| Since the 13th five-year Plan,China’s economy has developed rapidly,the new type of urbanization has entered the fast lane,the urban resident population is growing rapidly,and the land resources are increasingly scarce.Ordinary multi-storey housing has been unable to meet the needs of urban development.High-rise buildings have gradually become the mainstream building form.The increase of the height of the building puts forward higher requirements for the design and construction.Due to the requirements of structural deformation capacity and ductility,the thickness of the shear wall needs to increase with the increase of the building height,which not only reduces the use area,but also brings trouble to the construction.The traditional cast-in-place concrete(RC) structure still has some shortcomings,such as long construction period,too much pollution and waste,difficult to control the construction quality,high self-weight of the structure,poor seismic performance and so on,so it is difficult to meet the current building requirements,so the steel-concrete composite shear wall has been widely studied and applied.However,there are some problems in steel-concrete composite shear wall and single steel plate-concrete composite shear wall,such as complex structure and low degree of industrialization,double steel plate-concrete composite shear wall has some problems,such as easy buckling of steel plate,poor fire prevention and anti-corrosion performance,etc.Existing prefabricated steel-concrete composite shear walls have some problems,such as single connection mode,complex joint structure,difficult construction,difficult assembly quality control and so on.The prefabricated steel-concrete composite pipe shear wall(precast steel-reinforced concrete composite tube shear wall),referred to as prefabricated SRCT shear wall)proposed by the research group can better solve the above problems.In this paper,the axial compression performance and design method of prefabricated SRCT shear wall are studied.The main contents of the study are as follows:(1)The axial compression performance test of prefabricated SRCT shear wall is carried out,and the stress mechanism and failure form of the specimen under axial compression load are studied.The axial compression tests of 7 prefabricated SRCT shear wall specimens were carried out,and the stress of the wall under axial pressure was analyzed.The test process and failure mode of each specimen are described in detail,and the stress process of the specimen is divided into four stages.During the loading process of prefabricated SRCT shear wall specimens,steel plate and concrete are subjected to common stress,so the mechanical performance of the structure as a whole is better.(2)Based on the axial compression test,the influence of key parameters on the axial compression performance of fabricated SRCT shear wall is analyzed.Combined with the test results,the wall is analyzed from the aspects of stiffness degradation,strain of key parts,load-displacement curve,displacement ductility and so on.The test results show that the axial bearing capacity and initial stiffness of prefabricated SRCT shear wall are inversely proportional to the ratio of distance to thickness,and the displacement ductility is proportional to the ratio of distance to thickness.The prefabricated SRCT shear wall specimen with plum blossom-shaped tie bars has better bearing capacity than that with rectangular arrangement of tie bars,and the axial compression bearing capacity of the specimen increases with the strengthening of side anchor bolts.In order to give full play to the axial compression performance of prefabricated SRCT shear wall,it is necessary to design the wall structure scientifically.(3)Based on the basic principle of material mechanics,the theoretical calculation method of axial compression of prefabricated SRCT shear wall is put forward by using "superposition method".On the basis of experiments,combined with the section form of prefabricated SRCT shear wall,the calculation method of axial compressive stiffness of prefabricated SRCT shear wall is established by using "superposition method".A force analysis model considering the local buckling of steel plate and the restraint effect of steel pipe on concrete in the core area is established,which provides a feasible method for calculating the axial compressive bearing capacity of the wall.The test results are in good agreement with the calculated results,which shows that the stiffness and axial bearing capacity of prefabricated SRCT shear walls can be calculated by this method.(4)By establishing the finite element model of prefabricated SRCT shear wall and carrying out numerical simulation analysis,the axial compression performance of the specimen is further studied.First of all,the prefabricated SRCT shear wall is numerically simulated and analyzed by ABAQUS finite element software,and the reliability of the analysis method is proved by comparing with the experimental results.Then,on this basis,the parametric analysis is carried out.The results show that the greater the thickness of the steel plate is,the better the axial compression bearing capacity,initial stiffness and plastic deformation capacity of the members are;increasing the strength of the steel plate can improve the axial compression bearing capacity of the specimen,but has little effect on the initial stiffness of the specimen;in a certain range,the increase of tie bar section can improve the axial compression bearing capacity and deformation capacity of the specimen.Through the axial compression test and numerical simulation analysis of the prefabricated SRCT shear wall,this paper makes an in-depth analysis on the axial compression mechanism,failure pattern and axial compression bearing capacity of the prefabricated SRCT shear wall.It is proved that the prefabricated SRCT shear wall has better axial compression behavior,and the corresponding structural design suggestions are put forward.Then,by using the "superposition method",the theoretical calculation method related to the axial compression of prefabricated SRCT shear wall is put forward,which can provide reference for the follow-up research of prefabricated SRCT shear wall and provide the basis for the popularization and application of the structure. |
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