Performance and Design of LVL Walls Coupled with UFP Dissipaters

TLDR

Timber walls employ a hybrid design that uses U‑shaped plates to dissipate energy through yielding while post‑tensioning provides the restoring force, mirroring post‑tensioned precast concrete wall systems. The study investigates the seismic resistance of coupled post‑tensioned timber walls in multi‑story buildings, applying the hybrid plate‑post‑tensioning principles to timber. LVL walls are post‑tensioned with unbonded vertical tendons and coupled by mild steel U‑shaped flexural plates, and their seismic performance was assessed through quasi‑static cyclic and pseudo‑dynamic tests. The U‑shaped plates showed stable energy dissipation and flag‑shaped re‑centering hysteresis when combined with post‑tensioning, and their simplicity and low cost indicate strong practical potential.

Abstract

This article presents recent research on the seismic resistance of coupled post-tensioned timber walls for use in multi-story buildings. The walls are constructed from laminated veneer lumber (LVL), post-tensioned with unbonded vertical tendons, and coupled together with mild steel U-shaped flexural plates (UFPs) as energy dissipating elements. The timber wall design follows the same principles as used for post-tensioned precast concrete wall systems, using U-shaped plates to obtain a "hybrid" system, where energy is dissipated through yielding of the plates, while the vertical post-tensioning provides the restoring force. In this project, the same principles are applied to timber coupled walls. A series of quasi-static cyclic and pseudo-dynamic tests have been carried out to verify the applicability of the concept and the feasibility of the construction technology in timber buildings. The U-shaped plates showed stable energy dissipation characteristics and, in combination with the post-tensioning, desirable re-centering hysteretic behavior typically referred to as "flag-shape". Because of the simplicity of these elements and the low cost of implementation, they have good prospects for practical application.