1996 LRFD Supplements - unprotected PDF - American Wood Council

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<strong>LRFD</strong> STRUCTURAL LUMBER SUPPLEMENT31DESIGNADJUSTMENTFACTORS44.1 General 324.2 Use of Adjustment Factors 32Table 4.1 Wet Service Factor, C M ................................................................. 34Table 4.2 Temperature Factor, C t ................................................................. 34Table 4.3 Size Factor, C F ........................................................................................ 35Table 4.4 Shear Stress Factor, C H ................................................................ 36Table 4.5 Flat Use Factor, C fu ........................................................................... 36
32 DESIGN ADJUSTMENT FACTORS4.1 GeneralTwo alternative approaches may be used to generatemember design resistance. With the calculation method,reference strengths are multiplied by adjustment factorsand section properties to obtain member resistances. Withthe tabulation method, values which are fully factoredand adjusted for a given set of conditions are presented inthe tables.The member selection tables in Chapter 5 include precalculated<strong>LRFD</strong> factored resistance values for referenceconditions of use. For special design cases, an alternativeapproach permits the use of reference strength values(from Chapter 3), modified appropriately by the adjustmentfactors included in this chapter.The adjustment factors provided in this chapter arefor applications outside the reference end-use conditionsor for member configuration effects (i.e., flat use). Whenone or more of the specific end-use or member configurationconditions fall outside the range of the reference conditionsdefined in AF&PA/ASCE 16-95 Section 2.6, theseadjustment factors shall be used to modify the referencestrengths. Adjustment factors for the effects of moisture,temperature, size, shear stress and flat use are provided inthis supplement.4.2 Use of Adjustment FactorsTensionThe unfactored resistances for tension members canbe computed by the following equation:T′ = F′AwheretT′ is the adjusted tension resistance (unfactored), F t ′is the adjusted tension strength and A is the cross sectionalarea.The adjusted tension strength is computed by multiplyingthe reference strength by a series of adjustmentfactors.The reference values for F t are tabulated in Chapter 3of this supplement for all species and grades listed in the1991 NDS.andFtN = F(C t MCC t ptCrtC F)C M is 1.0C t is 1.0C pt is 1.0for 19% MC and less, or as shown in Table4.1 otherwiseunless temperatures exceed 100°F for extendedperiods of time, or as shown in Table4.2 otherwisefor members that are untreated orpreservatively treated in accordance with approvedstandardsC rt is 1.0for members that are not fire-retardanttreated. For fire-retardant treated members,the value of C rt shall be established by thesupplier of the treated products or treatmentchemicalsC F is as shown in Table 4.3CompressionThe unfactored resistances for compression memberscan be computed by the following equation:whereP′ = F cN AP′ is the adjusted compression resistance (unfactored),F c ′ is the adjusted compression strength and A is the crosssectional area.The adjusted compression strength is computed bymultiplying the reference strength by a series of adjustmentfactors.The reference values for F c are tabulated in Chapter 3of this supplement for all species and grades listed in the1991 NDS.andFcN = Fc(CMCtCptCrtCFC P)C M is 1.0for 19% MC and less, or as shown in Table4.1 otherwise
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Page 3: PrefaceThis supplement contains adj
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Page 9 and 10: 4 INTRODUCTION TO STRUCTURAL LUMBER
Page 11 and 12: 6 REFERENCE STRENGTHS3.1 GeneralThe
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Page 41 and 42: 36 DESIGN ADJUSTMENT FACTORSTable 4
Page 43 and 44: 38 MEMBER SELECTION TABLES5.1 Gener
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Page 55 and 56: 50MEMBER SELECTION TABLES
Page 57 and 58: 52 OTHER CONSIDERATIONS6.1 GeneralW
Page 59 and 60: 54OTHER CONSIDERATIONS
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Page 75 and 76: 70CROSS-SECTION PROPERTIES
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LRFD STRUCTURAL GLUED LAMINATED TIM
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LRFDGUIDELINESTRUCTURALTO LRFDGLUED
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SUPPLEMENTTimber Polesand PilesLRFD
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AMERICAN WOOD COUNCIL
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2 DESIGNER FLOWCHART1.1 FlowchartTi
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4 INTRODUCTION TO TIMBER POLES AND
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6 DESIGN ADJUSTMENT FACTORS3.1 Gene
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8 DESIGN ADJUSTMENT FACTORSTable 3.
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10 REFERENCE STRENGTHS4.1 GeneralTh
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12REFERENCE STRENGTHSAMERICAN WOOD
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14 POLE AND PILE SELECTION TABLES5.
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16 POLE AND PILE SELECTION TABLESTa
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18 POLE AND PILE SELECTION TABLESTa
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20POLE AND PILE SELECTION TABLESAME
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22 OTHER CONSIDERATIONS6.1 GeneralW
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24OTHER CONSIDERATIONSAMERICAN WOOD
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26 SECTION PROPERTIES7.1 SECTION PR
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28 SECTION PROPERTIESTable 7.4Speci
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30 SECTION PROPERTIESAMERICAN WOOD
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SUPPLEMENTStructural-UsePanelsLRFDL
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TABLE OF CONTENTSChapter/TitlePage4
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LRFD STRUCTURAL-USE PANELS SUPPLEME
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GUIDELINELRFD STRUCTURAL-USETO LRFD
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SUPPLEMENTStructuralConnectionsLRFD
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8.3D Factored Resistance Values (φ
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2 DESIGNER FLOWCHART1.1 FlowchartSt
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4 INTRODUCTION TO STRUCTURAL CONNEC
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6 DESIGN ADJUSTMENT FACTORS3.1 Gene
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8 DESIGN ADJUSTMENT FACTORSTable 3.
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10 DESIGN ADJUSTMENT FACTORSTable 3
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12 DESIGN ADJUSTMENT FACTORSTable 3
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14 FACTORED RESISTANCE VALUES4.1 Ge
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16 FACTORED RESISTANCE VALUESAMERIC
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18 FACTORED RESISTANCE VALUESTable
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62FACTORED RESISTANCE VALUESAMERICA
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64 OTHER CONSIDERATIONS5.1 GeneralW
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66 FASTENER DIMENSIONS6.1 Typical D
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68 APPENDIXSimplified Design Equati
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70 APPENDIXLimitations for Simplifi
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72 APPENDIXWood Screw ConnectionsLi
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74APPENDIXAMERICAN WOOD COUNCIL
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1996 LRFD Supplements - unprotected PDF - American Wood Council

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