TESTING AND MODELLING OF PRESTRESSED TIMBER BEAMS USING A MULTI SURFACE PLASTICITY MODEL

摘要

The refurbishment of old buildings often comes hand in hand with an increase of the dead- and live loads. The latter, combined with the higher safety factors often make a reinforcement of the old structures necessary. FEM calculations are a helpful tool to understand the complex stress sate in member with externally bonded prestressed reinforcement. The linear orthotropic elasticity does not allow considering, plasticity, softening or hardening. As in prestressed timber bending beams significant crushing can appear numerical modelling of the ultimate load should allow for plasticity on the compression side. The authors undertook extensive numerical and experimental investigations of the failure modes for reinforced glued laminated timber made of Picea Abies. Reinforcement was achieved with pre-stressed CFRP-lamellas.