The pile load carrying capacity depends on several factors, theses can be classified as factors related to pile (type, dimensions, method of installation) and factors related to ground conditions. In case that there is uncertainty of the soil properties, it is preferred to carry out reliability analysis taking into account the variance in soil properties (shear strength parameters).

Strength of pile depends on numerous factors i.e. soil properties, pile properties, method of installation and also to some extent expertise and skill of contractor who is casting the pile. Normally, the variance of soil properties is automatically handled if you are the calculating capacity of pile using any design code. All the design codes are conservative and recommends conservative design parameters. As a result the values of pile capacity calculated by codes is already lower than its actual capacity of the pile which it will offer in real. Hence if you follow the code guidelines correctly, we dont to worry about affect of pile capacity due to variance in the soil properties

I agree with both Mohammed and Salmon.

Thank you everyone for your answers.

As the respected researchers above indicated, the pile strength depends on several factors related to the pile structure itself and soil properties as well as to the soil-structure interaction. A parametric study is very helpful in identifying of the factors effecting the strength of the pile.

As a roughly and practical answer, For any type of piles and any installation procedure the strength Of any pile is increased with increasing depth of embedded (pile length) and increasing cross section area of pile.

With all due respect dear Ridz, your question is ambiguous. What do you mean by geotechnical uncertainties? Do you have incomplete or insufficient on site geotechnical data? Are you uncertain about the quality of the data? If any of the above questions holds, then how can you decide on the type of appropriate foundation, let alone design it? If I answered your question I might have made the mistake of encouraging you to carry out foundation design without propre investigation or sufficient data. This is wrong. My advice to you is : define the source of uncertainty and let everybody then help you out.

Dear Prof/Dr/Eng/Mr Georgios Tsifoutidis. Well done. You have provided an excellent, authoratative, experienced and very instructive answer and approach with the right questions? Our Colleague Prof/Dr/Eng/Mr Ridz Aquil might very well be in a very difficult position where his question is aligned to very commonly encountered 'modern day circumstances'. It comes down to the very limited budget (if any) for proper, detailed and thorough geotechnical investigations. We find this very often (in fact too often) when doing dams and hydro-power projects. The design engineer is expected to produce a pre-feasibility design, feasibility design or even a tender design based (with HIGHLY accurate costs) based on very little geotechnical investigation(s) MUCH to their peril. The structure is eventually safe, well designed and well constructed (after many, many years) BUT it comes at a price in the form of large variation orders (VOs) or projects being halted due to a lack of finance. Why is this so? Very few Clients, Banks (financing institutions) and even Members of Panels of Experts (PoE) 'lend an ear' to the questions (or similar questions) that you have posed. It is a case of "you (meaning them) don't know what you don't know", when will they learn AND if they will ever learn. Apologies for the (perhaps) angry essay - but it comes from 45 years of hard earned experience as a dam engineer. Yes, it is all about uncertainty and risk.

I recommed that you all have a look at 'Risk and Uncertainty in Deep Foundations' by Jack Hayes, Deep Foundation Conference (Al Bustan Rotana Hotel), Dubai, 1 February 2009. Do keep in touch. Alan Chemaly: Specialist Engineer: Dam Engineering: Aurecon South Africa (Pty) Ltd.

Dear Alan,

I fully concur with you grievances about stingy or ignorant clients. They usually pay a high end price or suffer massive delays. However, consultants must not refrain from putting forwards, even as a disclaimer, the ensuing risks of inadequate if none at all geotechnical investigation. The clients must become aware of the risks undertaken. By client I mean anyone who is hiring our services. I felt that it is my duty to bring this up the way I did, in order to help our young friend Ridz. If he could let us know of some of the design parameters and the missing details, we could offer a better and more to the point help. By the way I am not a Prof.

Dear Georgios. Thank you - yes, I agree with you wholeheartedly. I just needed to 'fuel the fire' and, just as you, was hoping that our colleague Ridz would oblige by prividing the information i.e. some (even if very, very few) of the design parameters and missing details. AND, of course we would be most pleased to assist. This what the spirit of ResearchGate is all about. Our 'colective input' would 'not cost him a cent'.