Second order time-dependent analysis of concrete slender compressed members. Linear viscoelastivity formulation, approaches for creep consideration and practical conclusions

Abstract

In this paper a second order and delayed analsis of a slendder member, composed by a linear viscoelastic material, in bending and compression, is made for applying to concrete; for that, different assumptions for creep effects (due to initial moments, due to present moments, wheighted for both, using an equivalent global modulus E*) are used, deriving from them several approaches, showing interesting phenomenta (i.e. non linear interaction between creep and second order effects, critical load reductin with time, etc.), that are analyzed and compared. Concluding, it is underlined, when a good precision required, the general need of a more accurate step by step analysis along time, due to the high non linearity involved in the whole problem.