Experimental Study On Seismic Behavior Of Non-formwork Shear Wall

In recent years,vigorously developing green buildings and achiving housing industrialization has become the main direction of th e development of China's construction industry.Therefore,more and more fabricated buildings have been popularized and applied in practical projects.Under this background,a new non-formwork shear wall is put forward by our research group.The non-formwork shear wall is a kind of assembled monolithic structure,which is composed of A,B side concrete prefabricated formwork,cast-in-place concrete layer and shear connector,and can be built in insulation layer to form a non-formwork insulation shear wall.This type of non-formwork shear wall has the advantages of good integrity of the cast in situ shear wall and the full prefabricated shear wall without the need of formwork and wet work.It is a new breakthrough for the traditional prefabricated shear wall and has a wide application prospect in engineering.As a new type of precast monolithic component,the non-formwork shear wall has little research on its performance at present.In this paper,the seismic behavior of non-formwork shear wall is the main research content,and the following work and study results have been completed.(1)The development status of fabricated shear walls at home and abroad is briefly introduced,and the research results of existing assembled shear walls are summarized.The existing problems of prefabricated shear walls and cast-in-place shear walls are analyzed in depth,and the purpose and significance of research on seismic performance of non-formwork shear wall is clarified.(2)The quasi-static test of one non-formwork insulation shear wall,one non-formwork shear wall and one cast-in-place shear wall were performed.The test results,such as,failure process,failure mode,hysteretic loops,skeleton curves,stiffness degradation,strength degradation,ductility performance and energy-dissipation were analyzed in detail.The difference of the seismic behavior between the non-formwork shear wall and the cast-in-place shear wall is mainly discussed,and the influence of insulation layer on the seismic performance of the non-formwork shear wall is also discussed.The test shows that the mechanical behavior and failure mode of non-formwork shear wall is the same as that of the cast-in-place shear wall,and the indices of the seismic performance is similar.Non-formwork shear walls have the similar seismic behavior to cast-in-place shear walls.The insulation layer between the cast-in-place area and the prefabricated formwork in the non-formwork insulation shear wall reduces the integrity of the wall to a certain extent,weakens the ability of the prefabricated formwork to participate in the work,but it has little effect on the working performance of the wall.The relative displacement of prefabricated formwork inside the plane and outside the plane is small,and there is no phenomenon of separation between the prefabricated formwork and the cast-in-place area in a larger range.The construction measures of shear connector and natural rough surface can better ensure the cooperative working ability of the components of the shear wall and the integrit y of the wall.(3)Based on the analysis of hysteretic curves and skeleton curves,a hysteretic model for non-formwork shear wall with stiffness reduction is proposed.The four fold line skeleton curve of shear wall is established by theoretical calculation method,and the formulas for calculating the load and displacement of the key points of the skeleton curve are derived.The loading and unloading stiffness and the walking route of the shear wall are determined by test data fitting method.The hysteretic model of the non-formwork shear wall is compared with the experimental results,and the correctness of the hysteretic model is verified.