Study On Strain Monitoring Of Reinforced Concrete Beams Based On BOTDA Intelligent Fiber Reinforcement

As one of the important building materials in civil engineering,reinforced concrete needs to be monitored to ensure the safety of reinforced concrete structures due to its own characteristics and service environment.The results of the research and practical engineering show that the optical fiber sensor has the advantages of high monitoring accuracy,strong anti-corrosion ability and strong anti-interference ability,but it is fragile in itself.Fiber vulnerability to overcome the shortcomings,giving full play to the advantages of its monitoring at the same time,this article is based on BOTDA monitoring system,with stainless steel pipe by FRP wrapped tight skin fiber,made with monitoring the long distance,high precision,fully distributed,strong durability advantages of FRP intelligence reinforced steel and stainless steel pipe intelligence,embedment of reinforced concrete,the strain of reinforced concrete structure and crack monitoring,intelligent and FRP reinforcement,stainless steel pipe intelligent reinforcement compared with resistance strain gauge measurement data,test of two kinds of fiber optic smart reinforcement strain monitoring performance.Finite element software was used to carry out experimental simulation,analyze and compare the experimental and simulation results,and evaluate the monitoring performance of two kinds of optical fiber smart bars.The main research work of this paper is as follows:(1)In order to protect the optical fiber sensors and make them suitable for strain monitoring in reinforced concrete structures,based on the brillouin distributed measurement technology,the optical fiber is encapsulated by stainless steel tube and FRP,and the fabrication process and flow of the intelligent stainless steel tube and FRP bar are developed by ourselves.(2)In order to solve the coupling effect of temperature and strain in optical fiber,a single variable control method was used to calibrate the temperature and strain performance of the intelligent fiber reinforcement.The equation of the relationship between the center frequency,temperature and strain of the intelligent fiber reinforcement is derived:1 2f =C(35)T +C(35)?,which is used for temperature compensation and the conversion between the center frequency and strain in the experiment of the intelligent fiber reinforcement strain monitoring.(3)In order to test fiber optic smart muscle strain monitoring performance,will be reinforced with FRP intelligence stainless steel tube smart reinforced concrete test beams along the beam length direction,and on the surface of the beam position with high resistance strain gages,the experimental beams flex test,test data,the contrast analysis of optical fiber smart rebar,strain gauge values and theoretical values,evaluation of FRP intelligent steel and stainless steel tube intelligent muscle strain monitoring performance.(4)Using ANSYS numerical simulation and comparison analysis,establishing of reinforced concrete beam model experiment,the situation of experimental simulation,the finite element model of the simulation value with the measured data of the two kinds of fiber optic smart muscle comparison,through the comparison and analysis of the overall evaluation of fiber optic smart reinforcement strain monitoring performance,demonstration of FRP intelligent steel and stainless steel tube intelligent bar used in reinforced concrete structural strain monitoring and the feasibility of fracture monitoring.