IRC Intermittent Bracing Methods

2m ago
203 Views
2 Downloads
1.57 MB
6 Pages
Last View : 1d ago
Last Download : 3d ago
Upload by : Mollie Blount
Share:
Transcription

Technical BulletinIRC Intermittent Bracing MethodsSolutions for Narrow Wall Segments Including Alternate Wall Bracing (AWB)Portalframe with Holdowns (PFH) and Portal Frame at Garage (PFG)Background: Lateral Bracing in the 2015 InternationalResidential Code (IRC )Lateral wall bracing requirements in the prescriptivebuilding codes have remained basically unchangedfor over 30 years until 2006. Catastrophic damageand financial losses from natural disasters in recentdecades prompted some significant changes andstricter enforcement of building codes nationwide.Historically, proper wall bracing construction per theIRC required a minimum of 4-feet of available walllength. With design trends calling for larger windowopenings and narrow garage return walls, the wallspace available for bracing has been limited.This bulletin outlines braced wall panel options fornarrow wall segments (IRC R602.10).Limitations of Prescriptive Wall Bracing and this Tech BulletinWood frame buildings are often constructed by following the prescriptive building codes without a design professional. Likewise, the wallbracing and intermittent braced wall panels described in this bulletin do not require additional engineering or the use of engineered shear walls.The prescriptive provisions of the IRC do have design limitations, listed below are some highlights of these limitations:Where the prescriptive provisions of the IRC and this document do not apply: Construction in regions where the ultimate design wind speeds Vult exceed 130 miles per hour. Buildings constructed in windborne debris regions without windborne debris protection. Buildings constructed in Seismic Design Category E. Building with height exceeding three stories above grade or story height exceedinglimitations of IRC R301.3.For a complete description of design limitations see IRC R301 or check with a local building official to see which bracing options are acceptedin your area.Customer Service & Technical AssistancePhone: 1-800-328-5934 Fax: 1-952-898-8605 Email: [email protected] 2019MiTek-US.comCopyright 2019 MiTek Industries, Inc. All Rights Reserved1#USP999

Technical BulletinIRC Intermittent Bracing MethodsSolutions for Narrow Wall Segments Including Alternate Wall Bracing (AWB)Portalframe with Holdowns (PFH) and Portal Frame at Garage (PFG)Portal Frame with Embedded Strap Holdowns (IRC R602.10.6.2) Method PFH for Concrete or Reinforced Masonry ConstructionAlternative Braced Wall Panel Construction OptionsPortal Frame with Embedded Strap Holdowns - Construction Options for Concrete Foundations Can be installed anywhere along a braced wall in 1 and 2 story applicationsadjacent to a window or door opening with full length header. 16" Minimum width for 1-story buildings. 24" Minimum width on the 1st story of 2-story buildings. 10' Maximum height to top of header.SeeDetailA&BTable 116" - 24" Portal Frame Braced Wall Panel withEmbedded Strap Holdowns (IRC R602.10.2) (See Fig. 1)Connector asCalled out in Drawing3500-lb Tie-Down DeviceUSPStock No.STAD14PonywallFastenerSchedule1,2Min 3" x 11-1/4" net headers. steel is prohibitedIf 1/2" spacer is used, place on back-side of header(28) 16d SinkerHPAHD22(23) 16d SinkerLSTAD8(16) 16d SinkerPAHD42(15) 16d SinkerAnchor Bolt 5/8" dia. x 12"AB5812-HDGMin. 7" Embed3/16" x 2" x 2" Plate WasherBP582--8d Common8d Common--16d Sinker16d Sinker--1000-lb Tie-Down Device forSingle Portal FrameExtent of header with double portal frames (two braced wall panels)Extent of header with single portal frames(one braced wall panels)2' – 18' Finished width of openingfor single or double portalHeader to jack studstrap per IRC Table R602.10.6.4installed on both sides of openingopposite side of sheathing (See Table 3).10' MaxHeightMin (2)3500 lb.strap typeholdownsMin length of panelper table R602.10.512' Maxtotal wallheightMin. (2) 3500 lb strap-typeholdowns (embedded intoconcrete and nailed into framing)1) Specified nails for tie-downs are 16d sinker nails.2) Minimum nail embedment shall be 1-5/8" for 16d Sinker nails.Min 1000lb, holdowndeviceMin. reinforcing of (embeddedfoundation, one #4 into concreteBar top and bottom and nailedof footing. Lapinto framing).bars 15" minSee Detail CMin. (1) 5/8" diameter anchor boltinstalled per section R403.1.6 - with3/16" x 2" x 2"plate washerFigure 1Header Connection DetailsSame for all anchorage optionsFasten sheathingto header with 8dcommonor galvanized boxnails in 3" gridpattern as shownEmbedded Strap Installation2 - 2x studs or4x postsFasten topplate toheader withtwo rows of16d nails at 3"O.C. typ.Min. 3/8" woodstructural panelwith 8d nails at3" O.C. (2) rowson each side ofvertical segmentportal frameMin. 3/8 wood structuralpanel with 8d nails at 3"O.C. 2 rows on each side ofvertical leg of portal frame3500 lb min. capacitystrap tie-downsstrap each sideper table602.10.6.45/8" x 12" standardanchor bolt andplate washerConsult localbuilding codefor reinforcingrequirements(2x) 2 x 4 studsor 4x postDetail A (outside)Min (1) 5/8" diameter anchor boltinstalled per section R403.1.6 with2" x 2" x 3/16" plate washer.Detail B (inside)Single treatedsill plateDetail C (bottom)Customer Service & Technical AssistancePhone: 1-800-328-5934 Fax: 1-952-898-8605 Email: [email protected] 2019MiTek-US.comCopyright 2019 MiTek Industries, Inc. All Rights Reserved2#USP999

Technical BulletinIRC Intermittent Bracing MethodsSolutions for Narrow Wall Segments Including Alternate Wall Bracing (AWB)Portalframe with Holdowns (PFH) and Portal Frame at Garage (PFG)Portal Frame Construction using common holdownswith anchor bolts.Table 2Portal Frame Holdowns and Retro-Fit Connection Options (See Fig. 2)PortalFrame Holdowns and Retro-Fit Connection Options16"-24" Portal Frame Braced Wall Panel with HoldownsConnector as Called Outin DrawingRetro-fit Option alternate to Method PFH This method is not described in the IRC, but is acceptedin certain jurisdictions at the local level. Check with alocal building official to see if it is approved for use inyour area.USPStock No.PHD4A3500-lb Tie-Down Device1000-lb Tie-Down Devicefor Single Portal Frame Can be installed anywhere along a braced wall in1 and 2-story applications adjacent to a window ordoor opening (i.e. garage door) with full length header.Fastener / Installation Schedule1(10) WS3 Wood Screws (Incl.);5/8" Anchor BoltHTT16(18) 10d; 5/8" Anchor BoltDTB-TZ(8) WS15 Wood Screws (Incl.);1/2" Anchor BoltPHD2A(6) WS3 Wood Screws (Incl.);5/8" Anchor Bolt(2) 5/8" Through Bolts5/8" Anchor BoltTDX2-TZ A standard holdown with an embedded anchor boltis used.Tie-DownAnchoringOptions Threaded rod with epoxy may be used for retro-fitif foundation is already in place.Cast-in-PlaceRetro-FitCast-in-Place Masonry foundation must be reinforced and tiedto the footing.5/8" Sill PlateAnchorageSTBL16THR5816-HDGConcrete Embed5/8" Threaded Rod (9" Embed),CIA-GEL 7000 Epoxy orCIA-EA Epoxy AcrylateSTB16Concrete EmbedAB5812-HDG7" Minimum EmbedTHR5816-HDGEA-105/8" Threaded Rod (9" Embed),CIA-GEL 7000 Epoxy orCIA-EA Epoxy Acrylate3/16" x 2" x 2" Plate WasherBP582--10d Common10d Common--10d x 1-1/2NA9D--16d Common16d Common--Retro-FitGEL7-10 or GEL7-221) Minimum nail embedment shall be 1-5/8" for 16d nails and 1-1/2" for 10d nails.Extent of header with double portal frames (two braced wall panels)Extent of header with single portal frames(one braced wall panels)2' – 18' Finished width of openingfor single or double portalPony wallMin 3" x 11-1/4" net header. Steel Header is prohibitedIf 1/2" spacer is used, place on back-side of header.Tension strap per table R602.10.6.4(on opposite side of sheathing)Header to jack stud strap installed per IRC Table R602.10.6.4on both sides of opening oppositeside of sheathing (See Table 3).12' Maxtotal wallheightMin length of panelper table R602.10.510' MaxheightMin. (2) 3500 lb strap-typeholdowns (embedded intoconcrete and nailed into framing)Min. reinforcing of foundation,one #4 Bar top and bottom offooting. Lap bars 15" minDetail DMin. (1) 5/8" diameter anchor boltinstalled per section R403.1.6 - with3/16" x 2" x 2"plate washerMin 1000 lb, holdown device(embedded into concrete andnailed into framing).See Detail EFigure 2Customer Service & Technical AssistancePhone: 1-800-328-5934 Fax: 1-952-898-8605 Email: [email protected] 2019MiTek-US.comCopyright 2019 MiTek Industries, Inc. All Rights Reserved3#USP999

Technical BulletinIRC Intermittent Bracing MethodsSolutions for Narrow Wall Segments Including Alternate Wall Bracing (AWB)Portalframe with Holdowns (PFH) and Portal Frame at Garage (PFG)TABLE 3AllowableStrapsfor ResistingWindPerpendicularFor Resisting WindPressures TensionPerpendicularto MethodsPHF, PFGand PressuresCS-PFGBracedWall Panels. Based on TabFor Resisting Wind Pressures Perpendicular to Methods PHF, PFG and CS-PFGBraced Wall Panels. Based on Tabto Methods PFH, PFG, and CS-PFG Braced Wall PanelsWall StudPony7Wall StudPony7FramingWallFramingWall(NominalSize Height(NominalSize Heightand Grade)(ft)and Grade)(ft)0012x42 x24GradeNo.No. 2 Grade221TotalTotal OpeningWallOpeningWall 69101816221010121291816918169181691816MiTek - USP Tension Strap Required1,2,3,6- USP Tension Strap Required1,2,3,6ExposureMiTekBExposure CExposureBC V (mph)Ultimate Design Wind Speed V ult (mph)Ultimate DesignExposureWind SpeedultUltimate Design Wind Speed V ult (mph)Ultimate Design Wind Speed V ult pGroupAAGroupGroupAAGroupGroup STC40GroupAAGroupGroup ARS250RS250MSTA21MSTA21Group AGroupRS14 roup AGroupAAGroupGroup A30MSTC40MSTC40DR4DR4 5MSTC28MSTC40MSTC28MSTC28DR4DR4 4DRDRMSTC2855MSTC28DR4DR4 4DRDR4 4DRMSTC40MSTC40MSTC40MSTC28MSTC28DR4DR4 4DRGroupAAGroupGroupRS14 pRS150RS150212RS14 AMSTC285MSTC2852 MSTC40MSTC40No. 2 Grade18RS14RS14MSTC40MSTC401) Connector suggestion is based on closest strap to the needed capacity. Geometry should be confirmed.Connectorsuggestionis basedon 1-1/2"closestforstrapthe neededcapacity.should be confirmed.2)1)Minimumnailembedmentshall be16dtoSinkernails and1-1/2"Geometryfor 10d nails.Minimumquantitynail embedmentshall16dequalSinkerfastenersnails andat1-1/2"for of10d3)2)Minimumof fastenersto be 1-1/2"installedforwitheach endthenails.connection.Minimumof fasteners to be installed with equal fasteners at each end of the connection.4)3)DR DesignquantityRequired.DR Design5)4)MSTC28must Required.be installed with 16d nails.MSTC28 Tensionmust be Loadsinstalled16d nails.Southern Pine, Spruce-Pine-Fir and Hem Fir.6)5)Allowablearewithfor Doug-Fir,Loadsare forinDoug-Fir,Pine, Spruce-Pine-Fir and Hem Fir.7)6)4'Allowablepony wallTensionloads areavailablethe 2015 SouthernIRC.7) 4' pony wall loads are available in the 2015 IRC.918169MSTC40GroupAGroup AMSTA36GroupAAGroupGroupRS14 AMSTA36MSTC40MSTC40DRDR4 DRStrap OptionsStrapStrapLSTA18LSTA18LSTA21LSTA21ST18Min LengthMin18"Length(18)10d10d(22)(22) ) 10dST18RS100RS100RS150RS150RS14RS14Group AGroup AFastenersFasteners(14) 10d18"21"21"17-3/4"17-3/4"16"Not in Group ANot in Group A(22) 10d(22) 10d24"24"DR4 4DRDR4 5MSTC285MSTC28DR44DR4DRDR4Portal Frame Construction Options for Concrete or Reinforced Masonry FoundationsCast in Place InstallationRetrofit Epoxy InstallationMin. 3/8 wood structuralpanel with 8d nails at 3"O.C. 2 rows on each side ofvertical leg of portal frameDouble 2 x 4’sor 4x post3500 lb min.capacity tie-downMin. 3/8 wood structuralpanel with 8d nails at 3"O.C. 2 rows on each side ofvertical leg of portal frameDouble 2 x 4’sor 4x posts3500 lb min.capacity tie-downSingle treatedsill platePlate washer(2) STB165/8" x 12" standardanchor bolt(2) 5/8" A36 threaded rod installedwith USP CIA-Gel 7000 EpoxyAcylate with 9" embedment5/8" x 12" standardanchor boltDetail DDetail ECustomer Service & Technical AssistancePhone: 1-800-328-5934 Fax: 1-952-898-8605 Email: [email protected] 2019MiTek-US.comCopyright 2019 MiTek Industries, Inc. All Rights Reserved4#USP999

Technical BulletinIRC Intermittent Bracing MethodsSolutions for Narrow Wall Segments Including Alternate Wall Bracing (AWB)Portalframe with Holdowns (PFH) and Portal Frame at Garage (PFG)Alternate Wall Bracing Methods (IRC Table R602.10.6.1)Panel Length PerTable R602.10.5Method ABW - Alternate Braced Wall Panel Either two holdown or two straps per table R602.10.6.1may be used. (one of each shown in image for clarity)Min 3/8" woodstructural panelsheathing on one face. Can be installed anywhere along a braced wall in1 and 2-story applications adjacent to a window ordoor opening (i.e. garage door) with full length header. A standard holdown with an embedded anchor boltmay be used.Jack studsunder header asrequired.Holdowns fromtable R602.10.6.1(shown below).Min 2x4 framing,Min double studsrequired. Threaded rod with epoxy may be used for retro-fitif foundation is already in place. Masonry foundation must be reinforced and tiedto the footing.8d common or Galv. boxnails @ 6' O.C. at paneledges for single storyand @ 4' O.C. forthe first of 2 stories.Figure 3(2) 1/2" diameter anchor boltslocated between 6" and 12" ofeach end of the segment.TABLE 4MinimumHoldownForcesMethodsAWBBracedBraced WallWall PanelsononTableR602.10.6.1(2015 (2015IRC) BasedTableR602.10.6.1Seismic Design Category / Wind SpeedMiTek-USP Embedded Strap Required2,3Height of Braced Wall PanelSupporting / Story8-ftEmbedded StrapsSDC A, B and CUltimate design wind speed 140 mphSDC D0, D1 and D2Ultimate design wind speed 140 mphSeismic Design Category / Wind SpeedSDC A, B and CUltimate design wind speed 140 mphSDC D0, D1 and D2Ultimate design wind speed 140 mph9-ft10-ft11-ft12-ftOne StoryLSTAD8LSTAD8LSTAD8HPAHD22HPAHD22First of Two StoriesSTAD14STAD14STAD14STAD14STAD14One StoryHPAHD22HPAHD22HPAHD22NP1NP1First of Two StoriesSTAD14HoldownsSTAD14STAD14NP1NP1MiTek-USP Holdown Required2,3,4Height of Braced Wall PanelSupporting / StoryOne D2AFirst of Two StoriesPHD4APHD4APHD4APHD4APHD4AOne StoryPHD2APHD2APHD2ANP1NP1First of Two StoriesPHD4APHD4APHD4A1NP1NP1) NP Not Permitted2) Connectors are based on a corner installation in cracked concrete.3) Allowable tension loads are for Doug-Fir, Southern Pine, Spruce-Pine-Fir and Hem Fir.4) TDX2-TZ may be substituted for PHD2A when a bolted connection is preferred.Customer Service & Technical AssistancePhone: 1-800-328-5934 Fax: 1-952-898-8605 Email: [email protected] 2019MiTek-US.comCopyright 2019 MiTek Industries, Inc. All Rights Reserved5#USP999

Technical BulletinIRC Intermittent Bracing MethodsSolutions for Narrow Wall Segments Including Alternate Wall Bracing (AWB)Portalframe with Holdowns (PFH) and Portal Frame at Garage (PFG)Method PFGPortal frame at garage door openings(IRC Figure R602.106.3)Portal Frame Construction Options forConcrete or Reinforced MasonryFoundationsExtent of header with double portal frames (two braced wall panels)Extent of header with single portal frames(one braced wall panels)2' – 18' Finished width of openingfor single or double portal16"-24" Portal Frame Braced Wall Panel withPony wallHoldowns and a Retro-fit Option Method PFG braced wall panel shall bepermitted on either side of garagedoor openings. Designed for seismic design catagoriesA, B and C. Threaded rod with epoxy may be usedfor retro-fit.Min 3" x 11-1/4" net header. Steel Header is prohibitedIf 1/2" spacer is used, place on back-side of header.Header to jack stud strap installed per IRC Table R602.10.6.4on both sides of opening oppositeside of sheathing (See Table 3).12' Maxtotal wallheight10' MaxheightMin length of panelper table R602.10.5Min. (2) 1/2" diameter anchor boltsinstalled per section R403.1.6 - with3/16" x 2" x 2" plate washerSee Detail EFigure 4Method PFGAnchor bolts persection R403.1.6Connection Options for Portal Frame Narrow-Wall BracingMethod Without Holdowns (Fig. 4)Connector as Called Outin DrawingUSPStock No.Cast-in-PlaceAnchor Boltper R403.1.6Retro-FitOptionAB1212-HDG––Fastener / Installation Schedule1,2Min 7" Embed1/2" Threaded Rod (7" Embed),CIA-GEL 7000 orCIA-GEL 7000C Epoxy1) Minimum nail embedment shall be 1-1/2" for 10d nails.2) Minimum quantity of fasteners to be installed with equal fasteners at each endof the connection.Customer Service & Technical AssistancePhone: 1-800-328-5934 Fax: 1-952-898-8605 Email: [email protected] 2019MiTek-US.comCopyright 2019 MiTek Industries, Inc. All Rights Reserved6#USP999

Historically, proper wall bracing construction per the IRC required a minimum of 4-feet of available wall length. With design trends calling for larger window openings and narrow garage return walls, the wall space available for bracing has been limited. This bulletin outlines braced wall panel options for narrow wall segments (IRC R602.10).