Nine–gauges device for strain measurements inside concrete

Surface strain measurements of bulk concrete structures such as dams provide insufficient information and embedded strain measuring devices are necessary. For complete analysis six strain measurements are required. The device described indicates nine independent readings from which not only is a complete analysis possible by solution of the strain matrix constructed from these readings, but gross errors in individual readings may be identified and these readings discarded. An evaluation may be made of the errors in the results determined from the remaining gauges.