Research On Durability Monitoring System Of Post-tensioning Tendons About 30m T Beams

Prestressed concrete structure is a type of concrete structure with internal stress which is built on prestressed tendons. The prestressed tendon is the key part of the force, which effectiveness or failure of is directly related to the safety, applicability and durability of the prestressed concrete structure. In recent years, there have been some incidents about durability failure of post-tensioning tendons, which seriously impact the service life of prestressed concrete structures. Therefore, the corrosion protection of tendons and durability monitoring of prestressed concrete structures become the research hotspot. This paper mainly researched the quality control by the method of improving the corrosion protection in post-tensioned concrete structure and monitoring the work condition of the pre-stressing tendons by a type of convenience and nondestructive method (measuring the impedance values of pre-stressing tendons and normal rebar in concrete structure). In this paper, combination with the latest development of Liuzhou OVM electrical insulation prestressed anchorage system, the main research work is done as follows:(1) By the research and analysis of main principles of durability, composition of foreign post-tensioned monitoring system, the electrical insulation system of prestressed concrete anchor structure is presented.(2) A 3m beam of durability monitoring system of post-tensioning tendons is established in the laboratory, the possibility of the construction process of electrical insulation prestressed anchorage system is tested, the capacitance and resistance values between PL1 system and PL3 system are compared, variation and trends are obtained, possibility of PL3 real-time monitoring system is tested, and comparing experiment with the Swiss indoor 1m beams is done.(3) Combined with engineering practice, we choose 4 T durability of post-tensioned beams embedded monitoring system (PL3 system) in Guangxi highway projects from Yulin to Tieshangang, describe in detail the production process and process of experimental beams ,analyze and compare the resistance and capacitance values between PL2 and PL3 system.(4) On the basis of the above work, we compare with foreign engineering and analyze the results of the differences and the reasons, analyze quality control elements of durability monitoring system of post-tensioning tendons, put forward the measures of improving durability and insulation of PL3 system. There will be taken a certain foundation for the application and popularization of PL3 system.(5) The main conclusions of research are summed up,and the future work is prospected...