Top plates of the corner framing were braced using 11mm-thick OSB sheets, fastened with 8d common nails (152mm o.c.) to simulate the assumed "lower bound" stiffening effect of a floor or ceiling diaphragm (Fig.
It is remarkable that except for the nails attaching the sheathing to the bottom plate, there were no typical damage signs of racking of the sheathing panels with corner framing. The taped joints between the drywall panels experienced no damage.
In addition, the high variation of the values obtained from the walls with 0.6-m corner framing and the small sample size may also be contributing to the observed difference.
On average, total stud movement at capacity was reduced by 36 and 41 percent for walls with 0.6-m and 1.2-m corner framing, respectively, compared to a straight wall with no overturning restraint.
In these tests, corner framing provided some hold-down effect when compared to straight walls with no overturning restraint and no perpendicular walls attached.
Based on this observation, shear wall tests carried out in the future should always have corner framing to insure a more realistic performance.