Strong-Wall^® Bracing Selector V1: Design Example

General Notes

Overview

The Strong-Wall Bracing Selector V1 provides equivalent wall-bracing solutions based on the wall-bracing requirements of the International Residential Code® (IRC) and the Conventional Light-Frame Construction Section 2308 of the International Building Code® (IBC). The required total length of bracing, as well as panel spacing, wall height limits, structure weight limits, and etc. shall be based on the governing code used for design. Code references in this tool refer to the 2012 IRC unless specific reference is made to the 2009 IRC. While the IRC edition used may affect the required bracing, it does not affect the Strong-Wall bracing substitutions. The wind and seismic wall-bracing solutions in this tool may be considered equivalent to the code braced-wall-panel construction Method WSP (Wood Structural Panel) with gypsum board applied on the opposite face as defined in table R602.10.4 of the 2012 IRC. The IBC refers to this as Method 3. The seismic-with-masonry-veneer wall-bracing solutions are designed to be equivalent to the construction method and hold down requirements in table R602.10.6.5 of the 2012 IRC and Sections 2308.11.2 and 2308.12.2 of the IBC.

Basic Bracing Requirements

The required length of bracing shall be based on sections R602.10.3, R602.10.6.5, and the braced-wallpanel-location requirements of Section R602.10.2.2. The minimum length of a braced-wall panel shall be based on Section R602.10.5. In general, the distance between adjacent edges of braced-wall-panels along a braced-wall line shall be no greater than 20 ft and begin not more than 10 ft from the end of the braced-wall line. Braced-wall-panels may be offset out-of-plane up to 4 ft from the braced-wall line with the total out-to-out offset limited to 8 ft The minimum number of braced-wall-panels required within a braced-wall line except at garage fronts with a continuous header or header splice is detailed in Section R602.10.3. Structures located in SDC C or higher except those exempted in section R301.2.2 of the IRC are subject to the limitations for weights of materials in section R301.2.2.2.1. In general, the combined roof and ceiling dead load may not exceed 15 lb per square foot (psf) unless the required wall-bracing length is adjusted per table R301.2.2.2.1 for roof/ceiling dead load up to 25 lb psf. For designs based on the IBC, the limitations of Section 2308.2 limit the roof/ceiling dead load to 15 lb psf. There are additional braced-wall-panel location requirements for higher seismic design categories that must be considered. For more detail, see the 2009 IRC or 2012 IRC tutorials in the Wall-Bracing-Length Calculator describing bracing requirements.

Braced-wall-panel heights greater than 10 ft and up to 12 ft are allowed provided the required length of bracing is increased as required by section R301.3. For designs based on the IBC, braced-wall-panel heights shall not exceed 10 ft Balloon-frame applications for tall walls up to 20 ft tall are designed to provide equivalent performance to a two-story braced-wall panel application and may exceed the braced-wall-panel height limits based on IRC section R301.3 or IBC Section 2308.1.1.

When structures or portions thereof are designed per the Conventional Light-Frame Construction Section 2308 of the IBC, bracing requirements including braced-wall line and braced-wall-panel length, spacing, and location shall be in accordance with the provisions contained therein. Typically, braced-wall line length requirements are listed as a percentage of wall length. Bracing requirements expressed as a percentage must be converted to a length in feet for use with the Strong-Wall Bracing Selector V1.

Strong-Wall Shearwalls – General

Wood and Steel Strong-Wall shearwalls have been evaluated to the 2012 IBC/IRC in ICC-ES code report ESR-1267 (wood) and ESR-1679 (steel). This tool expands on the braced-wall-panel allowance in the code reports to provide specific braced-wall-panel contributing lengths and corresponding anchorage solutions for various applications and foundation types. Balloon-frame applications for tall walls up to 20 ft are designed to provide equivalent performance to a two-story braced-wall-panel application. Required length of bracing for balloon-frame applications should be based on the length required for the bottom story assuming the balloon-framed wall counts as the bracing for both stories.

Steel Strong-Wall shearwall solutions are based on the following maximum total vertical loads acting along the length of the panel:

• 1000 lb
  • First Story – Single Story
  • Balloon-Framing
• 2000 lb
  • First Story – 1st of 2 or 3 Story on Wood Floor
  • Two Story stacked (1000 lb for each story)
• 4000 lb
  • First Story – 1st of 2 or 3 Story on Concrete or CMU
  • Garage Front – Single Story
• 7500 lb
  • Garage Front – 1st of 2 or 3 Story

Axial and out-of-plane loads for the Wood and Steel Strong-Wall shall be limited to values shown in the current Strong-Wall Shearwalls catalog.

Strong-Wall Shearwalls – Garage Front Applications

Spacing between adjacent Strong-Wall shearwall panel edges may exceed 20 ft or begin more than 10 ft from the end of the braced-wall line (such as at each end of a three-car garage or at one end of a two-car garage) provided a continuous header or header splice is used as a collector along the garage front. It is recommended that a minimum of two panels be provided at garage fronts except that garage fronts up to 25 ft in length may use a minimum of one panel with a 6 ft contributing length. The total length of braced-wall-panels and contributing length of Strong-Wall panels provided shall not be less than that required for the corresponding wind speed or SDC.

Header Support Post Installation Requirements

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See header support post installation requirements for Wood or Steel Strong-Wall shearwall portal installations.

Multi-ply Header Installation Requirements

Multi-ply headers for garage portal walls

1. Garage portal walls may be used with double 2x12 minimum or double 1 3/4" × 11 7/8" minimum LVL headers unless noted otherwise.
2. Headers shall be face nailed to each other with minimum 16d nails at 32" on center staggered along the top and bottom.
3. Double 2x12 require 1/2" ply or OSB shim to make the header assembly flush with Wood Strong-Wall panel. The shim shall match the header depth and Wood Strong-Wall panel width minimum. It may be placed on either face of header or between plies directly over the Wood Strong-Wall panel.

Okay

Multi-ply headers may be used for garage-front applications. See multi-ply header installation requirements. Solid headers shall be used with the Steel Strong-Wall shearwall in SDC D0, D1, and D2 (SDC D and E for IBC governed designs).

When a pony-wall occurs over the garage header, sheath the entire pony-wall area from top plates to header with minimum wood structural panels and nailing per Method WSP. For method BV-WSP, sheathing and nailing shall be per R602.10.6.

Anchorage

Anchorage solutions provided in this selector are for anchorage of Strong-Wall shearwalls only. The foundation construction should be specified by the Designer to meet all other code requirements. As a minimum, it is recommended that when using Strong-Wall shearwalls, the foundation match the requirements for the alternate braced-wall-panel (Method ABW) in the IRC or IBC. The alternate braced-wall-panel requires a continuous foundation across the length of the braced-wall line that is reinforced with a minimum of one #4 rebar top and bottom.

Cast-in-place SWAB and SSWAB anchorage solutions are designed based on ACI 318-11 Appendix D assuming uncracked concrete and no supplemental reinforcement. Anchorage solutions for seismic governed designs include a 0.75 reduction factor on breakout strength per Appendix D section D.3.3.3. SSTB and SB anchorage solutions are based on testing conforming to ICC-ES acceptance criteria AC 399.

Post-installed adhesive anchorage solutions are based on testing and finite element analysis (FEA) modeling into uncracked concrete with no supplemental reinforcement and a safety factor of 4.0 on ultimate loads when Wind Jobsite Category applies, and a safety factor of 5.0 on ultimate loads when Seismic Jobsite Category applies. For additional adhesive-anchor design and installation information, see the current Anchoring and Fastening Systems catalog or visit www.strongtie.com/products/anchorsystems/.

Cast-in-place Wood Strong-Wall mudsill anchors shall be 5/8" diameter × 12" long minimum embedded 7". For post-installed adhesive installation, use 5/8" diameter × 10" long all-thread rod minimum (model RFB#5x10) embedded 5".

Installations on CMU foundation walls are based on 8 in nominal grout filled CMU. CMU shall be grout filled at Strong-Wall locations minimum and fully grouted where required by code. The minimum CMU prism design compressive strength shall be f'm = 1500 psi or greater. To achieve f'm = 1500 psi, a minimum grout strength of 2000 psi using standard ASTM C90 concrete masonry units with 1900 psi minimum compressive strength and type M or S mortar is required.

For holdowns and anchor bolts, nuts should be finger-tight plus 1/3 to 1/2 turn with a hand wrench, with consideration given to possible future wood shrinkage. Care should be taken to not over-torque the nut. Impact wrenches should not be used as they may preload the anchor or holdown.

The Strong-Wall Bracing Selector V1 does not provide a complete building design. The user of this tool is responsible for complying with IRC/IBC prescriptive provisions or consulting a professional Designer to address all other structural elements not included herein. Refer to the applicable building code for all other structural elements, connections, fastening schedules, and member designs.

Strong-Wall shearwall panels used as braced-wall-panels are part of the overall lateral-force-resisting system of the structure. This tool provides equivalent braced-wall-panel replacements and anchorage solutions only. Specification of the remainder of the building’s lateral-force-resisting system, including the load path to transfer lateral forces to the Strong-Wall panels, is the responsibility of the Designer. Installation of Strong-Wall shearwalls shall be done in conformance with this tool and the current Strong-Wall Shearwalls catalog. Also refer to the Strong-Wall Shearwalls catalog for other important information including Terms and Conditions of Sale and other information. This information may also be obtained at www.strongtie.com.

Local and/or regional building codes may require meeting special conditions. For compliance with these requirements, it is necessary to contact the local and/or regional building authority. Except where mandated by code, Simpson Strong-Tie products do not require special inspection.

Simpson Strong-Tie reserves the right to change specifications, designs, and models without notice or liability for such changes.

Refer to current Wood Construction Connectors catalog for information and General Notes for Simpson Strong-Tie connectors.

IRC Map and Jobsite Category Table

For 2012 IRC designs use the table below to determine your jobsite category for use in this selector.

1. Regions where wind design is required are defined in figure R301.2(4)B and include portions of the U.S. Atlantic Ocean and Gulf of Mexico coasts, Hawaii, Puerto Rico, Guam, Virgin Islands and American Samoa.
2. "Not Permitted" indicates an engineered design is required.

3. IRC Map and Jobsite Category Table

   For 2009 IRC designs use the table below to determine your jobsite category for use in this selector.

   IRC	Basic Wind Speed (3 Second Gust)	Veneer Condition	SDC	Structure	Map Reference Color	Jobsite Category
   	85-109 MPH in Non-HPR2 or 89-99 MPH in HPR	With or Without Masonry Veneer	A,B	Detached one- and two-family dwellings and townhouses		Wind
   			C	Detached one- and two-family dwellings		Wind
   			C	Townhouses		Seismic
   		Without Masonry Veneer	D0, D1, D2	Detached one- and two-family dwellings and townhouses		Seismic
   		With Masonry Veneer	D0, D1, D2	Detached one- and two-family dwellings		Seismic with Masonry Veneer
   				Townhouses		Not Permitted
   		With or Without Masonry Veneer	E	Detached one- and two-family dwellings and townhouses		Not Permitted
   	≥ 100 in HPR or ≥ 110 in Non-HPR	With or Without Masonry Veneer	All	Detached one- and two-family dwellings and townhouses		Not Permitted

   1. "HPR" = Hurricane-Prone Region, which is defined in the IRC as the U.S. Atlantic Ocean and Gulf of Mexico coasts where the basic wind speed is greater than 90 mph and Hawaii, Puerto Rico, Guam, Virgin Islands, and American Samoa.
   2. The noted basic wind speed (3-second gust) is applicable to hurricane-prone regions for designs based on the 2000 or 2003 IRC.
   3. "Not Permitted" indicates an engineered design is required.

   Okay
   For designs based on the 2009 IRC, Click Here.

Local and/or regional building codes may have adopted specific amendments to the building code. For compliance with these amendments it is necessary to contact the local and/or regional building authority.

Wind and Seismic Map for IRC

The map below may be used as a general guide to determine the appropriate Strong-Wall wall bracing replacement tables to use based on the geographical location of your structure. The map is based on soil Site Class D. Contact your local Building Department for applicability in your area and to confirm wind speed, Seismic Design Category and Site Class requirements. The U.S. Geological Survey (USGS) offers an internet calculation tool to help determine the appropriate Seismic Design Category based on the project site zip code or longitude and latitude. Go to the USGS website at http://earthquake.usgs.gov/designmaps/us/application.php for more information.

IBC Jobsite Category Table

For 2012 IBC Section 2308 designs use the table below to determine your jobsite category for use in this selector.

1. "HPR" = Hurricane-prone region, which is defined in the IBC as the U.S. Atlantic Ocean and Gulf of Mexico coasts where the basic wind speed is greater than 90 mph and Hawaii, Puerto Rico, Guam, Virgin Islands, and American Samoa.
2. The noted basic wind speed (3 second gust) is also applicable to hurricane-prone regions for designs based on the 2000, 2003, or 2006 IBC.
3. The IBC permits masonry veneer in SDC D only when the provisions of Section 2308.12.2 are satisfied.
4. "Not Permitted" indicates an engineered design is required.

Local and/or regional building codes may have adopted specific amendments to the building code. For compliance with these amendments it is necessary to contact the local and/or regional building authority.

Design Example

Design Criteria

• 2012 IRC
• Basic Wind Speed - 90 mph, Exposure Category B
• Seismic Design Category B
• 3 Braced-Wall Lines at 10' and 19'
• 8' Eave-to-ridge height
• 8" wide concrete stemwall, f'c = 2500 psi

Step 1 – Enter Project Information

• Identify Braced-Wall Line of interest and note total length of bracing required per IRC using the Wall-Bracing-Length Calculator.

  Braced-Wall Line 1:

  Garage Front - First Story

  Second Story Wall Bracing constructed in accordance with the IRC

• Total Length of Bracing Required = 4.6 ft
• Total Length of qualifying bracing = 0 ft
• Remaining Length of Bracing Required = 4.6 ft

Step 2 – Enter Project Inputs

• Jobsite Category: Wind

  Jobsite Category automatically chosen if using Wall-Bracing-Length Calculator first then launching Strong-Wall Bracing Selector V1

• Application: Garage Front - 1st of 2 Story
• Foundation Type: Concrete Stemwall - Anchor into Wall
• Foundation Strength: 2500 psi
• First Story Wall Height: 8 ft with Header on Top

Step 3 - Enter Strong-Wall Information

• Strong-Wall Type: Steel Strong-Wall
• Portal Kit: Selected
• Available Wall Space: 24 in
• Strong-Wall Location:

  Option 1: Garage - Single Panel

  Use single Strong-Wall garage portal system at garage front. Solution based on 6 ft of contributing wall bracing length.

  Option 2: Garage - Double Panel

  Use double Strong-Wall garage portal system at garage front to reduce anchorage requirements and provide narrower wall bracing solution.

Available Solutions Summary

Option 1: Garage - Single Panel

• SSW15x8 w/SSWP-KT
• Anchored with SB1 × 30 (le = 24"). No Adhesive anchorage solutions available for the option.

Option 2: Garage - Double Panel

• Two SSW12x8 w/SSWP-KT
• Anchored with SSWAB3/4 × 30 (le = 20") or, 3/4" diameter adhesive anchor with 12" embedment using Simpson Strong-Tie SET or SET-XP™ or AT adhesive.

For additional Braced-Wall Lines, repeat Steps 1-3.