Experimental Study On Constraint Grout-filled Lap Connection Of Steel Bar Of Prefabricated Concrete Structure

Housing industrialization refers to the way of industrial production to build housing,the core meaning is to change the traditional mode of production of industrial construction to achieve industrialization of buildings.In the country that vigorously advocates energy-saving emission reduction,develops recycling economy and constructs ecological civilization environment,housing industrialization and building industrialization is the future direction of China's construction.The development of prefabricated concrete structures is one of the important ways to realize the industrialization of buildings,the structural design of the prefabricated joints is the key point of prefabricated concrete structures,the connection of reinforcing bars at the connecting nodes is to ensure the force transfer between reinforcing bars and the structure,and the refabricated steel reinforcement connection should be easy to construct in order to ensure the construction quality.The constrained bond anchor rebar connection for vertical connection of prefabricated precast concrete members is studied in this paper.The results of previous experiments prove the reliability of this connection method.The key to restrain the bond of rebar lies in the configuration of the buried rebar and lapped rebar,the method of forming holes and the performance of grouting material.Currently,there is no uniform size of the aperture for rebar connection.In this paper,the existing technology of lapped connection of constrained anchor and rebar is improved by inserting the inserted lapped grouted reinforcement lap joint technology and the NPC structure embedded metal corrugated lap joint connection technology.In order to study the connection performance of the connection technique,the connection technique uses the metal bellows to form the hole and to arrange the spiral stirrups on the outside of the reinforcing bar.In this paper,63 lap-connecting test pieces are designed by taking the diameter of the reinforcing bar,the diameter of the hole and the lap length as parameters to complete the unidirectional drawing test on test pieces with reference to "General Technical Specification for Mechanical Connection of Reinforcing Bar"(JGJ107).The main factors that affect the shape and damage type of the specimen are determined by the test failure phenomenon and the test data as well as give out the recommended lap length.The paper puts forward the development suggestions on the connection of reinforcing bars of prefabricated concrete structure.Based on the experimental phenomena and the experimental data,this paper improves the original mechanical model for analyzing the overlap length of rebar,and proposes the calculation formula of rebar bond strength and the calculation formula of rebar overlap length.At the same time,ABAQUS finite element analysis of the connection method is carried out.The experimental data and simulation results are in good agreement.The finite element analysis enlarges the range of the test parameters,which provides the basis for improving the design and engineering application of prefabricated fabricated concrete structures.