Numerical calibration of bond laws for GFRP bars embedded in steel fiber-reinforced self-compacting concrete

摘要

An experimental program was carried out at the Laboratory of Structural Division of the CivilEngineering Department of the University of Minho (LEST-UM) to investigate the bond behaviour of glassfibre reinforced polymer (GFRP) bars embedded in steel fibre reinforced self-compacting concrete(SFRSCC) for the development of an innovative structural system. Thirty-six pull-out-bending tests wereexecuted to assess the influence of the bond length, concrete cover, bar diameter and surface treatment on thebond of GFRP bars embedded in SFRSCC. This paper reports the results of a numerical study aiming toidentify an accurate GFRP–SFRSCC bond-slip law. Thus, the above mentioned pullout bending tests weresimulated by using a nonlinear finite element (FE) constitutive model available in FEMIX, a FEM basedcomputer program. The bond-slip relationship adopted for modelling the FE interface that simulates theinteraction between bar and concrete is the key nonlinear aspect considered in the FE analyses, but thenonlinear behaviour of SFRSCC due to crack initiation and propagation was also simulated. The evaluationof the values of the relevant parameters defining such a bond-slip relationship was executed by fitting theforce versus loaded end slip responses recorded in the experimental tests. Finally, correlations are proposedbetween the parameters identifying the bond-slip relationship and the relevant geometric and mechanicalproperties of the tested specimens.