Experimental And Theoretical Study On Seimic Performance Of Pre-cast Composite Shear Wall With Concrete Filled Steel Tube Columns

Pre-cast composite shear wall(PSW)structure is a new field assembly building structure system,which is a kind of suitable for industrialized production.Meeting the development requirements of China's building energy conservation and emission reduction and housing industrialization,the PSW structure has a better application prospect and economic value in the engineering field.In this paper a new composite shear wall with concrete filled steel tube columns(CFT)was proposed which can resist the earthquake by connecting the joints and seams to a whole.It is the critical factor that seismic performance of joints and structures for expanding the application of pre-cast structure.Therefore,the experimental and theoretical study on seismic performance of PSW-CFT has been investigated and the detailed work in this paper is stated as follow:(1)A new type of thread casing grouting connection has been designed.In order to study the connect reliability and the mechanical properties,5 specimens have been produced.The results show that the connection joint in the new structure is reliable by the quasi-static test.(2)A horizontal connection mode of the PSW-CFT has been proposed.The experimental study on the seismic behavior of three 1/3 scaled shear wall specimens with shear span ratios of 2.97 and with different axial-load ratios(0,0.1,0.2)has been done under the cyclic loading action.The failure characteristic,shearing capacity,deformation property and seismic behavior was compared among specimens in the three axial-load ratios.It is shown in the results that there is no slip failure in steel bar and steel tube grouting sleeve connection in the horizontal seam,which proves that the connection is reliable.With the increase of the axial-load ratio,the load value and the stiffness of the shear wall are obviously improved,while the ductility decreases.(3)The effect of eccentric opening ratio on the seismic behavior of PSW-CFT has been studied.Three 1/3 scaled shear wall specimens with the same opening area(less than 15%)and different eccentric opening ratios(0,0.3,0.6)have been done under the cyclic loading action.It is shown in the results that the seismic performance of the middle opening shear wall is very similar to the no opening shear wall.The seismic performance of the eccentric opening shear wall is slightly worse than the middle opening shear wall but all right.The seismic performance of the side opening shear wall is the worst of the three shear walls,which should be avoided in actual engineering.The opening offset causes difference on bearing capacity,shear stiffness and ductility in different loading direction.When acting load near the opening(opening under tension),the bearing capacity will increase,but the shear stiffness and ductility will decrease,and vice versa.(4)A vertical connection mode of the PSW-CFT has been proposed.The specimens with three cross-section form(horizontal-type,T-type,I-type)have been done under the cyclic loading action.The failure characteristic,shearing capacity,deformation property and seismic behavior was compared among specimens.It is shown in the results that the three specimens had almost no sliding displacement at the vertical and horizontal seams,which proves that the connection is reliable.As the energy dissipation device,the existence of the wall flange and the vertical seam is improved the ductility of the structure,the wall flange also has a certain degree of improvement in the bearing capacity.(5)Nonlinear finite element analysis of PSW-CFT has been carried out.The calculated results are in good agreement with experiments.Based on the good agreement of numerical simulation and experiment,the influence of parameters on the seismic performance is analyzed.It is shown that shear effect increased with the increase of axial-load ratio,and when the axial-load ratio is greater than 0.6,the shear wall will failure due to deficiency of bearing capacity.For shear wall with openings,the existence of the openings makes the shear force redistribution between the two wall limbs.The middle opening shear wall is consistent with the no opening shear wall,the eccentric opening shear is greatly influenced by the loading direction,the side opening shear wall is mainly borne by the large wall limb.The CFT will produce shear pin bolt force,which takes about 20% of the total shear force.(6)The mechanics model of loading-carring and restoring force of PSW-CFT have been established.The calculated results are in good agreement with those from experiments.Based on the theoretical analysis,the variation mechanism of force to deformation was revealed.