Long-term behaviour of beams prestressed with aramid fibre cables: Part 1: a general method

This paper deals with the analysis of the time evolution of stresses in statically determinate beams with compact cross-sections prestressed or partially prestressed by aramid fibre reinforced polymer cables. The long-term behaviour of both concrete and the cables is taken into account to suggest a general method that solves the problem. titutive law is needed to verity the reliability of the numerical solution by means of comparisons between experimental tests and numerical analyses and to evaluate the effect exerted by relaxation of the aramid cables on the cross-section behaviour. A long-term constitutive law of an aramid cable (based on the experimental tests performed by two research teams) is presented. arison with the only well-related experimental test that was found in the scientific literature justifies the hypotheses set to take into account the phase between pouring of concrete and release of the cables from the bulkheads in the pretensioning systems. eneral method will be adopted as the reference to verify the reliability of an approximate solution that will be presented in another paper.