posttension, non-linear deformation model, bi-linear state diagram, perfect elastic- plastic material, bending test

There is a description of a deflection calculation method of posttensioned unbonded concrete elements in this paper. Method is based on use of bi-linear diagram of concrete state. Loading process is suggested to track by strains. Some key stages of posttensioned unbonded beam work are deter-mined. For these stages calculated dependencies for estimation of curvature and ultimate bending moment of cross section are given. Calculation of some beams, which were investigated in previous experimental study, are made using suggested formulas. By comparison of experimental data and calculated results conclusion about possibility of use of suggested method is given.

Gavrilenko Alexey Vladimirovich, Postgraduate Student, Tver State Technical University, Tver, Russia.

Gultyaev   Vadim   Ivanovich,   Doctor   of   Technical   Sciences,   Ass.   Professor,   Tver   State TechnicalUniversity, Tver, Russia.

Subbotin     Sergey     Lvovich,     Doctor     of    Technical       Sciences,     Ass.     Professor,     Tver State TechnicalUniversity, Tver, Russia.