Experimental Study On Seismic Behavior Of PVA-steel Hybrid Fiber Reinforced Cementitious Composite Column

Traditional concrete substrate has a tensile strength,high brittleness,low toughness,easy to crack and other shortcomings.It can no longer meet the objective needs in a modern society with highly developed economy and sustainable development.As a reinforced concrete column that is mainly subjected to vertical pressure in a building structure,it is also subjected to shear and bending moments,and its damage has a very important impact on the overall seismic performance of the structure.Therefore,the use of high-performance PVA-steel hybrid fiber reinforced cementitious composites instead of ordinary concrete to study the failure form and deformation capacity of PVA-steel Hy FRCC columns and improve the seismic performance of components has important theoretical significance,which provides certain technical engineering applications for fiber reinforced concrete structures.Scientific basis.Engineered cementitious composite(ECC)is cement as a main material,a material using one or more high-performance fiber as ECC toughening material and one or more fibers as toughening materials.It has the characteristics of high tensile strength,good toughness,multiple cracking performance and tensile strain hardening.Uniaxial tension,the ultimate tensile strain exceeds 3%,and its deformability and crack development ability are better.The use of hybrid fiber engineered cementitious composites can effectively improve the characteristics of traditional concrete such as easy cracking and high brittleness,and improve the damage resistance and seismic performance of the column.Based on the research of domestic and foreign scholars,this paper conducts an in-depth study on the seismic performance of PVA-steel Hy FRCC columns.The main research contents are as follows:(1)Through the pseudo-static test,the influence laws of PVA-steel Hy FRCC column’s failure shape,hysteresis performance,ductility performance,energy dissipation capacity and stiffness degradation are studied.The results show that the good crack resistance and tensile strain hardening properties of PVA-steel Hy FRCC material can effectively transform the failure form of the column into bending failure,and improve the damage resistance and deformation ability of the column.The ductility and energy dissipation capacity of the test piece are greatly improved,absorb more seismic energy,and have better plastic deformation capacity and seismic performance.(2)The influence of changes in axial compression ratio,shear span ratio and stirrup ratio on the PVA-steel Hy FRCC column is analyzed.The results show that the failure morphology,deformation capacity and seismic performance of Hy FRCC specimens have certain effects under the conditions of different axial compression ratio,shear span ratio and stirrup spacing.When the shear span ratio increases,the load-bearing capacity of the specimen gradually decreases,but its ductility and energy dissipation capacity gradually increase;when the axial compression ratio increases,the load-bearing capacity and initial stiffness increase,but the ductility and energy dissipation ratio increase.The rate of stiffness degradation also becomes faster if it is reduced;the ductility and energy dissipation capacity of PVA-steel Hy FRCC specimens decrease with the increase of the stirrup ratio,but the decrease is not large.(3)The numerical simulation of PVA-steel HyFRCC column was carried out using Open Sees finite element software.Comparing the load-displacement curve(hysteresis curve and skeleton curve)of the specimen with the test data,the results show a good agreement,which proves the feasibility of the nonlinear finite element model.