Solid finite element limit analysis for modelling of pile caps

Solid reinforced concrete structures such as pile caps are generally designed using simple hand calculation methods originally developed for two-dimensional problems. These methods are not necessarily suited for the design of three-dimensional structures, and validation can be both cumbersome and give solutions with excessive material consumption.

Non-linear finite element programs, such as DIANA, can be used to give better solutions. However, the use of these programs requires a specialist and is time-consuming. Recently, Finite Element Limit Analysis (FELA) has emerged as a powerful tool in studying the collapse of reinforced concrete structures subject to in-plane forces in the ultimate limit state.

Recent research has paved the way for industrial use for plane problems. Computational capacity and available numerical solvers have previously impeded the research and use of FELA for three-dimensional structures with full triaxial stress state. However, this has changed with the power of modern computers and advances in the field of convex optimization.

The current study aims to test the capability of FELA with a smeared reinforcement material model in the modelling of pile caps. The numerical results are compared with experimental results from literature.