| The prefabricated concrete structure has the advantages of saving resources,reducing construction pollution and improving the efficiency and quality of production.Due to the improvement of safety level,prefabricated buildings have been vigorously developed in recent years.At present,the research and application of prefabricated concrete structures are mainly based on "wet" connections.Considering the importance of columns in the structure,the columns in actual prefabricated concrete engineering structures basically use cast-in-place technology.As for the "dry" connection technology,it is still in the research stage.As for the column-column "dry" connection technology,there are fewer studies and almost no applications.Considering that if a fabricated concrete structure with full "dry" connection is required,column-column "dry" connection technology is also indispensable.For this reason,this article aims at the shortcomings of the existing column-column "dry" connection technology,and proposes a prefabricated loading-unloading concrete column-column connection joints based on steel connection.This joints are removable,equivalent to cast-in-place,and has strong integrity.The main research contents are as follows:(1)Combining the current research status of the existing prefabricated concrete structure connection technology,a prefabricated loading-unloading concrete column-column connection joints based on steel connection is proposed to clarify the research significance and research content of this article.(2)The structural characteristics of the prefabricated loading-unloading concrete column-column connection joints are introduced in detail.Among them,the column-column connection is mainly using the connecting plates and high-strength bolts to connect the I-beam at the end of the column,and the clad plate is connected with the steel bars in the column by welding.In this way,the force of the concrete structure is stably transferred to the steel structure through the clad plate with studs.Then,combined with the national "Steel Structure Design Standard","Concrete Design Code" and "Steel Structure Connection Joint Design Manual" and other design specifications,the design method and design process of prefabricated loading-unloading concrete column-column joints are given.(3)Established the finite element models of the prefabricated loading-unloading concrete column-column connection joints and the cast-in-situ concrete column,and verified the correctness of the finite element models establishing method of the column-column connection through the test of loading-unloading concrete beam-column joints.By comparing the anti-seismic performance parameters such as the hysteresis curve,skeleton curve,ductility coefficient and energy dissipation capacity of the prefabricated loading-unloading concrete column-column joints and the cast-in-place concrete column.The results show that under monotonic displacement loading,the difference in bearing capacity between the two models is less than 4.5%;under low-cycle displacement loading,the ductility coefficient of prefabricated loading-unloading concrete column-column joints increases by 13.7% compared with the traditional cast-in-place concrete column and the ability of dissipated energy was reduced by 4.5%,indicating that the seismic performance of the prefabricated loading-unloading concrete column-column joints can reach "equivalent to cast-in-place".(4)The main parameters analysis of prefabricated loading-unloading concrete column-column joints include: eccentricity,axial compression ratio,length and thickness of cladding slab.By focusing on the influence of these parameters on the seismic performance parameters of the column-column joints,the optimal design scheme of the new prefabricated loading-unloading concrete column-column joints is given.The research results show that the optimal range of joint axial compression ratio is 0.5-0.7;the optimal value range of joint cladding plate thickness is 8mm-10mm;the optimal value range of joint cladding plate length is 160mm-180mm;and the eccentricity distance has a great influence on the energy dissipation capacity of the new prefabricated loading and unloading concrete column-column joint. |
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