| As a common connection method in structural reinforcement and reconstruction,planting bars are widely used in the reinforcement of building structures and municipal engineering projects.In China,the technology of rebar planting has been quite mature in engineering applications.The current specification requires that the rebar planting process should ensure that the inside of the rebar planting hole is dry and free of dust,but not all projects can ensure that the installation conditions of the rebar can meet the specification requirements.At the same time,the currently commonly used planting adhesives also have disadvantages such as poor anchoring performance,poor heat resistance and environmental protection under complex installation conditions.Therefore,in response to the above problems,this paper and Hunan Goodbond Company developed a new type of inorganic reinforcing bar-planting glue,and analyzed the anchorage performance of the planting bar under complex installation conditions through experimental research and simulation.The main research contents of this paper are as follows:(1)Study the bonding and anchoring mechanism of the planting bar system.Combined with the existing research results,the bond and anchorage mechanism and the composition of bond stress of the planted reinforcement system under tension are analyzed;the failure mode of the planted reinforcement system under tensile load is summarized,and the theoretical calculation formula of ultimate pull-out bearing capacity is deduced;The influencing factors affecting the bonding and anchoring performance of planted bars are analyzed to provide a theoretical basis for subsequent experiments.(2)Study the material properties of the new inorganic rebar-planting adhesive.The components and proportions of the new type of inorganic reinforcing bar-planting glue were analyzed,and the standard specimens of the new-type inorganic reinforcing bar-planting glue were prepared.The compressive strength,flexural strength and interfacial bonding strength of the new-type inorganic reinforcing bar-planting glue were studied by experiments.The results show that the new inorganic reinforcing bar-planting adhesive has good compressive strength,flexural resistance and interfacial bonding strength,and the new inorganic reinforcing bar-planting adhesive has excellent bonding and anchoring performance under complex installation conditions.(3)The influence of factors such as steel bar diameter,anchorage depth and complex installation conditions on the anchorage performance of planted bars was investigated through pull-out tests.The test results show that: when the anchoring depth is 7d,the complex installation conditions have the most significant influence on the anchorage performance of the planting bar.According to the measurement and calculation,it can be seen that the bonding stress distribution of the planted bar specimen is uneven during the pull-out test,and the peak value of the bond stress is close to the loading section of the planted bar and the peak value is about 1.5 times that of other measuring points.Finally,Abaqus finite element software is used to establish a pull-out test model,and the results of the pull-out test are compared to verify the rationality of the model.(4)From the perspective of structural safety and engineering economy,the calculation formula of the bearing capacity of the new inorganic reinforcing bar-planting adhesive under complex installation conditions is deduced according to the results of the bar-planting bar pull-out test.The validity of the established bearing capacity calculation formula is verified by comparative analysis with the pull-out test data of the planting bar in a drainage channel reinforcement project.Among them,the formula calculation results are in good agreement with the sampling pull test results,and the calculated value is slightly lower than the experimental value.Therefore,the formula has a certain safety reserve,which can provide a reference for the design of such planting bars. |
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