Benefits of multiple rocking segments for CLT and LVL Pres-Lam wall systems

Abstract

Abstract Press-Lam mass timber wall system is an adaptation of the Precast Seismic Structural System used for concrete and steel buildings to resist earthquakes. Single rocking segment systems with rigid connections between panels result in a dynamic amplification of the forces in the upper storeys. The objectives of this research were to compare through analytical studies the design requirements for Pres-Lam wall systems made of laminated veneer lumber (LVL) and cross-laminated timber (CLT) panels and to demonstrate through numerical modeling that the dynamic amplification can be reduced by introducing simple connections allowing a gap opening at construction joints. Results of the study demonstrated that the CLT walls needed approximately 20% wider panels and 10–30% less initial pre-stress in the post-tensioning bars to obtain the same moment-rotation behavior as in the LVL walls. Time history analyses on multiple rocking segment models showed that the shear and bending moment envelopes were reduced nearly 45% in comparison with the equivalent single rocking segment systems.