METHOD OF MEASURING DEFORMATIONS, STRESSES AND FORCES IN REINFORCEMENT OF EXPLOITED REINFORCED CONCRETE STRUCTURES

摘要

FIELD: defectoscopy.;SUBSTANCE: use for non-destructive testing of deformations, stresses and maximum efforts in operating reinforcement of exploited reinforced concrete structures. Summary of invention consists in fact that theoretically or experimentally detecting place (section) with maximum deformations in rods of working fittings, for example in section with crack in concrete of reinforced concrete structure of type of beam or plate, from operational load, after that, in the area of the structure in places with the greatest deformations, as a rule in the extreme rods of the lower row of reinforcement with the greatest deformations, along the rods, grooves of 120–150 mm are formed, then on the side surface of the working reinforcement of the element on the length of the grooves polishing the area for sticking strain gauges and attaching at least three strain gauges with base of not less than 10 mm and width of not more than 6–8 mm, isolating strain gauges with epoxy resin and measuring ohmic resistance R_0,i of all strain gauges, and from two other concrete-free adjacent sides of the reinforcement, rods-shorts of the same class and reinforcement diameter d with length of 100–120 mm are welded with length of welded seams at each end of shorts of not less than with provision of equal strength, firstly, shorts are welded on lower side of working reinforcement (with high voltage), and then on upper side (with lower voltage), then in working reinforcement rods under cover of shorts, two holes are drilled with diameter equal to diameter of working reinforcement d, at distance of not less than 2–3 diameters of reinforcement from extreme strain gauges and not less than 1.2–1.5d of reinforcement diameter from welded seam end, which is drilled in three steps, first with a drill of diameter d/3, then with diameter of 2d/3 and then with diameter equal to diameter of reinforcement d, to prevent dynamic impact, wherein for cooling of the reinforcement, it is watered, then the obtained section of the working reinforcement is removed and again the ohmic resistances of the strain gauges R_1,i are measured in this section of working fittings, then this operation is carried out with another rod of working reinforcement in same section of reinforced concrete element, at remote sections of working reinforcement there determined is maximum value of deformation from two rods of working reinforcement by all results of measurements resistance of resistance strain gauges by formula: $\mathop{\mathrm{image}}$. Maximum stress in the reinforcement rod is found by formula: $\mathop{\mathrm{image}}$. After removal of working reinforcement sections, protective concrete layer is restored, if necessary, reinforcement and weld seams are pre-protected against corrosion by existing methods, force in reinforcement is determined by formula $\mathop{\mathrm{image}}$, wherein the reinforcement is not subjected to dynamic stress relief, strength of the reinforced concrete bearing element is not reduced, and the protective layer of concrete is restored.;EFFECT: providing possibility of avoiding dynamic voltage reset; maintaining current level of safety of operation of reinforced concrete element; higher accuracy of determination of maximum deformation, stress and force in working reinforcement of reinforced concrete element.;1 cl, 4 dwg