Finite element analysis of experimentally tested RC and PC beams using the cracked membrane model

Investigating/modelling numerically the static behaviour of RC and PC beams with composite cross-sections, taking into account their materials-dependent nonlinearities, is still a challenge, but today's numerical tools are very effective in helping both designers and researchers to reduce the computer time and to take care of models complexity. In this paper, nonlinear finite element (NLFE) analysis is used to perform numerical analysis of experimentally tested directly and indirectly supported full-scale plates and beams. The constitutive law for reinforced concrete used in the NLFE analysis is based on the cracked membrane model and was implemented as a Usermat in ANSYS Mechanical APDL. The algorithm for the constitutive law and some important aspects of the modelling process are presented. As part of the NLFE analysis of the test specimens (one plate, one beam subjected to torsion, one directly supported reinforced concrete beam, one directly supported prestressed concrete beam, and one indirectly supported prestressed concrete beam), the calculated load-deformation curves, crack patterns, stress in the reinforcing steel at the cracks, and principal concrete compressive stresses are compared with the corresponding measured values.