Refined Finite Element Analysis Of The Novel Grouted-sleeve On The Connection Performance And Bond-slip Relationship

Grouted-sleeve connection is the most important connection technique of the reinforcing bars in the monolithic precast concrete structure,and is the key factor to ensure the integrity and safety of the building structures.However,the investigation of the grouted-sleeve connections on the micro-working mechanism and the general mechanical properties were unsystematic and remained to be further.Because the mechanical performance of the grouted-sleeve connection involves various interactions,such as the confining effect of the sleeve,the cracking of the grout material,and the interlocking between the rebar and the grout,resulting in the complicated stress state.The observation and data measurement in experiment are limited due to the hermetic structure of the connection.The drawbacks of current finite element(FE)simulations of the grouted-sleeve connections are also nonnegligible,such as the excessive difference of the parametric settings,the poor universality of the FE models,and the insufficient accuracy of FE analysis results.Therefore,it is necessary to establish a universal and refined FE model of grouted-sleeve connection.The micro-working mechanism and bond-slip relationship of the connection are investigated in this research,using the FE analysis method.The main contents are as follows:(1)Based on the uniaxial tensile tests of the novel welded rib sleeves.the rib-scale refined FE models of the connections were established,and the results of analyses were validated at multipy levels.The cracking and failure propagation of the grout as well as the force transfer mechanism of the connection were analyzed.The distribution of the cracks in the grout and the deformation of sleeve was summarised.(2)The bond-slip relationship of the grouted-sleeve connection under onedimensional condition was derived.Combining the results of FE analyses,the bondslip relationship was investigated,including the rebar bond stress,the relative slippage,the local bond-slip(τ-s)curve and the position function.(3)A multi-scale connection method was proposed for the precast beam connected by the grouted-sleeves to eatablish its multi-scale FE model.According to the results of FE analyses,the static performance of the precast beam,as well as the stress and working state of the grouted-sleeve connector in the beam,are analyzed.The multiscale model can give attention to both calculated accuracy and efficiency,and can be used as a reference for the FE analysis of prefabricated members connected by groutedsleeve connections.