PROCEDURE TESTING TECHNICAL STATE OF FRAMEWORK OF BRIDGE Russian patent published in 2002 - IPC

FIELD: non-destructive testing of frameworks. SUBSTANCE: procedure testing technical state of framework of bridge consists in action of dynamic load with wide spectrum of frequencies on framework, in measurement of parameters of mechanical vibration with the aid of accelerometers in check points of framework, in obtainment of parameter of diagnostic sign and in determination of zone of anomalous tension by change of this parameter on basis of criterion. Check points are selected on framework in pair symmetry relative to longitudinal and lateral symmetry axes of framework. Three angular accelerometers which sensitive axes lie on three mutually perpendicular directions are anchored in each check point. Framework is subjected to dynamic load symmetric with reference to axes of framework, root-mean-square value of output electric signal of each accelerometer is measured in this case in frequency range from 0.1-800.0 Hz. Ratios of RMS values per each pair of accelerometers with same orientation of sensitive axes in each pair of check points symmetric relative to longitudinal and lateral axes of framework are computed as parameter of diagnostic sign. These ratios are compared with the help of criterion by formula |1-r|>γ, where r is above-mentioned ratios of RMS values; γ is conventional numerical value specified in accord with technical standards for particular type of structure of framework and corresponding to anomalous deviation of mechanical stresses in framework from symmetry axis. Line connecting pair of check points symmetric with reference to longitudinal or lateral axes of framework for which value r satisfies given criterion indicates direction to position of zone of anomalous mechanical stress and crossing of these lines determines location of this zone. EFFECT: raised accuracy of location of zone of anomalous mechanical stress in framework. 2 dwg