Research Of The Interaction Between FRP Bars And Concrete

In the recent years, as a substitut material of steel bar, the significance of applicationof fiber reinforced polymer(FRP) rebars in the concrete structure area is becoming moreand more obviously. Besides the mechanical interaction between FRP rebars and concreteplay a huge important affection to the characteristics of FRP rebars reinforced concretestructure, while nowadays the research on this interaction mechanisim is not yet in-depth.Although an amount of adhesion test researches with any types of different rebars werealready conducted, the analytical model of quantifying basic bonding mechanism anddescribing the induced features are extremely in lack.The discussion was proceeding according to two main problems in this thesis. Firstly,the gradual failure mode has not yet suggested in the empirical models till now, which isone of the problems in this study. At the same time, considering the previous theoreticalmodels failed to propose the dependence of the bonding performance to the stress state orunable to precast the various failure modes(pullout, split and peel off), unable to producean entire mechanical description, which is another main problem for this research.A bar scale model(model originally for steel bar) is modified for FRP bar. The modelprovide a macro description of the bonding features in a elastic plastic mathematicaltheory frame. There is a relative flowing rule and an coupled effection included. Thecalibration and validation results of6and3pullout specimens separately demonstratingthe model’s ability to reproduce the shear strength and the quantitive representation of theplastic evolution of the interface indicating the great generalizations of the model.A rib scale model of fiber rebar is further established for explaining the2-dimensionalcharacteristics. As a meso mechanical description of FRP rebar, in order to describe theplasticity and damage features of the fiber reinforced composite materials, a elastoplasticdamage model is established within the continuum damage mechanics theory frame.Adopt a continuum condition on the interface, which reflect the mechanical characteristicsof the two phase interface; Within a accepted accuracy, rib scale model reproduce theshear strength of6independent examinations; Meanwhile interfacial radial stress and fiberrebars plastic and damage responses are also provided, the specimen failure modes and thedamage of fiber robs surface structure are consistent with the test observations, provingthe special multi-describing potential of the elastoplastic-damage model...