METHOD OF MEASURING FORCE IN WORKING REINFORCEMENT BARS OF REINFORCED CONCRETE STRUCTURE Russian patent published in 2010 - IPC G01L1/00 

FIELD: physics.

SUBSTANCE: two indents are formed on neighbouring bars relative the bar on which a force transducer is fitted, after which a indent is also formed on that bar. All three indents are on the same vertical for the reinforcement which lies horizontally, or are on the same horizontal for reinforcement lying vertically. The naked parts of the reinforcement in the three indents are each fitted with two strain gauges which are positioned symmetrically about neutral axes of corresponding reinforcement bars, and are used to measure initial values of longitudinal relative strain. A fourth indent is formed on the reinforcement bar which is fitted the force transducer at a distance from the first indent which is not less than anchorage distance. The reinforcement in the said indent is cut and longitudinal relative strain is measured again. Change in forces in the bars is calculated from the difference in the two measurement values of longitudinal relative strain in each bar. The concrete layer is successively opened up while exposing the reinforcement between the firs and fourth indents, after which longitudinal relative strain is measured again. Change in forces in the bars is calculated from the difference in the two measurement values of longitudinal relative strain in each bar. A bar is cut near the first indent and a force transducer and a tensioning device are installed in series where the reinforcement bar has been cut, where the tensioning device provides the given force value in the working reinforcement, while monitoring the said value with strain gauges in the first indent and the installed force transducer and simultaneously monitoring fall in readings of the strain gauges in the second and third indents. Based on the obtained experimental data, mathematical expectation of the acting force and mean-square deviation are determined using formulas.

EFFECT: increased measurement accuracy.

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