Seismic fragility assessment of residential anchored brick veneer walls

The out-of-plane seismic fragilities of single-story brick veneer walls built over a wood frame backup were evaluated analytically. Two-dimensional (2-D) finite element (FE) brick veneer wall strip models were developed, based in part on earlier experimental findings, and nonlinear time history analyses were then carried out by subjecting these FE models to synthetic earthquake ground motions representing the seismic characteristics of the central and eastern U.S. Onset of damage at key tie connection locations was used to evaluate the damage limit states of brick veneer walls; the two damage limit states evaluated in this fragility study were onset/accumulation of wall tie damage (described as repairable damage), and brick veneer wall instability/collapse. Throughout the analytical fragility study, brick veneer wall panel component properties were assumed to be deterministic, therefore mainly focusing the work on wall damage uncertainty due to seismic loads. Sensitivity of wall damage probabilities to variability in the ultimate capacities of the tie connections was reviewed afterwards. Three types of tie connection properties and two distinct tie layouts were represented in the FE wall models; the influence of typical wood frame house backup properties on out-of-plane seismic performance of brick veneer walls was also reviewed. Seismic fragility functions were computed to represent both current design standards and common practice for residential brick veneer construction.