Stress Monitoring And Safety Assessment For Steel Structures Strenghthened With Prestressed CFRP Plates

In the recent decades, structural health monitoring technology has been effectivelyimproved. There is a lot of steel structure projects in our country use advanced monitoringequipments in the actual monitoring, which includes fiber grating sensors. As to the steelstructure, it's a technical problem to make full use of the monitoring equipment to monitorthe structure. It also hardly timely makes both objective and scientific safety assessment toissue a warning before appearing structural damage or an accident.This paper aims to research the safety assessment of the steel structure strengthenedby prestressed CFRP plate. In order to achieve this purpose, we get the stress conditionmonitoring results by the static load test and the entire process theoretical calculations ofthe steel structure strengthened by prestressed CFRP plate. This paper depends on thenational natural science fund project <performance and intelligent monitoring technologyresearch of prestressed CFRP plate reinforced steel structures>, and the main contents andresults of research are as follows:(1) Establish a stress monitoring program of steel structure strengthened byprestressed CFRP plate on the basis of structural health monitoring technology. Monitorstress state of the three test steel beams during the test.(2) Refer to the prestress loss calculation methods of the concrete structurestrengthened by prestressed CFRP plate and put forward the prestress loss calculationmethods of the steel structure strengthened by prestressed CFRP plate. Analyze the wholeprocess of the bearing capacity and deflection of the steel structure strengthened withprestressed CFRP plate.Put forward stress, bending moment and deflection calculationformula in elastic stage and elastic-plastic stages based on the equivalent substitutionmethod of the cross section.(3) Put the stress, bending moment and displacement of control section as safetyassessment indicators of the steel structure strengthened with prestressed CFRP. Dividethe safety warning level of the steel structure strengthened with prestressed CFRP intofour levels: green security levels, yellow primary intermediate early warning, orange earlywarning, red advanced warning, and then put forward corresponding maintenancemeasures. Put the actual bending moment safety coefficient and the actual displacementsafety coefficient of the normal use of state and bearing capacity as bases for the safetyevaluation, thus establishing the safety assessment and early warning system.