Experimental Study On The Bonding Performance And Analysis Of Bond Anchoring Reiiabiiity Of Half Grouting Sleeve Connection

Prefabricated building is a new type of architectural form that has emerged in recentyears.It has many advantages in green construction,energy consumption,and environmental protection.Now,it has been widely promoted in China.Sleeve grouting connection is the main form of prefabricated construction connection.It has good development prospects and wide applicability in the market due to its reliable connection performance.However,the domestic technology is not mature enough.This limits the application of China’s building industrialization.Therefore,it is extremely important to study the sleeve grouting connection.In this paper,a series of semi-grouted sleeve connectors were produced.The optimal anchoring length and bonding performance of the specimens were studied by the combination of experimental research and theoretical analysis.The main research contents and conclusions of this article are as follows.(1)This paper summarizes the research status of sleeve grouting joints both at home and abroad.The article also points out the deficiencies of related research.The advantages and disadvantages of various types of steel sleeve grouted joints were compared and analyzed.The specifications of the sleeve grouting joints were listed in this paper.The research content provides a theoretical basis for experimental research.(2)In this paper,56 half-sleeve grouted joints were fabricated.The relative anchoring length and the relative thickness of the protective layer were used as influencing factors.Monotonic axial tensile tests were performed on the test pieces.The failure process,failure modes and load slip curves of the specimens were recorded.The P-S distribution of the specimens was obtained.Five slotted steel rebar specimens were designed and tested.Strain gauges were placed in the steel grooves to study the distribution of bond stress in the anchorage length range.The results show that the strain distribution of steel bars in the region of anchorage length is exponential,and the distribution law of bond stress is similar to that of strain,but the bond strength at the loading end is zero.(3)Based on the experimental results of 27 joints pulled out from the steel bars,the load-slip curve was analyzed.The statistical data of the micro-slip bond stress,critical bond stress and split bond stress of the half-sleeve grouted joints were obtained.Based on the grey relational theory,the relationship between the influencing factors and the bond strength of the specimen was studied.The results show that the anchorage length has the largest correlation factor,which are followed by the steel bar diameter and the protectivelayer thickness.Through the multivariate linear analysis,the expression of the bond strength between the reinforcing steel and the grouting material considering various parameters was fitted and compared with the experimental values.The results show that the theoretical values are generally consistent with the test.The half-sleeve grouting jointed bonded slip constitutive structure was proposed,the verified model curve is generally consistent with the test curve.(4)Based on the fitting expression of bond strength,the safety critical critical anchorage length design method and reliable critical anchorage length design method are introduced.The recommended critical anchorage length calculation value is given.The research results of this paper provide theoretical basis for related fields.At the same time,it provides guidance for practical engineering.