Load-bearing Cuvillier Load-bearing capacity of imperfection-sensitive timber members under combined bending and compression

This thesis discusses the load-bearing behaviour of imperfection-sensitive timbermembers under combined bending and axial compression. As there is a fl uent transitionbetween the stability phenomena of fl exural buckling and lateral torsionalbuckling, the stability phenomena were studied holistically.Imperfection measurements in 23 timber buildings, fl exural buckling tests on beechLVL columns, and lateral torsional buckling tests on glulam beams were conducted.Through analytical investigations, the knowledge of the theoretical backgroundof the stability behaviour was broadened. For the detailed study of the infl uenceof structural and geometrical imperfections and combined bending and axial compression,numerical models were developed and employed in extensive parameterstudies and Monte Carlo simulations.Thereby, the nonlinear Nx,c-My,1-interaction of the kc-km-method was validated, andconsistent equivalent imperfections for design were derived. Additionally, it wasdemonstrated that the shear and compressive plasticising and the cross-sectionalwarping due to shear can have a signifi cant infl uence on the load-bearing capacity.Design proposals were developed that modify and extend the design rules in EN1995-1-1, in favour of a more reliable, consistent, and economical design.For the fi rst time, by means of comprehensive experimental, analytical, and numericalinvestigations, fl exural buckling and lateral torsional buckling of timber memberswere combined in consistent analysis and design models. This provides a soundfoundation on which subsequent research can build and expand.