Wind Resistance and Fragility Functions for Wood-Framed Wall Sheathing Panels in Low-Rise Residential Construction

Abstract

The wind uplift resistance of wood roof sheathing panels has been the subject of many engineering studies due to the high probability that roofs are subjected to large uplift loads during intense wind events. However, few studies have focused on determining the out-of-plane wind resistance of wall sheathing for light-framed wood structures, which are integral to the construction of external walls in single-family residential housing. The objective of this research is to experimentally determine the out-of-plane wind resistance of wood framed walls as used in light-framed wood structural systems. Tests were conducted at the University of Florida on 1.22×2.44 m (4×8 ft) wood wall panels consisting of oriented strand board (OSB) and/or plywood sheathing nailed to wood studs. The panels were fabricated in accordance with the minimum requirements of the Florida Building Code. Each panel was subjected to a monotonic-increasing static pressure using a step-and-hold pressure test sequence until the panel failed. The mean out-of-plane structural resistance capacity of wood panels attained was 4.21 kPa (88.0 psf), and there was no statistical difference in performance between plywood and OSB sheathing panels. As expected, when results were compared with previous results from tests on wood roofs panels (conducted by the third author), the mean failure pressure of the wall panels was higher than the failure pressure of the roof panels. The ultimate nail-withdrawal load failure of the fasteners (by far the most common failure mechanism) in the wall sheathing was actually 21% lower than for the roof panels. Finally, the research has for the first time contributed experimentally determined fragility functions for wood wall panel systems and compared these to previously available fragilities for roof panels. Roof panels in the corners and along roof edges are more likely to fail in high wind events than are wall panels. The study shows that the failure probabilities for wall corner panels (in Zone 5) can exceed that of roof sheathing panels located in the field (Zone 1) of the roof. These results are important contributions for probabilistic modeling of wood framed building and for use in component-based wind-damage prediction models in hurricanes and in tornadoes.