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35-269 (10) r C 0.gorul Draciry-repeal a,+pp�o+nnateiY 0.+gonYS form bscetl D+V al spproa�mstYV 20 tee,mlwvsia.n lergln o1 Duiltlnp. 201+e,intervals:rpsl al boln eM. asa.a a�agon.i ,. of lne web manMrs, 1 1 ( ( 1 n .I 1 ui loo cnwm weve 1.at« ' morwnen,. _� nbnuous lour+)Drsnng a"buckle space.121ee,,o I6 lo[atM tl•agorul,pse,d, ( no n Ica,on teener ,' ppml. b.cvey. N6° across Du ltl�ng • •' br cools. I ...I ' ' / / spat,:8 stet on cen,er RMge line .-. Roos purl�n j �. Figure 41e1 :' eonom cnord pl p°sae, � � ' aroK,n nywc.n � I Truun hywcsll _45° " �' T''•' -�' "' Con,nuous lasers - 4 \ I I'�` 11 II II� Il b,nn9 m+nuna I I _ I I 11 1 1 II I I wc„e,ip ml�ermlu ' I II I I I 1 I II� Inarally. Top chortle can W kle dnwle llixiv nt purlins' I 1 I I I I Figure Will Figure 5 Permanent bracing must provide sufficient support at right angles to the plane of the truss to hold every truss member in the position should be placed on the trusses in any one area;they should be spread assumed for it in design. In addition, permanent bracing must be Fi nly over a large area so as to avoid overloading any one truss.All designed to resist lateral forces imposed on the completed building by fN re 416) out eve mechanical equipment should be located only on the trusses specifically wind or seismic forces. between laterals placed at approximately 45 degrees is recommended designed to support it.It should not be dropped or even set temporarily for stability of the bottom chord.Diagonal bracing in the plane of the in any other area unless the trusses are adequately shored.All floor Permanent bracing may be subdivided into three logical compo. bottom chord is generally not required throughout the length of the trusses should be adequately shored if pallets of masonry materials are nents: building,but it is recommended that it be located at least at each end to be stored temporarily until the next higher walls are finished. 1. Top Chord Plana. This bracing is designed to resist lateral of the building. In most cases,temporary bracing in the plane of the bottom chord is installed at the locations specified on the architectural STAGE THREE: Permanent Bracing is designed and specified by the movement of the top chord. If plywood floor roof ,aathua conting is for permanent bracing,and is,therefore,left in place as permanent architect or engineer for the structural safety of the building.It is the properly applied with staggered joints and adequate a nailing, bracing. Figure 5 illustrates bracing in the plane of the bottom chord. responsibility of the building designer to indicate size, location,and ous diaphragm action is developed and additional bracing in the plane is attachments for all permanent bracing as required by design analysis.In generally not required. Full bundles of plywood should not be placed on trusses.This general, it is desirable to design and locate all bracing so that it may ooratruction load should be limited to 8 sheets of plywood on any pair work together with other structural parts of the building(such as shear Some metal roofing materials may depended u to act as of trusses and should be located adjacent to the supports.No excess walls, portal frames, bearing walls,columns,beams,etc.)to achieve diaphragm when properly lapped and nailed.Selection anred d use of these concentration of any construction materials(such as gravel or shingles) total structural integrity. materials is at the discretion of the building designer. 10 11 12 Diagonals Iorm bacad Day.Repes,a1 both length of a web member. As described earlier in the discussion of ends am e,aop.o.�maero 20 building design and truss design(STAGE ONE),diagonal bracing or end anchorage is essential to stabilize the lateral bracing. Duaon0 bating Diagonal bracing in the plane of the web members is also used to +aatl,o uMer a�ee of,op—1d distribute unequal loading to adjacent trusses and to spread lateral n ,eql forces to diaphragmso(shear walls.Spacing of rows of diagonal bracing n1OVe"1e"'°"°p in the plane of the webs is a matter of judgment to be made by the cnord building designer,and will depend upon the truss span,truss configura- tion,type of building,and the loading. ., Generally,for roof trusses,the spacing ranges from 12 feet to 16 APPENDIX feet depending upon how it relates to the bracing in the plane of the Rbpa Ime top chord.For floor trusses the cross bracing should be approximately 8 feet on centers.Lateral 2x6 strong-backs may also be used for some It is intended that this appendix contain only tentative recort floor systems. mendations that may be used as a guide for on-site handling anc erection until a more complete statement can be prepared.There may Figure 1 and Figure 4 illustrate bracing in the plane of the webs. be some instances in which additional precautions will be necessary. - Top more brp�wl 3. Bottom Chord Plane. This bracing is required to maintain the UNLOADING. If possible, trusses shall be unloaded on relatively pwlma rommuom truss design spacing and to provide lateral support to the bottom chord smooth ground. They shall not be unloaded on rough terrain that -•. to resist buckling forces in the event of reversal of stress due to wind would cause undue lateral strain that might result in distortion of truss uplift or unequal roof or floor loadings. joints. Dumping of trusses is an acceptable practice provided that the trusses are not damaged or excessively stressed in the act of dumping. For multiple bearing trusses or cantilever conditions,portions of the bottom chord become compression members and should be braced The builder shall provide protection from damage that may be laterally to resist buckling in the same manner as the top chord of caused by on-site construction activity. Figure 6(b) simple span trusses. STORAGE. Care shall be taken so as not to allow excessive bending of Bracing in the plane of the bottom chord is also designed to transfer trusses or to allow tipping or toppling while the trusses are banded o1 If purlins are used,spaced not to exceed the buckling length of the lateral forces due to wind or seismic loads into side walls,shear walls or when the banding is removed. top chord, and adequately attached to the top chord, it is recom. other resisting structural elements. Diagonals between continuous mended that diagonal bracing be applied to the underside of the top lateral bracing serve to stabilize the bottom chord.It is recommended If trusses fabricated with fire retardant treated wood must be store) chord to prevent lateral shifting of the purlins. that one complete bay of diagonal bracing be installed at each end of prior to erection,they should be stored in a vertical position to preven Figure 6(0 illustrates the necessity for applying diagonal bracing in any building,and additional such bays be located at specified intervals water containing chemicals leached from the wood from standing o not to exceed 20 feet. Figure 5 illustrates the use of bracing in the the plates.A further precaution may be taken by providing a cover It the plane of the top chord despite the use of closely spaced purlins. plane of the bottom chord. the trusses that will prevent moisture from coming in direct conta. It is recommended that this diagonal bracing,as shown in Figure with the trusses and which can be ventilated to prevent condensatio 6(b be be installed on both sides of the ridge line in all end bays.If the These recommendations for bracing wood trusses have been derived building exceeds 60 feet in length,this bracing should be repeated at from the collective experience of leading technical personnel in the ERECTING TRUSSES. The truss erector or builder shall take tl intervals no greater than 20 feet. wood truss industry but must, due to the nature of responsibilities necessary precautions to insure that handling and erection procedure involved,be presented only as a guide for the use of a qualified building do not reduce the load-carrying capacity of the truss. 2.Web Member Plane. The purpose of this bracing is to hold the designer,builder,or erection contractor. trusses in a vertical position and to maintain the design spacing. In Truces shall be installed plumb,at specified spacing and in-plat addition,this lateral bracing may be required to shorten the buckling (i.e.,trusses will be properly aligned). 13 14 15 fV1sp.e,der er I 14----Aprro.im ', 2131°311°I reuse Ierp,n -P Tgnne �VAV/ V V/A/1 V/ Irk -7-Z �ADp•omusaly ll2,°2/J� ruu engln Taglme 2 tayine I I Sp.eatler W. I I E4----Approann+l+ly 21310 3/a of truta ie ryth—►� II Tp�n I�.AOpro,lma„Ir 1/?,.213 Figure A(3) of vmalergm T,gllne For lifting trusses with spans in excess of 60 feet,it is recom- mended that a strong-back be used as illustrated in Figure A(3).The Figure Al2)• strong-back should be attached to the top chord and web members at T.— intervals of approximately 10 feet.Further,the strong-backs should be Figure All) For truss spans between 30 feet and 60 feet a suggested lifting at or above the mid.height of the truss so as to prevent overturning.The procedure is shown in Figure AM. It should be noted that the lines strong-back can be of any material with sufficient strength to safely A suggested procedure for lifting trusses is illustrated in Figure All) from the ends of the spreader bar "toe-in." If these lines should carry the weight of the truss and sufficient rigidity to adequately resist if the truss span does not exceed 30 feet. "toe-out,"they will tend to cause buckling of the truss. bending of the truss. 16 17 18 _/ 9 LL, 1 BRACING WOOD TRUSSES: TRUSS PLATE INSTITUTi 583 COMMENTARY AND RECOMMENDATIONS _ Ma o nofrio Drive, suite 2 00 Madi son, WI /53719( _f ©TRUSS PLATE INSTITUTE,INC.,1976 The design of wood trusses in accordance with TPI design criteria assumes: However carefully wood trusses are designed and fabricated,all this 1. Truss members are initially straight,uniform in cross section, is at stake in the final erection and bracing of a roof or floor system.It and uniform in design properties. is at this critical stage of construction that many of the really significant design assumptions are either fulfilled or ignored.If ignored, 2. Trusses are plane structural components, installed vertica lly, INTRODUCTION the consequences may result in a collapse of the structure,which at braced to prevent lateral movement,and parallel to each other best is a substantial loss of time and materials,and which at worst could at the design spacing. result in a loss of life. 3. Truss members are pinned at joints for determination of axial In recognition of the inherent safety of a properly braced roof The Truss Plate Institute "Design Specifications for Light Metal forces only. system,the apparent lack of knowledge of how,when,and where to Plate Connected Wood Trusses"are recommended for the design of install adequate bracing,and in the interest of public safety,the Truss individual wood trusses as structural components only. 4. There is continuity of chord members at pints for determine- Plate Institute,Inc.,in consultation with its Component Manufacturers tion of moment stresses. Council membership,has undertaken the preparation of these recom- Lateral bracing,as may be required by design to reduce buckling 5. Compression members are laterally restrained at specific loca- mendations. length of individual truss members,is a part of the wood truss design tions or intervals. and is the only bracing that will be specified on the truss design Substantial concentrated study and deliberative review by the TPI drawings. Lateral bracing is to be supplied in the size specified and 6. Superimposed dead or live loads act vertically,wind loads are Technical Advisory Committee(comprising a membership of the chief installed at the location specified on the truss design drawings by the applied normal to the plane of the top chord,and concentrated structural engineers of member plate manufacturing companies,repre builder or erection contractor.The building designer or inspector must bads are applied at a point. eentatives of the academic community, and independent consulting ascertain that the specified lateral bracing is properly installed and that engineers)have been devoted to this effort.Consultation with the TPI this bracing is sufficiently anchored or restrained by diagonal bracing to 7. In addition to the lateral bracing specified by the truss designer, Component Manufacturers Council has resulted in bringing,practical prevent its movement. the building designer will specify sufficient bracing at right field handling and erection problems into a sharper focus.Inclusion of angles to the plane of the truss to hold every truss member in the tentative recommendations for on-site handling and erection Special design requirements,such as wind bracing,portal bracing, the position assumed for it in design. procedures is one direct result of the consultations. It is planned to seismic bracing,diaphragms,shear walls,or other load transfer elements 8. The building designer (not the truss designer) specify study further and enlarge upon these tentative recommendations. and their connections to the wood trusses most be considered g ) will I} separately by the building designer. He shall determine size,location, sufficient bracing and connections to withstand lateral loading While the recommendations for bracing contained herein are and method of connections for diagonal bracing as needed to resist of the entire structure. technically sound,it is not intended that they be considered the only these forces.Diagonal or cross bracing is recommended in the plane The theory of bracing is to apply sufficient support at right angles method for bracing a roof system.Neither should these recommenda formed by the top chords,in the plane formed by the bottom chords to the plane of the truss to hold ever tions be interpreted as superior to or a standard that would necessarily and perpendicular to the truss web members,as needed for the overall y truss member in the position be preferred in lieu of an architect's or engineer's design for bracing for stability of the entire structure.Truss bracing and connection details assumed for it in design.This theory must be applied at three stages. a particular roof system. should be shown on the building designer's framing plan as part of the STAGE ONE: During Building Design and Truss Design individual truss design drawings.Bracing materials are not usually furnished as part of These recommendations for bracing wood trusses originate from the the wood truss package, and should be provided by the builder or members are checked for buckling,and lateral bracing is specified as collective experience of leading technical personnel in the wood truss erection contractor. required for each truss member.The building designer must specify industry,but must,due to the nature of responsibilities involved,be how this lateral bracing is to be anchored or restrained to prevent presented only as a guide for the use of a qualified building designer, The builder or erection contractor is responsible for proper wood lateral movement should all truss members,so braced,tend to buckle builder,or erection contractor.Thus,the Truss Plate Institute expressly truss handling and for proper temporary bracing. He must assure that together as shown in Figure 1(b).This may be accomplished by: disclaims any responsibility for damages arising from the use,applica- the wood trusses are not structurally damaged during erection and that tion,or reliance on the recommendations and information contained they are maintained in alignment[vefore,daring,and after installation. 1. Anchorage to solid end walls(Figure l 1c)). herein by building designers or by erection contractors. Temporary or erection bracing may follow, but not necessarily be 2. Diagonal bracing in the plane of web memben(Figure I ld)l. limited to,the building designers framing plan. It is recommended that erection bracing be applied as each truss is placed in position. 3. Other means as determined by the building designer. 2 3 6Dnlnup cone F pure Ildl— bumg surpuerM NOTE: Ipdrl of Dues deuenl. Locale pdo.brae«f«tun lru. gncnwap,Ibv buud,rp di •F--F,gures I IDI q I lc dng-nr•r into soled.al M top—d onnu I—.W.., o,a to oednry or wane,0. - bat-ng yrDerebv Prevemmg web buckling. Connnuous la,eral bacim. Diagonal bracing j � Comprapon care Figure 11a1 Ll finu,Dmq eeu,ng Figure 1(c) cPmp.e,.nn w.m: Figure Val 1 1 t buckling. Grouts dace F,nt our to be well ar. 11 11 1 Com web-sloping bolo eclwn of eddillorW I I I I I or ve.,�cn units. Con,nuous lawn Dncng 1 ma mains sPac ng Dul laterel ,q j I I Pe m rs lateral puck ing Connnupus arena Dace 8rx Ip trun•a 11 1 11 of."web members a, Verta•I I / / m I I r .•5' Go—stakes ll D,ponal brace nauetl,o ll oPPOPI e ude of web p.eaems ll ,n0 mould ll peeepe.tee•,apProa,marely zo In,me,vals. �l/ Cal�ng li If Q 8,.­9 ror,russa Figure l(d) EM dreporyN,o erou.a•k« Figure 1(b) Figure 2(b) STAGE TWO: During Truss Erection the builder or erection contractor It is recommended that diagonal bracing(minimum 2-inch thick must take adequate precautions to assure that the wood trusses are not bracing system depends to a great extent on how well the first truss is nominal lumber)be installed at approximately a 45 degree angle to the structurally damaged.Proper rigging,including the use of spreader bars braced. lateral brace.Diagonal bracing should be attached to the opposite side and multiple pick-up points,where required,Is necessary to prevent of the same member requiring lateral bracing, damage during handling;tentative recommendations are presented in One satisfactory method is for the first truss top chord to be braced the Appendix hereto. to a stake driven into the ground and securely anchored.The ground This bracing may be continuous or intermittent at the building brace itself should be supported as shown in Figure 2 or it is apt to designer's option;however,it is recommended that intermittent spacing It is most Important to brace the first truss at the end of the buckle.Additional ground braces,in the opposite direction,inside the not exceed 20 feet,or twice the horizontal run of the diagonal bracing, building securely.All other trusses are tied to the first truss,thus the building are also recommended. 4 5 6 The ground braces should be located directly in line with all rows of recommended that continuous lateral bracing be installed within 6 2-I61 dovme top chord continuous lateral bracing.Otherwise,the top chord of the inches of the ridge line or center line and at approximately 8 feet to 10 slang nia°'d"+'I' first truss can bend sideways and allow the trusses to shift.This shift, feet intervals between the ridge line of sloped trusses or center line of flat trusses and the eaves. For double member trusses this s sP+rng samr,a Top e"md brace however slight, puts a tremendous strain on all connections of the pacing ,g,mr bracing system,i.e.,the weight of the trusses would then be added to between laterals may be increased to 12 feet to 14 feet. Diagonals, rvpaal n,�lmg any wind force or construction load such as bundles of plywood or roof located between the lateral bracing and set at approximately 45 degree shingles tending to tip the trusses over. angles,form the triangles required for stability in the plane of the top n.p.a dieeonrF chord.NOTE: Long spans or heavy loads may require closer spacing +r app.penn•IMr All nailing of bracing should be done so that if the trusses should between lateral bracing and closer intervals between diagonals* tend to buckle or tip, the nails will be loaded laterally, not in withdrawal. Figure 3(a) illustrates temporary bracing in the plane of the top chord for gable trusses. I It is not recommended to nail scabs to the end of the building to 46' brace the first truss.These scabs can break off or pull out,thus allowing If possible,the continuous lateral bracing for the top chord should be placed on the underside of the to chord so that it will not have to a total collapse. P se removed as the plywood decking applied The trusses are then held �,�� 5 As trusses are set In place,the builder or erection contractor must securely even during the decking process. apply sufficient temporary bracing to hold the trusses plumb, in It is equally important for the builder or erection contractor to alignment and in a safeyondition until the permanent bracing,decking, and/or sheathing can be installed.Temporary bracing should be not less install bracing in the plane of the top chord for flat roof or floor \` than 2x4 dimension lumber and should be as long as practical for trusses.The use of a similar bracing pattern is recommended for all flat handling.The use of short spacer pieces of lumber between adjacent trusses. Particular attention is directed to bracing at the end of flat Figure 31b1 trusses is no[recommended,unless used temporarily in preparation for trusses as shown in Figure 3(b). immediate installation of longer continuous bracing(8-feet minimum installed at the same locations specified on the architectural plan for length).Temporary bracing lumber should be nailed with two double 2.Web Member Plane. It is also necessary to install temporary permanent bracing,and may become part of the permanent bracing.It headed 16d nails at every intersection with the braced member, bracing in the plane of the web members. This bracing is usually is recommended that diagonal bracing be added at each web member requiring continuous lateral bracing. If none is specified, it is Pre-assembly of groups of trusses,on the ground,into structurally recommended that it be placed at no greater then 16 feet intervals braced units which are then lifted into lace as assemblies is an FPr angle membr.vPasu vz,nrn,m�knrsl P along the truss length for roof trusses and 8 fee[intervals for floor acceptable alternate to the one-at-a time method. �—For rouble mrmbr,,,,,a la min,meknaso trusses. loca,M w�ln,n 6�ncnes of r�tlge line Exact spacing between trusses should be maintained as bracing is ¢`�`�e%t It is not generally necessary for diagonal bracing to run continu- gona,v installed to avoid the hazardous practice of removing bracing to adjust ,1r .aggro:..1, ously for the full length of the building but it is recommended that the spacing as sheathing is applied. This act of"adjusting spacing"can / zo tl: spacing between sets of diagonal bracing not exceed 20 feet,or twice cause trusses to topple if a key connection is removed at the wrong � / the horizontal run of the diagonal bracing.Rows of 2x6 strong-backs time. may also be used to brace floor trusses where diagonal bracing is impractical.Figure 4(al illustrates diagonal bracing in the plane of the Truss bracing must be applied to three planes of reference in the web members;Figure 4(b) illustrates the lateral movement that may 16a do ^- uble root system to insure stability: 1.Top chord(sheathing)plane,2.web crab n•lc occur if lateral bracing is used without diagonal bracing. member plane or vertical plane perpendicular to tresses,and 3.bottom NOTE. Appro.�manly ,,[[ chord(ceiling)plane. long.can r.vaua ss a"°'"g 3. Bottom Chord Plane. In order to hold proper spacing on the may.egPnr=lo«. bottom chord,temporary bracing is recommended in the lane of the pxmg. Lap bm.al Draong ova .'Top cnma p 1. Top Chord Plane, Most important to the builder or erection a ,I leao,coo LUaaea �� bottom chord.Continuous lateral bracing at no greater than 8 feet to contractor is bracing in the plane of the top chord.Truss top chords are Tvpx•I nal„e 10 feet on centers along the truss length is recommended full length of susceptible to lateral buckling before they are braced or sheathed.It is Figure 3(a) the building,nailed to the top of the bottom chord.Diagonal bracing 7 8 9 Vale 1 11-e6-19ng _ Span 1 �8-8 QUR1111�Y IF� ,,iV._11yt�hl �:,�aL t�_6'r.f,usra Yt,4 K..ti,...� ArA•Ai.�rArtrtrtr*sRlfarrrarresats::�rrN•irr iAili�rrrrrrrrlosses Igo ION rttArr/t S_1L al• •-M %---�--------.... . M 11,JiFS1 r 1- Continuous bteting tO be 7Xb. COntisrtMa ► 4►.� ---_-_ .--- sa"ucwam'.�s.►°.+u►"' ''' ►•��1�— U!`.:: i'wninu enchor 'at 3-- 16d Hells. ' • In'-a" p.e• IM�+1• 2- Fnr opens ornr 1U -0 add extra continuous bracing ettnched to vertical veb members to Satisfy maximum 10'-0" o.c, "pacing. Gontlnuou/ '--- = 2XA bracing cony be tepleced by continuous I'll" bracing �ont� 6111811q to be ptavidsd at continuana btieing ands and in between (not to exceed 19`-U" a.Ct) and shall be 1K3 minimum with J-6-d nails At Inch end. bridiing at enda of 41(6 continuous btecing btidet�iq �•-• _ ' Piny be omitted It 2xd In attached to wall at iq a.e• ti�tt�ln/d by at11lr means.:, . •• ht'16tidging • �Y rlJlN yl�N� not to scale • �, 10'-0" 1111x. atdndard penell 13 tnchan pop"nine 1� 24 Inchle 1'AI(11A1, f ot e 7Xb Cents brSctng' • .n to "vale •. . z 4 13 7 tI • t st 11 i I t f 14 113, , lU -U Max �IU -0' max _ 1 30 29 29 21 26 23� A 23 22 21 20 111 19 t 1 ld , Z 3 4 13 f 7 0. 1 19 17 18 is 14 1 1>t • ttt•trtArAtrttrsrrssstttttA/Arssrrttttt left/t!■///rrftfa**rrtlrrA■ttAAAA1/I/I�,I LOApINc) IP6F 1 11141AX OF_MMIDA 111111111!11) OWE OF t,UJIUM 6ni1� � 50 DRIM111UbAlib DRAM OU HAgt`IUItUI�•� 110.2 I<d IF , I in,ilia.1 1 lIM-IPUG . V-1dc.11�EZ�1211��-1 . PAC1119 1 = In Give . . Iq. OF IIEIIBE 1• MATES ARTS MIAK-Kq Np1,110b4140 U11e1ON--349 511PAR-242 VIANUFACTIIRED t'ROII A9111 A 116 ORD A GALVANIZED SIE.EL• (EXCEPT AS SHOWN). PLATES IIIIST DE 1119TALlYn ON D()1II FACES OF JOIHIS, SY11E1RICALLY (EXCEPT AS SHOWN) DESIGN COHFORIIS NI'F11 1199 DESIGH SPECS Min UDC-PCC B0. BRACIN011111S DSCH 1S FOR 1RUSS FAHRICATIUN ONLY, FOR PERMANENT AND 7EIIVORARY BRACING (WHICH IS A1.11AYS REND) CON:jIi1.T DI.m. ARCIILTECT OR ENGINEER. - bear barren, r • ,On my J< tter of December 30 1996, I ixplained the 'tequltemente.of 0 strongbacke on floor trues syeteme. , Theeg 'strongbecks ere supposed to be braced, to avoid the lite"rei r,oremtnt ' n of the 'system in the some dirtction,by "X" btecing them an shown on the 6 r�4► �� �1'.� ,,,,•'_ attached drawing. Ile of qqA it .��NGIM�Cttitl�� . 4��tt ORATION (<letttue Ghdet (bAelpned Ir+611rpoil load IrotH USE LONG FLOOR flot7tue—Inlet inedlal► end I1earing condlllon T'Rl1SS HANGERS 1 G y USI, SHORT FLOOR TRUSS \l IIAIIGER OR TOP CIIOI?p BEARING DOUBLEI11"i 113ER i loin wllh A•91n cllln for @11111(311 al 2' 11't,r, Ihroughoul 111P chutde and 4'-0'o.c.lhtouyhmwl bollotd thotde as eltoan. REQUIRED FOR ALL FiUI;I'I 1'1,Y GIRDERM MANUFACTURERS OF HOOF i FLOOR TRUSS SYSTEMS 181 Goodwin Slreel P.O. Box 2l Inden Ordtutd, Meef. 0115) Tel. 113541-1298 C, ��h1�� ��ill�� 8'1au11c11AcK BRAC111a iii urtflrION V ._ btrongbacks, 2x6 minimum,nitould be securely Inakehed to a vertical member with ;1 16d nnils on all IAN Joist used for floors, Fo1 ' span8 below 20 fp.►t,one row of atronglincking at thh centerline is su!ficiento <{ For longer spnns,install ntrongbacking on 6 io ll C foot centers. Mocking behind tits vertical i,, reca- mmended while nailing the tron back in plac", Strongbeck lumber hhould 4 at least 14 lest is length and lapped 2 feet mt their ends, nUU 11R[UG 111(3 I:ontinttous class end/or ho'rize,ttal bridging between trusses shall. be provided nt spacings of approximately 10 feet for floors and 16 feet fee roofs. Cross bridging shall be minim m rf lx3's with two I1d halls ear-it end. 110r170nt0l bridging 1111811 be minimum 2x6 stiongbacks _ (on edge) attached to each truss with three Aod "ells. Strongbarks shell be rttaehed to wells, et th6tr outer ends or restrained by tAhbr menna, All trusses taunt be Internally braced to prevent buckling and/or overturning due to lateral forcen, MAIIUFACIU"Ens OF noof 0 FLOM InUSS 8vS1EMS Ill ODOM" abed P.O.DOx It Indian UMISMA Mein.01151 '114. 411941-1296 FEBRUARY 22, 1989 Metal Clips Delp Control Ceilin g o i Flt J Separation By David J.Conville,BSME,P.E. when uplift occurs, the fasteners at the President,Prest-on Co. Hot Springs,AR Crass carry the cantilevered load of the �1 \. /BEFORE gypsum and insulation. The resulting t- l • / Ua. T- A combination of sheet metal drywall downward pressure usually creates polls �Il L1rt I�•'' �.':}.L clips and a modified nailing technique can P y P P I I"Ill^I et or sags along the truss bottom. J help control ceiling partition separation •c__ - igstructures framed with wood trusses. Figure 3 illustrates the use of 22 ga. M _ - —- 7 steel clips as a backup."The clips are press- I Olin Research has shown that truss mane- u'I ed onto the gypsum board edges at 24"In- V'epa'raden r�-- facturers cannot reduce the phenomenon Ietvals before it is lifted to the ceiling. IcPS> by changing production techniques,web After a visual inspection of the camber configuration,lumber grade or species or dimension (i.e. the distance between the any other variable under their control. top of the wall and the bottom of the truss Corner drywall fasteners can reduce, chord)the drywall installer nails orscrews 14 guile 4 and in most cases eliminate, drywall BEFORE practicesjust don't work when ceilingpu•- cracks, blemishes or deformities when - UPLIFT tition separation occurs. Figure 4 il- properly applied in roof and floor truss in- '"°°'°"°^ stallations. --- lustrates how fastening the ceiling sheet to Installation Problem #1:Truss AFTr.R file truss next to the partition will resin! in UPLIFT destruction of the taped joint in an uplift Parallel to Wall or Partition - Load r 1\ r situation. In certain northern climai s, The builder cannot compensate for gaps as hr a as 1"can open. the ever-present concave truss camber ;� �• �-k �•_ f, P < g p A better approach would be to"Ir e- whenusingconventionalbaek-tiplumber. Truss last" eners float" the ceiling board. (Again check Any uplift phenomenon will only ag- r,- with the local building inspector.)A rnin- gravate the problem. Figure 1 illustrates _`_ r•I Stress point why wood backers don't work well with imam interval of 1Ggbetween the p<I ri- ' �t lion and the first row of truss fasteners trusses. Fil�iic 2 must be maintained. The sidewali stl yet Truss member (fie clip to the top plate with the proper edvl�dood).,. extension. Although this sounds compli- 1 E cited at first it quickly becomes routine. I �Inrtlal camber AFTER _The ceiling is now Ievet with the truss iln(1 UPLIFT Ihltlsl timber k the side wall panel can be installed. 7'he -- _ -ceiling is unstressed before uplift,as op-posed to Figure 1,where the installaton na°) was in trouble from the start.When uplift occurs,the clips continue I `" to share the weight of the wallboard and I insulation equally with the fasteners ni- -1- c Cached to the truss.Most importantly,the Figure I clip will flex or bend slightly to minimize Figure 5 The ceiling wall board is initially _��_ BEFORE will support the ceiling panel at the c lbe. stressed by the sharp edge of the overlap- I lowever, when uplift occurs the , ro- ping nailer.T he bend in file drywall to ac- steel clip UPLIFT 1 commodate the camber places stress on `^ tilevered piece places all the load on the first row of fasteners in the truss, v.ltile the fastening method used to attach the s• —,i AFTER pulling apart the corner joint. panel to the truss. Hence, uplift will K-'r UPLIFT Sleet clips provide the best engine red separate the gypsum board from the truss s° r { , at its weakest point. When the truss 01p1e%e' �' �' f solution. Spaced between trusses an I at- returns,fastener"pop"is likely to occur. / ;�- � �- tached to the top plate of the partition, Figure 2 illustrates the"free-floating" 1r�-r'\/ they easily compensate for camber c,f as k\— �',I tSharedload much as 1-1/4" (see Figure 5). V,hen approach. (Some loci! building codes r prohibit this method because of fire,shear r` �i:j uplift happens, the ceiling remains up- and strength considerations. Check with ported by the clips and the first ro of Figurr 3 truss fasteners,located 16'away frou 1 the your local municipality or inspector.) wall/ceiling Dint.Se aration is rave fled This method is better than fixed stress on the truss fasteners while holding g J P P wooden nailers because the camber is the ceiling panel tight against the sidewali because the;clips secure the drywall v,the tracked by pushing up on the side wall sheet. "this reduces stress on the taped top Plate and flex upward to place viini- sheet to level the ceiling sheet.however, joint and dramatically reduces corner mum stress on the panel. cracks. We suggest that the drywall in- Steel clips are recognized by 13('('A, I David J.Conville,president ofPrest-on Co.,has staller refrain from nailing the sidewall CABO,ICBO,SBCCI,CMHC,NA 1113, been associated with the constriction industry sheet to the top plate,instead leaving an FmHA and FfiA. Clips may be use I on for more tha+r 30 years.Nis fasteners have bcen 8"downward interval so the clip can hand- shear and fire walls and ceilings,wi,h up tested and witnessed by amnnbero independent to 2-hoar ratings. Prest-on Co. clip; are 1 !" p le minute Durward movements. g I research fruits and Tvcre first fic/d-tested ivith Installation Problem#2:Truss available at most drywall supply outl�is or tnissesinhontesondapartmcnts it,Illinois,blin- through Gold Bond Building Products Perpendicular to Wall or PartltIon nesota and Canada dwing 1979/82 Since t/rwr, P Co.representatives. j more Ilion 125 million clips have bcen success- Conventional drywall attachment For more information Circle No.5". I+ filly installed 26 Automated Builder December 1'188 TR Li 181 Goodwin Street SCHED.SHIP DATE I PAGE NO.I WOR";�p P.O.Box 51027 WEEK OF No CANCELLATION DATE CUSTNO. Indian Orchard,MA 0 1151 1 12/1' 4 1 BE �1�..���. _11.x.► Telephone: BROTHERS BISBEE P. O. DI 1 78 TURKEY HILL ` fir CHESTERFIELD, MA 01012 r ra FLORENCE, DESCRIPTION QUANTITY QUANTITY QUANTITY ORDERED BACK ORD. SHIPPED . . Ire-te`t ,; < ; PARTIAL SCIS • r, W/4' -0" CANT. ONE SIDE-2X6 WALLS 7 Al Oqvr+ �.= ti r s Orr-' il ILA it L.V �► +4 V fid S v kv, •`' /y h /y— 16 A �AR �Jn•j -1 lK�� �yv ..i/ t DECEMBER 15, 1989 TO OUR CUSTOMERS: In as much as ceiling seperation is not a common occurence, it does happen. In order to take precautions, STUD CLAW has devised a backing system for sheet rock. You may want to refer this information to your contractors. IM Sw a SPECIFICATIONS: Stud ChAW DUAIL3 I. Trusses shall be manufactured with kiln dried lumber wllh a • moisture content not to exceed 19%. Deliver trusses close to — i Installation time and protect from wet ground contact at site. WARNING: (Brief rain welting does not penetrate kiln drled trusses sEnton TRUSSES .Y EX. 1 lEmon wAUS oNEr. _ �10�'�to`• 2. All trusses shall be securely fastened to exterior walls b toe- lnusn[s MUST FLOAT IRA nailing or appropriate steel brackets. y OVER INTERIOR r'An"no"s•DO NOT TOE 3. Interior partitions shall be secured at each truss Intersection NIT with STUD CLAW 18Ga.Steel Trus-Floal-R Brackets,Installed In —G+�-F{ t-R accordance with manufacturers Instructions: Screw toiiate A. Butt self-centering Trus-Flost-R Brackets against aligned CX I -RIOR stud truss ctlord and nail to lop plate with two 8d(21/4)nails. WALL IV B. Depress truss to contact top plate and nail 8d(21/ I through plastic slider of arrow location. IN I I_IZIOIZ C. Allow truss and plasll6 slider to float to original position. �AR I I I IONS ro UPLIFT IS NORMAL RL e� AV-)- 4. Gypsum drywall backing shall be provided with STUD CLAW �� 13Ga. steel wire Gyp-Floal-R Clips Installed In accordance with Tius-Moat K manufacturers Instructions: _ A. Space Gyp-Floal-R Clips 24"(600mm)along all ceiling (iI rc Screw plates(1st b 2nd floor),but never more than 4"(10omm) 8d tlaif from corners or wall Intersections. a• Tiuss Clx,+d y .. B. Space Gyp•Flost-R Clips 16"(400mm)along vertical corner studs where drywall backing Is normally required. - C. Provide additional Gyp•Floal-R Clips 4"(100mm) from 4—11 OAT DISTANCE—► - I wallboard panel joints. �5� 6oa+d] N�+Is F- 1 I6" 10omm 5. Drywall backing must be In place before Interior vapor barrier IY' boolnrn ��2 �oa+d) 8° Is Installed. stud 200ffm f Gypsum wallboard (load distances(distance from corner to first Vaslener)must be strictly adhered to: ScCrew A. Collings constructed with 112•'Gypsum Panels shall be Installed with the first fastener spaced 12"(300mm)from e I BUSSES . the corner B. Callings constructed with 518"Gypsum Panels shall be ( Installed with the first fastener spaced 16"(400mm)from the corner. Add I!S,k�kg JJ(( C. lhterlor partitions shall have gypsum panels Installed with $ -gloat the first fastener spaced 8"(200rnm)from the ceiling o corner. 7. Where trusses run parallel to Interior partitions,bridging a first " between the trusses must be Installed when drywall float Screw — FLOAT DISTAICE—t►' St- distances differ from truss location. of I6'. 400"W l [5/e 15oard I Stud ri' F V 8. Gypsum wallboard panels must be fastened to lop plates of all z exterior walls. 12" 300"" 11 6oartj� 2oCfTrn �z CC,, JCrcW — %K1 CIaw�Canada JIW CIanN/US.A, ontnrit: 3017 St.Clair Ave. 5370 Chestnut Ph1 g 'RECOMMENDED DRYWA L IIISTAU-Ens MUST USE Burlington,ONT UN 3P5 Orchard Perk,NY 14127 rLOAI DISTANCES. (416) 634-9540 (716) 662-7877 01989 SIUDCIAW Thank you, TRUSS ENGINEERING CORPORATION Warren I. Griswo d General •Manager