Study On Health Monitoring Of Prestressed Structure With Smart FRP-OFBG Strand

Since the advent of fiber grating, it has been widely applied in the optical fiber sensing fields. FBG sensing technology relies on its own related attributes quickly becomes the object of study, and it becomes more and more mature. At present, thousands of people are engaged in research and application of fiber grating sensing technology at home and abroad, hundreds of papers have been published, which cover many fields of fiber grating and make great achievements. According to statistics, the vast majority of existing results is limited to seeing the fiber Bragg grating sensor as an alternative to the traditional resistance strain gauge sensor for the object to study at present. However, the research and application of new building materials in the structural health monitoring which set strain perception and stress in one sense are few. This paper using nonlinear finite element knowledge, established prestressed structure in the whole process of stress analysis model, and produced a new type of intelligent FRP-OFBG strand cable, of which diameter is 15.2mm( using a diameter 5mm fiber reinforced polymer-optical fiber Bragg grating (FRP-OFBG bars) to replace ordinary strand of wire), and this new intelligent FRP-OFBG strand cable was studied as a prestressed tendons in prestressed concrete beams' health monitoring, to verify the correctness of the theoretical model.The purpose of this paper is to calculate the force of its own strain value through the wavelength changing value of FRP- OFBG, and then through the strain value set up the full mathematical model to get concrete beam section strain values of each place. So we can healthy monitor the whole structure of the component in all stages in stress.This paper from material constitutive relationship start, selecting proper stress-strain relationship, established the bonded partial prestressed concrete(PPC) beams and unbonded partial prestressed concrete(UPPC) beams with full force analysis mathematical model; What's more, using MATLAB software, it combined with this unbonded partial prestressed concrete reinforced beam of optimal mathematical model of bending moment - curvature analysis program; Respectively it made a CFRP-OFBG beams and a GFRP-OFBG beams of UPPC by bending property of the static load test. Compared to the experimental beams data and the theoretical model data, the results are in good agreement.Results and conclusions: the first time it put forward the virtual concrete strip and successfully used it on the concrete beam section while loading stages warning system. A more comprehensive considering the influence of the concrete, compression reinforced, tensile strength of prestressed and reinforced section, it's deduced that nonlinear equations accorded with cross-section deformation, and accurately calculated section in various parts of real-time strain value under the monitoring of FRP-OFBG intelligent strands while the partial prestressed concrete beams bending, to ensure the excellent health monitoring. It successfully used MATLAB software to draw up unbonded partial prestressed concrete beam subjected to bend curvature of moment the relationship. Compared with the tests, it proved the model credible and scientifically, and the program write accuracy.