Research On The Constitutive Relationship Of The Confined Concrete Based On The Interfacial Bond And Slippage

As the rapid development of modern architecture, the confined concrete column,depending on its own advantages, is widely used in the field of civil engineering,especially in high-rise structure and seismic reinforcement aspects. At present, there aremany test researches and theoretical researches on the confined concrete column’smechanical property, but most of these studies do not consider the bond-slip effectbetween longitudinal reinforcement and concrete or just simply analyze the effect offrame joints with longitudinal ribs slip on the structure’s seismic response. So it isessential to conduct researches on bond-slip between longitudinal reinforcement andconcrete in column bottom plastic hinge region.This paper, targeting at confined concrete column, chooses Mander model as thebasic constitutive model. Through the finite element software-OpenSees, the zero-lengthelement modeling method with considering longitudinal bar bond-slip attached to fibercross-section was used to establish the simulation model of the stirrup confined concretecolumn. This paper realized the non-linear finite simulation of the stirrup confinedconcrete column with bond-slip under consideration and verified the accuracy of thebond-slip model and parameter setting. CFRP confined concrete column model was buildbased on the stirrup confined column modeling method to consider the effects ofinterface bond-slip, CFRP parcel layer number and length, the concrete strength grade onthe mechanical property of CFRP confined concrete column. Some conclusions areobtained: the interfacial bond-slip influences more on the local deformation of confinedconcrete column seriously; the optimal number of layers for wrapping CFRP is3~4; thebest length is larger than the plastic hinge; the higher the concrete strength grade is, theworse the effect of CFRP constraint is.