Research And Application On Key Joints Connection Technology Of Precast Concrete Structure Based On The Modular

With the continuous development of modern housing industrialization,precast concrete structure adopt the method of prefabricated molding and on-site assembly combination,to assure quality and shorten the construction duration.Precast concrete structure has been significantly improved in the production efficiency,while saving energy and resources,embodying the concept of green environment protection.The key joint connection in precast concrete structure is a key issue and has a profound impact.At present,there are two main ways of rebar connecting joints in domestic precast concrete structure:rebar splicing by grout-filled coupling sleeve and rebar lapping in grout-filled hole.Analyze the two kinds of connection method in connection structure,basic principle,failure mode and construction technology respectively,the current structural design is based on equivalent cast or basic equivalent cast design calculations.Since the precast concrete structure is not the same as the cast-in-place concrete structure,it is unreasonable to fully apply to calculation system and method of the cast-in-place concrete structure.There is a problem in design.Through the deep understanding of the difference between the precast concrete structure and the cast-in-place concrete structure,finding the calculation system and method of the joint connection of the precast concrete structure.The original beam-column connection and precast column is treated as follows:(1)The rebar connection of the beam-column is changed to rebar splicing by grout-filled coupling sleeve.The concrete is changed from grout to grouting,and the rigid connection of the beam-column is changed to sleeve grouting connection;(2)The precast column is divided into sections,and The rebar connection of the column-column is changed to rebar splicing by grout-filled coupling sleeve.The sleeve grouting is also used in the precast column.Using the equicohesive connection derived structural optimization program design.The beam-column joints and the column-column joints are optimized by the combination of concrete application and the steel sleeve grouting connection technology.The results show that rebar splicing by grout-filled coupling sleeve is a better way than concrete pouring connection in performance.The following experiments were carried out on the connection joints that use rebar splicing by grout-filled coupling sleeve:offset uniaxial tensile test,alignment uniaxial tensile test,repeated high-stress ensioning and pressing test and repeated large-deformation tensioning and pressing test.The test results show that the connection rebar is broken before the sleeve is pulled off and the grout is pulled out,further verify the rationality and safety of beam-column joint and column-column joint with the grooved grouting connection.The application of rebar splicing by grout-filled coupling sleeve for key joint has a wide prospect for the development of prefabricated concrete structure.