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<br /> BRACING WOOD TRUSSES: �� Dlsfrlbuted by:
<br /> ECOMMEHDATIONS w"'i'�� WOOD TRUSS COUNCIL
<br /> COMMENTARY AHD R OF AMERICA
<br /> pTRUSSPLATE INSTITUTE,INC.,1976 `�'s��
<br /> The des�gn ol wood truse+i�accordance wit�TPI dai�vitw4
<br /> nmmes:
<br /> Howerer carcfully wood Truves are da�gned and fabrioted,all thn 1. Truss members�re initidly straiqht,unilorm in pplt�ttipn,
<br /> is at stake�n the hnal erecuon and Draang of a root or Iloor syztem.It and uniform in desiqn propMies.
<br /> is at this v�ucal stage ot co�strucbon that many ot the really
<br /> ugnihcant design aaumptwn:are either fuIfIII.W or�gnored.If Ignared, 7. Trustes are plane structuwl compon�nu, irntalNd wrtiplly,
<br /> the conseQuenca may rewlt in a colNpse o�the structure,whlch at b.aced ro D�avent Isteral movement,�nd prallel to wcA otf�
<br /> INTRODUCTION best is a wbstan[ial lots ol nme and materials,and wMch at worst could at Ma de�gn spac�rg.
<br /> rey�lt in a loss ol life.
<br /> 3. Truss members are D���ed at pints for M2rmi�vtio�of�xi�l
<br /> In racoqniGon o1 tAe �nhnent sahty of a properly Waced roof The Truss �late Institute "Design Speafiotlons br Ligh[Metal lorcesonly.
<br /> tyrtem,tM aDV+rmt lack of knowledqe ol how,when,aM where to Plate Connected Wood Trussrs"arc recommmAed for the des�gn of 4. Therc rs conunuiry of cMrA memWrs�t pints for d�nrminF
<br /> inMll�dpurit bnting,arM in tfx interes[ot public safety,the Truss mdrvidual wood trones as structural Components only. hon oi moment s�reues.
<br /> Gl�te Inqitute,Inc.,in co�sulUtion wi[h its Component Manufatturers
<br /> Cou�til memberShlO.Ms undaUkm Ihe O�eparaUon o�t�ese remm� Laroral braang,as may be required by Cevgn to reduce Duckling 5. Comprealon members are 4teqlly rettoioed st fpecilic IocF
<br /> rtNrdriions. lenqth of mdmdual truss members,rs a Dart o1 the wood iruss daign tions or mrorvals.
<br /> and is the only bracing t�at will �e spec��ied o� the truss design
<br /> Subsueual concentnted study and deliber�tive review by the TPI d.awings. Lateral braang is ro be wppfied in the siae speufied and 6. Supaimpofed dead or Fve bads xt vMiully,wind Iwd�ar�
<br /> T�chnital Advlsory Committee(tompris��q a membership of[Ae chitl mstalled at the lotauon specd¢d on the truss des�g�drawings by the ap0���d normN to[he D���of tM tOp CAad,�nd Conc�nt�tM
<br /> strucWql engmeers of inember plate manuhcWnng compan�es,reprr builda or erectlon tontractor.The Gwlding dmgner or inspecbr musi bads are�OVGed at a point.
<br /> »nWivss of Ihe andem�c [ommunity, and mdependenl mmulUrg ascer[am thal the sDK����lateral Dracmg is properly mstalled a�d that
<br /> u�qineers)hava Wen devotad to this eHort Conwltauon wrth the TPI thu Eracing rs suH�uently anchored or restra�ned by diagonal b.aung ro 7. In addnion to tha laaral bncinq�pecified by tM nun dsiqw,
<br /> Compon�nt M�nufaaurcrs Council has resulted m brin9ing practiol prevent�ts movement. the building designer will ipecify suHiciwrt Waeinq at rpM
<br /> lield Mndlinq ard erection problems�mto a sharper focu:.Indusion ol angles to the plane of the vuu to hoW avwy trup rrwmEw ie
<br /> Me tenutive nmmmmAitions tor oo-site handling aM erettion Speual design.eqwremmts,such as wmd bracing,portal bracing, tAe position�swmsd tor it in de�ign.
<br /> procadures is ona dirett rewit ol the conwltabo�n. It is planned to ursmic bncing,diaphragms,shear walls,or other load transfer dements 8. The building daigner (not the trus A�fqnw) will
<br /> Rudy furihlr�nd enWrge upo�[hese Ienbtiv!reCommerda�ions. and tAe�r connecvons to the wood trusses muzt be considered � ��h
<br /> teparately by t�e bwlding desiqner. He s�all determine size,lowtlon, wHluent braang and connattions to withriard 4lwal bWiq
<br /> WhiM tA' r�comm�nAat�or. to• �ncing mnbined he.e+� an anE m�tnoA ot connxtiorn �o.dugo�al brac��g as noeded to.esnt o�the eMin svucwre.
<br /> uchniplty tounA,rt is not mtendad that they be cons�dered the onty these torces. Diagonal or cross bracmg is recommended in the plane The theory of b�acmg is to apply wtfiCiMt wpport at riqht�nyNt
<br /> mathod tor Wacin9 a roof system.Neither shouW these recommenda� formad by the top chords,in the plane lo�med by tAe bottom chords �o t�e plane oi the Vuss to hold every trua member in the position
<br /> [ions W ioterOreted as supenor ro or a sUndard tlw[would necasanly and prrpendicular to Ihe Iruss web mem�ers,n needed lor the overall assumed for II in dalgn.Thrs Iheory must ba sppliM at thrw fbpM.
<br /> W pnferrW m lieu ol�n arcninct's or engineer's design for MaNng for stab�llty of the enure structure. Truss bracmg arW connectron detads
<br /> a yrticu4r roof system. should be shown on Ihe building designer's frammg plan as part of tAe STAGE ONE: Dunrg BuAding Dnign�nd T�ua D�fiqn mdnidwl tri.s
<br /> design drawingy.Bracinq mater�als are not uwally furnished as part of inembers sre checked lor buckli
<br /> Thafe recommmdatio�s lor bracing wood trusses wiginate hom the the wood vuss package, and shoul0 be Orovided by the bwlder or ^9.+^4 4teral bncirq if fp¢ifi�d.r
<br /> collectiH ex nence o�leadm tec�mcsl sonnN m tne wood truss aection contractor. repuved for exh truu member.The buildinq deaiqner mutt 1p�ify
<br /> Pe 9 Dr now thls lannl bncirg is ro be�neM1ored w rmtninW to prn�nt
<br /> iadurtry,but must,due to the nature uf responsibilities Vnwlved,be latenl movemmt sAould all truu members,so W�ad,Md to d#M
<br /> pefented only as s yude tor the uu ot a pualifled Duilding designer. The builder o�erxGon contracto.is respon�ible tor wopn wood together as shown in Figure 11bL Thn m�y ba aecomplishM Dy:
<br /> builder,or enction contractor.Tnus,the Truss Plate Insufute e.pressly t�us handling�nd ta Dropn tempwary br�cing. He muft mure that
<br /> d�uldms any responeibiGty�or damaqes ansing from the use,applira� [he woOd trufses are not rtrutturalty d�maped dunng erection and th�t �. q�chwage to tolid end walls(Fiqure 11c11.
<br /> liOn,or rellance oo[he retommenAaUons and mformanon conu�oed [hey are mainbined in alignment before,during,and alter insnllnion.
<br /> hw�in by building designers or by erecGo�contractas. Tempoqry or erection DrKing may follow, but no[ nxesHrily be 4. Diagorul braong in Me plane of web mem0�n(Fiqun l(d11.
<br /> limited�o,the building designer'f ham�ng plan. It if rxommended[�st 3. Other me,ns as determined by the buildinq dqiyrw.
<br /> erectio�brscing be aDPlled p e�ch trufs i�placed in position.
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<br /> MO�E
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<br /> Firn tlbl Fiyur�21b)
<br /> STAGE TWO: During Truss Erection the bwlder or ercctlon tontracror
<br /> It rs recommendeG Mat d�agonal braang(mm�mum 2-�nch thick must take adeVuate precauUons to assure�hat the wood Iruzses are not bratin9 sys[em depends to a gre�t eM[ent on how wdl th�firft trw it
<br /> nominal lumber)be mstalltd al aOVroximately a 45deqree angle ro Ne structurally damaged.Proper nqgmg,mcludmg ihe use of sDieade�Da�s braced.
<br /> 4[e�al b�ace.Ougooal Dracmg should be atUched to tIK opposne s�de and multlple pick-up pomts,where reQu�red, iz neceswry [o prevent .
<br /> of the same member requuing lateral braong. damage dunng hand6ng,tenuuve retommenda�ions are presented in O�e saUsfat[ory met�od it for the fir�t[rua fo0 chord to W bK�d
<br /> roe Append�.hereto to a stake d.iven mto the grouM�M securely aaAored.The yound
<br /> Th1s bncmg may be continuous or mtermrttent at �he build�ng Drace itxll snoulG be wOPo�t�d as�hown in FVqwe I a it i�ipt to
<br /> designa's opUon;however,it is rocommended that mtermittent spatin9 It u most �mportant to b�att t�e hnt vuss at ihe e�C of the buckle.Additional ground bracef,in[he opposite d�ec[ion,iMiM tM
<br /> nOt exceed 20�cet,or iwice the�or�:ontal run o1 the diagonal D�acing. builGing securely. All other trusies are t�ed to the firit truss,thus the building are also recommendeC.
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<br /> The yrourW brxes should De located d�rectly in line with all rows of recommended ihat continuous lateral brac�ng De installed w�th�n 6 e.K � �eaaow•
<br /> to0���d co�bnuous Wteral Draung.ONerw�se,the top chord of Ne ���hes o�the ndge Ime or center line and a�appro:�mately 8�eet Io 10 �° "i0i°"""
<br /> IiM[rua ca�bend zideways and allow the trusses to shdt.Thls sAift, ����^rcrvals between ihe ridge Ime of slopM Iruues or center line o�
<br />� Ipvmer slight, puts a tremendous stram o� all connecUons of the Nat [ruaes and Ne eaves. For dou6le member Vusses this spaung 5°�°e"'"iN; roo no.e
<br /> { bxinq system,i.e.,[he weig�t o�the truaes would then be added to ��`�'een laterals may be mcreased to 12 fee[to 14 feet. Diagonals, .�,� TYOa'M�un�M upb�wtlbsv�ww
<br />� My wind lorce a construttion load such as bundles of plVwood or rool located between the lateral bracing and set at approximately AS dcgree � ' •�""�°"O""�.
<br /> ` f�inqles tendirg to t�p[he trusses ova. angles,�orm the tria�gies required for stab�lity in the Olane of Ihe top - �w.erw�r.
<br /> - c�ord. NOTE� Long spans or�eavy loads may require clour spadng •�swo...wrr
<br /> All nailing ol braung fhould be done w that d the vusses should betwxn lateral bracmg anA closer intervals between diagonals. ��������
<br /> tend to Duckle or t�p, ine nails will �t loeded Iaterally, Tot i� ���
<br /> w����iwa� F�gure 31a) iilustrates temporary braung�n�he plane of the top '-��
<br /> chord for gable trusus.
<br /> It i�not repommmded to nail soDs to the end of the bwlding to . �y� �
<br /> bxe IAe first truss.Thme scabs un break oH or pull out,thus allowing ��P�mble,the con�,nuous lattral braung for the�op chord should �;
<br /> be placed on tne underside ol the top chord so that it w�ll not have to ��� � /�
<br /> a toUl collapfe. be removeG as Ihe I � -
<br /> p ywood decking s applieC.The Irusses are then held
<br /> As I�usset are set in plat4 tAe Dwlder or erectw�contnctor must K��rely even during the decking process- � ���
<br /> � apply sufficient lanporary Drxmg to holE Ne vusxs plumb, in i
<br /> sliqnmsnl and in a sale cooditron untJ the Dermanmt bracmg,decking, h rs equally imponant for the bwlGer or erection contracto� [o �
<br /> �nsiall Gracing in tne plane ol the top chord lor Ilat roo�or floo�
<br /> and/or sheathing un be installed.Temporary bnung should be not less �rusus.T�e uce o�a similar brann atrern n recommerWed�or all flat �
<br />�. Ihan 2x4 dimension lumpp and shou�d be as long as practifvl for ��usses. 7articular attent�on is d�recPted to D�acin at tl+e entl of Ilat Fi �\\
<br /> frntlliry.The u�e ol shwt spacer piecn of lumbr between ad�acmt 9 pun 31b)
<br /> t�usas If not recommanded,unlas used temponrily in preparation(or �russes as shown In Figure 31b1
<br /> immWirte installauon o�lorger co�Unuous braung IB��eet mmimum msulled at the fame louLone specifiad on Ihe archidctur�l pqn fof
<br /> �� krqthl.Temporary bracing IumDer should be naile[1 with two double 2. WW Mambar Vlana. It n also necessary ro insta�l temporarv permanent brac�n a�d ma become
<br /> g, y psrt of[he parmaoeat brKiny.h
<br /> Maded l6d nails at every intersection wrth the braced memDer. braung m the piane o� the web members. This bracmg is usually is recommendcd [nat disgorul braung be added tl qch w�p mMn6w
<br /> reduu�ng mntmuous latenl brsang. II none is fp�clfi�d, it it
<br /> Prtassembly of groups of trusses,on the grourW,into structurally recommended inat n be olaceA at rro grsat�r th�n 16 Iwt iat�rv�b
<br /> Wipd units which sre Ihen Idted mto pWte as assembhes rs an ••"'q'•'^'"0e„°••"��1.^�n�^��•^•.,� along the truss length for roof trusxs arM 8 leet int�rvaM fpr Ilop
<br /> •ccsDbbl��Iterna[e to the ono-atrlime method. �-/—�o•ao„en m...,e..,,,,,,u,Mn,n.���«.� irussm.
<br /> o/ loc��M�v��n�n 6�ncn��o��Aqe i��<
<br /> ��F C�.
<br /> Eiuct fpating between trusm shouid be mainbmed as Gr�ong�s e����,d / a�^ It �s not qenenlly necesyary for diagoMl bxrtq to�un Wntinu-
<br /> intnlled to avoid the husrdout pracbce o�remoa�9 braang ro ad�ust � �' ously for�he lull length of Ihe Dwldirg bu[rt it reoomm�nCW tivt the
<br /> fpacmy as sneatMng Is aDVGed. Th�s act ol"adiusLnq spaung"can � ,/,. ��,°„a,��,�„�� spaung between uts of diaqonal Draunq not e:cNd 70 fett,a twia
<br /> �nuse trusses to top0le d a key wnnecbon n�emoved at tf+e wrong � / / the hor�zomal run ol t�e diagooal bracinq.Rowf of 1K6 stror�qbKki
<br />� [ime. may also be used to D.ace floor trunes wMre d�ponal b�cinp if
<br /> impractical.Fqure<la)dlusvans diaqonal braciny m tM p1aM ol tM�
<br /> Trus bnung mur be aDD���d ro tnree planes of reference in the web memberz: Figure 4�D) illustotes tAe I�tval mpwm�nt tMt m�y}
<br /> ropl syttem to insure sUDd�ty�. 1.Top chord(shwth�ng)plane,2.weD �-�6°°0�°1 occm if lateral bracing n ufed wrthout tliagonal bncinq.
<br /> m�mDer Dl�ne or vertiul pbne perpendicu4r ro trusses,and 3.bottom NprE .a '
<br /> chwd(dihnq)PV^e. `o a w „,u �oo-o.,m«�s �e,X� 3. Bottom CApd Pbro. In ord�r m hoW �
<br /> propw tp�tinp on tM
<br /> �..��"�����, wi.,«,ia.�;Ao..� Dottom chord.temporary bracing it recommmdW�n tM pl�r»ol th�
<br /> 1. Top CAord V4n�. Most imporunt m ehe budder or necno� , ,,,,,,,o,,,,,,, ��TO°`"°'°�` Dottom chord.Cont�nuous Ineral Dncmq at no prwnr than E Mt to
<br /> mn[nctor if Dracirg in the plane o}the top c�o�d.Truu top c�ords ue ' �T•oK�^�"�^0 10 fee[on centers along the truss I�ngtA u�eepmmeMM fyli NrqtA pf
<br /> wcptibN to luenl buckhng pefore tAey are b�aad or sheathed.It n F'Wn 31+) �ne bwld�ng,nailed to t�e ro0 a+Me Dottom cAord.Diaporwl Eneirp
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