Development, validation, and application of reduced-order numerical models for post-tensioned cross-laminated timber rocking walls

Post-tensioned cross-laminated timber (PT-CLT) rocking walls have emerged as an effective low-damage lateral force-resisting system. As urban densification and decarbonization trends drive the adoption of sustainable high-rise timber construction, taller and flexible PT-CLT buildings with longer natural periods are expected to become increasingly common. However, such structures are potentially susceptible to subduction earthquakes, as well as to excessive wind-induced vibrations. To support nonlinear dynamic analyses and structural reliability assessments for such structures under long-duration loads, computationally efficient yet robust numerical models are required. Although existing high-fidelity models can capture system behavior, they are computationally intensive and not well-suited for iterative analyses. Reduced-order models, which concentrate nonlinear behavior at the wall base to represent both geometric and material nonlinearity as well as rocking and energy dissipation, offer a practical alternative. However, their applicability to tall mass-timber buildings, where flexural behavior and higher-mode effects become significant, remains underexplored. This study first develops and validates a conventional reduced-order model (CROM) against full-scale building-level shaking-table test results and high-fidelity numerical models, demonstrating its capability in predicting global seismic responses. Building on the CROM, a refined reduced-order model (RROM) is developed, incorporating energy dissipation through an equivalent viscous damping formulation. Both models show strong agreement with shaking-table test results. To further demonstrate their versatility, the reduced-order models are extended to include an upper rocking joint in a tall PT-CLT rocking wall, enabling investigation of higher-mode mitigation strategies. The results highlight the computational efficiency, adaptability, and practicality of the proposed reduced-order models for PT-CLT walls.