Wood-Frame Shear Walls Tests Counter Claims of Diminished Performance

Recent claims in the seismic design community have suggested that the presence of gypsum wallboard (GWB) panels may diminish the performance of wood-frame buildings braced with wood structural panel (WSP) shear walls. These claims have been based on modeling by researchers using limited test data from WSP-sheathed shear wall tests and GWB wall tests that were tested separately. To respond to this, AWC funded a series of shear wall tests at Weyerhaeuser’s ISO 17025 accredited test facility in Federal Way, Washington. The tests focused on the combination of 5/8” Type X GWB-sheathed walls (attached as required for fire-resistance rated [FRR] wood-frame walls) in combination with WSP sheathed shear walls. The tests were designed to address unfounded conjecture about the safety of large wood-frame buildings and give our industry data to demonstrate the safety of wood construction.

While analysis of these latest test results is ongoing, including significant P695 modeling for seismic design, preliminary results indicate that the claims that the presence of GWB panels diminishes the seismic performance of large four and five story wood-frame buildings braced with WSP sheathed shear walls are unfounded. The results from this test program are valuable in countering these claims derived without the backing of representative data on the performance of wood frame shear wall systems.

These tests align with AWC’s continual modeling and analysis work, which includes the evaluation of four and five story wood-frame buildings supported by structural podiums and addresses a separate area of concern over possible amplification of seismic forces in this common construction archetype. AWC’s work on the wood over podium structure type is already proving to be influential. Seismic code writers are using it to simplify and propose new criteria to improve seismic performance of podium supported structures.