename:  Design of Slab Type Raft or Footing for Moment & Shear.xls
 Filesize:  182.5 KB
 Downloaded:  111 Time(s)

Back to top
View user's profile Send private message
sathyace
...
...


Joined: 04 Jun 2011
Posts: 60

PostPosted: Sat Oct 26, 2019 2:01 am    Post subject: Reply with quote

Thank you sir for the valuable reply.


Practically,we get both case of eccentric footing since the column has to be placed on the site boundary or closer to site boundary.

In this case,if we do not provide the stiffner beam how do we design the eccentric footing in first case?Also, how to design the second case eccentric footing?

Is it advisable to provide strap beam in eccentric footing and connect to the near by isolated footing? Please refer the attachment.

Kindly clarify which is the efficient method to design both case eccentric footing

Sathya.



strap beam.png
 Description:
 Filesize:  7.41 KB
 Viewed:  40 Time(s)

strap beam.png


Back to top
View user's profile Send private message
es_jayakumar
General Sponsor
General Sponsor


Joined: 24 Nov 2011
Posts: 1246
Location: Cochin

PostPosted: Sat Oct 26, 2019 4:21 am    Post subject: Reply with quote

You are welcome, Er. Sathya.... You have found the solution on your own ! Strap footing or Combined footing is the solution. Never attempt the proposals you had envisaged earlier, which is atrocious, at least theoretically !

E S Jayakumar
Back to top
View user's profile Send private message
es_jayakumar
General Sponsor
General Sponsor


Joined: 24 Nov 2011
Posts: 1246
Location: Cochin

PostPosted: Sat Oct 26, 2019 7:27 am    Post subject: Reply with quote

I wish to add that, in the 2nd case, you make a strap / combined footing by combining the column existing in the diagonal direction, if it is a must that the column has to rest on the corner of the footing..

E S Jayakumar
Back to top
View user's profile Send private message
sathyace
...
...


Joined: 04 Jun 2011
Posts: 60

PostPosted: Sat Oct 26, 2019 10:32 am    Post subject: Reply with quote

Thank you sir,

Now clearly understood the concept.

Analysed the strap beam as simply supported beam, here i have attached the strap beam staad file for reference.

Kindly check and let me know if any corrections.

Thank you.
Sathya.



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.
SB1.zip
 Description:

Download
 Filename:  SB1.zip
 Filesize:  672 Bytes
 Downloaded:  71 Time(s)

Back to top
View user's profile Send private message
es_jayakumar
General Sponsor
General Sponsor


Joined: 24 Nov 2011
Posts: 1246
Location: Cochin

PostPosted: Sat Oct 26, 2019 2:52 pm    Post subject: Reply with quote

This is not the method to analyse Strap footings. You can refer books "Design of Reinforced Concrete Foundation" by Varghese (contains a number different cases / examples) or "Design of Reinforced Concrete Structures" by Gambhir, for guidance. If the distance of the column in question to the adjacent column is not much, you can better go for a combined footing.  

E S Jayakumar
Back to top
View user's profile Send private message
sathyace
...
...


Joined: 04 Jun 2011
Posts: 60

PostPosted: Thu Oct 31, 2019 1:38 pm    Post subject: Reply with quote

Thank you sir.I will refer those books.

Regards,
Sathya.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> Speak Out Box 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 cannot 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