SOME OBSERVATIONS ABOUT STRAIN LOCALIZATION AND SHEAR-BAND FORMATION IN CONCRETE SAMPLES

Strain localisation in concrete is reproduced by introducing a softeni ng law coupled with damage in the stress-strain relationship and also considering coupling with damage. A quasi-static approach is developed , which requires initial imperfections to trigger off localisation. Th e model takes into account thermal, hygral and mechanical transient be haviour of concrete, through non-linear heat and mass transfer equatio ns expressed as functions of relative humidity and temperature. The nu merical code DAMAGE analyses the behaviour of viscoelastic damaged mat erials, under thermal flux and moisture diffusion, due to external for ces, thermal loadings and imposed displacements or humidities. (C) 199 8 Elsevier Science S.A. All rights reserved.