Study On Interfacial Behavior And Axial Loading Test Of Centrifugation Precast Concrete Column(CPCC)

Centrifugation precast concrete column(CPCC)is a new type composite structure which is one of the key objective research to develop an innovative,economical and efficient method for construction.CPCC is prefabricated at factory and transport to the construction site which can reduce the lifting weight due to hollow precast section,reduce formwork,reduce the construction period,and the process of installation becomes simplified due to eliminating reinforcement work.After concrete filled into the hollow section,the material constitutes of the column is not a single material.The contact surface of two different classes of concrete forms a composite structure.During the compressive performance,hollow precast column and cast-in-place concrete are subjected to differences in the axial stresses and deformation when the bonding shear failure at the interface of these two materials.This research is mainly divided into two parts which are an interfacial shear test and axial loading test.This research is focused on interfacial bonding failure of the CPCC column under the push-out test to understand the bond-slip relationship and failure mechanism.Moreover,this research aims to investigate the behavior of CPCC column under axial loading by present the experimental work combined with finite element analysis to classified the failure mechanism and investigated the parameter that affects the mechanical properties of the column.The main contents of this study are as follow:1)In order to evaluated interfacial shear of CPCC column,push-out tests on 4 square specimens have been carried out under the effect of cross tie ratio.The influence of this parameter on the failure mode,load-slip relationship,and peak load was analyzed.The test results showed that the specimen with crosstie did not signification increase the bonding stress compare to the specimen without crosstie.The splitting failure is induced to CPCC specimens under the effect of different crosstie spacing.Therefore,the splitting failure should be prevented by increasing the thickness of outer precast part through adjustment the hollow diameter of the column.2)The experiment was performed on a total of 3 short CPCC columns in order to investigate the behavior under axial compressive load.The main parameter was the effect of the crosstie ratio.The influence parameter on ultimate loading and the failure mode was analyzed.The results showed that by increased the volumetric crosstie ratio from 0 to 0.68%,the ultimate loading increased over 13%.All the design code underestimated the peak load of the CPCC column compared to the experimental result.The result obtained from the proposed model agreed well with the experiment result.3)The finite element models of the CPCC column subjected to uniaxial loading were developed for simulation using the commercial software ABAQUS.The result of FEM validated with the experimental result.The results of FEM showed that the stress transfer and crack pattern behavior were similar to the experimental results.In addition,the ultimate loading,the load-displacement relationship,the trend of the descending branches and the overall behavior of the CPCC column can be predicted accurately.4)The parametric study using ABAQUS was carried out to study the influence of thickness,and strength of concrete for load-bearing capacity of CPCC column subjected to uniaxial loading.It observed that the ultimate load of the CPCC column increased significantly with increased thickness of outer precast column.The strength of outer precast concrete played an important role to reduce the thickness of the outer tube.