Experimental Study On Eccentric Compression Performance And Bearing Capacity Of Partially Prefabricated Steel Reinforced Concrete Columns

Partially prefabricated steel reinforced concrete(PPSRC)column is a new kind of structural member proposed to effectively solve the complex construction process of steel reinforced concrete structure,whose combines the characteristics of prefabricated assembly structure and steel reinforced concrete structure.The core idea of PPSRC column is partial prefabrication and partial cast-in-place,that is,the outer partial reinforced concrete of PPSRC column is prefabricated in the factory,and then be poured cast-in-place partial concrete after being transported to the site and being completely assembled.It has the advantages of high bearing capacity,large stiffness,simple construction and superior fire resistance.It is a new type of green building structural member with good application prospects.In view of few studies on the eccentric compression performance of PPSRC structure at home and abroad,and PPSRC column as a new kind of component with many advantages,it is particularly important to carry out the experimental study on the eccentric compression performance and bearing capacity of PPSRC column.Based on above,this paper mainly discusses the eccentric compression behavior and bearing capacity of PPSRC columns.The main research contents and conclusions are as follows:Firstly,six specimens of PPSRC column were tested under eccentric compression.The crack development process and final failure model of the specimens during the loading process were described in detail.The load-lateral deflection curve,lateraldeflection distribution and section strain distribution of typical specimens was obtained.The influences of relative eccentricity,internal cast-in-place concrete strength grade,and section form(solid and hollow section)on the bearing capacity,deformation performance and failure mode of PPSRC eccentric compressed columns are discussed emphatically.The test results show that PPSRC column prefabricated shell concrete,internal cast-in-place concrete and section steel work well together.with the increase of relative eccentricity,the bearing capacity of the specimen gradually decrease.At the same relative eccentricity,as the strength grade of the internal cast-in-place concrete increases,the bending stiffness and bearing capacity increase correspondingly,but the increase is little.Secondly,using ABAQUS finite element analysis software,the finite element model of eccentric compressed PPSRC column is established,and the load-lateral deflection curves of each specimen are obtained.The simulation results are compared with the test results,which are in good agreement with the test results.Based on above,the finite element model is established,and the relative eccentricity,prefabrication rate of outer concrete,internal cast-in-place concrete strength grade and steel ratio of section steel are considered.The simulation results show that the bearing capacity of eccentric compressed PPSRC column decreases with the increase of relative eccentricity,increases linearly with the increase of steel ratio,and increases with the increase of internal cast-in-place concrete strength grade,but for large eccentric compressed columns,the increase of bearing capacity is little.The optimum prefabrication rate in outer concrete of PPSRC column is 75%(hollow rate is 25%).Finally,on the basis of experimental research and finite element analysis,the formulas for calculating the normal section bearing capacity of eccentric compressed PPSRC columns are proposed based on the ultimate state design method and the analytical method of superposition method respectively,and then the calculated values are compared with the experimental values.The comparison results shows that the bearing capacity and the N-M correlation curve calculated by the formula based on the ultimate state design method are in good agreement with the experimental values,which can be used to calculate the normal section bearing capacity of eccentric compressed PPSRC columns.The bearing capacity and the N-M correlation curvecalculated by the formula based on the analytical method of superposition method differs greatly from the experimental values and is too conservative,which can only be used for the primary selection of section and the estimation of bearing capacity.