MATERIAL AND GEOMETRIC NONLINEAR ANALYSIS OF REINFORCED CONCRETE FRAME STRUCTURES CONSIDERING THE INFLUENCE OF SHEAR STRENGTH COMPLEMENTARY MECHANISMS

Abstract

A MECHANICAL MODEL FOR THE ANALYSIS OF REINFORCED CONCRETE FRAME STRUCTURES BASED ON THE FINITE ELEMENT METHOD (FEM) IS PROPOSED IN THIS PAPER. THE NONLINEAR BEHAVIOR OF THE STEEL AND CONCRETE IS MODELED BY PLASTICITY AND DAMAGE MODELS, RESPECTIVELY. IN ADDITION, GEOMETRIC NONLINEARITY IS CONSIDERED BY AN UPDATED LAGRANGIAN DESCRIPTION, WHICH ALLOWS WRITING THE STRUCTURE EQUILIBRIUM IN THE LAST BALANCED CONFIGURATION. TO IMPROVE THE MODELING OF THE SHEAR INFLUENCE, CONCRETE STRENGTH COMPLEMENTARY MECHANISMS, SUCH AS AGGREGATE INTERLOCK AND DOWEL ACTION ARE TAKEN INTO ACCOUNT. A SIMPLIFIED MODEL TO COMPUTE THE SHEAR REINFORCEMENT CONTRIBUTION IS ALSO PROPOSED. THE MAIN ADVANTAGE OF SUCH A MODEL IS THAT IT INCORPORATES ALL THESE EFFECTS IN A ONE-DIMENSIONAL FINITE ELEMENT FORMULATION. TWO TESTS WERE PERFORMED TO COMPARE THE PROVIDED NUMERICAL SOLUTIONS WITH EXPERIMENTAL RESULTS AND OTHER ONE- AND BI-DIMENSIONAL NUMERICAL APPROACHES. THE TESTS HAVE SHOWN A GOOD AGREEMENT BETWEEN THE PROPOSED MODEL AND EXPERIMENTAL RESULTS, ESPECIALLY WHEN THE SHEAR COMPLEMENTARY MECHANISMS ARE CONSIDERED.