Strong Frame™ Ordinary Moment Frame: Wall Bracing: Balloon Framing

Two‑story and balloon framing applications also require the number of braced-wall panels to be based on the minimum percentages of wall bracing and spacing per the IRC. The two‑story application requires both the upper story and first story of a two story to be evaluated. Simpson Strong‑Tie recommends that balloon-framing applications use the first story of a two story bracing percentages specified in the IRC. The required length of wall-bracing panels shall be determined by using the formula:

Wall Length x Wall-Bracing Percentage = Wall-Bracing Panels Required (examples below)

Balloon Framing Example:

Seismic SDC-C, first story of two story – 30% wall bracing required per IRC table R602.10.11
Wall length = 16', 19' plate height, 12' clear opening, slab-on-grade foundation
Balloon wall: 16' x 30% = 4.8'
Use Strong Frame ordinary moment frame equivalent to 8'‑0" substitution: OMF1212‑12x19 (see Strong Frame catalog, page 48 (PDF) )

Footing:

minimum width = 32"
minimum depth = 16"
3-#4 rebar in the bottom (see Strong Frame catalog, pages 59-60 (PDF) )

Grade beam: 12" x 12" grade beam with 2-#4 rebar top and bottom (see Strong Frame catalog, page 59-60 (PDF) )

Anchorage:

OMFSL9-24 (see Strong Frame catalog, page 48 (PDF) )
4 1/2" minimum end distance
1 1/2" minimum edge distance