Research On Reinforced Concrete Bond-slip Constitutive Realation Under Coupled Action Of Corrosion And Fatigue

For existing reinforced concrete (RC) structures, rebar corrosion leading tostructural failure has become one of the most common phenomena. Bridges andmarine structures not only face the problem of rebar corrosion during the period ofservice, but also bear the fatigue load of vehicles and the waves. Corrosion fatiguedamage has become the main failure mode of such kind of structures. Reinforcingsteel rust erosion can not only reduce the bearing capacity of the bar, but also cangreatly reduce the bond capacity between steel bars and concrete. Fatigue loadingleads to the generation and development of micro cracks in the structures, and can dodamage to structures potentially, finally causing brittle failure of RC structures. Bothconsidering the influence of rebar corrosion and fatigue loading on the bond-slipbehavior in RC structures and establishing constitutive law of bond-slip betweencorroded bar and concrete under fatigue loading are very important for calculating andanalyzing existing structures. And thereby engineers can utilize this theory to predictthe residual life of existing structures and employ the research results to repair andreinforce the damaged structures. The main research contents of this thesis include:1. The thesis reviews the impact of rebar corrosion and fatigue loading on RCstructures given by previous researchers including experiment research, theory studyand numerical simulation method. The basic concept and mechanism of bond-slipinteraction are introduced as well as the achievements on each aspect.2. Considering the rebar corrosion and fatigue load separately, the individualeffect of two factors affecting the bond properties is analyzed. The bond-slipconstitutive law considering the coupled action of fatigue loading and rebar corrosionis established.3. Based on the bond-slip constitutive law achieved in the former part, a finiteelement model is established by nonlinear software ABAQUS according to theexisting experiment. The bond action between steel and concrete is simulated byspring element Spring2and the simulation results are achieved after computation. Byanalyzing the existing experiments and comparing the numerical simulation resultswith experimental results, the correctness of the constitutive law derived in this thesisis verified, and some questions on the derived constitutive law are explained at last.The bond-slip constitutive law in this thesis provides the theory basis to the analysis of the existing structures and to predict the remaining bearing capacity and residuallife of the existing structures.