Monitoring Research Of External Prestress Based On Magnetic Flux Sensing Technology

Externally prestressed concrete structure, it is a structure system of structure prestressreinforcement located in the outside and prestress structure through the anchorage anddeviator. External prestressed concrete structure, prestressed loss directly affects the size ofthe effective prestress, thus impact the using performance of the whole structure. As a result,the effective prestress value of externally prestressed concrete structure has been a veryimportant research subject. More factors that lead to loss of prestress, however, and there ismutual influence between the loss of prestress. So, get effective prestress by precisecalculation of the prestressing loss value is a complex work. Timely monitoring theimportance of the stress during the construction period and operation period and require anew nondestructive testing method, rapidly measuring structure effective prestress intensioning period and operation period, implementation in each construction stage ofconstruction quality control. On the basis of the research tensioning stage and long-term lossof prestress rule. Combining with LiuGong OVM machinery co., LTD. Research anddevelopment of the magnetic flux sensor, conducted the following research contents:(1)To introduce the concept of external prestressing, the development of externalprestressing structure and external prestressing structure characteristics, analyzing thecurrent some problems urgently to be solved in externally prestressed structure.(2) The external prestressing loss theory was described in detail and thecorresponding calculation formula.(3) The magnetic flux sensor testing system and OVM-TJ. E in external prestressedsteel beam system was introduced.(4)The scene of the specimen to make use of magnetic flux sensor effective prestressprestressed tensioning stage related section of test.(5) At the end of the tensioning, using a magnetic flux sensor for long-termmonitoring of external prestressing reinforcement, record analysis change law for a longtime, and use the reference of the method of computing nodes in different time effectiveprestressing force. Compare the measured values and calculated values, analyze its rule，andput forward a modified method.(6) To summarize the main research conclusion, this article puts forward relatedproblems in further research. Research on friction coefficient was tested. Discussed themethod for calculating the ultimate stress of externally prestressed steel beam.