CHAPTER 2 RESPONSIBILITIES IN THE DESIGN PROCESS INVOLVING METAL PLATE CONNECTED · PDF fileRESPONSIBILITIES IN THE DESIGN PROCESS INVOLVING METAL PLATE CONNECTED WOOD TRUSSES

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Truss Plate Institute ANSI/TPI 1-2002Mandatory InformationRevision Date: January 2005

CHAPTER 2RESPONSIBILITIES IN THE DESIGN PROCESS INVOLVING METAL

PLATE CONNECTED WOOD TRUSSES2.1 PURPOSE

The purpose of this chapter is as follows:

2.1.1 To define and draw attention to thetypical duties and responsibilities of the TrussManufacturer, Truss Designer, Owner, BuildingDesigner and Contractor so that all parties have anunderstanding of the typical division of professionalresponsibilities with respect to wood Trusses. Thiswill result in safer, more effective and efficient useof Trusses, and more economical Buildings overall.

2.1.2 To provide requirements to the Owner,Building Designer and Contractor on matters relatedto the use of Trusses.

2.2 CONTRACTUAL AGREEMENTS

The provisions of Chapter 2 are intended toapply where no specific contractual relationshipexists between the parties addressed herein,pertaining to Design Responsibilities. This section isnot intended to take precedence over contractualrelationships developed between any of the partiesinvolved in a particular construction project.

2.3 DEFINITIONS

2.3.1 Architect: Any Licensed DesignProfessional practicing architecture who designs allor a part of the Building Structural System and/orwho produces all or part of the ConstructionDocuments and which may include all or part of theStructural Design Documents.

2.3.2 Building: Any structure used or intendedfor supporting or sheltering any use or occupancy.

2.3.3 Building Designer: The Owner of theBuilding or the individual or organization (includingeither an Architect or Engineer or the Contractor)that contracts with the Owner for the design of theBuilding Structural System and/or who produces theStructural Design Documents.

2.3.4 Building Structural System: Thecompleted combination of Structural Elements,Trusses, connections and systems, which serve tosupport the Building’s self weight, the applicablelive load(s), and environmental loads.

2.3.5 Construction Documents: Written,graphic and pictorial documents, including theStructural Design Documents, prepared orassembled for describing the design, location andphysical characteristics of the elements of aproject necessary for obtaining a permit andconstructing a building.

2.3.6 Contract: A legally recognizeddocument between two or more parties thatincludes the agreement between the TrussManufacturer and its customer which sets forththe terms and conditions and scope ofresponsibilities applicable to the TrussManufacturer.

2.3.7 Contractor: The Owner of the Buildingor the individual or organization who contractswith the Owner and is responsible for theconstruction of the Building Structural System inaccordance with all Legal Requirements. Theterm “Contractor” shall include thosesubcontractors who have a direct contract withthe Contractor to perform all or a portion of thestorage, handling, installation, and bracing(temporary and permanent) of the Trusses.

2.3.8 Conventional Light-frame WoodConstruction: A type of construction whoseprimary structural elements are formed by asystem of repetitive wood-framing members. Thisincludes wood Truss construction.

2.3.9 Engineer: Any Licensed DesignProfessional practicing engineering who designsall or a part of the Building Structural System and/or who produces all or a part of the StructuralDesign Documents.

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ANSI/TPI 1-2002Truss Plate Institute Mandatory InformationRevision Date: January 2005

2.3.10 Jurisdiction: The governmental unit thathas adopted this standard under due legislativeauthority.

2.3.11 Legal Requirements: Applicableprovisions of all statutes, laws, rules, regulations,ordinances, codes, or orders of any governmentalauthority or Jurisdiction of the United States ofAmerica, any state, and any political subdivision orquasi-governmental authority or Jurisdiction of anyof the same, including, but not limited to,departments, commissions, boards, bureaus,agencies, counties, municipalities, provinces, andother instrumentalities.

2.3.12 Local Building Official: The officer orother designated authority charged with theadministration and enforcement of the applicablebuilding code, or a duly authorized representative,who in accordance with the Legal Requirementsmay impose requirements on Truss Manufacturersand Truss Designers relating to the Trusses and theTruss Submittals.

2.3.13 Owner: The individual or organizationwho owns the Building, and: (a) either designs andprepares, or retains the Building Designer to designand prepare, the Building’s Structural System andthe Structural Design Documents; and (b) eitherconstructs, or retains the Contractor to construct,the Building’s Structural System.

2.3.14 Registered Design Professional: Anindividual who is registered or licensed to practicetheir respective design profession as defined by thestatutory requirements of the professionalregistration laws of the state or Jurisdiction in whichthe project is to be constructed.

2.3.15 Structural Design Documents: Written,graphic and pictorial architectural or structuraldocuments, specifications and addenda prepared orassembled for the overall construction of theBuilding Structural System, which are part of theConstruction Documents.

2.3.16 Structural Element: A single joist,rafter, beam, or other structural member (notincluding the Trusses) designed by others and

supplied for the Building Structural System by eitherthe Truss Manufacturer or others.

2.3.17 Structural Element Submittals:Documentation relating to the Structural Elementsthat are supplied by the Truss Manufacturer, ifrequired by the Contract, to the Local BuildingOfficial, Owner, Building Designer and/orContractor for their review and/or approval.

2.3.18 Truss: An individual metal plateconnected wood component supplied for theBuilding Structural System.

2.3.19 Truss Design Drawing: The written,graphic and pictorial depiction of an individual Truss.

2.3.20 Truss Designer: The individual ororganization responsible for the design of Trusses.

2.3.21 Truss Manufacturer: An individual ororganization engaged in the manufacturing ofTrusses.

2.3.22 Truss Placement Diagram: Theillustration supplied by the Truss Manufactureridentifying the location assumed for each Truss,which references each individually designated TrussDesign Drawing.

2.3.23 Truss Submittals: The Truss DesignDrawings, and the Truss Placement Diagram ifrequired by the Contract, submitted by the TrussManufacturer to the Local Building Official, Owner,Building Designer and/or Contractor for their reviewand/or approval.

2.4 REQUIREMENTS OF BUILDINGOWNER, AND QUALIFICATIONS OFBUILDING DESIGNER AND CONTRACTOR

The Owner shall be responsible to comply withany requirements from a Jurisdiction that the designand/or construction of a building be performed by aspecially qualified person, such as a RegisteredDesign Professional or a Contractor with a specifictype of license. The Owner shall be responsible forall matters of the design and construction of theBuilding Structural System except as defined in this

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chapter and any applicable contractual agreement.

2.5 BUILDING STRUCTURAL SYSTEMDESIGN DOCUMENTS

2.5.1 The Building Designer, through theStructural Design Documents, shall provide that theStructural Elements and Trusses shall not besubjected to adverse influences including, but notlimited to moisture, temperature, and corrosivechemicals and gases. This provision shallspecifically include notice for the Truss Designer ofenvironments expected to result in wood moisturecontent exceeding 19 percent, and temperaturesand/or corrosion potential that are unusually highrelative to typical wood buildings.

2.5.2 The Building Designer, through theStructural Design Documents shall provideinformation sufficiently accurate and reliable to beused for facilitating the supply of the StructuralElements and for developing the design of theTrusses for the Building, and shall provide thefollowing:

2.5.2.1 All Structural Element and Trussorientations and locations;

2.5.2.2 Information to fully determine allTruss profiles;

2.5.2.3 All Structural Element and Trussbearing conditions;

2.5.2.4 The location, direction, and magnitudeof all dead and live loads applicable to eachStructural Element and Truss including, but notlimited to, loads attributable to: roof, floor,partition including any directions other thangiven in section 6.2.2.1, mechanical, firesprinkler, attic, storage, rain loads and ponding,design wind speed and exposure category,snow, snow drift, unbalanced snow load, andseismic forces;

2.5.2.5 All Structural Element and Trussanchorage designs required to resist uplift,gravity, and lateral loads;

2.5.2.6 Allowable vertical and horizontal deflection criteria and any specific criteria per section 6.1.3;

2.5.2.7 Proper transfer of design loadsaffecting the Structural Elements and Trusses;

2.5.2.8 Adequate connections between Trussesand between Structural Elements, includingTruss to Structural Element connections, but notTruss to Truss girder connections except suchconnections that are excluded from the scope ofthe Truss Designer’s responsibilities.

2.5.2.9 Permanent bracing design for theBuilding, including bracing to resist wind,seismic, or other lateral forces, and permanentbracing for all Structural Elements and Trusses.The permanent bracing design shall incorporatethe continuous lateral chord and web memberbracing that is designated on the individual TrussDesign Drawings into the overall bracing for theentire Building Structural System.

2.5.3 The Building Designer shall beresponsible for the adequacy of the design of theBuilding Structural System or the adequacy of theStructural Design Documents. The BuildingDesigner shall evaluate the effect of the Trussesand the Structural Elements supplied, on the BuildingStructural System.

2.6 CONSTRUCTION RELATED ITEMS

2.6.1 Truss Submittals and Structural ElementSubmittals, and any supplemental informationprovided by the Truss Manufacturer, shall beprovided to the Contractor or the individual ororganization responsible for the installation of theTrusses and Structural Elements.

2.6.2 The Building Designer shall beresponsible for determining appropriate field storage,handling, and installation measures for the Trussesand Structural Elements. The Contractor, unlessotherwise specifically assigned by Contract, shalldetermine the requirements of, and provide allmaterials for construction in accordance with the

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ANSI/TPI 1-2002Truss Plate Institute Mandatory InformationRevision Date: January 2005

Structural Elements in accordance with the handlingand installation information and/or the StructuralDesign Documents.

2.6.6 The Truss Manufacturer and TrussDesigner shall not be responsible for the design,materials, or installation of permanent bracing forthe Building, including bracing for all or any of theTrusses and Structural Elements. The approximatelocation for, or the maximum spacing between,permanent lateral bracing of Truss members will beindicated on the Truss Design and it shall be theresponsibility of the Owner to engage the BuildingDesigner or others to specify how the permanentlateral bracing is to be anchored or restrained toprevent lateral movement of all Truss memberstogether. Consideration shall be given to one of thefollowing methods for providing this restraint oranchorage: (a) permanent diagonal bracing in theplane of the Truss members; or (b) other meanswhen demonstrated by the Building Designer orother qualified person to provide equivalent lateralresistance.

2.7 TRUSS MANUFACTURERRESPONSIBILITIES

2.7.1 The Truss Manufacturer shallcommunicate the Truss design criteria andrequirements from the Structural Design Documentsand those requirements set forth in writing by theOwner, Building Designer or Contractor, to theTruss Designer.

2.7.2 A Truss Design Drawing is a substitutefor the building code based prescriptive span tablesused to select and apply structural elements inConventional Light-frame Wood Construction.

2.7.3 The Truss Manufacturer shall supply aTruss design drawing, a Truss placement diagram orspecial detail drawings to the Contractor todocument the location of special bearing conditions,permanent bracing, and orientation of Trusses,unless the provisions of Section 2.7.3.1 are followed.

2.7.3.1 In lieu of a Truss Design Drawing,Truss Placement Diagram or special detail drawings

Structural Design Documents. These requirementsand materials for construction shall include allnecessary items for safe construction, includingdesign and installation of, adequate temporarybracing during construction for the BuildingStructural System.

2.6.3 The Contractor shall be responsible,unless otherwise assigned by Contract, to review orinspect Trusses delivered or to review and inspectTrusses after erection for any problems, includingdislodged/missing connectors, cracked, dislodged orbroken members, or any other damage that mayimpair the structural integrity of the Truss. In theevent that damage to the Truss is discovered thatwould likely impair the structural integrity of theTruss, the Contractor shall be responsible to ensurethat the Truss not be erected and that any areawithin the Building supported by any such Trussalready erected shall be appropriately shored orsupported to prevent further damage from occurringand shall remain clear and free of any load imposedby people, plumbing, electrical, mechanical, bridging,bracing, etc. until such field repairs have beenproperly completed. In the event of such damageand unless otherwise specified by Contract, theContractor shall contact the appropriate designprofessional to determine an adequate field repairand the Contractor shall be responsible to constructany such field repair.

2.6.4 All Truss repairs shall be approved inwriting by a Building Designer or a Truss Designeror other qualified person prior to the performance ofthe repair.

2.6.5 The Truss Manufacturer and TrussDesigner are not responsible for, nor do the TrussManufacturer and Truss Designer have control of,construction means, methods, techniques,sequences, procedures, programs and safety inconnection with the handling, storing, installation andbracing of the Trusses. These topics are covered inthe BCSI 1-03: Guide to Good Practice forHandling, Installing & Bracing of Metal PlateConnected Wood Trusses. The TrussManufacturer and Truss Designer are also notresponsible for the failure to carry out theconstruction work related to the Trusses and the

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being provided as specified in Section 2.7.2, theTruss Manufacturer shall ensure the following:

a) required bottom chord bearing parallelchord Trusses shall be clearly marked orconfigured in a manner which will avoidinverted installation, and shall permit visualverification or proper orientation afterinstallation;

b) Trusses having bearing locations otherthan at the end or heel locations shall havebearing points clearly marked; and

c) Truss chord and web members thatrequire lateral bracing to prevent lateralbuckling (such as, but not limited to, topchords of piggyback Trusses, longcompression webs, and bottom chords atcantilevers) shall be clearly marked to callattention to the need for such field bracingduring and after installation.

2.7.3.2 Where required by Contract, LegalRequirements or the Local Building Official, theTruss Manufacturer shall provide Truss DesignDrawing(s) sealed by a Truss Design Engineer (asdefined in 2.8).

2.7.4 Where required by Contract, LegalRequirements or the Local Building Official, theTruss Manufacturer shall submit the TrussSubmittals and Structural Element Submittals to theLocal Building Official, Owner, Building Designerand/or Contractor for review and/or approval.

2.7.5 In preparing the Truss Submittals and theStructural Element Submittals, the TrussManufacturer shall be permitted to rely on theaccuracy and completeness of informationfurnished, in writing, by the Owner, BuildingDesigner or Contractor, and by the StructuralDesign Documents.

2.7.6 The Truss Manufacturer shallmanufacture the Trusses in accordance with thefinal Truss Design Drawings, using the qualitycriteria required by this standard.

2.7.7 Where required by the Contract, theTruss Manufacturer shall prepare the TrussPlacement Diagram. The Truss PlacementDiagram shall be permitted to include identifyingmarks for other products, including StructuralElements supplied by someone other than the TrussManufacturer, so that they may be more easilyidentified by the Contractor during field erection.As the Truss Placement Diagram serves only as aguide for Truss installation and requires noengineering input, it does not require the seal of aTruss Design Engineer (as defined in 2.8).

2.7.8 The Truss Manufacturer shall determinethe value for the quality control factor (Cq) to beused in the design of the metal plate connectedwood Trusses (See Section 6.4.11). This value forCq shall be provided to the Truss Designer, withevidence of conformance with Chapter 3 from aninspection agency or other means when required by6.4.11.

2.8 TRUSS DESIGNER RESPONSIBILITIES

2.8.1 The Truss Designer shall prepare theTruss Design Drawings based on the truss designcriteria and requirements set forth in writing by theOwner, Building Designer or Contractor, by theStructural Design Documents, and in conformancewith the requirements set forth in this standard.

2.8.2 The Truss Designer shall be responsiblefor the single Truss design depicted on the TrussDesign Drawing.

2.8.3 Repair designs shall be based on:Applicable wood engineering standards such as thisstandard, the National Design Specification® forWood Construction, NDS® and other coderecognized reports and standards; design loadsspecified in the Structural Design Documents, orotherwise specified in writing, and used in thepreparation of the original Truss Design Drawing(s);the determination of forces and moments present atthe repair location based on structural analysis; re-evaluation of all member stresses and deflectionsand joint designs (plating) for the repaired conditionusing this standard’s design criteria; and thejudgment of the engineer undertaking the repair.