Material-based modelling of CLT shear walls considering compression and connection zones

This study addresses a critical gap in modelling the nonlinear response of cross-laminated timber (CLT) shear walls by proposing a unified framework that explicitly captures compression-toe crushing, contact evolution, and biaxial/rotational connection-zone effects for CLT shear wall systems, including platform-type and balloon-type configurations. A material-based finite element (FE) framework is developed in which compression-toe region is modelled using Wood ST , an orthotropic damage–plasticity constitutive model, while connection-zone behaviour is represented through multiple nonlinear connector elements for hold-down connections. Model validation is based on eight full-scale balloon-type CLT shear wall tests with aspect ratios of 4:1 and 6:1 under monotonic and cyclic pushover loading without externally applied vertical loads. Validation focuses on monotonic and envelope (backbone) responses extracted from cyclic hysteresis loops, without calibration at the wall (system) level. The proposed framework successfully reproduces global load-displacement response, compression-zone migration and length evolution, uplift distribution, and connector-level force paths. A simplified modelling strategy is also proposed, employing elasto-plastic CLT properties and a single multi-degree-of-freedom connector per hold-down with coupled moment-axial-shear ( M – N – V ) interaction. The simplified model achieves close agreement with both advanced FE simulations and experimental results while providing a computationally efficient tool for nonlinear analysis. The results establish a mechanism-based foundation for seismic modelling, analysis, and design of mass-timber systems, supported by validation on balloon-type walls, in terms of backbone response, and providing a basis for extension to full hysteretic behaviour.