Experimental and analytical analysis of a post-tensioned timber connection under gravity loads

• Post-tensioned timber connection without steel reinforcement was used.
• Static bending tests were carried out.
• Experimental analysis was performed.
• Analytical spring-based model for different load cases was developed.
• Analytical model is validated with the test results.

The moment-rotation-behaviour of a post-tensioned beam–column timber joint has been analysed extensively with a series of static bending tests. The timber joint was loaded at the end of the beams in order to apply a moment to the connection. The tests were conducted with various forces in the tendon, from 300 kN up to 700 kN. The bending tests were performed with a controlled load level, so that no failure perpendicular to the grain in the column occurred. The maximal allowable vertical load to be applied was estimated using a simple spring model. A final bending test was conducted in order to study the failure mode of the post-tensioned timber joint. The vertical load on the beams was increased until the tendon elongation got so high that the test had to be aborted. The results of bending tests of the post-tensioned timber joint are presented herein. Attention will be given to the structural behaviour and to the influence of the applied post-tensioning force on the connection stiffness. The experimental results will be compared to the results obtained using a simplified analytical calculation model.