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Pile cap design

Pile cap design

Pile cap design

(OP)
Hello followers engineers,

I am a junior structural engineer designing a 52x48m pile cap for an industriel projet where different dead and live loads are applied. Steel filled-concrete piles will be used for this projet. the lenght of piles will deep for 16m to rest on rock soil. My question is what are the main steps to design the pile cap and how to check the lateral load on piles.

Thanks to all,

RE: Pile cap design

I wouldn't call a slab that large a pile cap.  But it would be designed like any other slab, with all load cases considered.  Do you have any specific questions?

RE: Pile cap design

(OP)
Thanks hokie66 for your answer,

Yes it is designed as a slab where I have to check for bearing and punching. What I am confusing about it is how can I know if my piles will resist the lateral loads and in the case of earthquake with a soil of different layers.
 

RE: Pile cap design

I wonder, as I presume you are fairly new to the design game, why your company would be putting you in charge of such a complex design - I would think that you should be reporting to an experienced mentor; ask him how to go about it - it is his responsibility to mentor the younger engineers in his stead.  You are speaking of a pile supported mat foundation.  Poulos has several papers on the subject and you might want to google and read some of them.  Are you in an area of high seismic loading?

RE: Pile cap design

I would suggest:
He should sit back and look at his project and see what has to be done.  This should/can involve the EOR to see if anything has been 'missed'. What the loads are, how are the loads taken out, etc. including lateral. Once he looks into it and if he has a 'bunch' of questions, he should talk to the engineer in charge and then proceed with his design.

Dik

RE: Pile cap design

(OP)
BigH you're right this is my first job in the field and design problemes were only done at school, this is as mentioned before a lateral loads probleme and I dont know from where I can start.

RE: Pile cap design

This is usually called a piled raft foundation.

A bit of reading:

http://www.sbe.napier.ac.uk/projects/piledesign/guide/contents.htm
http://www.issmge.org/getfile.ashx?cid=78815&cc=3&refid=1

http://books.google.co.uk/books?id=YfFP2ejTujoC&pg=PA323&lpg=PA323&dq=piled+raft&source=bl&ots=d_om-7eMQq&sig=aRPWwQ0qbyuc_JepXVf7cB3z7dw&hl=en&ei=rDthTN-BPY-RjAef8-THCQ&sa=X&oi=book_result&ct=result&;resnum=12&ved=0CD4Q6AEwCw
http://www.ejge.com/2010/Ppr10.041/Ppr10.041.pdf
http://www.crt.ntust.edu.tw/jcie/pdf/29-6-PDF/1091-1097.PDF
http://www.ejge.com/2004/Ppr0349/Ppr0349.htm
http://www.gnpgeo.com.my/download/publication/Design%20of%20Piled%20Raft%20Foundation%20on%20Soft%20Ground(Final).pdf
http://www.issmge.org/getfile.ashx?cid=78815&cc=3&refid=1

There is a lot to know about these things.

A few preliminary things to consider:

Are the piles supported on rock or on soft soil - this will determine if they are treated as stiff supports or if soil structure interaction should be considered.
What strata do they go through and how does this effect their behaviour under lateral loads. This can effect both moment distribution and magnitude.
The above items determine the raft analysis - do pile top moments need to be taken by the raft?e.t.c.
Pile groups effects - a group behaves differently to single piles.
Types, magnitudes and locations of applied loads.

I agree with the above comments that your superiors should be supporting you on this but a bit of preparation and research on your part will go a long way.

Good luck!

RE: Pile cap design

Check out the web for batter piles

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