00 Design of Wood Structures - Thiết kế công trình gỗ

i Design of Wood Structures—ASD/LRFD Donald E Breyer, P.E Professor Emeritus Department of Engineering Technology California State Polytechnic University Pomona, California Kenneth J Fridley, Ph.D Professor and Head Department of Civil, Construction, and Environmental Engineering University of Alabama Tuscaloosa, Alabama Kelly E Cobeen, S.E Principal Cobeen & Associates Structural Engineering Lafayette, California David G Pollock, Ph.D., P.E Associate Professor Department of Civil and Environmental Engineering Washington State University Pullman, Washington Sixth Edition McGraw-Hill New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto ii Copyright © 2007, 2003, 1998, 1993, 1988, 1980 by The McGraw-Hill Companies, Inc All rights reserved Printed in the United States of America Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher DOC/DOC ISBN-13: 978-0-07-145539-8 ISBN-10: 0-07-145539-6 The sponsoring editor for this book was Larry S Hager and the production supervisor was Pamela A Pelton It was set in Century Schoolbook by International Typesetting and Composition The art director for the cover was Anthony Landi Printed and bound by RR Donnelley McGraw-Hill books are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs For more information, please write to the Director of Special Sales, McGraw-Hill Professional, Two Penn Plaza, New York, NY 10121-2298 Or contact your local bookstore This book is printed on acid-free paper Information contained in this work has been obtained by The McGraw-Hill Companies, Inc (“McGraw-Hill”) from sources believed to be reliable However, neither McGraw-Hill nor its authors guarantee the accuracy or completeness of any information published herein and neither McGraw-Hill nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information This work is published with the understanding that McGraw-Hill and its authors are supplying information but are not attempting to render engineering or other professional services If such services are required, the assistance of an appropriate professional should be sought iii Contents Preface ix Nomenclature xiii Abbreviations xvi Chapter Wood Buildings and Design Criteria 1.1 1.1 Introduction 1.1 1.2 Types of Buildings 1.2 1.3 Required and Recommended References 1.4 1.4 Building Codes and Design Criteria 1.7 1.5 ASD and LRFD 1.8 1.6 Organization of the Text 1.9 1.7 Structural Calculations 1.10 1.8 Detailing Conventions 1.12 1.9 Fire-Resistive Requirements 1.12 1.10 Industry Organizations 1.13 1.11 References 1.13 Chapter Design Loads 2.1 2.1 Introduction 2.1 2.2 Dead Loads 2.3 2.3 Live Loads 2.7 2.4 Snow Loads 2.14 2.5 Soil Loads and Hydrostatic Pressure 2.21 2.6 Loads due to Fluids 2.21 2.7 Rain Loads 2.21 2.8 Flood Loads 2.22 2.9 Self-straining Loads 2.22 2.10 Wind Loads—Introduction 2.23 2.11 Wind Forces—Main Wind Force Resisting System 2.28 2.12 Wind Forces—Components and Cladding 2.37 2.13 Seismic Forces—Introduction 2.42 2.14 Seismic Forces 2.47 2.15 Seismic Forces—Primary System 2.61 iv 2.16 Seismic Forces—Wall Components 2.68 2.17 Load Combinations 2.73 2.18 Serviceability/Deflection Criteria 2.78 2.19 References 2.84 2.20 Problems 2.85 Chapter Behavior of Structures under Loads and Forces 3.1 3.1 Introduction 3.1 3.2 Structures Subject to Vertical Loads 3.1 3.3 Structures Subject to Lateral Forces 3.5 3.4 Lateral Forces in Buildings with Diaphragms and Shearwalls 3.12 3.5 Design Problem: Lateral Forces on One-Story Building 3.18 3.6 Design Problem: Lateral Forces on Two-Story Building 3.33 3.7 References 3.53 3.8 Problems 3.53 Chapter Properties of Wood and Lumber Grades 4.1 4.1 Introduction 4.1 4.2 Design Specification 4.2 4.3 Methods of Grading Structural Lumber 4.5 4.4 In-Grade Versus Clear Wood Design Values 4.7 4.5 Species and Species Groups 4.9 4.6 Cellular Makeup 4.11 4.7 Moisture Content and Shrinkage 4.12 4.8 Effect of Moisture Content on Lumber Sizes 4.20 4.9 Durability of Wood and the Need for Pressure Treatment 4.21 4.10 Growth Characteristics of Wood 4.24 4.11 Sizes of Structural Lumber 4.26 4.12 Size Categories and Commercial Grades 4.29 4.13 General Notation 4.33 4.14 Wet Service Factor CM 4.39 4.15 Load Duration Factor CD (ASD Only) 4.40 4.16 Time Effect Factor Ȝ (LRFD Only) 4.44 4.17 Size Factor CF 4.45 4.18 Repetitive Member Factor Cr 4.46 4.19 Flat Use Factor Cfu 4.47 4.20 Temperature Factor Ct 4.47 4.21 Incising Factor Ci 4.48 4.22 Resistance Factor (LRFD Only) 4.48 4.23 Format Conversion Factor KF (LRFD Only) 4.49 4.24 Design Problem: Adjusted Design Values 4.50 4.25 Future Directions in Wood Design 4.60 4.26 References 4.61 4.27 Problems 4.62 Chapter Structural Glued Laminated Timber 5.1 5.1 Introduction 5.1 5.2 Sizes of Glulam Members 5.1 v 5.3 Resawn Glulam 5.4 5.4 Fabrication of Glulams 5.5 5.5 Grades of Glulam Members 5.11 5.6 Adjustment Factors for Glulam 5.16 5.7 Design Problem: Adjusted Design Values 5.19 5.8 References 5.23 5.9 Problems 5.23 Chapter Beam Design 6.1 6.1 Introduction 6.1 6.2 Bending 6.2 6.3 Lateral Stability 6.14 6.4 Adjusted Bending Design Value Summary 6.23 6.5 Shear 6.29 6.6 Deflection 6.36 6.7 Design Summary 6.38 6.8 Bearing at Supports 6.40 6.9 Design Problem: Sawn Beam 6.47 6.10 Design Problem: Rough-Sawn Beam Using ASD 6.54 6.11 Design Problem: Notched Beam 6.56 6.12 Design Problem: Sawn-Beam Analysis 6.58 6.13 Design Problem: Glulam Beam with Full Lateral Support 6.62 6.14 Design Problem: Glulam Beam with Lateral Support at ft-0 in 6.68 6.15 Design Problem: Glulam Beam with Lateral Support at 48 ft-0 in 6.72 6.16 Design Problem: Glulam with Compression Zone Stressed in Tension 6.75 6.17 Cantilever Beam Systems 6.79 6.18 Lumber Roof and Floor Decking 6.83 6.19 Fabricated Wood Components 6.85 6.20 References 6.94 6.21 Problems 6.95 Chapter Axial Forces and Combined Bending and Axial Forces 7.1 Introduction 7.1 7.1 7.2 Axial Tension Members 7.2 7.3 Design Problem: Tension Member 7.7 7.4 Columns 7.11 7.5 Detailed Analysis of Slenderness Ratio 7.19 7.6 Design Problem: Axially Loaded Column 7.25 7.7 Design Problem: Capacity of a Glulam Column 7.30 7.8 Design Problem: Capacity of a Bearing Wall 7.36 7.9 Built-Up Columns 7.39 7.10 Combined Bending and Tension 7.42 7.11 Design Problem: Combined Bending and Tension 7.47 7.12 Combined Bending and Compression 7.52 7.13 Design Problem: Beam-Column 7.59 7.14 Design Problem: Beam-Column Action in a Stud Wall Using LRFD 7.64 7.15 Design Problem: Glulam Beam-Column Using ASD 7.73 7.16 Design for Minimum Eccentricity 7.80 vi 7.17 Design Problem: Column with Eccentric Load Using ASD 7.81 7.18 References 7.87 7.19 Problems 7.88 Chapter Wood Structural Panels 8.1 8.1 Introduction 8.1 8.2 Panel Dimensions and Installation Recommendations 8.3 8.3 Plywood Makeup 8.5 8.4 Species Groups for Plywood 8.8 8.5 Veneer Grades 8.11 8.6 Exposure Durability Classifications 8.13 8.7 Plywood Grades 8.14 8.8 Other Wood Structural Panels 8.17 8.9 Roof Sheathing 8.20 8.10 Design Problem: Roof Sheathing 8.23 8.11 Floor Sheathing 8.27 8.12 Design Problem: Floor Sheathing 8.30 8.13 Wall Sheathing and Siding 8.32 8.14 Stress Calculations for Wood Structural Panels 8.36 8.15 References 8.47 8.16 Problems 8.47 Chapter Diaphragms 9.1 9.1 Introduction 9.1 9.2 Basic Diaphragm Action 9.2 9.3 Shear Resistance 9.7 9.4 Diaphragm Chords 9.16 9.5 Design Problem: Roof Diaphragm 9.20 9.6 Distribution of Lateral Forces in a Shearwall 9.28 9.7 Collector (Strut) Forces 9.32 9.8 Diaphragm Deflections 9.37 9.9 Diaphragms with Interior Shearwalls 9.43 9.10 Interior Shearwalls with Collectors 9.47 9.11 Diaphragm Flexibility 9.51 9.12 References 9.54 9.13 Problems 9.55 Design of Wood Structures—ASD/LRFD:Sixth Edition yield modes, 11.22–11.26, 12.10–12.11 sketches, 11.23 sizes of nails and spikes, 12.13 spacing requirements, 12.59–12.63 splitting of lumber, 9.10, 10.6, 12.59–12.60 toenail, 12.27–12.29 seismic, not allowed for, 15.15 shear (lateral load), 12.27–12.29 withdrawal, 12.28–12.29, 12.54–12.56 types of nails, 12.2–12.7 withdrawal, 11.4–11.5, 12.52–12.58 adjusted ASD design value Wƍ, 12.52 adjusted LRFD design value , 12.53 adjustment factors, 12.52–12.53, 12.55 design example: basic withdrawal connection, 12.56–12.57 toenail withdrawal connection, 12.57–12.58 format conversion factor KF, 12.53, 12.55 load duration factor CD, 12.52, 12.55 penetration p, 12.7–12.9, 12.52–12.53, 12.56 toenail pW, 12.28–12.29, 12.57 reference design value W, 12.52–12.53 resistance factor , 12.53, 12.55 seismic, not allowed for, 15.16 tabulated design value w, 12.52 temperature factor Ct, 12.52–12.53, 12.55 time effect factor Ȝ, 12.53, 12.55 toenail factor Ctn, 12.52–12.55 wet service factor CM, 12.52–12.55 Nail plates, 11.6–11.7 Nail popping, 8.4–8.5 Nail sizes, 12.13 Nail types, 12.2–12.7 National Design Specification for Wood Construction (2005 NDS): Commentary, 4.4, 11.25, 12.59–12.63 example reference to, 1.6–1.7 required reference, 1.4–1.7 Supplement, 4.3–4.4 NEHRP Provisions and Commentary, 2.42, 2.51 Net area: columns, 7.11–7.12 tension members, 7.2–7.6, 13.30–13.34 Net design wind pressure pnet30 (components and cladding), 2.25–2.26 Net overturning moment, 16.14–16.29 Nominal LRFD design value, 4.36–4.37, 6.7, 6.20–6.21, 6.24–6.28, 6.31, 6.40–6.41, 6.44, 7.6, 7.13, 7.17–7.18, 7.43–7.44, 7.54–7.58, 11.12–11.13, 12.23, 12.53, 13.19, 13.31, 13.63, 13.74 Nominal lumber size, 4.26–4.29 Notation system for wood design, 4.33–4.39 Notching of beams: bending strength, effect on, 6.13–6.14 mechanical reinforcement, 6.35 shear strength, effect on, 6.34–6.36, 6.56–6.57, 14.10–14.13 splitting, 6.34–6.35, 14.10–14.14 stress concentrations, 6.34–6.36, 6.57 I_13 Occupancy category, 2.15 Oilborne treatments, 4.23 Open structure (wind), 2.28 Ordinary plain concrete shearwalls, 2.60–2.61 Ordinary plain masonry shearwalls, 2.60–2.61 Ordinary steel moment frames, 2.60 Oriented strand board (OSB), 4.1, 8.18, 8.19 Out-of-plane offset (seismic irregularity), 16.9–16.10 Overturning, 10.11–10.13, 10.17–10.22, 10.35–10.36, 16.14–16.29 basic static problem, 16.16–16.23 design example, 10.17–10.22 seismic, 16.23–16.29 with irregularity, 16.27–16.29 wind, 2.36–2.37, 16.19–16.22 (See also Anchorage) P-ǻ effect, 7.52–7.59 Panelized roof system, 1.2, 3.2–3.3, 8.20 Parallel strand lumber (PSL), 6.86, 6.88–6.89 Peeler logs, 8.5 Penetration: lag bolt connections: shear (laterally loaded) p, 13.59, 13.63, 13.65 withdrawal pw, 13.73 nail connections: shear (laterally loaded) p, 12.7–12.9, 12.22, 12.25 toenail shear (laterally loaded) pL, 12.27–12.28 toenail withdrawal pW, 12.28–12.29 withdrawal, 12.7–12.9, 12.52–12.53 pressure treated lumber, of chemicals, 4.23 Pentachlorophenol, 4.23 Perforated shearwalls, 10.7–10.8, 10.28–10.33 Period of vibration T, 2.52–2.55 Piers (see Shearwalls) Plan (horizontal) seismic irregularity, 16.3–16.10 Plastic hinge, 11.17–11.23, 12.11, 13.3 Design of Wood Structures—ASD/LRFD:Sixth Edition Plywood: allowable stresses, 8.8–8.11, 8.36–8.43 blocking, 8.21–8.23, 9.8–9.10 cross-lamination of layers, 8.6–8.8, 8.35 design aids, 8.2–8.3 diaphragms (see Diaphragms) dimensions, 3.4, 8.3–8.5, 8.14 sized for spacing, 8.4 edge support requirements, 8.16, 8.21–8.22, 9.7, 9.15 Exposure and 2, 8.14 exposure durability classifications, 8.13–8.14 exterior-type, 8.13–8.14 floor sheathing, 8.25–8.29 design example, 8.29–8.30 glue, 8.13–8.14 grades, 8.11–8.13, 8.14–8.17 sanded panels, 8.14–8.15 sheathing grades, 8.15–8.17 installation recommendations, 8.3–8.5 interior, 8.13 with exterior glue, 8.13–8.14 layers, 8.6–8.9 Marine grade, 8.12, 8.36 nail popping, 8.4–8.5 nail strength in, 9.8, 9.14–9.15 panel clips, 8.21–8.22 peeler logs, 8.5 performance standard, 8.14–8.15 plies, 8.7–8.8 pressure treated, 8.13 Product Standard PS (all veneer panels), 8.14, 8.19, 8.36 Product Standard PS2, 8.18, 8.19 rolling shear, 8.37–8.39 roof sheathing, 8.20–8.23 design example, 8.23–8.25 sanded panels, 8.14–8.15, 8.36 section properties, 8.8, 8.35–8.37 shear through the thickness, 8.38–8.39 shearwalls (see Shearwalls) sheathing grades, 8.16–8.17 sheathing loads, 8.2–8.3, 8.36–8.37 span rating, 8.16–8.17, 8.20–8.21 species groups, 8.8–8.11, 8.36 stress calculations, 8.8, 8.34–8.43 strong and weak orientation (sheathing loads), 8.8, 8.21 Structural I, 8.11, 8.16, 8.36, 9.12, 10.4 Sturd-1–Floor, 8.18 thickness, 9.1 tongue-and-groove edges, 8.21–8.22 touch sanded panels, 8.14–8.15, 8.36 unsanded panels, 8.14–8.17, 8.36 veneer, 8.5–8.8 grades, 8.11–8.13 wall sheathing and siding, 8.31–8.34, 10.3–10.5 Ponding on roofs, 2.83–2.84 Post-and-beam framing, 3.1 Posts and Timbers (P&T), 4.30–4.31, 6.10, 7.27–7.30 I_14 Prescriptive construction provisions, 2.2 Preservative treatments, 4.23–4.24 Pressure treated wood, 4.23–4.24 fire-retardant treated, 4.24 penetration and retention, 4.23 preservative treated, 4.23 wall plate (bottom), 4.23 Probability-based design, 4.61 Quality assurance: glulam, 5.10 plywood, 8.3–8.15, 8.19 Rain load, 2.21 Reaction wood, 4.26 Recommended Lateral Force Requirements and Commentary (Blue Book), 2.43–2.44 Reentrant comer (seismic irregularity), 16.4–16.5 Reference design values, 4.3–4.4, 4.7–4.9, 4.35, 5.13 Regular structure (seismic), 2.44–2.45, 16.1–16.5 Reinforcing steel as diaphragm chord, 9.18–9.19, 9.25–9.26 Relative rigidity (see Shearwall piers) Reliability-based design, 4.61 Repetitive member factor Cr, 4.46–4.47, 6.7–6.8, 6.24, 6.47–6.53 Resistance factors, 4.48–4.49 Resisting moment (overturning), 2.36–2.37 Response modification factor, R-factor, 2.58–2.61 Response spectrum, 2.53–2.57 Rigid diaphragm (see Diaphragms) Rolling shear, 8.38–8.39 Roof sheathing, 8.20–8.25 (See also Plywood, roof sheathing) Roof slope: beam span, effect on, 2.13–2.14 combining loads, effect on, 2.13–2.14 minimum, to prevent ponding, 2.83–2.84 Roof slope factor (snow), 2.18 Design of Wood Structures—ASD/LRFD:Sixth Edition Roofs: panelized, 1.2, 3.2–3.3, 8.20 ponding on, 2.83–2.84 Rough sawn lumber, 4.27 beam design example, 6.54–6.57 Row spacing: bolts, 13.27–13.29 lag bolts, 13.27–13.29, 13.65 nails, 12.59–12.63 Row tear-out, 13.30–13.47 Sapwood, 4.11–4.12 Sawn lumber (see Lumber) Scarf joint, 5.9 Seasoning, 2.80, 4.14 Section properties, 4.28–4.29 Seismic design spectral response acceleration one second, SD1, 2.50–2.55 short period, SDS, 2.50–2.55 element over-strength ȍ0, 2.59 equivalent lateral force procedure, 2.43–2.68 light-framed walls sheathed with steel sheets, 2.60–2.61 light-framed walls sheathed with wood structural panels, 2.60–2.61 light-framed walls with shear panels of all other materials, 2.60–2.61 mapped spectral accelerations one second S1, 2.51 short period SS, 2.51 maximum considered earthquake, 2.51 maximum considered spectral response accelerations one second SM1, 2.51 short period SMS; 2.51 occupancy category, 2.57–2.58 ordinary plain concrete shearwalls, 2.60–2.61 ordinary plain masonry shearwalls, 2.60–2.61 ordinary steel moment frames, 2.60–2.61 response modification factor, R-factor, 2.58–2.61 Seismic Design Category, SDC, 2.58 seismic response coefficient, CS, 2.49–2.50 simplified alternative structural design procedure, 2.43 site coefficient, Fa, and Fv, 2.51 site (soil) class, A through F, 2.51 special reinforced concrete walls, 2.60–2.61 special reinforced masonry walls, 2.60–2.61 wall component forces, Fc, 2.66–2.73, 3.13 Seismic Design Category, SDC, 2.58 Seismic forces (see Loads and forces) Seismic irregularity, 16.3–16.13 design penalties, 16.10–16.13 diaphragm discontinuity, 16.5–16.8 in-plane offset, 16.10 mass, 16.4 I_15 out-of-plane offset, 16.9–16.10 plan, 16.3–16.10 reentrant comer, 16.4–16.5 torsional, 16.4 vertical, 16.10 Seismic response coefficient, Cs, 2.49–2.50 Seismic tie, 14.28–14.29, 14.32–14.33 (See also Subdiaphragms, subchords; Subdiaphragms, subties) Self-straining load, 2.22 Shakes, 4.14–4.15, 4.24–4.26 Shear (laterally loaded) connections, 11.2–11.3, 11.7–11.9 adjusted design value Zƍ, 11.5 reference design value Z, 11.5 Shear panels (see Shearwalls) Shear plate connectors, 11.2–11.3, 13.77–13.83 Shear plugs, 13.30, 13.32 Shear stresses: at connections, 13.30–13.39, 13.45, 13.47–13.55, 14.16 (See also Beams, shear stresses) Shearwalls: anchorage (see Anchorage) blocking, 10.6 chords, 10.11–10.13 anchorage connection, 10.35–10.39, 16.20 nailed tie splice, 12.42–12.45 collector, 10.3 (See also Collector (strut)) defined, 3.8 deflections, 10.39–10.44 design for continuity around openings, 10.7–10.8, 10.22–10.28 distribution of lateral force to, 9.28–9.31 concrete and masonry piers, 9.29–9.31 wood shear panels, 9.28–9.31 drywall, 10.1, 10.9–10.10 effectiveness, 9.49–9.51 fiberboard, 10.1, 10.9–10.10 gypsum sheathing, 10.1, 10.9–10.10 height-to-width ratio, 10.8–10.10 interior, 9.43–9.51 load duration factor CD, 10.4 lumber sheathing, 10.1, 10.9–10.10 nailing at plywood grooves, 8.34, 10.5 nailing requirements, 10.4–10.6 Design of Wood Structures—ASD/LRFD:Sixth Edition Shearwalls (Cont.): overturning, 10.11–10.13, 10.17–10.22 perforated, 10.28–10.33 piers (concrete or masonry), 9.30 plaster and stucco, 10.1, 10.9–10.10 plywood, 10.1, 10.3–10.9 relative rigidity: concrete and masonry, 9.29–9.31 wood, 9.28–9.29 sheathing materials, 10.1 sheathing thickness, 8.31–8.34, 10.3 unit shear calculation: one-story building, 3.30–3.33 two-story building, 3.44–3.48 unit shear distribution, 9.28–9.30 wood structural panels, 10.1, 10.3–10.10 Sheathing: plywood (see Plywood) Shrinkage, 4.28–4.29 built-in stresses caused by, 13.21–13.23 calculations, 4.16–4.18 multistory building example, 4.17–4.18 checking, 4.14–4.15 cross-grain cracking, 13.21–13.23 distress caused by, 4.20 longitudinal (parallel to grain), 4.15, 4.17–4.18 perpendicular to grain (cross grain), 4.15, 4.17–4.18, 13.21–13.23 radial, tangential, and volumetric, 4.15, 4.17–4.18 shrinkage value (SV), 4.18 (See also Cross-grain cracking) Sidesway, column, 7.23–7.25 Simplified alternative structural design procedure (seismic), 2.43 Simplified design wind pressure, ps30 (main windforce-resisting systems), 2.25 Simplified method (wind), 2.23–2.41 Site (soil) class, A through F, 2.51 Size categories (see Lumber) Size factor CF: Dimension lumber, 4.45–4.46 bending, 6.7, 6.47–6.53, 6.58–6.61, 7.44–7.45, 7.49–7.51, 7.55, 7.61, 7.66 compression, 7.12–7.13, 7.26–7.30, 7.37, 7.40–7.41, 7.54, 7.61–7.63, 7.66–7.72 tension, 7.6–7.7, 7.44, 7.49–7.50 Timbers, 4.46 bending, 6.7, 6.55 Slenderness ratio: beam RB, 6.18–6.22 effective unbraced lengths, 6.18–6.19 design examples, 6.68–6.74, 6.77–6.78 unbraced length, 6.15–6.16 column (le/d), 7.12–7.25, 7.53–7.56 bracing conditions, 7.20–7.25 effective length factors, 7.22–7.24 end conditions, 7.20–7.25 for P-ǻ amplification, 7.53–7.56 sidesway, 7.23–7.25 unbraced length, 7.19–7.25 Slope of grain, 4.26 Sloping beam method, 2.19–2.20 I_16 Sloping roof (loads on), 2.13–2.14, 2.19–2.20 horizontal plane method, 2.19–2.20 sloping beam method, 2.19–2.20 Snow exposure category, 2.16–2.17 exposure factor, 2.16–2.17 ground snow load, 2.15 importance factor, 2.15–2.16 roof slope factor, 2.18 thermal factor, 2.17 Snow load, 2.14–2.21 Softwoods, 4.11 Soil load, 2.21 Soil-structure resonance, 2.54–2.55 Spacing of fasteners: bolt connections, 13.25–13.30 lag bolt connections, 13.25–13.30, 13.65 nail connections, 12.59–12.63 Span length: for bending, 6.4 for shear, 6.32–6.33 Special Design Provisions for Wind and Seismic (SDPWS), 9.7, 9.11–9.15, 10.3–10.11 Special reinforced concrete walls, 2.60–2.61 Special reinforced masonry walls, 2.60–2.61 Species: groups, 4.9–4.10 individual, 4.9–4.10 Spike grids, 11.6–11.7 Split ring connectors, 11.2–11.3, 13.77–13.81 Splits, 4.24–4.26 Splitting of lumber: cross-grain tension, 4.20, 13.21–13.23, 14.8–14.9 exposed end grain, 14.12 nailing, 9.14, 10.6 notching, 6.34–6.36, 14.11–14.13 Spreadsheet: applications in wood design, 1.10, 11.9 template, 1.10, 6.2, 11.9 Springwood, 4.12 Design of Wood Structures—ASD/LRFD:Sixth Edition Standard Building Code, 1.7, 2.42 Standard net size (lumber), 4.26 Staples, 8.21–8.22 (See also Diaphragms, blocked) Steel reinforcing as diaphragm chord, 9.18–9.19, 9.25–9.26 Steel side plate factor Cst (for timber connectors), 13.82 Story forces (seismic), 2.61–2.66, 3.13 Strength ratio, 4.8 Stress concentration factor (shear), 6.34–6.35, 13.47–13.49 Stress concentrations, 6.14, 6.34–6.36, 6.56–6.57, 13.47–13.49 Stress grades (see Lumber) Structural calculations: accuracy, 1.11 significant figures, 1.11 units, 1.11–1.12 Structural composite lumber (SCL), 6.86–6.91 laminated veneer lumber (LVL), 6.86–6.87, 6.90 parallel strand lumber (PSL), 6.88–6.89 Structural detailing, 1.12 Structural Engineers Association of California (SEAOC), 2.48 Structural Engineers Association of Washington (SEAW), 2.23 Structural glued laminated timber (see Glulam) Structural Joists and Planks, 4.30–4.32 Structural Light Framing, 4.30–4.32 Structural particleboard (see Wood structural panels) Strut (see Collector (strut)) Stud: beam column action, 7.64–7.72 column action, bearing wall, 7.20–7.21, 7.36–7.38 grade, 4.30–4.32 Subdiaphragms, 15.31–15.45 anchorage force, 15.31 continuous cross tie requirement, 15.31–15.32 design example, 15.33–15.35, 15.38–15.45 unit shear capacity (calculation), 15.38–15.45 proportions (span-to-width ratio), 15.16 subchords, 15.33–15.35 subties, 15.33 Summerwood, 4.12 Suspending loads from beams, 6.32, 14.14–14.16 Swelling (due to increase in MC), 4.20 Symmetry, need for structural, 9.53 System ductility, 2.45 Temperature factor Ct, 4.47–4.48, 5.17 bending stress, 6.7–6.8, 6.24–6.28 column stress, 7.12–7.13, 7.15–7.16 compression parallel to grain (end grain bearing), 6.44–6.45 compression perpendicular to grain, 6.40–6.41 connections: bolts, 13.19, 13.23 lag bolts, 13.63–13.64, 13.74 nails, 12.23, 12.25, 12.52–12.53, 12.55 split ring and shear plate connectors, 13.82 modulus of elasticity, 6.36–6.37, 7.17–7.18 I_17 shear stress, 6.31–6.32 tension stress, 7.6–7.7 Template, spreadsheet and equation-solving software,1.10, 6.2, 11.9 Tension, fasteners in, 11.4–11.5 Tension members, 7.1–7.11 , 4.34, 7.2, 7.6 adjusted adjusted , 4.36, 7.3–7.4, 7.6 actual stress ft, 4.34, 7.2 adjustment factors, 7.6–7.7 combined with bending (see Combined stresses) design example, 7.7–7.11 format conversion factor KF, 4.49–4.50, 7.6 incising factor Ci, 4.48, 7.6–7.7 load duration factor CD, 4.40–4.44, 7.6 net area, 7.2, 7.4–7.6 reference design value Ft, 4.34, 4.36, 7.6 resistance factor , 4.48–4.49, 7.6 size factor CF, 4.45–4.46, 7.6–7.7 temperature factor Ct, 4.47–4.48, 7.6–7.7 time effect factor Ȝ, 4.44–4.45, 7.6 wet service factor CM, 4.39–4.40, 7.6–7.7 Tension perpendicular to grain, 4.20, 6.2 Tension stresses at connections, 13.30–13.39 Termites, 4.22–4.23 Thermal factor (snow), 2.17 Threaded hardened steel nails, 12.2–12.4, 12.12, 12.55 Tie straps, 14.30, 14.33 Timber connectors (see Shear plates; Split nngs) Timber Construction Manual (TCM), 1.6, 5.4, 6.85 Timbers (see Lumber) Time effect factor Ȝ, 4.44–4.45, 12.24, 12.55, 13.20, 13.64 Design of Wood Structures—ASD/LRFD:Sixth Edition Toenail factor Ctn, 12.23, 12.27–12.29, 12.52–12.53, 12.55, 15.13 Toenails: shear (laterally loaded) connection, 12.27–12.29 withdrawal connection, 12.27–12.29, 12.54–12.56 Torsional seismic irregularity, 16.4 Transverse direction (defined), 2.66–2.67 Treated zone (pressure treated lumber), 4.22–4.23 Tributary area, 2.5–2.8, 3.3 Trusses: connection details, 14.16–14.18 horizontal LFRS, 3.8–3.10 light-frame wood, 6.86, 6.92–6.93 metal plate connected, 6.92–6.93, 11.6–11.7 vertical LFRS, 3.6–3.7 Types of construction (fire-resistive requirements), 1.12–1.13 Unbalanced loads, 2.13, 6.80–6.81 Unbraced length: of beams, 6.15–6.16 cantilever beam systems, 6.82 effective unbraced length, 6.18–6.19 of columns, 7.19–7.25 effective unbraced lengths, 7.19–7.25 UNDERLAYMENT, 8.25–8.31 Uniform Building Code (UBC), 1.7, 2.42 United States Geological Survey (USGS), 2.51 Units: conversion (pounds to kips), 1.11 conversion (U.S Customary to SI), D.2–D.3 SI Metric, 1.12, D.1–D.3 U.S Customary, 1.11–1.12, D.1–D.3 Uplift (wind), 2.29–2.36 roof connection, 14.9 overturning, 2.36–2.37, 10.30, 16.23–16.27 Variability in wood, 4.8, 6.37–6.38 Veneer, 6.86–6.87, 8.5–8.7, 8.11–8.13 Vertical load carrying system, 3.1–3.5, 8.1 Vertical load and lateral force (distinction), 2.1–2.2 Vertical loads, 2.1–2.2, 3.1–3.2 dead, 2.3–2.7 live, 2.7–2.14, 3.4 (See also Loads) Vertical seismic irregularity, 16.10 Vertical truss, 3.6–3.8 Visually graded lumber (see Lumber) Volume factor CV, 5.17–5.18, 6.7–6.8, 6.62–6.67, 6.75–6.79, 7.79 Waferboard (see Wood structural panels) Wall: I_18 anchors, 14.32, 15.17–15.30 bearing, 3.2 bearing wall system (LFRS), 1.2, 2.60 bracing (prescriptive construction), 2.2 column capacity of a stud, 7.20–7.21, 7.36–7.38, 7.64–7.72 piers, 9.28–9.31 sheathing and siding, 8.31–8.34 (See also Shearwalls) Wall component forces (seismic), Fc, 2.68–2.73, 3.13 Waterborne oxides, 4.23–4.24 Wet service factor CM, 4.39–4.40 bending stress, 6.7, 6.24–6.28 column stress, 7.12–7.13, 7.15–7.16 compression parallel to grain (end grain bearing), 6.44–6.45 compression perpendicular to grain, 6.40–6.41 connections: bolts, 13.19–13.23 lag bolts, 13.63–13.64, 13.74 nails, 12.23–12.25, 12.52–12.53, 12.55 split ring and shear plate connectors, 13.82 glulam, 5.16 modulus of elasticity, 6.36–6.37, 7.17–7.18 sawn lumber, 4.39 shear stress, 6.31 tension stress, 7.6–7.7 Wind analytical method, 2.23 design wind pressure, pnet, (components and cladding), 2.25 design wind pressure, ps, (main windforce-resisting system), 2.24 main windforce-resisting system, 2.23–2.24 net design wind pressure, pnet30, (components and cladding), 2.25–2.26 simplified method, 2.23–2.41 simplified design wind pressure, ps30, (main windforce-resisting systems), 2.25 Wind (see Loads and forces) Withdrawal connections, 11.4–11.5 adjusted design value Wƍ, 11.5 reference design value W, 11.5 Wood cells, 4.11– 4.12 Wood screws, 11.6, 13.55–13.56 Wood structural panels, 4.1, 8.1–8.3, 8.17–8.20, 8.34–8.43 composite panels (COMPLY), 8.19 diaphragms (see Diaphragms) Design of Wood Structures—ASD/LRFD:Sixth Edition dimensions, 8.3–8.5 edge support requirements, 8.21–8.23 fiber-reinforced plywood, 8.19 floor sheathing, 8.25–8.29 installation recommendations, 8.3–8.5 oriented strand board (OSB), 8.18, 8.19 performance standard, 8.14–8.15 plywood (see Plywood) prescriptive standard, 8.17 roof sheathing, 8.16–8.17, 8.20–8.23 shearwalls (see Shearwalls) span rating, 8.20–8.21 stress calculations, 8.34–8.43 structural particleboard, 8.19 Wood structural panels (Cont,): waferboard, 8.19 wall sheathing and siding, 8.31–8.34 Wood variability, 4.8, 6.37–6.38 Working stress design (WSD), 4.33–4.61 Yield limit equations, 11.24–11.25 bolt connections, 13.5–13.18 lag bolt (lag screw) connections, 13.5–13.7, 13.59–13.62 nails, 12.7–12.11 Yield model (dowel fasteners), 11.1, 11.7–11.9, 11.22–11.25 adjusted design value Zƍ, 11.5, 11.12–11.13 adjustment factors, 11.5 angle of load to grain 6, 11.11–11.15 bending yield strength Fyb, 11.10 bolts, 13.3–13.4 lag bolts, 13.57 nails, 12.11–12.13 connection geometry, 11.10–11.12, 11.23 dowel bearing strength, 11.10–11.17 dowel-type fasteners, 11.1, 11.8 embedding strength, 11.10, 11.13 glulam members, 11.16 material properties, 11.10–11.11, 11.23 metal side plate, 11.10–11.12, 11.15 modes (yield), 11.22–11.26 summary sketches, 11.23 oriented strand board (OSB), 11.17 plastic hinge in fastener, 11.17–11.22 plywood, 11.17 reference design value Z, 11.5, 11.24–11.25 shear (laterally loaded) connection, 11.2–11.3, 11.8 structural panels, 11.17 yield limit mechanism, 11.8, 11.22–11.26 Ylinen column equation, 6.22–6.23, 7.15–7.19, 7.53–7.56 basis for beam stability factor, 6.22–6.23 Z flashing, 8.34 I_19 Zinc-coated (galvanized) nails, 12.4–12.5 Design of Wood Structures—ASD/LRFD:Sixth Edition I_20 ABOUT THE AUTHORS DONALD E BREYER, P.E., is Professor Emeritus of Engineering Technology and Civil Engineering, California State Polytechnic University KENNETH J FRIDLEY, Ph.D., is Professor and Head, Department of Civil, Construction, and Environmental Engineering, University of Alabama He is an active member of the Wood Design Committee of the American Forest & Paper Association (AF&PA), which oversees the development of all design guides and specification, including the NDS, related to wood construction He is also a member of the American Society of Civil Engineers’ LRFD Engineered Wood Standards Committee KELLY E COBEEN, S.E., is Principal, Cobeen & Associates Structural Engineering, Lafayette, California She is an active participant in the development of codes, standards, and guideline documents DAVID G POLLOCK, Ph.D., P.E., is Associate Professor, Department of Civil and Environmental Engineering, Washington State University Prior to joining the faculty at WSU, he was Director of Engineering for the AF&PA American Wood Council