Solutions Manual For Design Of Wood Structures ASD-LRFD . PDF

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Solutions Manual for Design Of Wood Structures ASD-LRFD 7th Edition by BreyerFull Download: eyer/Chapter 4 SolutionsPage 1 of 19DESIGN OF WOOD STRUCTURES – ASD/LRFD (7th edition)4.1a. narrow, needle-like leaves; evergreens; conifersb. broadleafed; deciduousc. softwoods4.2See Fig. 4.3.a. Annual Ring – wood cells developed on the outside of the tree in one growingseasonb. Latewood (summerwood) – smaller, darker, more dense, from late in growingseasonEarlywood (springwood) – larger, light color, less dense, from early in growingseasonc. Heartwood –center of log; inactive cells; collects deposits as tree ages; darkerSapwood – outer, living, active cells; stores food and transports water4.3a. Amount of water expressed as percent of dry weight of wood material:moistweight ovendryweightMC x100%ovendryweightb. FSP MC at point of “no free water” and fully saturated (bound water) wood.c. EMC MC wood assumes in service for a given set of atmosphericconditions4.4a. MC 19%b. MC 19%Note: These values are for sawn lumber; for glulam see Chap. 5 (dry MC 16%).4.5EMC for buildings in “dry southwest states” is approximately 9%, ranging from7% to 12% (Ref. 4.4)4.6National Design Specification for Wood Construction (NDS) with CommentaryDesign Values for Wood Construction (NDS Design Values Supplement)Special Design Provisions for Wind & Seismic (NDS Wind & SeismicSupplement)ASD/LRFD Manual for Engineered Wood ConstructionFull download all chapters instantly please go to Solutions Manual, Test Bank site: TestBankLive.com

Chapter 4 SolutionsPage 2 of 194.7bending stress (Fb)tension stress parallel to grain (Ft)shear stress parallel to grain (Fv)compression stress parallel to grain (Fc)compression stress perpendicular to grain (Fc )modulus of elasticity (E)4.8NominalSize2x48x84 x 106 x 16a.b.c.d.Dressed(in. x in.)1.5 x 3.57.5 x 7.53.5 x 9.255.5 x .733.05214.9Sy(in3)1.31370.3118.8978.154.9a. Nominal 2 to 4 in. thick; any width; practically 2 x 2 to 4 x 16.b. Minimum nominal dimension of 5 in. or larger; includes beams & stringers(width more than 2 in. thickness) and posts & timbers (square; not morethan 2 in. out of square).c. Design values for the main size categories are determined following differentprocedures.Dimension Lumber- primarily from in-grade test program: ASTM D1990.Timbers – tests of small clear specimens: ASTM D2555 & D245Dimension Lumber: NDS Supplement Tables 4A, 4B, 4C, 4E, 4FTimbers: NDS Supplement Table 4D4.10a.b.c.d.e.f.g.4.11Visually graded is graded visually by inspecting and marking each piece. NDSSupplement Tables 4A, 4B, 4D, 4E, and 4FMSR refers to lumber graded mechanically by subjecting each piece to anondestructive test that measure E about the weak axis. A visual check is alsoincluded. MSR grading is only used for lumber with thickness 2 in. NDSSupplement Table 4CTimbers; 5 in. and thicker, width more than 2 in. thicknessDimension Lumber; 2 to 4 in. thick, 2 to 4 in. wideDimension Lumber; 2 to 4 in. thick, 4 in. and widerDimension Lumber, 2 to 4 in. thick, 5 in. and widerTimbers; 5 in. and thicker, width not more than 2 in. thicknessDimension Lumber; 2 to 4 in. thick, 2 to 4 in. wideDimension Lumber; 2 to 4 in. thick, 2 in. and wider, 10 ft long

Chapter 4 SolutionsPage 3 of 194.12 Visually graded sawn lumber other than Southern Pinea.b.c.d.e.f.g.h.Size10 x 1214 x 144x84x42 x 126 x 128 x 128 x 10Size NDS SupplementTable 4DTable 4DTable 4ATable 4ATable 4ATable 4DTable 4DTable 4D4.13 Visually graded sawn lumber – Southern Pinea.b.c.d.e.f.g.h.Size10 x 1214 x 144x84x42 x 126 x 128 x 128 x 10Size NDS SupplementTable 4DTable 4DTable 4BTable 4BTable 4BTable 4DTable 4DTable 4D4.14 Stress grades of visually graded Hem-Fira. Dimension Lumber (NDS Supplement Table 4A)Select Structural; No.1 & Btr; No.1; No.2; No.3; Stud; Construction;Standard; Utilityb. Beams and Stringers (NDS Supplement Table 4D)Select Structural; No.1; No.2c. Posts and Timbers (NDS Supplement Table 4D)Select Structural; No.1; No.2

Chapter 4 SolutionsPage 4 of 194.15 Stress grades of visually graded Southern Pinea. Dimension Lumber-stress grades vary with size (NDS Supplement Table 4B)2 in. – 4 in. thickDense Select Structural;2 in. – 12 in. wideSelect Structural;Non-Dense Select Structural;No.1 Dense; No.1; No.1 NonDense;No. 2 Dense; No. 2; No.2 NonDense;No.3 and Stud2 in. – 4 in. thickConstruction; Standard; Utility4 in. wide2 – 4 in. thick2 in. and widerDense Structural 86;Dense Structural 72;Dense Structural 65b. Beams & Stringers and c. Posts & Timbers (NDS Supplement Table 4D)5 in. x 5 in. and largerDense Select Structural;Select Structural;No. 1 Dense; No.1;No.2 Dense; No. 2;Dense Structural 86;Dense Structural 72;Dense Structural 65

Chapter 4 SolutionsPage 5 of 194.16Reference design values for No. 2 DF-LDimension Lumber (NDS Supplement Table 4A)c. 4 x 16 – Dimension Lumberd. 4 x 4 – Dimension Lumbere. 2 x 10 – Dimension LumberFb 900 psiFt 575 psiFv 180 psiFc 625 psiFc 1350 psiE 1,600,000 psiEmin 580,000 psiBeams and Stringers (NDS Supplement Table 4D)f. 6 x 12 – Beams & Stringersh. 10 x 14 – Beams & Stringers 875 psiFbFt 425 psiFv 170 psiFc 625 psi 600 psiFcE 1,300,000 psiEmin 470,000 psiPosts and Timbers (NDS Supplement Table 4D)a. 10 x 10 – Posts & Timbersb. 12 x 14 – Posts & Timbersg. 6 x 8 – Posts & TimbersFb 750 psiFt 475 psi 170 psiFvFc 625 psi 700 psiFcE 1,300,000 psiEmin 470,000 psi

Chapter 4 SolutionsPage 6 of 194.17Nominal design values (LRFD) for No. 2 DF-LDimension Lumber (NDS Supplement Table 4A)c. 4 x 16 – Dimension Lumberd. 4 x 4 – Dimension Lumbere. 2 x 10 – Dimension LumberFbn Fb (KF) 900 psi (2.54) 2.29 ksiFtn Ft (KF) 575 psi (2.70) 1.55 ksiFvn Fv (KF) 180 psi (2.88) 0.518 ksiFc n Fc (KF) 625 psi (1.67) 1.04 ksiFcn Fc (KF) 1350 psi (2.40) 3.24 ksiE 1,600,000 psiEmin-n Emin (KF) 580,000 psi (1.76) 1021 ksiBeams and Stringers (NDS Supplement Table 4D)f. 6 x 12 – Beams & Stringersh. 10 x 14 – Beams & Stringers Fb (KF) 875 psi (2.54) 2.22 ksiFbnFtn Ft (KF) 425 psi (2.70) 1.15 ksiFvn Fv (KF) 170 psi (2.88) 0.490 ksiFc n Fc (KF) 625 psi (1.67) 1.04 ksiFcn Fc (KF) 600 psi (2.40) 1.44 ksiE 1,300,000 psiEmin-n Emin (KF) 470,000 psi (1.76) 827 ksiPosts and Timbers (NDS Supplement Table 4D)a. 10 x 10 – Posts & Timbersb. 12 x 14 – Posts & Timbersg. 6 x 8 – Posts & TimbersFbn Fb (KF) 750 psi (2.54) 1.91 ksiFtn Ft (KF) 475 psi (2.70) 1.28 ksiFvn Fv (KF) 170 psi (2.88) 0.490 ksiFc n Fc (KF) 625 psi (1.67) 1.04 ksi Fc (KF) 700 psi (2.40) 1.68 ksiFcnE 1,300,000 psiEmin-n Emin (KF) 470,000 psi (1.76) 827 ksi(Φb 0.85)(Φt 0.8)(Φv 0.75)(Φc 0.9)(Φc 0.9)(Φs 0.85)(Φb 0.85)(Φt 0.8)(Φv 0.75)(Φc 0.9)(Φc 0.9)(Φs 0.85)(Φb 0.85)(Φt 0.8)(Φv 0.75)(Φc 0.9)(Φc 0.9)(Φs 0.85)4.18Adjustment Factora. Size Factor (CF)b. Time Effect Factor (λ)c. Load Duration Factor (CD)d. Repetitive Member Factor (Cr)e. Temperature Factor (Ct)f. Wet Service Factor (CM)g. Flat Use Factor (Cfu)Design values that may require adjustmentFb; Ft; FcFb; Ft; Fv; FcFb; Ft; Fv; FcFbFb; Ft; Fv; Fc; Fc ; E; EminFb; Ft; Fv; Fc; Fc ; E; EminFb

Chapter 4 SolutionsPage 7 of 194.19a. Load Duration Factor, CD: The strength of a wood member is affected by thetotal accumulated length of time that a load is applied. The shorter theduration of load, the higher the strength of a wood member. CD is themultiplier that adjusts reference design values (Fb, Ft, Fv and Fc) from normalduration (10 years) to other durations for ASD. See NDS 2.3.2 and AppendixB.b. Time Effect Factor, λ: The strength of a wood member is affected by the totalaccumulated length of time that a load is applied. λ is the multiplier thatadjusts the LRFD resistance of wood members (Fb, Ft, Fv and Fc) to ensurethat consistent reliability is achieved for load duration effects in variousLRFD load combinations. See NDS Appendix N.c. Wet Service Factor, CM: The moisture content (MC) of a wood memberaffects its load capacity. Most reference design values for sawn lumber applyto MC 19 percent in service. Higher moisture contents require reduction ofdesign values by CM. The following reference design values are subject toadjustment for increased moisture content: Fb, Ft, Fv, Fc , Fc, E and Emin. SeeNDS 4.3.3 and the Adjustment Factors sections of NDS Supplement Tables4A, 4B, 4C, 4D, 4E, and 4F.d. Size Factor, CF: The size of a wood member affects its strength. For visuallygraded Dimension Lumber, CF applies to Fb, Ft and Fc. See NDS 4.3.6.1 andthe Adjustment Factor section of NDS Supplement Tables 4A and 4F. ForTimbers, the size factor applies to Fb. See NDS 4.3.6.2 and the AdjustmentFactors section of NDS Supplement Table 4D. For Decking, CF applies onlyto Fb. See NDS 4.3.6.4 and the Adjustment Factors section of NDSSupplement Table 4E.e. Repetitive Member Factor, Cr: Applies to Dimension Lumber, but not toTimbers. When three or more wood members are spaced not more that 24 in.o/c and are connected together by a load distributing element (such assheathing), the bending design value Fb may be increased by Cr 1.15. Thisis a 15 percent increase over single member bending design values. The Cradjustment recognizes that failure of a single member in a repetitiveapplication will not mean failure of the overall system. The load will bedistributed to other members.4.20Wood has the ability to support higher stresses for short periods of time. Both theload duration factor (CD) and the time effect factor (λ) are employed to adjustwood strength properties based on the duration of applied design loads. The loadduration factor (CD) is used to adjust reference design values in allowable stressdesign (ASD), and is based on the shortest duration load in an ASD loadcombination. The time effect factor (λ) is used to adjust nominal design values inload and resistance factor design (LRFD), and is based on the dominant transientload in an LRFD load combination. Time effect factors (λ) are intended to ensureconsistent reliability for load duration effects across various load combinations.

Chapter 4 SolutionsPage 8 of 194.21a.b.c.d.e.Snow (S):Wind (W):Floor Live Load (L):Roof Live Load (Lr):Dead Load (D):CD 1.15CD 1.6CD 1.0CD 1.25CD 0.94.22a.b.c.d.e.1.2D 1.6S L:1.2D W L 0.5S:1.2D 1.6L 0.5S:1.2D 1.6Lr L:1.4D:λ 0.8λ 1.0λ 0.8 (for L due to occupancy)λ 0.8λ 0.64.23Compression perpendicular to grain (Fc ), average modulus of elasticity (E), andreduced modulus of elasticity for stability calculations (Emin) are not adjusted byCD in ASD calculations.Compression perpendicular to grain (Fc ), average modulus of elasticity (E) andreduced modulus of elasticity for stability calculations (Emin) are not adjusted by λin LRFD calculations.4.24Most reference design values apply to dry service conditions*. Dry serviceconditions are defined as:a. Sawn LumberMC 19 percentb. GlulamMC 16 percentWhen the moisture content exceeds these limits, the reference design values arereduced by a wet service factor CM that is less than 1.0* Southern Pine has CM included in some of the reference design values (NDSSupplement Table 4B). Many of the reference design values for Timbers (NDSSupplement Table 4D) have already been adjusted for CM.4.25The load capacity of wood decreases as the temperature increases. Reductions instrength caused by heating up to 150 degrees F are generally reversible when thetemperature returns to normal. Reductions in strength may not be reversible whenheating exceeds 150 degrees F. Reduction in strength occurs when the member issubjected to the full design capacity.When a wood member is consistently heated above 100 degrees F and issubjected to the full design load, an adjustment for temperature effects will berequired. This may occur in an industrial plant, but reductions are not normallyrequired in ordinary roof structures. See NDS 2.3.3 and Appendix C.

Chapter 4 SolutionsPage 9 of 194.26Pressure preservative treated wood has chemicals impregnated in the treated zonewhich resist attack by decay, termites and other insects, and marine borers.Reference design values apply directly to preservative treated wood, and anadjustment factor is not required unless the member has been incised to increasethe penetration of preservatives.Fire-retardant-treated wood has much higher concentrations of chemicals thanpreservative treated wood. At one time a 10 percent reduction in reference designvalues was specified. However, the reduction in strength varies with the treatingprocess, and the NDS refers the designer to the company providing the fireretardant treatment for appropriate reduction factors.4.27Wood that is continuously submerged in fresh water will not decay and does notneed to be preservative treated. However, wood that is partially submerged, orwood that undergoes cycles of submersion followed by exposure to theatmosphere, should be preservative treated. Wood that is submerged in saltwater should be preservative treated to protect from marine borers. Preservativetreated wood has an extensive record of resisting attack in both fresh water andsalt water environments.4.28Critical ASD load combination for a fully braced memberLoad/CD*ASD CombinationLoadCDD (roof floor)3 6 9k0.910 kD L9 10 19 k119 kD Lr9 5 14 k1.2511.2 kD 0.6W9 10.2 19.2 k1.612 kD ¾ (L Lr)9 ¾ (10 5) 20.25 k1.2516.2 kD ¾(0.6W L Lr) 9 ¾ (10.2 10 5) 27.75 k1.617.4 k* The largest load in this column defines the critical ASD load combination for afully braced member: D LNote: Actual loads (i.e., loads that have not been divided by CD) should be usedin design calculations. The load duration factor should then be used to adjust theappropriate reference design values. In this problem, the actual critical load is 19k and CD 1.0. The above analysis is used to define the critical combination onlyfor fully braced members, tension members, or connections.

Chapter 4 SolutionsPage 10 of 194.29Critical ASD load combination for a fully braced member[0.6W 0.6(17 k) 10.2 k] [0.7E 0.7(12 k) 8.4 k][S 18 k] [Lr 7 k]CombinationLoadCD Load/CD*D (roof floor)5 6 11 k0.912.2 kD L11 15 26 k126.0 kD S11 18 29 k1.1525.2 kD Lr11 7 18 k1.2514.4 kD 0.75(L S)11 0.75(15 18) 35.75 k1.1531.1 kD 0.75(L Lr)11 0.75(15 7) 27.5 k1.2522.0 kD (0.6W or 0.7E)11 10.2 21.2 k1.613.3 kD 0.75(0.6W or 0.7E) 11 0.75(10.2 15 18) 1.627.1 k 0.75L 0.75(Lr or S)43.4 k* The largest load in this column defines the critical ASD load combinationfor afully braced member: D 0.75(L S)Not

DESIGN OF WOOD STRUCTURES – ASD/LRFD (7. th. edition) 4.1 a. narrow, needle-like leaves; evergreens; conifers b. broadleafed; deciduous . c. softwoods . 4.2 See Fig. 4.3. a. Annual Ring – wood cells developed on the outside of the tree in one growing season . b. Latewood (summerwood) – smaller, darker, more dense, from late in growing season