The Influence of Brick Veneer on Racking Behavior of Light Frame Wood Shear Walls

The racking behavior of an anchored brick veneer – wood frame wall system was investigated analytically. The core wall model simulated a wood frame sheathed with oriented strand board. Brick veneer was then tied to the exterior wall face, and gypsum wallboard sheathing was added on the interior wall face. Two-dimensional linear elastic beam and continuum type elements were used to model these principal wall components. Gap elements were used to prevent sheathing overlap and to model panel bearing at the base. The veneer was supported on compression-only spring elements in the vertical direction and perfectly plastic spring elements in the horizontal direction. The fasteners connecting the sheathing to the frame backing, and the ties anchoring the veneer were modeled with pairs of orthogonal independent nonlinear inelastic springs. Common force-displacement relations were used for the springs that approximated the fasteners, while an experimental study was carried out to determine constitutive relations for corrugated metal ties that anchor the brick veneer to its wood frame backing.

Connection subassemblies were tested under monotonic and cyclic shear loading, and it was determined that fastener slippage during cyclic loading enabled by the localized damage of the surrounding wood fibers diminished the energy absorption capacity of the connection and caused pronounced pinching in the hystereses. Considering corrugated ties with minimum thickness permitted by the MSJC Code, tie design and bent eccentricity were found to be the most important factors, while tie location in the bed joint, fastener type and fastener quantity were influential to a lesser degree.

Of particular interest in the analytical investigation were the effects resulting from the inclusion of brick veneer on the outer wall face and/or gypsum wallboard sheathing on the interior wall face, as well as the viability of the created integral wall system. It was determined that both brick veneer and wallboard sheathing stiffen significantly the core light frame wood shear wall and alter its response. Their simultaneous presence increased racking wall strength, but diminished its ductility. The addition of anchored brick veneer limited wood shear wall displacements and reduced wall’s base shear under dynamic excitation.