Seismic Performance Study Of Limestone Powder-fly Ash-Slag Concrete Frame-Shear Wall Structures With Energy-Consuming Connections

Limestone powder-flyash-slag concrete energy-dissipation coupled frame-shear wall structure is a new type of prefabricated structure with a new ratio of concrete materials.The structural components are connected by steel plates embedded in concrete through high-strength bolts,and flange connecting plates are improved in the connection area.According to the principle of metal tension and pressure damping energy dissipation,In order to absorb and dissipate seismic energy under earthquake conditions,flange plate is used to weaken the yield deformation of steel in the upper part of the hole.In addition,the raw material formula of physical test component pouring concrete is self-developed by the research group.Fly ash and slag are used to replace part of traditional cement as cementing material,thus saving traditional building materials.In addition,the strength of concrete cube test blocks under the same conditions can meet the test requirements.This connection mode eliminates the traditional wet operation assembly of the post-cast belt.After the components are prefabricated in the factory,it is convenient for construction and can reduce pollution and save resources.In this thesis,based on the local selected test prototype in Xuzhou,six frame-shear wall structures with different structural forms,different concrete strengths and different reinforcement rates were set up based on different seismic fortification intensities in Xuzhou to compare and verify the seismic performance of the new prefabricated frame-shear wall structure.PKPM software was used to create a prototype based structural model and calculate the maximum interlayer displacement Angle,maximum interlayer displacement and axial compression ratio of the selected isolation body,which were used as boundary conditions for physical tests and numerical simulation.In this thesis,physical tests and finite element numerical simulation software ABAQUS are combined to analyze the seismic performance of a new type of assembled frame-shear wall.The failure form,failure process,stress distribution and development,energy dissipation capacity,ductility,ultimate bearing capacity,stiffness degradation and other mechanical properties are studied.A variable parameter model was established by ABAQUS to study the effects of flange joint plate thick Ness,wall column axial compression ratio,hole size,shape,bolt preload and steel strength on structural mechanical properties.Combined with the numerical calculation results of the isolation body in the connection area by finite element software,the theoretical analysis of the ultimate flexural capacity of the connection area is carried out,and the calculation formula of the ultimate bearing capacity of the new energy dissipation connection area is put forward as well as the structural design and construction suggestions.The main innovations and research conclusions of this thesis are as follows:(1)The failure development process of shear wall of prefabricated frame is basically the same as that of cast-in-place structure,but the failure form is different.The number of joint cracks of prefabricated members is significantly less than that of cast-in-place members,and the existence of joint areas can make the plastic hinges appear far away from the joints under seismic action,which can effectively protect the joints.The skeleton curve of prefabricated members is fuller,the energy dissipation capacity is more prominent,and the structural ultimate bearing capacity is not different.Secant stiffness of prefabricated structure is 2%～23% higher than that of cast-in-place member at the same displacement grade,and is related to concrete strength and reinforcement ratio.(2)Under the same boundary conditions,geometric size,material properties and other conditions as the physical test,the finite element numerical calculation results and test results are basically the same.The development process of concrete damage nephogram is consistent with the development process of crack and crushing phenomenon of the tested concrete.The ultimate bearing capacity results are different from the physical tests.The analysis is that the numerical calculation cannot simulate the sliding effect of concrete and steel components,the low temperature during the test pouring of components,and the slight differences in loading modes will affect the results.(3)Through the stress-strain comprehensive analysis based on the stress-strain data collected from the resistance strain gauge in the test combined with the finite element numerical calculation,the shaping development law of the flange connecting plate and the stress distribution and the stress distribution in the connecting area were obtained.Under the action of horizontal force,the hole weakening of flange connecting plate first enters the yield stage,and at the end of the test,the plastic deformation range is controlled within the flange connecting plate,so as to achieve the purpose of "metal plastic deformation energy dissipation" and "easy repair after earthquake".The development of the cage stress of the column wall is obtained,and the bottom of the wall and the bottom of the column longitudinal bars yield at the end of the test.(4)The influences of different parameters on the mechanical properties of prefabricated frame-shear wall structures are obtained.The optimal thick Ness of flange plate is 8mm,which can not only have a higher ultimate flexural capacity of the connection area,but also achieve energy dissipation through plastic deformation under the action of horizontal force.The axial compression ratio has obvious effect on the skeleton curve,which can effectively improve the bearing capacity and stiffness of the structure,but has little effect on the yield strength of the structure.The bolt preload shall be applied in accordance with the specification.The use of Q345 steel makes the structure yield strength,ultimate bearing capacity,initial stiffness are slightly improved.(5)The theoretical analysis results and calculation formula of the ultimate flexural capacity of the connection area are proposed,so that the limited development of the plastic deformation of the connection area is controlled above the flange holes of the flange connecting plate or the full section of the flange connecting plate.Thus two calculation formulas are obtained.The error of the calculation formula is 14.9%～26.6%by combining with the finite element simulation.The design and construction suggestions of new type connected prefabricated structure are given.This thesis has 69 figures,13 tables and 152 references.