Probabilistic Prediction of Pile Group Capacity

A reliability analysis of a group of free standing piles in clay is carried out using Monte Carlo simulation. The pile material strength, soil capacity, and the load on the pile group are treated as random variables following lognormal distribution. The pile structural failure, the yielding of soil around each pile are the modes of failure considered. Effects of the non-uniform load distribution among piles and the spacing of piles on the group reliability are also studied. It was found that a minimum mean factor of safety of 2.5 reduces the effects of minor uncertainties in soil, pile and external load, and it is preferable to design a pile group based on zero pile failure.