Experimental Study And Finite Element Analysis On The Bond Stress Slip Relationship Of RC Structure

Bond is the complex interaction between concrete and steel bar, and it is the presence of bond that prevents excessive slip between the steel bars and concrete and ensures that the average strain in the embedded reinforcing bar is equal to that of the surrounding concrete. Adequate bonding between reinforcing bars and concrete is essential for satisfactory performance of reinforced concrete structures. Therefore, the investigation on the bond behaviour is essential in the mechanical analysis of reinforced concrete structures. The present paper investigated the influence of concrete confinements and stirrup confinements on the bond behavior between concrete and deformed steel bar through beam end specimens. Based on test result, empirical model of ultimate bond strength and bond stress-slip relationship model was proposd. Using the derived bond stress-slip relationship model, finite element analysis of reinforced concrete beam was carried out andcompasions were made between experimental results and numerical modelling.(1) The effects of concrete cover and stirrups on the ultimate bond strength were thougouhlyinvestiaged and empirical equations were proposed. Through systematical analyses of measured bond stress-slip curves and data regressions, confinements-dependent bond stress-slip relationship model was established.(2) Three-dimensional model of the beam end specimens were established, and finite element analysis was carried out by ABQUS to model the overall pullout process of deformed steel bar. Concrete cover and stirrup spacing was set as the parameter to study their effects on the bond behavior. Compasion was also madewith the experimental results. The stress distribution of concrete and steel bar was also derived in the numerical modelling, which is a great compensation of experiments.(3) Utilizing the bond stress-slip relationship model from the beam end specimens, finite element analysis was carried out to study the mechanical performance of reinforced concrete beams with different corrosion level. The influence of position function on the numerical results was explored. Based on the numerical model, the influence of bond length, concrete cover, stirrup, diameter of tensile steel bar and number of the tensile steel bar on the ultimate load and deflection of the beamswas analyzed.