The first NDS (1944) was based on allowable stress design (ASD). Copyright American Wood Council. All rights reserved.

Transcription

1 History ASD and LRFD with the 2005 NDS Part 1 Member Design Presented by: John Buddy Showalter, P.E. Vice President, Technology Transfer The first NDS (1944) was based on allowable stress design (ASD). ASD through 2001 NDS Load Resistance Factor Design

2 ASD and LRFD in 2005 NDS Outline Document organization Overview of LRFD Concept Chapter-by-chapter description Changes from previous editions Examples NDS 2005 and Supplement Chapters 16 Chapters 13 Appendices 14 Appendices What s changed? NDS 2005 Chapters General Requirements for Building Design 2 Design Values for Structural Members 3 Design Provisions and Equations 4 Sawn Lumber 5 Structural Glued Laminated Timber 6 Round Timber Poles and Piles 7 Prefabricated Wood I-Joists 8 Structural Composite Lumber 9 Wood Structural Panels 10 Mechanical Connections 11 Dowel-Type Fasteners 12 Split Ring and Shear Plate Connectors 13 Timber Rivets 14 Shear Walls and Diaphragms 15 Special Loading Conditions 16 Fire Design of Wood Members

3 NDS 2005 Appendices NDS 2005 Supplement 2005 A Construction and Design Practices B Load Duration C Temperature Effects D Lateral Stability of Beams E Local Stresses in Fastener Groups Important! F Design for Creep and Critical Deflection Applications G Effective Column Length H Lateral Stability of Columns I Yield Limit Equations for Connections J Solution of Hankinson Equation K Typical Dimensions for Split Ring and Shear Plate Connectors L Typical Dimensions for Standard Hex Bolts, Hex Lag Screws, Wood Screws, Common, Box, and Sinker Nails M Manufacturing Tolerances for Rivets and Steel Side Plates for Timber Rivet Connections N Appendix for Load and Resistance Factor Design (LRFD) - Mandatory Sawn Lumber Grading Agencies 2 Species Combinations 3 Section Properties 4 Design Values - Lumber and Timber -Non-North North American Sawn Lumber - Structural Glued Laminated Timber - MSR and MEL Outline Document organization Overview of LRFD Concept Chapter-by-chapter description Changes from previous editions Examples Overview of LRFD Design process Design concepts Comparison with ASD

4 Design Process Design Process Demand Capacity Load Support Conditions Geometry Materials Performance Fire Economics Aesthetics. Demand Capacity Design Concepts Serviceability Two Limit State concerns: safety against failure or collapse Serviceability (performance in service) Unfactored loads Mean (avg) material strength values

5 LRFD - Safety Property Variability Factored loads Material strength values - modified Re elative Fre equency x = mean x = standard deviation COV x = x x Load x x x SCL I-Joist Glulam MSR Lumber Visually Graded Lumber Material Property Values Statistical Model Normal Distribution Curve for Load or Resistance Statistical Model Normal Distribution Curves for Load, S, and Resistance, R Based on actual physical measurements - data sets failure

6 Statistical Model LRFD - Probability of Failure Normal Distribution Curves for Safety Function, Z f Z =f R - f S m Z = m R -m S z m z z 2 R 2 S P f = one failure expected for x number of structures t designed d and built with a given P f : 10,000, : 1,000, : 100, : 10, : 1, : : 10 LRFD - Range on LRFD Safety Design Equation Range for Wood Strength Low Typical High P f 1 : 25 1 : 63 1 : 251 Demand Capacity n Q R i=1 n

7 Allowable Stress Design What stays the same as ASD? Same basic equation format Same adjustment factors Same behavioral equations Formatted for compatibility LRFD vs. ASD What changes from ASD? Three new notations -,, and K F Design loads (factored) for safety are bigger Design loads (unfactored) for serviceability are the same Material resistance values are bigger Load Duration factor changes to Time Effect Factor

8 LRFD vs. ASD LRFD vs. ASD ASD applied stress allowable stress Theoretical safety margin applied to material stresses LRFD factored load factored resistance Load factors to account for variations in loads Member performance factor Estimated loads Design Load Adjusted Resistance Tested material strength Estimated loads Factored Design Load Factored Design Resistance Tested member resistance Design values Design values 2005 NDS LRFD Standard NDS 2005 LRFD Specification Factored Load Combinations ASCE 7-02 F = flood H = hydrostatic

9 NDS 2005 LRFD Specification tied to ASCE 7-02 Factored Load Equations: NDS 2005 LRFD Specification Format Conversion Factor K F : F ASD R N = R ASD LRFD R N = K F R ASD RASD reference strengths NDS 2005 LRFD Specification Format Conversion Factor K F : R N = K F R ASD 2005 NDS LRFD Specification Why use LRFD for wood? ease of fdesigning i with multiple l materials that use an LRFD basis (steel or concrete) more rational treatment of loads rather than penalizing material strength for unknowns on loads realize efficiencies with: multiple transient live loads extreme event loads ASD load combinations have not been maintained in deference to LRFD load combinations

10 Outline Document organization Overview of LRFD Concept Chapter-by-chapter description Changes from previous editions Examples Chapter 1 - Terminology Basic requirements for checking strength are revised to use terminology applicable to both ASD and LRFD Example: The actual bending stress or moment shall not exceed the adjusted allowable bending design value. In equation format, this takes the standard form f b F b ' allowable (typically associated with ASD) replaced by adjusted more generally applicable to either ASD or LRFD better describe applying adjustment factors to reference design values Reference design values (F b, F t, F v, F c, F c, E, E min ) are multiplied by adjustment factors to determine adjusted design values (F b ', F t ', F v ', F c ', F c ', E', E min ') Chapter 1 Design Loads references loads in accordance with minimum load standards, such as ASCE 7 02 Chapter 2 Adjustment Factors Applicable to ALL defined wood products Adjusts from reference to site conditions C D, time-dependent C M wet service C t temperature

11 Chapter 2 Adjustment Factors Wet Service Factor, C M Wet Service Conditions 30 Wood EMC % Relative Humidity % Temp 30 deg F Temp 70 deg F Temp 130 deg F Wet Service Conditions Content Wet Service Factor, C M values found in the NDS Supplement for lumber %Stre ength at 12% Moisture Moisture Content of Wood (%) Impact Strength Modulus of Elasticity Modulus of Rupture Crushing Strength

12 Chapter 3 Behavioral Equations ASD vs LRFD adjusted stresses from reference Chapter 3 Behavioral Equations Beams C L beam stability ASD F n =F n C D x adjustment factors LRFD F n = F n K F n x adjustment factors Chapter 3 Behavioral Equations Beams F be equivalence 1.20E K ' min be FbE 2 2 Rb Rb ' E NDS NDS Chapter 3 Behavioral Equations TR14 - Designing for Lateral-Torsional Stability in Wood Members Basis B i of current NDS effective length approach Summarizes equivalent uniform moment factor approach Provides comparison E min adjusted for safety for both ASD and LRFD processes

13 Application - LRFD vs. ASD Application - LRFD vs. ASD Beam Example - UDL Simply Supported DEMAND LOADS Q L LRFD A, S, I ASD Safety w f = Q w = Q Serviceability w L = Q L w L = Q L Beam Example - UDL Simply Supported Safety Limit State 1 SHEAR demand LRFD w f L 2 v K F F v A 2 3 capacity demand Prime denotes inclusion of applicable C factors except C D ASD w L 2 F v C D A 2 3 capacity Application - LRFD vs. ASD Application - LRFD vs. ASD Beam Example - UDL Simply Supported Safety Limit State 2 Beam Example - UDL Simply Supported Serviceability Limit State FLEXURE LRFD ASD DISPLACEMENT LRFD ASD w f L 2 8 b K F F b S wl 2 F b C D S 8 L 5 w L L E I L 5 w L L E I demand capacity demand capacity capacity demand capacity demand Prime denotes inclusion of applicable C factors except C D

14 Chapter 3 Behavioral Equations Columns C P column stability Chapter 3 Behavioral Equations Columns F ce equivalence F 0.822E K E ' ' min ce ce 2 2 le le d d NDS NDS E min adjusted for safety for both ASD and LRFD processes Chapter 3 Behavioral Equations E min F ce equivalence E 1.03E( (COV ))/1. 66 min E = reference MOE 1.03 = adjustment factor to convert E to a pure bending basis (shear-free) (use 1.05 for glulam) 1.66 = factor of safety COV E = coefficient of variation in MOE (NDS Appendix F) E Chapter 3 Column Equations Column Example Axial Load only Safety Limit State LRFD ASD P P P P (Q) A F c K F c C P C M C t (Q) A F c C D C P C M C t demand capacity demand capacity

15 Chapter 3 Column Equations Chapter 3 Column Equations Column Example Column Example Dead Load = 5500 lbs Live Load = lbs Normal Time Duration L = 16 ft (each direction) L P A, S, I LOADS Safety LRFD P = Q = 1.2 D L = 1.2 (5500) (31500) = lbs ASD P = Q = D + L = = lbs Ends pinned Chapter 3 Column Equations Chapter 3 Column Equations Column Example GEOMETRY Section d = 9 in b=675in 6.75 Try 6-3/4 x 9 Glulam visually graded western species, 16F-1.3E X-X Pinned end K =10 L d = 16 ft L ed = K ed L d A = 61 in 2 K ed = 1.0 Y-Y X-X L Slenderness = max b =28 Y-Y Pinned end K eb = L b = 16 ft L eb = K eb L b eb L, d ed Column Example SERVICE CONDITIONS Adjustment Factors Try 6 3/4 x 9 Glulam visually graded western species, 16F-1.3E LRFD ASD Time-dependent (normal) λ = 0.8 C D = 1.0 Wet-service (dry) C M Temperature (normal) C t C t

16 Chapter 3 Column Equations Chapter 3 Column Equations Column Example MATERIALS F c E E min c (Glulam) φ c (compression) φ s (stability) K F compression K F stability Try 6 3/4 x 9 Glulam visually graded western species, 16F-1.3E LRFD 1,550 psi 1,500,000 psi 780,000 psi / c = / s = 1.76 ASD 1,550 psi 1,500, psi 780,000 psi 0.9 Column Example CAPACITY Crushing LRFD ASD F c * = F c K F c C M C t F c * = F c C D C M C t = (1,550)(2.40)(0.8)(0.9)(1.0 all) = (1,550)(1.0)(1.0 all) = 2,678 psi = 1,550 psi P 0 = A F c * = (61)(2,678) = 163,382 lbs P 0 = A F c * = (61)(1,550) = 94,550 lbs Chapter 3 Column Equations Chapter 3 Column Equations Column Example CAPACITY LRFD ASD Buckling E min = E min K F s C M C t E min = E min C M C t F ce = (780,000)(1.76)(0.85)(1.0) = 1,166,880 psi ' 0.822Emin (Slenderness) (0.822)( ) 2 (28) = 1,223 psi 2 F ce = 780,000 psi ' 0.822Emin (Slenderness) (0.822)(780000) 2 (28) = 818 psi 2 Column Example CAPACITY c Ratios F F ce * c LRFD F F ce * c ASD = 0.46 = 0.53

17 Chapter 3 Column Equations Column Example CAPACITY LRFD ASD Chapter 3 Column Equations Column Example Axial Load only Safety Limit State C p C p FcE 1 * Fc 2c FcE 1 * Fc 2c 2 FcE * Fc = 0.43 = 0.48 c COMPRESSION LRFD ASD P P P P 57,000 lbs 69,914 lbs 37,000 lbs 45,384 lbs P = A F c* C p = (61)(2,678)(0.43) = (61) (1,146) = 69,914 lbs P = A F c * C p = (61)(1,550)(0.48) = (61)(744) ) = 45,384 lbs Load / Capacity Ratio demand capacity demand capacity Chapter 3 Behavioral Equations Tension members (tension parallel to grain) Chapter 3 Behavioral Equations wood and tension perpendicular to grain Not recommended per NDS ASD F t = F t C D x adjustment factors LRFD F t = F t K F t x adjustment factors initiators: notches moment connections hanging loads

18 Chapter 3 Behavioral Equations Combined bi-axial bending and axial compression Chapter 3 Behavioral Equations Combined bending and axial - compression Chapter 3 Behavioral Equations Bearing perpendicular to grain F c = F c C M C t C i C b (ASD) F c = F c C M C t C i C b K f c (LRFD) C b bearing area factor Chapter 4 Lumber Design values Visually graded lumber MSR / MEL Timber Decking same as NDS 2001

19 Chapter 4 Lumber Lumber adjustment factors C F - size factor C fu - flat use C i - incisingi i C T - buckling stiffness C r - repetitive member Chapter 4 Lumber Lumber adjustment factors C F - size factor C fu -flat use Chapter 4 Lumber Lumber adjustment factors C i - incising C T - buckling stiffness Chapter 4 Lumber Lumber adjustment factors C r repetitive member

20 Chapter 4 Lumber Adjustment factors C f form factor removed Why? derived from plastic deformation in small clear specimens that may not be applicable to full-size members applicability to standard wood products was limited (not allowed in poles & piles it s built into the reference design value) Chapter 4 Lumber Example F t = F t C D C F (ASD) F t = F t C F K F t (LRFD) Unincised, axially loaded tension member in normal environment Chapter 4 Finger-Jointed Lumber Widely accepted for use by IBC and IRC Interchangeable with solid sawn lumber with certain limitations: HRA/NON-HRA Moisture Load conditions Chapter 4 Finger-Jointed Lumber HRA Heat Resistant t Adhesive Designated on grade stamp Used where fire rated assemblies are required by code Exterior walls Dwelling unit separations Commercial tenant separations

21 Chapter 4 Finger-Jointed Lumber NON-HRA Adhesive not rated for heat resistance Designated on grade stamp Chapter 4 Finger-Jointed Lumber HRA marks absent? Treat same as NON-HRA? Chapter 4 Finger-Jointed Lumber Other Stamp Designations Exterior Use allowed Structural applications are not limited Must meet HRA criteria in rated assemblies Chapter 4 Finger-Jointed Lumber Other Stamp Designations STUD USE ONLY or VERT USE ONLY Limited to use where bending or tension stresses are of short duration

22 Chapter 4 Finger-Jointed Lumber Older Stamps Old grade marks Obliterated New finger-jointed grade stamps apply Chapter 5 Glued Laminated Timber Design values added to NDS Supplement Reformatted glulam radial tension values Shear values increased 10% Chapter 5 Glulam Design values F rt radial tension Chapter 5 Glulam Adjustment factors C V volume Not cumulative with C L

23 Chapter 5 Glulam Adjustment factors C c curvature Applies to F b Curved portion of bending member Not applied to straight portion of member Chapter 5 Glulam Example F c = F c C D C P (ASD) F c = F c C P K F c (LRFD) Axially loaded compression member in normal environment Chapter 6 Poles & Piles Poles - post-frame Piles - foundations Chapter 6 Poles & Piles Design values No changes from 2001 NDS

24 Chapter 6 Poles & Piles Adjustment factors LRFD provisions Chapter 6 Poles & Piles Adjustment factors C u - untreated C cs - critical section C sp -single pile Chapter 6 Poles & Piles Example F c = F c C D C sp (ASD) F c = F c C sp K F c (LRFD) Single, axial load, treated, full lateral support, normal environment Chapter 7 I-joists Design values M, V, EI, K no changes Evaluation Reports Contain proprietary design

25 Chapter 7 I-joists Adjustment factors LRFD provisions Chapter 7 I-Joists Adjustment factors C r = 1.0 revised to agree with ASTM D factor of 1.0 maintained for clarity transitioning from 2001 NDS Chapter 7 I-joists Chapter 8 Structural Composite Lumber (SCL) Example M r = M r C D (ASD) M r = M r K F b (LRFD) Full lateral l support, bending member, normal environment Design values in evaluation reports Note less variability (low COV) No changes from 2001 NDS Evaluation Reports Contain proprietary design requency Relative Fr x = mean COV x xx x = Load x SCL I-Joist Glulam MSR Lumber Visually Graded Lumber Material Property Values

26 Chapter 8 Structural Composite Lumber (SCL) Adjustment factors C V volume Not cumulative with lateral stability factor, C L Chapter 8 Structural Composite Lumber (SCL) Adjustment factors C r = 1.04 C r is different than lumber (C r lumber = 1.15) Applied to F b Chapter 8 Structural Composite Lumber (SCL) Example F b = F b C D C V (ASD) F b = F b C V K F b (LRFD) Full lateral support, bending member, normal environment Chapter 9 Wood Structural Panels (WSP) Design values obtain from an approved source F b S F t A F v t v F s F c A EI EA G v t v F c

27 Chapter 9 Wood Structural t Panels (WSP) Adjustment factors C G - grade & construction C s - panel size C M -wet service C t - temperature Chapter 9 Wood Structural t Panels (WSP) Adjustment factors C G - grade & construction Chapter 9 Wood Structural t Panels (WSP) Adjustment factors C s - panel size C M - wet service C t - temperaturet Chapter 9 Wood Structural t Panels (WSP) Example F b S = F b S C D (ASD) F b S = F b S K F b (LRFD) Non-structural t I, >24 width, loaded in bending, normal environment

28 Chapters Mechanical Connections Chapter 10 mechanical connections Chapter 11 dowel-type connectors (nails, bolts, lag/wood screws) Chapter 12 split rings and shear plates Chapter 13 timber rivets Chapter 14 Shear Walls and Diaphragms enabling language for shear wall and diaphragm design design information and values in: ANSI / AF&PA SDPWS standard Covered in Part 2 September 30 ANSI / AF&PA SDPWS WIND & SEISMIC standard references 2005 NDS Special design provisions for wind and seismic loads Values for a wide variety of panel products Future Webinar October 14 Chapter 15 Special Loading Built-up columns Revised to correct limitation on short built-up columns Each ratio shall be used to calculate a column stability factor, C P, per section and the smaller C P shall be used in determining the allowable compression design value parallel to grain, F c ', for the column. F c ' for built-up columns need not be less than F c ' for the individual laminations designed as individual solid columns per section 3.7.

29 Chapter 16 Fire Design Applies to ASD only Chapter 16 Fire (ASD) Fire resistance up to two hours Columns Beams Tension Members Combined Loading Additional special provisions for glulam Chapter 16 Fire (ASD) TR10 - Calculating the Fire Resistance of Exposed Wood Members Expands uses for large, exposed wood members Expands applicability of current methods to other EWP s (SCL) Chapter 16 Fire Superior fire performance of heavy timbers attributed to the charring effect of wood Benefits of charring an insulating char layer is formed protects the core of the section Expands use of large, exposed wood members to 2 hour fire endurance applications

30 Analog for Cross-Sectional Dimensionsi Estimating Cross-sectional Dimensions due to Charring 4-Sided Exposure (i.e. columns) b = B - 2t d = D - 2t 3-Sided Exposure (i.e. beams) b = B - 2t d = D - t 2-Sided Exposure (i.e. decking) b = B - t d = D - t where: t is the char rate of the material is the fire exposure time Model for Charring of Wood Nonlinear char model used - nominal linear char rate input. To account for rounding at corners and reduction of strength and stiffness of the heated zone, the nominal char rate values, n, are increased 20%. eff n eff = 1.2 n t where: is the effective char rate (in/hr), adjusted for exposure time, t n is the nominal linear char rate (in/hr), based on 1-hr exposure t is the exposure time (hrs) Effective Char Rates and Char Layer Thickness (for n = 1.5 inches/hour) Required Fire Effective Char Effective Char Layer Endurance Rate, eff Thickness, char (hr) (in/hr) (in) 1-Hour ½-Hour Hour

31 Design for Member Capacity Allowable Design Stress to Average Ultimate Strength Adjustment Factor where: K Dead Load + Live Load K * Allowable Design Capacity is a factor to adjust from allowable design capacity to average ultimate capacity Member Capacity Bending Moment Capacity, in-lb Tensile Capacity, lb Compression Capacity, lb Beam Buckling Capacity, lb Column Buckling Capacity, lb K Fire Design Example (ASD) Fire Design Example (ASD) Douglas fir glulam beams Span L = 18 feet Spaced at s = 6 feet Design Load q live = 100 psf q dead = 15 psf For the structural design of the beam, calculate the induced moment: Beam load: w total = s (q dead + q live ) = (6 )(15+100) Induced demand moment: M max = w total L 2 / 8 = (690)(18) 2 / 8 = 690 plf = 27,945 ft-lb Timber decking nailed to the compression edge of beams provides lateral bracing Size the beam for required bending strength for 1 hour fire duration

32 Fire Design Example (ASD) Fire Design Example (ASD) Select a 6-3/4 x 12 24F-V4 Douglas-fir glulam beam Tabulated bending stress, F b, equal to 2400 psi Calculate the design resisting moment: M = F b S s = (2371)(162) / 12= 32,009 ft-lb Calculate the beam section modulus: S s = BD 2 /6 = (6.75)(12) 2 / 6 = in 3 Calculate the adjusted allowable bending stress: Assuming: C D = 1.0, C M = 1.0, C t = 1.0, C L = 1.0, C V = 0.99 F b = F b C D C M C t (lesser of C L or C V ) = 2400(1.0)(1.0)(1.0)(0.99) = 2371 psi Structural Capacity Check: M > M max 32,009 ft-lb > 27,945 ft-lb Fire Design Example (ASD) Fire Design Example (ASD) For the fire design of the wood beam: the loading is unchanged, therefore, the maximum moment is unchanged, the fire resistance must be calculated From NDS Table , find charring depth char for 1 hour duration: Required Fire Effective Char Effective Char Layer Endurance Rate, eff Thickness, char (hr) (in/hr) (in) 1-Hour ½-Hour Hour Substitute in residual cross-section dimensions for 3-sided beam into the section modulus relation, i.e.: 3-Sided Exposure (i.e. beams) b = B - 2t d = D - t = B - 2 char = D - char Calculate charred beam section modulus exposed on 3-sides: S f = (B-2 char )(D- char ) 2 / 6 = (6.75-2(1.8))(12-1.8) 2 / 6 = 54.6 in 3

33 Fire Design Example (ASD) Calculate the adjusted allowable bending stress (some adjustment factors don t apply and may have been other than 1.0 before): F b = F b (lesser of C L or C V ) = 2400 (0.99) = 2371 psi Calculate strength resisting moment using charred cross-section: M =KF b S f = (2.85)(2371)(54.6) / 12 = 30,758 ft-lb Fire Capacity Check: M > M max 30,758 ft-lb > 27,945 ft-lb NDS 2005 Appendices Layout 2005 A Construction and Design Practices B Load Duration C Temperature Effects D Lateral Stability of Beams E Local Stresses in Fastener Groups Important! F Design for Creep and Critical Deflection Applications G Effective Column Length H Lateral Stability of Columns I Yield Limit Equations for Connections J Solution of Hankinson Equation K Typical Dimensions for Split Ring and Shear Plate Connectors L Typical Dimensions for Standard Hex Bolts, Hex Lag Screws, Wood Screws, Common, Box, and Sinker Nails M Manufacturing Tolerances for Rivets and Steel Side Plates for Timber Rivet Connections N Appendix for Load and Resistance Factor Design (LRFD) - Mandatory Appendix N new! Load and Resistance Factor Design source for new variables ASTM D5457 Standard Specification for Computing the Reference Resistance of Wood-Based Materials and Structural Connections for Load and Resistance Factor Design tabulates K F conversion factors to convert from ASD reference values (see NDS Supplement) to LRFD reference values 2005 NDS Supplement Updated to include latest reference values for: visually graded lumber and timber mechanically ygraded lumber glued laminated timber tabulates resistance factors tabulates time effect factors for load combinations listed in: ASCE 7-02 Minimum Design Loads for Buildings and Other Structures NDS clarified for cases involving hydrostatic loads (H) and for cases where H is not in combination with L, use =06 0.6

34 2005 NDS Supplement - E min E min addition for reference MOE for beam and column stability: visually graded lumber and timber mechanically graded lumber glued laminated timber Represents 5% lower exclusion shear-free E value so that design value adjustments are not part of the basic design equation for column and beam stability 2005 NDS Supplement - Lumber Visually graded dimension lumber (Table 4A) Four new species added: Alaska cedar (Alaska & Western states) Alaska Hemlock (Alaska & Western states) Alaska Yellow Cedar (Alaska only) Baldcypress 2005 NDS Supplement - Timber Visually graded timber (Table 4D) Two new species added: Alaska cedar (Alaska & Western states) Baldcypress 2005 NDS Supplement Non-north north American Species Non-north north American Species (Table 4F) Several new species added: Montane pine (South Africa) Norway Spruce (Romania and the Ukraine) Silver fir (Germany, NE France, and Switzerland) Southern pine (Misiones Argentina) Southern pine (Misiones Argentina free of heart center and medium grain density

35 2005 NDS Supplement - MSR and MEL Mechanically graded dimension lumber (Table 4C) New design values added: Table 4C Footnote 2 new G, F v,f c values for MSR and MEL Table 4C new E min values for MSR and MEL 2005 NDS Supplement - Glulam Structural glued laminated timber (Table 5A) New design values added: Table 5A new E min values added Table 5A 16F stress class revised F t, F c, G Table 5A values now match Table 5A-Expanded d values Species groups for split ring and shear plate connectors removed (NDS Table 12A values inappropriate) use G of the wood located on the face receiving the connector with NDS Table 12A assignment of species group. F v values increased for prismatic members (Footnote d revised) use of test-based shear values removing the 10% reduction used previously (AITC and APA). F v values increased for non-prismatic members unchanged (AITC and APA). Non-prismatic F rt (radial tension) for D.fir-L, and SP glulam increased slightly 2005 NDS Supplement - Glulam Structural glued laminated timber (Table 5B) New combinations added for Southern Pine with more information on slope of grain differences. F bx design values reformatted to include footnoted table adjustments for special tension laminations. F vy columns consolidated and values updated with Table 5A info. Changes from previous editions NDS is one volume!! = + +

36 2005 Wood Design Package ANSI/AF&PA NDS-2005 National Design Specification (NDS) for Wood Construction with Commentary and Supplement ANSI/AF&PA SDPWS-2005 Special Design Provisions for Wind and Seismic - with Commentary ASD/LRFD Manual for Engineered Wood Construction Manual for Engineered Wood Construction ti Most non-mandatory information contained in 2001 ASD Manual, Supplements, and Guidelines bound in one volume Manual Chapters correspond to NDS Chapters Structural Wood Design Solved Example Problems (Workbook) Solved Examples (Workbook) ASD solutions in addition to the 40 examples and solutions in the current LRFD Workbook updated to the 2005 NDS NDS 2005 Summary format changes to accommodate addition of LRFD: Revised terminology Expanded applicability of adjustment factor tables Re-format of radial tension design values Revised format of beam and column stability provisions (addition of E min property) Addition of NDS Appendix N Load and Resistance Factor Design other changes introduced in the 2005 Edition: Removal of form factor Revision of repetitive member factor for I-joists Revision of full-design value terminology Clarification of built-up column provisions

37 NDS 2005 Supplement Summary 2005 Wood Design Package changes in design value tables : E min values added for all materials F v values for prismatic glulam increased minor re-formatting updated to include latest reference values for: visually graded lumber and timber mechanically graded lumber glued laminated timber