Title: Creep Prediction for Concrete Under Multiaxial Stress

Author(s): John M. Illston and Ian J. Jordaan

Publication: Journal Proceedings

Volume: 69

Issue: 3

Appears on pages(s): 158-164

Keywords: axial loads;biaxial loads;compression;concretes;creep properties;deformation; Poisson's ratio;research;strains;stresses;structural analysis;triaxial loads.

DOI: 10.14359/11259

Date: 3/1/1972

Abstract:
Previous texts indicate that a reasonable, although not exact, assumption in the prediction of creep strains resulting from multiaxial stresses is that the Poisson's ratio for creep is constant and equal to the state elastic value. To predict creep under multiaxial loading this assumption was combined with the rate of flow method, developed essentially for the prediction of axial creep strains under uniaxial loading. Creep predictions, on the basis of independently obtained control data, are compared with the experimental strains obtained from multiaxially loaded concrete specimens. Only moderate stress levels were considered and all specimens were sealed. The results of the comparision indicate satisfactory agreement between the proposed method and the test results. Second-order effects not taken into account in the analysis are discussed. A numerical example is included in the Appendix to show the application of the proposed method.