Study On Seismic Performance Of Precast Shear Wall With Lightweight Opening Filling And Lapped Joint Of Overlap-joint Restraint Grouting-anchoring

As the main part of resisting lateral force in the shear wall structure,the shear wall has large stiffness and can bear high horizontal load.During the stage of structure design,considering that large stiffness is not needed in some loction,the hole will be set in the shear wall to reduce the stiffness and be filled with blocks at the time of construction.However,if we don't consider the effect of the filling block on seismic performance of structure,adverse consequences will appear.In this case,the precast fabricated integration shear wall has been proposed in order to reduce the lateral stiffness.On this basis,two new types of precast fabricated RC shear wall with lightweight opening filling are presented in this paper.The filling methods are respectively concrete integration infill with polystyrene plate sandwich and environmental lightweight partition board infill(The raw material of environmental lightweight partition board includes sulphoaluminate cement,fiber grid cloth,foam cement and coal ash.).A series of experimental,theoretical research and numerical study about the new types of precast fabricated RC shear walls with lightweight opening filling were conducted.Finally,the reliability of overlap-joint restraint grouting-anchoring and the influence of that to the seismic performance of the shear walls are studied combining with experimental and finite element analysis results.The major research contents are as follows:1.Two geometrically identical full size precast fabricated RC shear wall specimens with different opening filling methods were constructed and tested,the filling methods were respectively concrete integration infill with polystyrene plate sandwich and lightweight partition board infill.Based on the quasi-static experiment results,characteristics like failure mode,stress features,bearing capacity,deformability,stiffness,ductility and energy-dissipating capacity were obtained and compared with the unfilled wall,the ceramsite concrete hollow block masonry infill wall,the concrete integration infill wall with hollow tube and the ceramsite concrete infill wall.Experiment results shows that,under quasi-static cyclic lateral loading,the concrete integration infill wall with polystyrene plate sandwich was failured by bending and shearing,the specimen has the characteristics of high bearing capacity,high initial stiffness,bad ductility and poor energy dissipation capacity;the lightweight partition board infill wall was failured by bending,the specimen has the characteristics of low bearing capacity,small initial stiffness,good ductility and enough energy dissipation capacity.2.Based on finite element software OpenSEES,finite element numerical modeling and experimental results verification on precast fabricated RC shear wall with lightweight opening filling were obtained by using multi-layer shell element,concrete constitutive of amendatory Kent-Park and the reinforced constitutive of Pinto.The hysteretic curve and longitudinal strain obtained by finite element are in good agreement with that of the experiment,which verifies that the finite element model is applicable to the precast fabricated RC shear wall with lightweight opening filling.3.The influence law of various parameters including the length of the infill wall,concrete strength,ratio of longitudinal reinforcement in wall limbs,axial compression ratio and thickness of polystyrene plate sandwich to the seismic performance including bearing capacity,stiffness,ductility and energy-dissipating capacity were studied by FE method,the results indicate that;increasing the length of the infill wall,the concrete strength,the ratio of longitudinal reinforcement of wall limbs and the axial compression ratio can improve the bearing capacity of the precast shear walls;increasing the thickness of the polystyrene plate can effectively reduce the stiffness of the concrete integration infill wall with polystyrene plate sandwich;the ductility of the precast shear wall can be improved by increasing the strength of concrete and the thickness of polystyrene plate;increasing the concrete strength,the length of the infill wall and the ratio of longitudinal reinforcement of wall limbs can effectively enhance the energy-dissipation capacity of precast shear walls.Finally,based on the simulation and test results,the computational method of horizontal carrying capacity and stiffness on precast fabricated RC shear wall with lightweight opening filling are put forward.4.By finite element simulation results,the seismic behavior including bearing capacity,deformability,etc between the precast fabricated shear wall which uses the overlap-joint restraint grouting-anchoring and the cast-in-situ shear wall were compared and analyzed,the strain transformation law of the longitudinal bars in the overlap-joint restraint grouting-anchoring of the precast fabricated shear wall was obtained and compared with the longitudinal bars in the cast-in-situ shear wall.Finally,based on the test result on the specimen of overlap-joint restraint grouting-anchoring,the finite element model which considered the bond-slip between the concrete and the reinforcement was founded.According to the numerical simulation on 15 specimens of overlap-joint restraint grouting-anchoring,the influence law of the factors including the overlapping length,the concrete strength and the diameter of overlapping reinforcement and hoop on the lapped joint performance of the overlap-joint restraint grouting-anchoring were taken.