Finite element size effect on post-cracking behaviour of reinforced concrete members

Abstract

Present research was dedicated to investigation of finite element size effect on deformational behaviour of reinforced concrete members. Post-cracking behaviour of reinforced concrete beams assuming different finite element sizes has been investigated by commercial finite element software ATENA. Softening behaviour of tensile concrete has been modelled by three different approaches based on: a stress-crack width relationship with constant fracture energy; a stress-strain relationship with a constant ultimate strain; a stress-strain relationship with an ultimate strain adjusted according to the finite element size. Almost identical results were obtained in the first and third approaches using the adjusted descending branch of the constitutive relationships. A simple statistical analysis has shown that the calculation results for the second approach based on a constant value of the ultimate strain were more dependent on the finite element size in respect to other analyses.