Research On Shear Behavior Of Joints With Inclined Interfaces Connected By Precompression Of Precast Concrete Members

The wave of construction industrialization at the core of prefabricated assembly technology is sweeping our country.However,the assembly connected interface always becomes the physical weak part of the assembly structure and needs to carry out complex construction treatment.Therefore,it has become one of the restrictive factors for the development of assembly structure technology.In this regard,in order to slove the traditional vertical slit shear connection problem,the inclined interface connected technology by precompression of precast concrete members is put forward,which makes the joint enhance the shear ability of the joint through friction and lap two mechanisms and save the interface roughening processing sequence.In order to optimize the comprehensive technical index based on this technical idea,the influence of the style of inclined slit(single or double slits),joint prepressure and interface angle on the shear performance rule of the joint are investigated,and calculation models of shear ability.are established The specific work is as follows:(1)The structure form of joints with inclined interfaces connected by precompression and its application in the connection of plate-beam,primary beamsecondary beam and box bridge section are put forward.(2)The influence of the interface angle and prepressure on the shear performance of joints with inclined interfaces connected by precompression is researched through the physical test and the finite element simulation analysis in primary beam-secondary beam connection.The results show that even the angle of the inclined interface(relative to the horizontal surface,the same below)is close to 90 degrees for joints with single inclined interface connected under the condition of conventional prepressure,it is difficult for the interface to slip obviously before the failure section of the diagonal section.The angle of the inclined interface mainly affects shear span ratio and the shear strength of the stirrup to influence shear capacity of oblique section of joints.The smaller the angle of the interface is,the stronger the shear capacity of the oblique section is.On the other hand,the decrease of the interface angle and the increase of the prepressure will help to improve the interface anti-slip ability of joints with single inclined interface connected by precompression at the stage of shear failure with continuing load.For joints with double inclined interfaces connected by precompression,the angle of the inclined interface mainly affects the shear span ratio,the shear strength of the stirrup,the stress concentration at the corner to influence shear capacity of oblique section of joints.The smaller the angle of the interface is,the smaller the shear capacity of the oblique section is.On the other hand,the decrease of the interface angle and the increase of prepressure can help to improve the overall anti-slip ability of the interface.(3)Taking the shear behavior of joints with the traditional vertical interface connected by precompression as a reference,the influence of connected forms on the shear behavior is researched.The results show that the shear capacity of oblique section of joints with single inclined interface connected by precompression is better than the joint with the traditionarl vertical interface connected by precompression.The shear capacity of oblique section of joints with the traditional vertical interface connected by precompression is better than joints with double inclined interfaces connected by precompression.The anti-slip interface ability of joints with single inclined interface connected by precompression is stronger than the traditional vertical interface connected by precompression and joints with double inclined interfaces connected by precompression in the same angle of the interface.The anti-slip interface ability of joints with traditional vertical connected by precompression is better than joints with double inclined interfaces connected by precompression in the large angle of the interface and less than that in the small angle of the interface.Based on the above comparison results,the angle ranges of the interface of the joint with single or double inclined interfaces connected by precompression are suggested.(4)Taking the finite element simulation data as the basis,the design shear bearing capacity formula and the predictable model of the interface total slip of joints with inclined interfaces connected by precompression through the regression analysis are put forward.The prospect and suggestions of the research and extension for the inclined connection in the furture are given.