N° 80.1972. Manual 'Structural effects of time-dependent behaviour of concrete' (Second Draft)

The pattern of stresses and strains in concrete structures under normal service conditions is widely influenced by the time-dependent behaviour of concrete.

This influence is often emphasized by a trend, which is becoming increasingly frequent in the conception of modern structures, toward a rather complex evolution of loading and restraint conditions during the construction phase and the early life of the structure.

The aim of the present manual is to provide means for evaluating the structural effects of the time-dependent behaviour of concrete (i.e. for carrying out so-called creep analysis of concrete structures); the basic idea is to present mathematical solutions within the reach of structural designers.

In the first chapter, a critical discussion is given of the currently available methods of creep analysis; the methods that permit a satisfactory interpretation of the actual behaviour of concrete through the use of elementary mathematical formulations are retained for application.

Two levels of approximation are considered. For the first degree of approximation, a method is presented which is based on a simplified creep law. For the second degree of approximation, two methods are suggested, one of them requiring the use of a computer.