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.

IS IT POSSIBLE TO PROVIDE BOTH PILE FOUNDATIONS AND ISOLATED FOOTINGS IN A MIXED FASHION FOR A BUILDING?

 
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI General Discussion
View previous topic :: View next topic  
Author Message
renju mathew
SEFI Member
SEFI Member


Joined: 18 Feb 2016
Posts: 13

PostPosted: Tue May 21, 2019 4:47 am    Post subject: IS IT POSSIBLE TO PROVIDE BOTH PILE FOUNDATIONS AND ISOLATED FOOTINGS IN A MIXED FASHION FOR A BUILDING? Reply with quote

Dear All,

I just want to know, whether it is possible to provide both pile foundation and isolated footings in a mixed fashion for a two storey Residential building?

SBC of soil is just 70kN/m2 for 1.2m wide Isolated footing and Pile foundations can bear upto 750KN load.

There are about 25 column. The column loads are ranging from 150kN to 730kN.  I found that a few columns come within the range for Isolated footings. and a few can only be supported over pile foundation.

Client can't afford the expense of 25 piles.

Thanks in Advance
R Mathew
Back to top
View user's profile Send private message
abhio
...
...


Joined: 08 Mar 2010
Posts: 519

PostPosted: Wed May 22, 2019 7:01 am    Post subject: Reply with quote

Dear Er Matthew,

Pile foundations will be substantially stiffer (in general) than spread footings, and will attract a larger share of load. This will result in your assumed load paths being disturbed - unless you carry out a proper soil-foundation-structure interaction analysis.

Hence, I would recommend that you ought not to mix piles and spread footings in the same structure.
Back to top
View user's profile Send private message
sjgandhi
SEFI Regulars
SEFI Regulars


Joined: 26 Jan 2003
Posts: 20

PostPosted: Wed May 22, 2019 11:30 am    Post subject: IS IT POSSIBLE TO PROVIDE BOTH PILE FOUNDATIONS AND ISOLATED FOOTINGS IN A MIXED FASHION FOR A BUILDING? Reply with quote

Dear Mathew,

If both pile foundatiion and spread footing system adopted simultaneously , the building will rest on different mass with different soil parameters which requires care of differential settlement in design of foundation and superstructure.


In the event of eathquake and wind effects, the superstructure of building may vibrate with different frequencies and amplitudes on account of different soil mass through which seismic wave propagates and transmitted to superstructure via foundations. This may create non uniform drift of the storeys at different levels under earthquake effects which may ultimately trigger distresses in rcc members after and during earthquakes.


It is advisable to separate the building in two or three parts with separate foundations and superstructure with a separation joint wherever required.
Regards,


SUNIL GANDHI
Structural Engineer,

108 Amrut Commercial Centre,
 Sardarnagar Main Road,
 Rajkot. 360001
 Gujarat(India)
 Mobile : +919825147661
 Office  : +912812467661
 E-mail : suniljgandhi@gmail.com (suniljgandhi@gmail.com)

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


Joined: 04 May 2019
Posts: 5

PostPosted: Thu May 23, 2019 12:16 pm    Post subject: Reply with quote

Dear Er Matthew,


You can try to go for a mat foundation or a grid type of foundation. That would be an economical option compared to some deep foundation (pile) and some isolated ones.


If you can share the loads and the structural file with me, I can help you with designing a grid type of foundation (mat with openings at some places to save material).


Thanks,
Anunay Jain
Senior Undergraduate Student
IIT (BHU) Varanasi
Back to top
View user's profile Send private message
rojanmathewtsy
General Sponsor
General Sponsor


Joined: 21 Apr 2013
Posts: 29

PostPosted: Fri May 24, 2019 9:04 am    Post subject: Re: IS IT POSSIBLE TO PROVIDE BOTH PILE FOUNDATIONS AND ISOLATED FOOTINGS IN A MIXED FASHION FOR A BUILDING? Reply with quote

renju mathew wrote:
Dear All,

I just want to know, whether it is possible to provide both pile foundation and isolated footings in a mixed fashion for a two storey Residential building?

SBC of soil is just 70kN/m2 for 1.2m wide Isolated footing and Pile foundations can bear upto 750KN load.

There are about 25 column. The column loads are ranging from 150kN to 730kN.  I found that a few columns come within the range for Isolated footings. and a few can only be supported over pile foundation.

Client can't afford the expense of 25 piles.

Thanks in Advance
R Mathew


Dear Renju Mathew,

I think you can go with this type of foundation if you tie the isolated footings with pile foundation using rigid beams. That may limit the difference in settlement. But u should do the proper analysis to check the load flow through the rigid beam. Simply connecting the two foundation using beam  without any calculations may leads to errors. Other wise the best option will be the raft foundation.

Rojan Mathew
Back to top
View user's profile Send private message
mandeep_singh_kohli
SEFI Member
SEFI Member


Joined: 29 May 2019
Posts: 11

PostPosted: Wed May 29, 2019 12:03 pm    Post subject: Re: IS IT POSSIBLE TO PROVIDE BOTH PILE FOUNDATIONS AND ISOLATED FOOTINGS IN A MIXED FASHION FOR A BUILDING? Reply with quote

Dear renju,

I do not concur with the views that this is not  possible and also do not concur wit the view that you have to provide grid beams to take care of differential settlement ( that will be catastrophic).

The building can be supported on two different foundation systems, but those two foundation systems and buildings need to be isolated. You will have to isolate the foundations completely and also isolate the structures. You may have to give flexible connections between the buildings or sliding connections to account for unequal drift.

Seismic load paths, like any other lateral load path will have to be separated for both the portions.

Alternatively, you may go for Stone column foundation system which will be much cheaper than piled foundations, and can offer great savings.



renju mathew wrote:
Dear All,

I just want to know, whether it is possible to provide both pile foundation and isolated footings in a mixed fashion for a two storey Residential building?

SBC of soil is just 70kN/m2 for 1.2m wide Isolated footing and Pile foundations can bear upto 750KN load.

There are about 25 column. The column loads are ranging from 150kN to 730kN.  I found that a few columns come within the range for Isolated footings. and a few can only be supported over pile foundation.

Client can't afford the expense of 25 piles.

Thanks in Advance
R Mathew
Back to top
View user's profile Send private message
renju mathew
SEFI Member
SEFI Member


Joined: 18 Feb 2016
Posts: 13

PostPosted: Fri May 31, 2019 10:19 am    Post subject: Reply with quote

Anunay_Jain wrote:
Dear Er Matthew,


You can try to go for a mat foundation or a grid type of foundation. That would be an economical option compared to some deep foundation (pile) and some isolated ones.


If you can share the loads and the structural file with me, I can help you with designing a grid type of foundation (mat with openings at some places to save material).


Thanks,
Anunay Jain
Senior Undergraduate Student
IIT (BHU) Varanasi



The N value is less than 5.
Please give me your EMAIL ID
Back to top
View user's profile Send private message
ramprasad e
SEFI Member
SEFI Member


Joined: 27 Oct 2010
Posts: 7

PostPosted: Sat Jun 01, 2019 9:47 am    Post subject: Reply with quote

Dear Safin,
Both the foundations can not mix in one structure due to differential settlement ,however you can provide the expansion joint between the pile
foundation and spread footing.

Best Regards,
Ramprasad enugula
Back to top
View user's profile Send private message
spsvasan
...
...


Joined: 18 Dec 2008
Posts: 327

PostPosted: Sat Jun 08, 2019 3:13 am    Post subject: Re: IS IT POSSIBLE TO PROVIDE BOTH PILE FOUNDATIONS AND ISOLATED FOOTINGS IN A MIXED FASHION FOR A BUILDING? Reply with quote

Dear Er.R.Mathew

The mixing of deep foundation and shallow foundation shall be avoided

Even if a separation joint is provided between the portions with deep foundation and portions with shallow foundation, the difference in settlement will introduce difference in floor levels and this is not acceptable

For a two storeyed building a properly designed mat foundation should be feasible

Economics of ground improvement may also be investigated

S.P.Srinivasan


renju mathew wrote:
Dear All,

I just want to know, whether it is possible to provide both pile foundation and isolated footings in a mixed fashion for a two storey Residential building?

SBC of soil is just 70kN/m2 for 1.2m wide Isolated footing and Pile foundations can bear upto 750KN load.

There are about 25 column. The column loads are ranging from 150kN to 730kN.  I found that a few columns come within the range for Isolated footings. and a few can only be supported over pile foundation.

Client can't afford the expense of 25 piles.

Thanks in Advance
R Mathew
Back to top
View user's profile Send private message
Yogesh.Pisal
General Sponsor
General Sponsor


Joined: 18 May 2008
Posts: 406

PostPosted: Tue Jun 18, 2019 9:40 am    Post subject: Reply with quote

Dear Renju,

Considering two stories and 25 columns, I presume that you will be having lighter loads for peripheral columns. Hence isolating building to account for differential settlement may not be possible.

I will suggest to go for soil treatment (e.g. stone piles) to improve SBC and use open foundations for all columns.

Best Regards,
Yogesh Pisal
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 -> SEFI General Discussion 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