Mathematical modelling of time-dependent creep deformation in reinforced and prestressed concrete structures is investigated. The basic expression for the creep function is outlined, and subsequently applied to the solution of various practical structural engineering problems including loss of prestress, and redistribution of stress and deformations in statical systems subjected to changes in constraint. It is shown that the creep function can be used in these calculations, either directly, or through its inverse, the relaxation function. The use of the latter simplifies calculations in certain cases.
Current methods for calculation of time-dependent loss of prestress are given thorough examination. Deficiencies of simplified methods are exposed, and the superiority of more refined methods is demonstrated.