Rigid Moment-Resisting Frame Walls: The Frame Method of Analysis - The Analysis of Irregular Shaped Structures - page 506

F i g u r e 14.14 Buckling issues.
Buckling at the Opening Corner (See Fig. 14.14)
Buckling at the corners of the opening was a common mode of failure in tests on shear
walls with openings. Installing tie straps and blocking at the bottom of the header and
top of a sill section provides some fixity to the corner joint. When a moment is applied
to the joint that causes the bottom flange of the header to go into compression, a lateral
out-of-plane buckling force will occur. Light-gauge shear clips can be installed on the
flange to resist these lateral forces and transfer them into the vertical studs. Clips should
also be installed on the blocking on the opposite side of the vertical studs. It can be seen
that the buckling forces will cause biaxial bending in the vertical studs. The studs must
be designed for these forces plus the axial forces applied to the pier section.
14.5 Nailed-Only Partially Composite Sections
Considerable research and testing have been conducted in Australia on nailed plywood
box beams. The Plywood Association of Australia Ltd. developed the Design Guide for
Plywood Webbed Beams, 6 which covers glued and nailed-only box beam assemblies that
consist of plywood webs with lumber flanges. These box beams are the same as the
composite sections covered in this chapter (APA PDS, Supplement 2). When referring to
these box beams or composite beam sections, it should be understood that their design
and use is directly related to the moment-resisting wall frame members covered in this