Structural Timber Design to Eurocode 5

Jack Porteous is a consulting engineer specialising in timber engineering. He is a Chartered Engineer, Fellow of the Institution of Civil Engineers and Member of the Institution of Structural Engineers. He is a member of the BSI committee B/525/5, which is responsible for the structural use of timber in the UK and for the production of UK input to EN 1995-1-1. He is a member of the editorial advisory panel of the ICE publication, Construction Materials and a visiting scholar and lecturer in timber engineering at Edinburgh Napier University. Abdy Kermani is the Professor of Timber Engineering and Director of the UK's Centre for Timber Engineering at Edinburgh Napier University. He is a Chartered Engineer, Fellow of the Institution of Structural Engineers and Fellow of the Institute of Wood Science. He has served on the organising committees and editorial technical advisory boards of international journals and conferences on timber engineering and the innovative use of construction materials. He is the appointed principal consultant to several UK and European structural and timber engineering firms and manufacturing industries.

Preface to the Second Edition xii 1 Timber as a Structural Material 1 1.1 Introduction 1 1.2 The structure of timber 2 1.3 Types of timber 3 1.3.1 Softwoods 3 1.3.2 Hardwoods 4 1.4 Natural characteristics of timber 4 1.4.1 Knots 4 1.4.2 Slope of grain 5 1.4.3 Reaction wood 5 1.4.4 Juvenile wood 6 1.4.5 Density and annual ring widths 6 1.4.6 Conversion of timber 7 1.4.7 Seasoning 11 1.4.8 Seasoning defects 11 1.4.9 Cracks and fissures 11 1.4.10 Fungal decay 11 1.5 Strength grading of timber 11 1.5.1 Visual grading 12 1.5.2 Machine grading 12 1.5.3 Strength classes 15 1.6 Section sizes 16 1.7 Engineered wood products (EWPs) 16 1.7.1 Glued-laminated timber (glulam) 18 1.7.2 Cross-laminated timber (CLT or X-Lam) 20 1.7.3 Plywood 21 1.7.4 Laminated veneer lumber (LVL) 25 1.7.5 Laminated Strand Lumber (LSL), TimberStrand (R) 25 1.7.6 Parallel Strand Lumber (PSL), Parallam (R) 27 1.7.7 Oriented Strand Board (OSB) 27 1.7.8 Particleboards and fibre composites 39 1.7.9 Thin webbed joists (I-joists) 39 1.7.10 Thin webbed beams (box beams) 41 1.7.11 Structural Insulated Panels (SIPs) 42 1.8 Suspended timber flooring 44 1.9 Adhesive bonding of timber 46 1.10 Preservative treatment for timber 47 1.11 Fire safety and resistance 48 1.12 References 50 2 Introduction to Relevant Eurocodes 52 2.1 Eurocodes: General structure 52 2.2 Eurocode 0: Basis of structural design (EC0) 54 2.2.1 Terms and definitions (EC0, 1.5) 54 2.2.2 Basic requirements (EC0, 2.1) 55 2.2.3 Reliability management (EC0, 2.2) 56 2.2.4 Design working life (EC0, 2.3) 56 2.2.5 Durability (EC0, 2.4) 57 2.2.6 Quality management (EC0, 2.5) 58 2.2.7 Principles of limit state design: General (EC0, 3.1) 58 2.2.8 Design situations (EC0, 3.2) 58 2.2.9 Ultimate limit states (EC0, 3.3) 59 2.2.10 Serviceability limit states (EC0, 3.4) 59 2.2.11 Limit states design (EC0, 3.5) 60 2.2.12 Classification of actions (EC0, 4.1.1) 60 2.2.13 Characteristic values of actions (EC0, 4.1.2) 60 2.2.14 Other representative values of variable actions (EC0, 4.1.3) 61 2.2.15 Material and product properties (EC0, 4.2) 62 2.2.16 Structural analysis (EC0, 5.1) 62 2.2.17 Verification by the partial factor method: General (EC0, 6.1) 65 2.2.18 Design values of actions (EC0, 6.3.1) 65 2.2.19 Design values of the effects of actions (EC0, 6.3.2) 66 2.2.20 Design values of material or product properties (EC0, 6.3.3) 66 2.2.21 Factors applied to a design strength at the ULS 71 2.2.22 Design values of geometrical data (EC0, 6.3.4) 71 2.2.23 Design resistance (EC0, 6.3.5) 71 2.2.24 Ultimate limit states (EC0, 6.4.1-6.4.5) 73 2.2.25 Serviceability limit states: General (EC0, 6.5) 77 2.3 Eurocode 5: Design of Timber Structures - Part 1-1: General - Common Rules and Rules for Buildings (EC5) 79 2.3.1 General matters 79 2.3.2 Serviceability limit states (EC5, 2.2.3) 80 2.3.3 Load duration and moisture influences on strength (EC5, 2.3.2.1) 84 2.3.4 Load duration and moisture influences on deformations (EC5, 2.3.2.2) 84 2.3.5 Stress-strain relations (EC5, 3.1.2) 87 2.3.6 Size and stress distribution effects (EC5, 3.2, 3.3, 3.4 and 6.4.3) 87 2.3.7 System strength (EC5, 6.6) 90 2.4 Symbols 93 2.5 References 98 3 Using Mathcad (R) for Design Calculations 100 3.1 Introduction 100 3.2 What is Mathcad? 100 3.3 What does Mathcad do? 101 3.3.1 A simple calculation 101 3.3.2 Definitions and variables 102 3.3.3 Entering text 102 3.3.4 Working with units 103 3.3.5 Commonly used Mathcad functions 104 3.4 Summary 106 3.5 References 106 4 Design of Members Subjected to Flexure 107 4.1 Introduction 107 4.2 Design considerations 107 4.3 Design value of the effect of actions 109