Research On Seismic Behavior Of Prefabricated Concrete T-shaped Column Joints After Eccentric Reinforcement Connection

With the changes of construction technology,precast concrete frame structure has been widely used in the structure system.Generally,the width of the column limb of the special-shaped column is the same as the thickness of the wall.Compared with the conventional section column such as rectangular and circular columns,the frame structure with special-shaped columns is more flexible,convenient,aesthetic for people to apply.However,the present construction technology of assembled concrete joints have yet to be further improved,such as the complex connection of reinforcement because of the dense distribution both of bars and sleeves,and the narrow space in special-shaped column joints.Form an engineering example,this paper studies the seismic performance of the joints of assembled special-shaped columns with steel bars and sleeves dislocation connection through low-cycle repeated load tests.After concluding the experiments,put forward suggestions for the design and construction of the joints of assembled special-shaped column frame structure.The main contents and conclusions are as follows:1.The internal and external nodes of assembled t-shaped column were loaded respectively during the tests.The results of experiments showed that the misaligned bars which after bending and connecting to sleeve can steady transfer internal force.The seismic performance indexes such as the bearing capacity and ductility in different force direction of the external joints vary widely,which was mainly caused by the structure with remarkably uneven and asymmetric distribution stiffness.The ultimate displacement angles of the specimens all meet the requirements of the limit of the elastic-plastic interlayer displacement angles,indicating that the assembled t-column joints have high deformation capacity and collapse resistance.2.By observing the experimental phenomena and analyzing the strains of reinforcement,the seismic design requirements of "strong joints and weak members,strong columns and weak beams" were realized of the external joint specimens.The failure form both of the internal joints was shear failure in the core area,which was mainly resulted from the insufficient stiffness and complex stress of the column web.3.The stress model and mechanism of the special-shaped column joints were simply discussed.Compared with the calculated and the experimental value of shear strength of the special-shaped joints’ core region.The applicability and rationality of the stress mechanism were verified.4.The key technologies and quality management points of joint construction of prefabricated concrete building are expounded in detail,especially combine with experiments and specifications for the design and construction technical of precast column and post-cast area.The development of information technology is used to improve the accuracy and safety of complex prefabricated structural design.To promote the application of “Building Information Modeling” in building industrialization is essential.Some corresponding treatment suggestions are put forward for the common construction quality problems of prefabricated concrete structure.