Basic Theory And Application Of Bond Slip Of Section Steel-ECC

Steel-ECC put steel in reinforced concrete structure,make the steel,reinforcing cage(longitudinal reinforcement and stirrup)and ECC play a synergistic effect,to resist the external effect,this is a new type of building material structure,both the ECC ductility characteristics and optimize the structure performance,aims to improve their own lack of concrete under the ultimate load caused by high ductility of brittle failure,enhance the structure performance,which improves the life span of the structure.At present,the research on the structure of steel-ECC mainly focuses on the bearing capacity,deformation performance and so on,and there are relatively few studies on its bonding slip performance,the influence of ECC interface on the bonding slip mechanism,especially the performance of ECC elongation and the numerical simulation of the adhesive slip is rarely reported.Polyethylene(PE)not only affects the ECC's elongation,but also reflects the characteristics of ECC multi-crack development duet effect on structural bonding and slip performance.Therefore,this paper takes section steel-ECC specimens as the research object,combines the methods of theory,experiment and numerical simulation,and makes a comprehensive analysis of them.The specific research contents mainly include:(1)Nine section steel-ECC specimens were designed and prepared by taking four factors as variables: volume hoop ratio,section steel protective layer thickness,embedded length and ECC strength.The failure pattern and crack development were observed,and the corresponding conclusion was made.Meanwhile,the load-slip curve of the loading end was measured by the micrometer table,and the change rule of the curve was summarized.(2)Experimental data obtained in conjunction with the above-described four factors affect analysis of bond strength,and thus gives the formula of the characteristic slip value and the characteristic average bond strength.(3)By means of a finite element method for the introduction of the specimen steel-ECC simulation analysis,combined with the bond stress test piece-the specific distribution of the reference slip constitutive relationship,whereby the bonding interface steel-ECC understanding of the stress test to verify under the influence of different factors affect bond strength steel-ECC suffered,and finally to carry out research variables by means of the finite element method,more in-depth understanding of the mechanism of bond-slip and reveal the mechanical properties of steel for the whole steel-ECC Numerical analysis of the structure provides an advantageous reference.(4)In the ABAQUS analysis,the short beam was analyzed according to the two conditions of considering the bond slip between the section steel and ECC and not considering the slip between the section steel and ECC: its crack development status,failure form,bearing capacity,the load-span middeflection curve,ductility,steel bar and section steel strain,and the simulation results considering the bond-slip short beam between the section steel and the ECC are in good agreement with the experimental results.