Research On Intelligent Anchorage Device Of Prestressed Carbon Fiberboard

The technology of using prestressed CFRP reinforced construction has been developed rapidly in recent years.Currently,the anchorage device for prestressed CFRP plate can play a role as a reinforcing component,however,it can not establish a health monitoring system for tensile end CFRP plate prestressed holding condition.It is one of the scientific issues facing the field of structural reinforcement testing that how to better achieve a monitoring system that combines both reinforcement components and safety and health monitoring.For this reason,starting from the screw members in the anchorage device for prestressed CFRP plate,coupled into the fiber Bragg grating establish a health monitoring system and forming intelligent anchorage device to make a little contribution to the long-term health monitoring and safety assessment system for the stretching end CFRP prestress maintenance situation.For the core component of the anchorage device,two screws are taken as the main line to carry out research.The anchorage device components is designed by using the method of theoretical calculations combined with experimental numerical analysis,what is more,the relationship between the stress of the screw and the strain of the fiber brag grating,the stability and reliability of the intelligent screw monitoring and the expected target of measuring and controlling the radio error of the stress of the screw to the actual stress within 3% are verified through experiments when the single screw reaches the designed upper limit load in the anchoring system,which provides the design method and theoretical basis for the research and development of the same type of self-sensing components.Main contents include:Firstly,according to the strain transfer coefficient of the screw and the environment temperature variation,the stress of screw,the association with temperature rise or fall of small,and the adhesive process has great influence is calculated,the main reason of the strain transfer coefficient of the screw is due to the deformation of the screw.The influence of strain transfer coefficient and ambient temperature change on the force value of screw rod is analyzed,and the stress equation of the screw is deduced.Secondly,the relationship between the force of 8 screws and the strain of grating strain was analyzed by means of tensile test.Stretch to 180 kn design value,the relationship between the stress of the screw and grating strain can be deduced the stress of the screw and the mathematical expressions of grating strain,which calculating the stress of the screw and the ratio of the actual bearing error within 3%,meeting the design requirements and the late test were provided for the reasonable adjustment screw of the stress calculation of theoretical guidance.Thirdly,the cyclic tensile test method was adopted to select 4 intelligent screws for 50 cyclic tensile tests,which getting the test tensile load value was 24kN-140 kN.On this basis,the establishment of a screw force and grating strain curve change rule is analyzed,its associatedwith the increase of cycling times grating strain change rule was studied,and its reliabili-ty and stability were determined.Fourthly,on the basis of single and cyclic tensile tests,the four groups of eight intelligent screws on the test beam were carried out on four single axis and five cyclic tensile tests,which designing value was 300 kN.Using the intelligent screw as the main line,the carbon fiber board,anchor and tensioning table are used as the auxiliary equipment to carry out the test,which monitoring whether there is eccentricity and eccentricity in the single axial tensile carbon fiber plate.Finally,the carbon fiber board smart anchorage device was putted forward applied in the experimental study of reinforced concrete beam,through the core of the anchor device component,two intelligent screw implementation of the carbon fiber plate prestressed tensioning end keep monitoring method,the calculation results between the intelligent screw measured results and the intelligent carbon fiber board were be compared,which getting the error is within 3% and meeting the design requirements.