Structural Behaviour of Folded Timber Sandwich Structures

This paper aims to characterise the mechanical behaviour of folded timber sandwich structures developed using integral rotational press-fit (RPF) joints. Six folded arches are tested to failure, under three load cases designed to induce different sagging and hogging conditions at internal joints. Experimental testing showed failures occurring at joint locations with maximum hogging moment, with two failure types observed as FRP tensile and core compressive rupture. A nonlinear static analysis and simplified 2D frame model is proposed to predict moment distribution and failure load for FRP fracture modes. This model characterises the RPF joint as a nonlinear semi-rigid hinge, with assigned bilinear moment-curvature relation obtained from analysis of joint strain data collected during arch testing. Core compressive failures are shown to occur as an inelastic core buckling behaviour when there is misalignment between assembled core segments.