MODELING PARTICLES ELEMENTS IN DAMAGED REINFORCED CONCRETE STRUCTURES

Abstract

IN THIS PAPER, WE INTRODUCE A FINITE ELEMENT MESOSCALE MODELING OF DAMAGED CONCRETE STRUCTURES, BASED ON NODAL POSITIONS. THE MESOSCALE MODELING CONSISTS OF PARTICLE AND FIBER FINITE ELEMENTS EMBEDDED IN MATRIX FINITE ELEMENTS. WHILE THE MATRIX ELEMENTS REPRESENT THE CEMENT MATRIX, PARTICLE ELEMENTS ARE USED TO SIMULATE THE COARSE AGGREGATES AND FIBER ELEMENTS ARE USED FOR REINFORCEMENT REBARS. THE EMBEDDED THEORY IS USED TO IMMERSE THE REINFORCEMENT (BOTH PARTICLE AND FIBER ELEMENTS) WITHOUT INCREASING THE TOTAL NUMBER OF DEGREES OF FREEDOM. THIS STRATEGY DOES NOT REQUIRE NODAL COINCIDENCE, ALLOWING RANDOMLY DISTRIBUTE THE COARSE AGGREGATES. THE MATERIALS NONLINEAR BEHAVIOR IS CONSIDERED BY A SCALAR DAMAGE MODEL FOR THE CEMENT MATRIX AND COARSE AGGREGATES, AND ONE-DIMENSIONAL ELASTOPLASTIC MODEL IS USED FOR THE STEEL REBARS. FOUR EXAMPLES ARE PRESENTED, WITH GOOD CORRELATION BETWEEN NUMERICAL AND EXPERIMENTAL RESULTS. IT IS SHOWN THAT STRUCTURES SIMULATED WITH PARTICULATE ELEMENTS COULD ENDURE HIGHER LOADS FOR THE SAME DISPLACEMENT, ALTHOUGH THE MAXIMUM FORCE IS OBTAINED IN MODELS WITHOUT INCLUSION OF PARTICLE ELEMENTS.