A novel balloon-framed rocking CLT shear wall system: Kinetics and proof of concept

Abstract

As seismic force-resisting systems (SFRS), the balloon-framed cross-laminated timber (CLT) configuration offers several advantages, but current code provisions and design guidelines in North America are limited to platform-framed construction. Due to their inherent limitations, platform-framed systems are challenging to implement for taller buildings in seismically active regions, thereby posing barriers to the broader applications of CLT. To address this challenge, an innovative balloon-framed CLT shear wall system is proposed in this paper. This system leverages rocking and pivoting actions to minimize damage to CLT shear wall panels and incorporates distributed hysteretic dampers to achieve the desired kinematics and energy dissipation. The basic concept, configuration, and kinetics of the system are introduced as proof of concept. An analytical model of a two-story assembly is developed, establishing the relationships between global structural behavior and the geometric and mechanical properties of the kinematic components and supplemental damping devices. To verify the analytically derived behavior, nonlinear numerical models are developed for two-, six-, and twelve-story archetype buildings. Monotonic pushover analyses are conducted to investigate system behavior, focusing on characteristic response states and their transitions. Based on the presented analyses, mechanical behaviors are discussed for key components in the proposed system, paving the way for further investigations through dynamic numerical analyses and large-scale experimental tests.