Stress Measurements in Concrete Structures with Modified Doorstopper Technique

Abstract

This paper describes the use of a modified doorstopper technique for measuring both absolute and relative stresses in concrete structures. The equipment, field procedure, and stress calculation model are presented and are followed by the results of some stress measurement campaigns in concrete structures. The poly-technique stressmeter, a stressmeter designed for monitoring the very low stress variations in concrete structures such as dams, is also described. Results from lab tests and a 7-month field monitoring period show the stability and sensitivity attainable with the new stressmeter. The stress calculation model for both absolute and relative stresses requires no hypotheses concerning the principal stress orientation or magnitude and can take into account the heterogeneous, anisotropic, and eventually nonlinear behavior of concrete found at the measurement scale.