FIELD: construction.
SUBSTANCE: invention can be used for control of cracks. Invention consists in that at distance of 10-20 mm from section of element, in which there is a crack, resistive strain gauges are glued to right and left of cracks on both side walls so that, 2-3 resistive strain gauges are located along length of crack perpendicular to crack, and 2-3 resistive strain gauges are located above visible vertex of crack. Electric resistance of resistive strain gauges is then measured, followed by loading or unloading element with an experimental load and re-measuring electric resistance of resistive strain gauges, and relative deformation is calculated by a certain mathematical expression. Obtained values of relative deformations show on diagram of deformation of εi on height of cross section of element on both sides of crack for each side wall of element. Through vertices ordinate of deformations perpendicular to side walls of element lines are made to their intersection with walls and distance from said intersection points to wall element, from crack begins, is measured. Distances measured on curves εi taking into account scales are used to calculate of length of crack l'tr and l''tr on surfaces of side walls of element and average length of cracks. Based on results of 3-5 measurements of crack length ltr in initial moment of time and after a certain time t crack growth rate under load is determined.
EFFECT: technical result is improved accuracy of determining length of cracks in building structures.
1 cl, 3 dwg
