Non-linear analysis of concrete structures: a practical design approach to Eurocode

Reinforced concrete is an inherently non-linear material with non-linear compressive behaviour, concrete cracking and reinforcement yielding altering the stiffness and causing redistribution of forces within statically indeterminate structures. A practical design approach is described that has been developed to ensure robust computation of serviceability limit state and ultimate limit state demand in line with Eurocode BS EN 1992, including explicit modelling of material and geometric non-linearities and construction imperfections. The approach uses the MAT_CONCRETE_EC2 material model within the LS-DYNA finite-element analysis package and has been extensively used during the detailed engineering design of the concrete gravity substructure for the White Rose Extension Project off the coast of Newfoundland, Canada. The material model and validation of its behaviour in accordance with the Eurocode standard are described, along with other typical engineering applications where the approach may be of benefit. Specific benefits and implementation challenges encountered during the design process are also highlighted with a non-linear buckling assessment case study.