METHOD FOR DETERMINING THE VALUE OF OPERATIONAL LOAD ON A REINFORCED CONCRETE PILE IN COMPOSITION OF BUILDINGS OR STRUCTURES Russian patent published in 2022 - IPC E02D33/00 

FIELD: testing.

SUBSTANCE: invention relates to the field of non-destructive testing of reinforced concrete piles in pile foundation of buildings and structures at the stage of operation during inspection and estimation of the safety level thereof based on the strength condition. A method for determining the bearing capacity of a reinforced concrete pile of a building or a structure at the stage of operation, consisting in selecting a pile from the pile foundation with the greatest load thereon from the above structures or a pile with the most damage and degradation of the concrete, then, in the weakest point of the pile as a result of degradation of concrete of the pile, four working strain gauges are adhered to surface of the pile cleaned from soil along the pile in parallel relative to each other at the points of the pile without reinforcement at a distance of 100 to 200 mm from each other along the pile and 4 compensation strain gauges across the piles at any point, four bridge circuits are created from said strain gauges, and the ohmic resistance of all working gauges R_0,i is measured. Holes with a diameter equal to 3-4 widths of the strain gauge substrate with a depth of 40-80 mm are then milled above and below the strain gauges with a diamond cutter, at a distance of 30-40 mm above and below the strain gauge, and after 4 or more hours, the resistance of the working strain gauges R_1,i is measured again, and the deformation of the concrete of the pile is determined according to the specified dependence. The operation is conducted on all four strain gauges on a pile, and in order to restore the initial bearing capacity, two metal semi-cylinders 3 to 5 mm smaller than the diameter of the hole are embedded in each hole, and a steel wedge with a width equal to the diameter of the semi-cylinders is hammered between the cylinders, bringing the ohmic resistance R_1,i to the value R_0,i on each strain gauge. The surface of the pile at the sites of the holes with steel semi-cylinders is then covered with epoxy resin against corrosion, and based on the results of measurements of deformations of the concrete of the pile at four opposite sites, the average value of deformation of the concrete and reinforcement is calculated by the formula , and the stress in the reinforcement and in the concrete is determined by the formulas, and , wherein E_s is the modulus of elasticity of the reinforcement steel, taken as 2·10¹¹ Pa; E_b is the modulus of elasticity of the concrete, determined by non-destructive methods, and the load on the pile is determined by the formula , wherein A_s, A_b are the cross-sectional areas of the reinforcement and the concrete, respectively.

EFFECT: increase in the accuracy and reliability of estimation of the operational load on a reinforced concrete pile.

1 cl, 1 dwg