Transformation from Measured Strains to Viscoelastic Stresses considering Temperature History for Concrete Dams

Abstract

Strain and stress monitoring is an important approach for evaluating the stress state of concrete dams. Since the hydration rate of cement increases with increasing temperature, the parameters of the thermal and mechanical properties of concrete are related to its temperature and temperature history. However, the influence of temperature history has not been taken into account in theories of transformation from measured strains to stresses used for analysis of concrete dams. Hence, significant errors can occur in stress evaluations of concrete dams. In this paper, based on the equivalent age theory and deformation method, we investigate a transformation equation from measured strains to viscoelastic stresses that considers the temperature history and describe the calculation steps in detail. The new algorithm is implemented by a comparative analysis of the viscoelastic stresses transformed from measured strains with and without considering the temperature history for a typical concrete dam located in northwestern China. The analysis results show that the trends of the transformed stresses with and without considering the temperature history are essentially the same, while the maximum normal stress difference is 0.49 MPa in the early stage.