Structural Capacity of the Pile 1

[Khurram Shehzad]

Hi guys,

I have to design the pile. I know how to calculate the compression and uplift pile capacity. But i don't know how to calculate the structural capacity for compression, uplift and lateral. Can you please help me and guide how to do the complete pile design. Any link or software recommendation will be very welcome.

 

[BridgeSmith]

What type of pile is it?

 

[oldestguy]

I'd do Google search "pile foundations" and look for a text book or an on line text. US corps of Engineers, US Navy have on-line engineering texts on this subject. It is probably too complicated for this forum, since it depends on ground conditions and type of job, etc.

 

[jayrod12]

If you mean the structural capacity of the pile, neglecting the geotechnical capacity, then it would be designed just like a column. The trick is determining the appropriate unbraced length to use.

 

[Khurram Shehzad]

It is bored pile. Actually I never do the design of the column, can you please suggest me any software which can perform this analysis.

 

[BridgeSmith]

So, it's cast-in-place reinforced concrete drilled shaft? In that case, once you have the moments and shears from a pile/drilled shaft analysis program (Allpile, L-pile, etc.), there are numerous options for structural analysis programs that will analyze and provide the capacity of a reinforced concrete column, which is what a drilled shaft is for structural design purposes.

However, by way of a warning and disclaimer, the structural design should be done by a qualified structural engineer, even for something as seemingly simple as a drilled shaft design.

 

[Khurram Shehzad]

Thanks HotRod10, yes I got the moments and share with the Allpile. I have a design which calculated the reinforcement using the S-Concrete. I am studding it and I will utilize this to design the shaft. No structure engineer is available here and company does not want spend money to some exterior resources. Can you please suggest me any reading material for the beginners.

 

[EireChch]

Google worked examples of structural design to Eurocodes. Thats a good starting point for design of columns.

A software will give you the answer but if you dont know the inputs or the parameters than are most influential then its meaningless.

I am definitely no expert in structural design but the below is some preliminary design information that may be of use. Its for a secant piled wall but the theory is still applicable. As above you need to design it as a column and use the column design charts.

You say your company doesnt want to spend money on exterior resources but they are happy to let you "waste" time by doing it yourself with limited starting knowledge. I am all for learning on the job but to me it would be much more beneficial if you paid a structural engineer to do the design (by hand and with software). You could spend hours and hours reading material etc and still not do the design correctly.

It would likely be only be a few hours work an experienced geotechnical/structural engineer. You could always pay for some additional time and have them come to the office to work through the calculations.

I would also recommend that you try it by hand and upload the calcs here. Folks are good on this site, while they wont do the work for you or "sign off" on calculations they are more than happy to help and answer questions on specific steps of a calculation etc.

 

[Khurram Shehzad]

Thanks Eriechch, you are right but I don't have a choice. I will study this design and try to understand the inputs.

 

[EireChch]

Khurram Shehzad - the above is preliminary and doesnt cover everything for structural design of piles. For example, the shear links are estimated in a very simplistic way. It is only a very basic starting point.

I have been in a similar position as you where you havent got the skills yourself or in the office and are forced to try your hand at something new. I would never try my hand at something that had a serious conscious if it failed but smaller less critical things are ok. While its ok from time to time, I wouldnt work for a company that operated like that continuously.

You will probably learn a lot form this exercise which is good!

Good luck.

 

[Khurram Shehzad]

Thanks, I will just try to understand and will avoid any critical thing by myself. I am studding this example it has minor calculation mistakes, but anyway it is a good example.

 

[EireChch]

'I am studding this example it has minor calculation mistakes' - a good reason to never trust anything you find on the internet

 

[PROFR]

What is the cross section shape of the pile? is it rectangular or circular? Do you just need to plot the interaction diagram?

 

[Khurram Shehzad]

The Cross-section is circular with dia of 100cm. I need to design the 20m long pile reinforcement.