A two-dimensional numerical model for the seismic collapse assessment of light-frame wood structures

This paper presents the development and validation of a new two-dimensional (2D) numerical framework, suitable for nonlinear inelastic static and dynamic analysis of light-frame wood buildings that incorporate sheathed woodframe shear walls as a lateral-load-resisting system. The 2D building model is based on a sub-structuring approach that considers each floor diaphragm as a rigid body with three kinematic degrees-of-freedom (DOF). A sub-structure model is developed for each individual single-story wall assembly that interacts with the adjacent diaphragms and generates the resisting internal forces. The 2D shear wall model takes explicit consideration of all sheathing-to-framing connections while offers the capability to optionally simulate deformations in the framing members and contact/separation phenomena between framing members and diaphragms, as well as any anchoring equipment (i.e. anchor bolts, holdown devices) typically installed in light-frame shear walls to develop a vertical load path that resists overturning moments. Corotational descriptions are used to solve for displacement fields that satisfy the equilibrium equations in the deformed configuration, accounting for geometric nonlinearity and P-Δ effects. To validate the proposed numerical framework, a number of simulation examples are presented, based on experimental results from pseudo-static cyclic tests of single- and two-story full-scale shear wall specimens. These examples demonstrate the capability of the model to simulate accurate load paths in the structure and successfully predict variations in strength, stiffness and energy dissipation characteristics of the lateral-load-resisting system.