Modeling Long-term Delayed Strains of Prestressed Concrete with Real Temperature and Relative Humidity History

Abstract

The prediction of delayed strains is very important in prestressed concrete structures. The temperature and relative humidity of concrete structures are two important parameters for this prediction, and they vary over time on site. Based on model code 2010 and the superposition principle, the authors propose an analytical method that takes account of such variations in temperature and relative humidity. The coupling between delayed strains in concrete and stress relaxation in prestressing bars is also considered. The proposed method is validated with respect to in-situ measurements on the VeRCoRs mock-up, which is a 1/3 scale mock-up of a biaxially prestressed confining structure. At the end of the paper, the authors discuss the importance of taking into account the coupling between delayed strains and stress relaxation, the influence of variations in temperature on the delayed strains of concrete and the value of Poisson’s ratio for drying creep.