Evolutionary parameter hysteretic model for wood shear walls

The hysteretic behavior of wood shear walls subjected to cyclic loading exhibit highly nonlinear force-displacement responses. There exists a careful balance between model complexity and necessary accuracy. In fact, the most widely used models for hysteretic behavior utilize piecewise-linear functions with static parameters to model the nonlinear hysteretic response and are often unable to capture some of the significant characteristics observed under experimental testing. This paper describes a new evolutionary parameter hysteretic model (EPHM) and illustrates its use in a number of applications including the development of seismic fragility curves. The proposed model is validated using the results of two full-scale shake table tests and eight cyclic shear wall tests with varying wall configurations and tested using different loading protocols. Good agreement is observed between the EPHM model and the test data. The EPHM is shown to be a better choice of hysteretic model than a static parameter model for performance-based seismic design applications when accurate prediction of displacement throughout the entire deformation demand range is required.