Stiffness and strength evaluation of prestressed timber beam with unbonded steel Strand and reinforced concrete Beam-Column joint

The deformation behavior of prestressed timber beams after a gap opens at the beam-column interface is evaluated in this study using the compressive stress distribution along the beam length. The correlation between moment at the beam end and beam deformation is studied for three types of specimens. The evaluation results indicate that the prediction is in good agreement with the experimental results up to the proportional limit of the material. In addition, the bending ultimate strength calculated using the compressive stress distribution at the beam end, which is obtained from the compressive stress-strain relationship, is also verified with the values of moments in the experiment. Finally, an alternative elastic element model with a quadrilinear rigid-plastic spring at the element end was proposed.