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EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
EN 199511:2004+A1
June 2008
ICS 91.010.30; 91.080.20
Incorporating corrigendum June 2006
Supersedes ENV 199511:1993
English version
Eurocode 5: Conception et calcul des structures en bois  Partie 11 : Généralités  Règles communes et règles pour les bâtiments  Eurocode 5: Bemessung und Konstruktion von Holzbauten  Teil 11: Allgemeines  Allgemeine Regeln und Regeln für den Hochbau 
This European Standard was approved by CEN on 16 April 2004.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Uptodate lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2004 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.
Ref. No. EN 199511:2004: E
1Page  
Foreword  7  
SECTION 1 GENERAL  10  
1.1  SCOPE  10  
1.1.1  Scope of EN 1995  10  
1.1.2  Scope of EN 199511  10  
1.2  NORMATIVE REFERENCES  11  
1.3  ASSUMPTIONS  13  
1.4  DISTINCTION BETWEEN PRINCIPLES AND APPLICATION RULES  13  
1.5  TERMS AND DEFINITIONS  13  
1.5.1  General  13  
1.5.2  Additional terms and definitions used in this present standard  13  
1.6  SYMBOLS USED IN EN 199511  14  
SECTION 2 BASIS OF DESIGN  19  
2.1  REQUIREMENTS  19  
2.1.1  Basic requirements  19  
2.1.2  Reliability management  19  
2.1.3  Design working life and durability  19  
2.2  PRINCIPLES OF LIMIT STATE DESIGN  19  
2.2.1  General  19  
2.2.2  Ultimate limit states  19  
2.2.3  Serviceability limit states  20  
2.3  BASIC VARIABLES  21  
2.3.1  Actions and environmental influences  21  
2.3.1.1  General  21  
2.3.1.2  Loadduration classes  21  
2.3.1.3  Service classes  22  
2.3.2  Materials and product properties  22  
2.3.2.1  Loadduration and moisture influences on strength  22  
2.3.2.2  Loadduration and moisture influences on deformations  22  
2.4  VERIFICATION BY THE PARTIAL FACTOR METHOD  24  
2.4.1  Design value of material property  24  
2.4.2  Design value of geometrical data  25  
2.4.3  Design resistances  25  
2.4.4  Verification of equilibrium (EQU)  25  
SECTION 3 MATERIAL PROPERTIES  26  
3.1  GENERAL  26  
3.1.1  Strength and stiffness parameters  26  
3.1.2  Stressstrain relations  26  
3.1.3  Strength modification factors for service classes and loadduration classes  26  
3.1.4  Deformation modification factors for service classes  26  
3.2  SOLID TIMBER  26  
3.3  GLUED LAMINATED TIMBER  27  
3.4  LAMINATED VENEER LUMBER (LVL)  28  
3.5  WOODBASED PANELS  29  
3.6  ADHESIVES  29  
3.7  METAL FASTENERS  29  
SECTION 4 DURABILITY  30  
4.1  RESISTANCE TO BIOLOGICAL ORGANISMS  30  
4.2  RESISTANCE TO CORROSION  30  
SECTION 5 BASIS OF STRUCTURAL ANALYSIS  31  
5.1  GENERAL  31 2  
5.2  MEMBERS  31  
5.3  CONNECTIONS  31  
5.4  ASSEMBLIES  32  
5.4.1  General  32  
5.4.2  Frame structures  32  
5.4.3  Simplified analysis of trusses with punched metal plate fasteners  33  
5.4.4  Plane frames and arches  34  
SECTION 6 ULTIMATE LIMIT STATES  36  
6.1  DESIGN OF CROSSSECTIONS SUBJECTED TO STRESS IN ONE PRINCIPAL DIRECTION  36  
6.1.1  General  36  
6.1.2  Tension parallel to the grain  36  
6.1.3  Tension perpendicular to the grain  36  
6.1.4  Compression parallel to the grain  36  
6.1.5  Compression perpendicular to the grain  36  
6.1.6  Bending  38  
6.1.7  Shear  38  
6.1.8  Torsion  39  
6.2  DESIGN OF CROSSSECTIONS SUBJECTED TO COMBINED STRESSES  40  
6.2.1  General  40  
6.2.2  Compression stresses at an angle to the grain  40  
6.2.3  Combined bending and axial tension  40  
6.2.4  Combined bending and axial compression  40  
6.3  STABILITY OF MEMBERS  41  
6.3.1  General  41  
6.3.2  Columns subjected to either compression or combined compression and bending  41  
6.3.3  Beams subjected to either bending or combined bending and compression  42  
6.4  DESIGN OF CROSSSECTIONS IN MEMBERS WITH VARYING CROSSSECTION OR CURVED SHAPE  44  
6.4.1  General  44  
6.4.2  Single tapered beams  44  
6.4.3  Double tapered, curved and pitched cambered beams  45  
6.5  NOTCHED MEMBERS  49  
6.5.1  General  49  
6.5.2  Beams with a notch at the support  49  
6.6  SYSTEM STRENGTH  50  
SECTION 7 SERVICEABILITY LIMIT STATES  52  
7.1  JOINT SLIP  52  
7.2  LIMITING VALUES FOR DEFLECTIONS OF BEAMS  52  
7.3  VIBRATIONS  53  
7.3.1  General  53  
7.3.2  Vibrations from machinery  53  
7.3.3  Residential floors  53  
SECTION 8 CONNECTIONS WITH METAL FASTENERS  56  
8.1  GENERAL  56  
8.1.1  Fastener requirements  56  
8.1.2  Multiple fastener connections  56  
8.1.3  Multiple shear plane connections  56  
8.1.4  Connection forces at an angle to the grain  56  
8.1.5  Alternating connection forces  58  
8.2  LATERAL LOADCARRYING CAPACITY OF METAL DOWELTYPE FASTENERS  58  
8.2.1  General  58  
8.2.2  Timbertotimber and paneltotimber connections  58  
8.2.3  Steeltotimber connections  60  
8.3  NAILED CONNECTIONS  62  
8.3.1  Laterally loaded nails  62 3  
8.3.1.1  General  62  
8.3.1.2  Nailed timbertotimber connections  64  
8.3.1.3  Nailed paneltotimber connections  67  
8.3.1.4  Nailed steeltotimber connections  67  
8.3.2  Axially loaded nails  67  
8.3.3  Combined laterally and axially loaded nails  69  
8.4  STAPLED CONNECTIONS  69  
8.5  BOLTED CONNECTIONS  71  
8.5.1  Laterally loaded bolts  71  
8.5.1.1  General and bolted timbertotimber connections  71  
8.5.1.2  Bolted paneltotimber connections  72  
8.5.1.3  Bolted steeltotimber connections  73  
8.5.2  Axially loaded bolts  73  
8.6  DOWELLED CONNECTIONS  73  
8.7  SCREWED CONNECTIONS  74  
8.7.1  Laterally loaded screws  74  
8.7.2  Axially loaded screws  74  
8.7.3  Combined laterally and axially loaded screws  77  
8.8  CONNECTIONS MADE WITH PUNCHED METAL PLATE FASTENERS  77  
8.8.1  General  77  
8.8.2  Plate geometry  77  
8.8.3  Plate strength properties  77  
8.8.4  Plate anchorage strengths  78  
8.8.5  Connection strength verification  78  
8.8.5.1  Plate anchorage capacity  78  
8.8.5.2  Plate capacity  80  
8.9  SPLIT RING AND SHEAR PLATE CONNECTORS  81  
8.10  TOOTHEDPLATE CONNECTORS  84  
SECTION 9 COMPONENTS AND ASSEMBLIES  87  
9.1  COMPONENTS  87  
9.1.1  Glued thinwebbed beams  87  
9.1.2  Glued thinflanged beams  89  
9.1.3  Mechanically jointed beams  90  
9.1.4  Mechanically jointed and glued columns  91  
9.2  ASSEMBLIES  91  
9.2.1  Trusses  91  
9.2.2  Trusses with punched metal plate fasteners  92  
9.2.3  Roof and floor diaphragms  93  
9.2.3.1  General  93  
9.2.3.2  Simplified analysis of roof and floor diaphragms.  93  
9.2.4  Wall diaphragms  94  
9.2.4.1  General  94  
9.2.4.2  Simplified analysis of wall diaphragms – Method A  94  
9.2.4.3  Simplified analysis of wall diaphragms – Method B  97  
9.2.4.3.1  Construction of walls and panels to meet the requirements of the simplified analysis  97  
9.2.4.3.2  Design procedure  98  
9.2.5  Bracing  100  
9.2.5.1  General  100  
9.2.5.2  Single members in compression  100  
9.2.5.3  Bracing of beam or truss systems  101  
SECTION 10 STRUCTURAL DETAILING AND CONTROL  103  
10.1  GENERAL  103  
10.2  MATERIALS  103  
10.3  GLUED JOINTS  103  
10.4  CONNECTIONS WITH MECHANICAL FASTENERS  103  
10.4.1  General  103  
10.4.2  Nails  103  
10.4.3  Bolts and washers  103 4  
10.4.4  Dowels  104  
10.4.5  Screws  104  
10.5  ASSEMBLY  104  
10.6  TRANSPORTATION AND ERECTION  105  
10.7  CONTROL  105  
10.8  SPECIAL RULES FOR DIAPHRAGM STRUCTURES  105  
10.8.1  Floor and roof diaphragms  105  
10.8.2  Wall diaphragms  106  
10.9  SPECIAL RULES FOR TRUSSES WITH PUNCHED METAL PLATE FASTENERS  106  
10.9.1  Fabrication  106  
10.9.2  Erection  106  
ANNEX A (INFORMATIVE): BLOCK SHEAR AND PLUG SHEAR FAILURE AT MULTIPLE DOWELTYPE STEELTOTIMBER CONNECTIONS  108  
ANNEX B (INFORMATIVE): MECHANICALLY JOINTED BEAMS  110  
B.1  SIMPLIFIED ANALYSIS  110  
B.1.1  Crosssections  110  
B.1.2  Assumptions  110  
B.1.3  Spacings  110  
B.1.4  Deflections resulting from bending moments  110  
B.2  EFFECTIVE BENDING STIFFNESS  112  
B.3  NORMAL STRESSES  112  
B.4  MAXIMUM SHEAR STRESS  112  
B.5  FASTENER LOAD  112  
ANNEX C (INFORMATIVE): BUILTUP COLUMNS  114  
C.1  GENERAL  114  
C.1.1  Assumptions  114  
C.1.2  Loadcarrying capacity  114  
C.2  MECHANICALLY JOINTED COLUMNS  114  
C.2.1  Effective slenderness ratio  114  
C.2.2  Load on fasteners  114  
C.2.3  Combined loads  115  
C.3  SPACED COLUMNS WITH PACKS OR GUSSETS  115  
C.3.1  Assumptions  115  
C.3.2  Axial loadcarrying capacity  116  
C.3.3  Load on fasteners, gussets or packs  117  
C.4  LATTICE COLUMNS WITH GLUED OR NAILED JOINTS  117  
C.4.1  Assumptions  117  
C.4.2  Loadcarrying capacity  118  
C.4.3  Shear forces  120  
ANNEX D (INFORMATIVE): BIBLIOGRAPHY  121 
This European Standard EN 199511 has been prepared by Technical Committee CEN/TC250 “Structural Eurocodes”, the Secretariat of which is held by BSI.
This European Standard shall be given the status of a National Standard, either by publication of an identical text or by endorsement, at the latest by May 2005, and conflicting national standards shall be withdrawn at the latest by March 2010.
This European Standard supersedes ENV 199511:1993.
CEN/TC250 is responsible for all Structural Eurocodes.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxemburg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
In 1975, the Commission of the European Community decided on an action programme in the field of construction, based on article 95 of the Treaty. The objective of the programme was the elimination of technical obstacles to trade and the harmonisation of technical specifications.
Within this action programme, the Commission took the initiative to establish a set of harmonised technical rules for the design of construction works which, in a first stage, would serve as an alternative to the national rules in force in the Member States and, ultimately, would replace them.
For fifteen years, the Commission, with the help of a Steering Committee with Representatives of Member States, conducted the development of the Eurocodes programme, which led to the first generation of European codes in the 1980s.
In 1989, the Commission and the Member States of the EU and EFTA decided, on the basis of an agreement^{1} between the Commission and CEN, to transfer the preparation and the publication of the Eurocodes to CEN through a series of Mandates, in order to provide them with a future status of European Standard (EN). This links de facto the Eurocodes with the provisions of all the Council’s Directives and/or Commission’s Decisions dealing with European standards (e.g. the Council Directive 89/106/EEC on construction products – CPD – and Council Directives 93/37/EEC, 92/50/EEC and 89/440/EEC on public works and services and equivalent EFTA Directives initiated in pursuit of setting up the internal market).
The Structural Eurocode programme comprises the following standards generally consisting of a number of Parts:
^{1} Agreement between the commission of the European Communities and the European Committee for Standardisation (CEN) concerning the work on EUROCODES for the design of buildings and civil engineering works (BC/CEN/03/89).
EN 1990:2002  Eurocode:  Basis of Structural Design 
EN 1991  Eurocode 1:  Actions on structures 
EN 1992  Eurocode 2:  Design of concrete structures 
EN 1993  Eurocode 3:  Design of steel structures 
EN 1994  Eurocode 4:  Design of composite steel and concrete structures 
EN 1995  Eurocode 5:  Design of timber structures 
EN 1996  Eurocode 6:  Design of masonry structures 
EN 1997  Eurocode 7:  Geotechnical design 
EN 1998  Eurocode 8:  Design of structures for earthquake resistance 
EN 1999  Eurocode 9:  Design of aluminium structures 
Eurocode standards recognise the responsibility of regulatory authorities in each Member State and have safeguarded their right to determine values related to regulatory safety matters at national level where these continue to vary from State to State.
The Member States of the EU and EFTA recognise that Eurocodes serve as reference documents for the following purposes:
The Eurocodes, as far as they concern the construction works themselves, have a direct relationship with the Interpretative Documents^{2} referred to in Article 12 of the CPD, although they are of a different nature from harmonised product standards^{3}. Therefore, technical aspects arising from the Eurocodes work need to be adequately considered by CEN Technical Committees and/or EOTA Working Groups working on product standards with a view to achieving full compatibility of these technical specifications with the Eurocodes.
The Eurocode standards provide common structural design rules for everyday use for the design of whole structures and component products of both a traditional and an innovative nature. Unusual forms of construction or design conditions are not specifically covered and additional expert consideration will be required by the designer in such cases.
The National Standards implementing Eurocodes will comprise the full text of the Eurocode (including any annexes), as published by CEN, which may be preceded by a National title page and National foreword, and may be followed by a National annex.
The National annex may only contain information on those parameters which are left open in the Eurocode for national choice, known as Nationally Determined Parameters, to be used for the design of buildings and civil engineering works to be constructed in the country concerned, i.e.:
^{2} According to Art. 3.3 of the CPD, the essential requirements (ERs) shall be given concrete form in interpretative documents for the creation of the necessary links between the essential requirements and the mandates for harmonised ENs and ETAGs/ETAs.
^{3} According to Art. 12 of the CPD the interpretative documents shall:
give concrete form to the essential requirements by harmonising the terminology and the technical bases and indicating classes or levels for each requirement where necessary ;
indicate methods of correlating these classes or levels of requirement with the technical specifications, e.g. methods of calculation and of proof, technical rules for project design, etc. ;
serve as a reference for the establishment of harmonised standards and guidelines for European technical approvals.
The Eurocodes, de facto, play a similar role in the field of the ER 1 and a part of ER 2.
8There is a need for consistency between the harmonised technical specifications for construction products and the technical rules for works^{4}. Furthermore, all the information accompanying the CE Marking of the construction products which refer to Eurocodes shall clearly mention which Nationally Determined Parameters have been taken into account.
EN 1995 describes the Principles and requirements for safety, serviceability and durability of timber structures. It is based on the limit state concept used in conjunction with a partial factor method.
For the design of new structures, EN 1995 is intended to be used, for direct application, together with EN 1990:2002 and relevant Parts of EN 1991.
Numerical values for partial factors and other reliability parameters are recommended as basic values that provide an acceptable level of reliability. They have been selected assuming that an appropriate level of workmanship and of quality management applies. When EN 199511 is used as a base document by other CEN/TCs the same values need to be taken.
This standard gives alternative procedures, values and recommendations with notes indicating where national choices may have to be made. Therefore the National Standard implementing EN 199511 should have a National annex containing all Nationally Determined Parameters to be used for the design of buildings and civil engineering works to be constructed in the relevant country.
National choice is allowed in EN 199511 through clauses:
2.3.1.2(2)P  Assignment of loads to loadduration classes; 
2.3.1.3(1)P  Assignment of structures to service classes; 
2.4.1(1)P  Partial factors for material properties; 
6.1.7(2)  Shear; 
6.4.3(8)  Double tapered, curved and pitched cambered beams; 
7.2(2)  Limiting values for deflections; 
7.3.3(2)  Limiting values for vibrations; 
8.3.1.2(4)  Nailed timbertotimber connections: Rules for nails in end grain; 
8.3.1.2(7)  Nailed timbertotimber connections: Species sensitive to splitting; 
9.2.4.1(7)  Design method for wall diaphragms; 
9.2.5.3(1)  Bracing modification factors for beam or truss systems; 
10.9.2(3)  Erection of trusses with punched metal plate fasteners: Maximum bow; 
10.9.2(4)  Erection of trusses with punched metal plate fasteners: Maximum deviation. 
This document (EN 19951 1:2004/A1:2008) has been prepared by Technical Committee CEN/TC 250 “Structural Eurocodes”, the secretariat of which is held by BSI.
9This Amendment to the European Standard EN 199511:2004 shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2008, and conflicting national standards shall be withdrawn at the latest by March 2010.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
^{4} see Art.3.3 and Art. 12 of the CPD, as well as clauses 4.2, 4.3.1, 4.3.2 and 5.2 of ID 1.
EN 1990:2002 Eurocode – Basis of design
EN 1991 “Actions on structures”
EN’s for construction products relevant to timber structures
EN 1998 “Design of structures for earthquake resistance”, when timber structures are built in seismic regions
EN 19951 General
EN 19952 Bridges
EN 199511 General – Common rules and rules for buildings
EN 199512 General rules – Structural Fire Design
Section 1:  General 
Section 2:  Basis of design 
Section 3:  Material properties 
Section 4:  Durability 10 
Section 5:  Basis of structural analysis 
Section 6:  Ultimate limit states 
Section 7:  Serviceability limit states 
Section 8:  Connections with metal fasteners 
Section 9:  Components and assemblies 
Section 10:  Structural detailing and control. 
ISO standards:
ISO 2081  Metallic coatings. Electroplated coatings of zinc on iron or steel 
ISO 26312:1989  Evaluation of human exposure to wholebody vibration. Part 2: Continuous and shockinduced vibrations in buildings (1 to 80 Hz) 
European Standards:
EN 300  Oriented Strand Board (OSB) – Definition, classification and specifications 
EN 301  Adhesives, phenolic and aminoplastic for loadbearing timber structures; Classification and performance requirements 
EN 312  Paricleboards – Specifications 
EN 3351  Durability of wood and woodbased products – definition of hazard classes of biological attack – Part 1: General 
EN 3352  Durability of wood and woodbased products – definition of hazard classes of biological attack – Part 2: Application to solid wood 
EN 3353  Durability of wood and woodbased products – Definition of hazard classes of biological attack – Part 3: Application to wood–based panels 
EN 3502  Durability of wood and woodbased products – Natural durability of solid wood – Part 2: Guide to natural durability and treatability of selected wood species of importance in Europe 
EN 3511  Durability of wood and woodbased products – Preservative treated solid wood – Part 1: Classification of preservative penetration and retention 
EN 383  Timber structures – Test methods – Determination of embedding strength and foundation values for dowel type fasteners 
EN 385  Finger jointed structural timber – Performance requirements and minimum production requirements 
EN 387  Glued laminated timber – Large finger joints – Performance requirements and minimum production requirements 
EN 409  Timber structures – Test methods. Determination of the yield moment of dowel type fasteners – Nails 11 
EN 460  Durability of wood and woodbased products – Natural durability of solid wood – Guide of the durability requirements for wood to be used in hazard classes 
EN 594  Timber structures – Test methods – Racking strength and stiffness of timber frame wall panels 
EN 6222  Fibreboards – Specifications. Part 2: Requirements for hardboards 
EN 6223  Fibreboards – Specifications. Part 3: Requirements for medium boards 
EN 6224  Fibreboards – Specifications. Part 4: Requirements for softboards 
EN 6225  Fibreboards – Specifications. Part 5: Requirements for dry process boards (MDF) 
EN 636  Plywood – Specifications 
EN 912  Timber fasteners – Specifications for connectors for timber 
EN 1075  Timber structures – Test methods – Testing of joints made with punched metal plate fasteners 
EN 1380  Timber structures – Test methods – Load bearing nailed joints 
EN 1381  Timber structures – Test methods – Load bearing stapled joints 
EN 1382  Timber structures – Test methods – Withdrawal capacity of timber fasteners 
EN 1383  Timber structures – Test methods – Pull through testing of timber fasteners 
EN 1990:2002  Eurocode – Basis of structural design 
EN 199111  Eurocode 1: Actions on structures – Part 11: General actions – Densities, selfweight and imposed loads 
EN 199113  Eurocode 1: Actions on structures – Part 13: General actions – Snow loads 
EN 199114  Eurocode 1: Actions on structures – Part 14: General actions – Wind loads 
EN 199115  Eurocode 1: Actions on structures – Part 15: General actions – Thermal actions 
EN 199116  Eurocode 1: Actions on structures – Part 16: General actions – Actions during execution 
EN 199117  Eurocode 1: Actions on structures – Part 17: General actions – Accidental actions due to impact and explosions 
EN 10147  Specification for continuously hotdip zinc coated structural steel sheet and strip – Technical delivery conditions 
EN 13271  Timber fasteners – Characteristic loadcarrying capacities and slip moduli for connector joints 
EN 13986  Woodbased panels for use in construction – Characteristics, evaluation of conformity and marking 
EN 14080  Timber structures – Glued laminated timber – Requirements 
EN 140811  Timber structures – Strength graded structural timber with rectangular crosssection – Part 1, General requirements 
EN 14250  Timber structures – Production requirements for fabricated trusses using punched metal plate fasteners 
EN 14279  Laminated veneer lumber (LVL) – Specifications, definitions, classification and requirements 12 
EN 14358  Timber structures – Fasteners and woodbased products – Calculation of characteristic 5percentile value and acceptance criteria for a sample 
EN 14374  Timber structures – Structural laminated veneer lumber – Requirements 
EN 14545  Timber structures – Connectors – Requirements 
EN 14592  Timber structures – Fasteners – Requirements 
EN 26891  Timber structures – Joints made with mechanical fasteners – General principles for the determination of strength and deformation characteristics 
EN 28970  Timber structures – Testing of joints made with mechanical fasteners; Requirements for wood density (ISO 8970:1989) 
NOTE: As long as EN 14545 and EN 14592 are not available as European standards, more information may be given in the National annex.
Refer to EN 1990:2002 subclause 1.5.4.1.
Connection made with a circular cylindrical rod usually of steel, with or without a head, fitting tightly in prebored holes and used for transferring loads perpendicular to the dowel axis.
The moisture content at which wood neither gains nor loses moisture to the surrounding air.
Moisture content at which the wood cells are completely saturated.
13Laminated veneer lumber, defined according to EN 14279 and EN 14374
A plate made of abutting parallel and solid laminations connected together by nails or screws or prestressing or gluing.
The mass of water in wood expressed as a proportion of its ovendry mass.
Effect caused by horizontal actions in the plane of a wall.
A property used in the calculation of the deformation of the structure, such as modulus of elasticity, shear modulus, slip modulus.
A property used in the calculation of the deformation between two members of a structure.
For the purpose of EN 199511, the following symbols apply.
Latin upper case letters
A  Crosssectional area 
A_{ef}  Effective area of the total contact surface between a punched metal plate fastener and the timber; Effective contact area in compression perpendicular to the grain 
A_{f}  Crosssectional area of flange 
A_{net,t}  Net crosssectional area perpendicular to the grain 
A_{net,v}  Net shear area parallel to the grain 
C  Spring stiffness 
E_{0,05}  Fifth percentile value of modulus of elasticity; 
E_{d}  Design value of modulus of elasticity; 
E_{mean}  Mean value of modulus of elasticity; 
E_{mean,fin}  Final mean value of modulus of elasticity; 
F  Force 
F_{A,Ed}  Design force acting on a punched metal plate fastener at the centroid of the effective area 
F_{A,min,d}  Minimum design force acting on a punched metal plate fastener at the centroid of the effective area 
F_{ax,Ed}  Design axial force on fastener; 
F_{ax,Rd}  Design value of axial withdrawal capacity of the fastener; 
F_{ax,Rk}  Characteristic axial withdrawal capacity of the fastener; 
F_{c}  Compressive force 14 
F_{d}  Design force 
F_{d,ser}  Design force at the serviceability limit state 
F_{f,Rd}  Design loadcarrying capacity per fastener in wall diaphragm 
F_{i,c,Ed}  Design compressive reaction force at end of shear wall 
F_{i,t,Ed}  Design tensile reaction force at end of shear wall 
F_{i,vert,Ed}  Vertical load on wall 
F_{i,v,Rd}  Design racking resistance of panel i (in 9.2.4.2)or wall i (in 9.2.4.3) 
F_{la}  Lateral load 
F_{M,Ed}  Design force from a design moment 
F_{t}  Tensile force 
F_{t,Rk}  Characteristic tensile resistance of connection 
F_{v,0,Rk}  Characteristic loadcarrying capacity of a connector along the grain; 
F_{v,Ed}  Design shear force per shear plane of fastener; Horizontal design effect on wall diaphragm 
F_{v,Rd}  Design loadcarrying capacity per shear plane per fastener; Design racking load capacity 
F_{v,Rk}  Characteristic loadcarrying capacity per shear plane per fastener 
F_{v,w,Ed}  Design shear force acting on web; 
F_{x,Ed}  Design value of a force in xdirection 
F_{y,Ed}  Design value of a force in ydirection 
F_{x,Rd}  Design value of plate capacity in xdirection; 
F_{y,Rd}  Design value of plate capacity in ydirection; 
F_{x,Rk}  Characteristic plate capacity in xdirection; 
F_{y,Rk}  Characteristic plate capacity in ydirection; 
G_{0,05}  Fifth percentile value of shear modulus 
G_{d}  Design value of shear modulus 
G_{mean}  Mean value of shear modulus 
H  Overall rise of a truss 
I_{f}  Second moment of area of flange 
I_{tor}  Torsional moment of inertia 
I_{z}  Second moment of area about the weak axis 
K_{ser}  Slip modulus 
K_{ser,fin}  Final slip modulus 
K_{u}  Instantaneous slip modulus for ultimate limit states 
L_{net,t}  Net width of the crosssection perpendicular to the grain 
L_{net,v}  Net length of the fracture area in shear 
M_{A,Ed}  Design moment acting on a punched metal plate fastener 
M_{ap,d}  Design moment at apex zone 
M_{d}  Design moment 
M_{y,Rk}  Characteristic yield moment of fastener 
N  Axial force 
R_{90,d}  Design splitting capacity 
R_{90,k}  Characteristic splitting capacity 
R_{ax,d}  Design loadcarrying capacity of an axially loaded connection 
R_{ax,k}  Characteristic loadcarrying capacity of an axially loaded connection 
R_{ax,α,k}  Characteristic loadcarrying capacity at an angle to grain 
R_{d}  Design value of a loadcarrying capacity 
R_{ef,k}  Effective characteristic loadcarrying capacity of a connection 
R_{iv,d}  Design racking racking capacity of a wall 
R_{k}  Characteristic loadcarrying capacity 
R_{sp,k}  Characteristic splitting capacity 
R_{to,k}  Characteristic loadcarrying capacity of a toothed plate connector 
R_{v,d}  Design racking capacity of a wall diaphragm 
V  Shear force; Volume 
V_{u}, V_{l}  Shear forces in upper and lower part of beam with a hole 
W_{y}  Section modulus about axis y 
X_{d}  Design value of a strength property 
X_{k}  Characteristic value of a strength property 
Latin lower case letters
a  Distance 
a_{1}  Spacing, parallel to grain, of fasteners within one row 
a_{1,CG}  End distance of centre of gravity of the threaded part of screw in the member 
a_{2}  Spacing, perpendicular to grain, between rows of fasteners 
a_{2, CG}  Edge distance of centre of gravity of the threaded part of screw in the member 
a_{3,c}  Distance between fastener and unloaded end 
a_{3,t}  Distance between fastener and loaded end 
a_{4,c}  Distance between fastener and unloaded edge 
a_{4,t}  Distance between fastener and loaded edge 
a_{bow}  Maximum bow of truss member 
a_{bow,perm}  Maximum permitted bow of truss member 
a_{dev}  Maximum deviation of truss 
a_{dev,perm}  Maximum permitted deviation of truss 
b  Width 
b_{i}  Width of panel i (in 9.2.4.2)or wall i (in 9.2.4.3) 
b_{net}  Clear distance between studs 
b_{w}  Web width 
d  Diameter; Outer thread diameter 
d_{1}  Inner thread diameter 
d_{c}  Connector diameter 
d_{ef}  Effective diameter 
d_{h}  Head diameter of screws 
f_{h,i,k}  Characteristic embedment strength of timber member i 
f_{a,0,0}  Characteristic anchorage capacity per unit area for α = 0° and β = 0° 
f_{a,90,90}  Characteristic anchorage capacity per unit area for α = 90° and β = 90° 
f_{a,α,β,k}  Characteristic anchorage strength 
f_{ax,k}  Characteristic pointside withdrawal strength for nails; Characteristic withdrawal strength 
f_{c,0,d}  Design compressive strength along the grain 
f_{c,w,d}  Design compressive strength of web 
f_{f,c,d}  Design compressive strength of flange 
f_{c,90,k}  Characteristic compressive strength perpendicular to grain 
f_{f,t,d}  Design tensile strength of flange 
f_{h,k}  Characteristic embedment strength 
f_{head,k}  Characteristic pull through parameter for nails 
f_{l}  Fundamental frequency 
f_{m,k}  Characteristic bending strength 
f_{m,y,d}  Design bending strength about the principal yaxis 
f_{m,z,d}  Design bending strength about the principal zaxis 
f_{m,α,d}  Design bending strength at an angle α to the grain 
f_{t,0,d}  Design tensile strength along the grain 
f_{t,0,k}  Characteristic tensile strength along the grain 
f_{t,90,d}  Design tensile strength perpendicular to the grain 
f_{t,w,d}  Design tensile strength of the web 
f_{u,k}  Characteristic tensile strength of bolts 
f_{v,0,d}  Design panel shear strength 
f_{v,ax,α,k}  Characteristic withdrawal strength at an angle to grain 
f_{v,ax,90,k}  Characteristic withdrawal strength perpendicular to grain 
f_{v,d}  Design shear strength 
h  Depth; Height of wall 
h_{ap}  Depth of the apex zone 
h_{d}  Hole depth 
h_{e}  Embedment depth 
h  Loaded edge distance 
h_{ef}  Effective depth 
h_{f,c}  Depth of compression flange 16 
h_{f,t}  Depth of tension flange 
h_{r1}  Distance from lower edge of hole to bottom of member 
h_{ru}  Distance from upper edge of hole to top of member 
h_{w}  Web depth 
i  Notch inclination 
k_{c,y} or k_{c,z}  Instability factor 
k_{cr}  Crack factor for shear resistance 
k_{crit}  Factor used for lateral buckling 
k_{d}  Dimension factor for panel 
k_{def}  Deformation factor 
k_{dis}  Factor taking into account the distribution of stresses in an apex zone 
k_{f,1}, k_{f,2}, k_{f,3}  Modification factors for bracing resistance 
k_{h}  Depth factor 
k_{i,q}  Uniformly distributed load factor 
k_{m}  Factor considering redistribution of bending stresses in a crosssection 
k_{mod}  Modification factor for duration of load and moisture content 
k_{n}  Sheathing material factor 
k_{r}  Reduction factor 
k_{R,red}  Reduction factor for loadcarrying capacity 
k_{s}  Fastener spacing factor; Modification factor for spring stiffness 
k_{s,red}  Reduction factor for spacing 
k_{shape}  Factor depending on the shape of the crosssection 
k_{sys}  System strength factor 
k_{v}  Reduction factor for notched beams 
k_{vol}  Volume factor 
k_{y} or k_{z}  Instability factor 
ℓ_{a,min}  Minimum anchorage length for a gluedin rod 
ℓ  Span; contact length 
ℓ_{A}  Support distance of a hole 
ℓ_{ef}  Effective length; Effective length of distribution 
ℓ_{V}  Distance from a hole to the end of the member 
ℓ_{Z}  Spacing between holes 
m  Mass per unit area 
n_{40}  Number of frequencies below 40 Hz 
n_{ef}  Effective number of fasteners 
p_{d}  Distributed load 
q_{i}  Equivalent uniformly distributed load 
r  Radius of curvature 
s  Spacing 
s_{0}  Basic fastener spacing 
r_{in}  Inner radius 
t  Thickness 
t_{pen}  Penetration depth 
u_{creep}  Creep deformation 
u_{fin}  Final deformation 
u_{fin,G}  Final deformation for a permanent action G 
u_{fin,Q,l}  Final deformation for the leading variable action Q_{1} 
u_{fin,Q,i}  Final deformation for accompanying variable actions Q_{i} 
u_{inst}  Instantaneous deformation 
u_{inst,G}  Instantaneous deformation for a permanent action G 
u_{inst,Q,l}  Instantaneous deformation for the leading variable action Q_{1} 
u_{inst,Q,i}  Instantaneous deformation for accompanying variable actions Q_{i} 
w_{c}  Precamber 
w_{creep}  Creep deflection 
w_{fin}  Final deflection 
w_{inst}  Instantaneous deflection 
w_{net,fin}  Net final deflection 
v  Unit impulse velocity response 
Greek lower case letters
α  Angle between the xdirection and the force for a punched metal plate; Angle between a force and the direction of grain; Angle between the direction of the load and the loaded edge (or end) 
β  Angle between the grain direction and the force for a punched metal plate 
β_{c}  Straightness factor 
γ  Angle between the xdirection and the timber connection line for a punched metal plate 
γ_{M}  Partial factor for material properties, also accounting for model uncertainties and dimensional variations 
λ_{y}  Slendemess ratio corresponding to bending about the yaxis 
λ_{z}  Slenderness ratio corresponding to bending about the zaxis 
λ_{rel,y}  Relative slenderness ratio corresponding to bending about the yaxis 
λ_{rel,z}  Relative slenderness ratio corresponding to bending about the zaxis 
ρ_{a}  Associated density 
ρ_{k}  Characteristic density 
ρ_{m}  Mean density 
σ_{c,0,d}  Design compressive stress along the grain 
σ_{c,α,d}  Design compressive stress at an angle α to the grain 
σ_{f,c,d}  Mean design compressive stress of flange 
σ_{f,c,max,d}  Design compressive stress of extreme fibres of flange 
σ_{f,t,d}  Mean design tensile stress of flange 
σ_{f,t,max,d}  Design tensile stress of extreme fibres of flange 
σ_{m,crit}  Critical bending stress 
σ_{m,y,d}  Design bending stress about the principal yaxis 
σ_{m,z,d}  Design bending stress about the principal zaxis 
σ_{m,α,d}  Design bending stress at an angle α to the grain 
σ_{N}  Axial stress 
σ_{t,0,d}  Design tensile stress along the grain 
σ_{t,90,d}  Design tensile stress perpendicular to the grain 
σ_{w,c,d}  Design compressive stress of web 
σ_{w,t,d}  Design tensile stress of web 
τ_{d}  Design shear stress 
τ_{F,d}  Design anchorage stress from axial force 
τ_{M,d}  Design anchorage stress from moment 
τ_{tor,d}  Design shear stress from torsion 
ψ_{0}  Factor for combination value of a variable action 
ψ_{2}  Factor for quasipermanent value of a variable action 
ζ  Modal damping ratio 
NOTE 1: For final mean values adjusted to the duration of load, see 2.3.2.2(2).
NOTE 2: For design values of stiffness properties, see 2.4.1 (2)P.
where K_{ser} is the slip modulus, see 7.1(1).
u_{fin} = u_{fin,G} + u_{fin,Q1} + Σu_{fin,Qi} (2.2)
where:
u_{fin,G} = u_{inst,G} (1 + k_{def})  for a permanent action, G (2.3) 
u_{fin,Q,1} = u_{inst,Q,1} (1 + ψ_{2,1}k_{def})  for the leading variable action, Q_{1} (2.4) 
u_{fin,Q,i} = u_{inst,Q,1} (ψ_{0,i} + ψ_{2,i}k_{def})  for accompanying variable actions, Q_{i} (i > 1) (2.5) 
u_{inst,G} , u_{inst,Q,1} , u_{inst,Q,i}  are the instantaneous deformations for action G, Q_{1} , Q_{i} respectively; 
ψ_{2,1}, ψ_{2,i}  are the factors for the quasipermanent value of variable actions; 
ψ_{0,i}  are the factors for the combination value of variable actions; 
k_{def}  is given in table 3.2 for timber and woodbased materials, and in 2.3.2.2 (3) and 2.3.2.2 (4) for connections. 
When expressions (2.3) to (2.5) are used, the ψ_{2} factors should be omitted from expressions (6.16 a) and (6.16 b) of EN1990:2002.
Note: In most cases, it will be appropriate to apply the simplified method.
Note 1: The relevant parts of EN 1991 for use in design include:
EN 199111  Densities, selfweight and imposed loads 
EN 199113  Snow loads 
EN 199114  Wind actions 
EN 199115  Thermal actions 
EN 199116  Actions during execution 
EN 199117  Accidental actions 
Loadduration class  Order of accumulated duration of characteristic load 

Permanent  more than 10 years 
Longterm  6 months – 10 years 
Mediumterm  1 week – 6 months 
Shortterm  less than one week 
Instantaneous 
NOTE: Examples of loadduration assignment are given in Table 2.2. Since climate loads(snow, wind) vary between countries, the assignment of loadduration classes may be specified in the National annex.
21Loadduration class  Exampels of loading 

Permanent  selfweight 
Longterm  storage 
Mediumterm  imposed floor load, snow 
Shortterm  snow, wind 
Instantaneous  wind, accidental load 
NOTE 1: The service class system is mainly aimed at assigning strength values and for calculating deformations under defined environmental conditions.
NOTE 2: Information on the assignment of structures to service classes given in (2)P, (3)P and (4)P may be given in the National annex.
NOTE: In service class 1 the average moisture content in most softwoods will not exceed 12 %.
NOTE: In service class 2 the average moisture content in most softwoods will not exceed 20 %.
where k_{mod,1} and k_{mod,2} are the modification factors for the two timber elements.
where:
E_{mean}  is the mean value of modulus of elasticity; 
G_{mean}  is the mean value of shear modulus; 
K_{ser}  is the slip modulus; 
k_{def}  is a factor for the evaluation of creep deformation taking into account the relevant service class; 
ψ_{2}  is the factor for the quasipermanent value of the action causing the largest stress in relation to the strength (if this action is a permanent action, ψ_{2} should be replaced by 1). 
NOTE 1: Values of k_{def} are given in 3.1.4.
NOTE 2: Values of ψ_{2} are given in EN 1990:2002.
where k_{def,1} and k_{def,2} are the deformation factors for the two timber elements.
where:
X_{k}  is the characteristic value of a strength property; 
γ_{M}  is the partial factor for a material property; 
k_{mod}  is a modification factor taking into account the effect of the duration of load and moisture content. 
NOTE 1: Values of k_{mod} are given in 3.1.3.
NOTE 2: The recommended partial factors for material properties (γ_{M}) are given in Table 2.3. Information on the National choice may be found in the National annex.
Fundamental combinations:  
Solid timber  1,3 
Glued laminated timber  1,25 
LVL, plywood, OSB,  1,2 
Particleboards  1,3 
Fibreboards, hard  1,3 
Fibreboards, medium  1,3 
Fibreboards, MDF  1,3 
Fibreboards, soft  1,3 
Connections  1,3 
Punched metal plate fasteners  1,25 
Accidental combinations  1,0 
where:
E_{mean}  is the mean value of modulus of elasticity; 
G_{mean}  is the mean value of shear modulus. 
where:
R_{k}  is the characteristic value of loadcarrying capacity; 
γ_{M}  is the partial factor for a material property, 
k_{mod}  is a modification factor taking into account the effect of the duration of load and moisture content. 
NOTE 1: Values of k_{mod} are given in 3.1.3.
NOTE 2: For partial factors, see 2.4.1.
NOTE: Strength classes for timber are given in EN 338.
where h is the depth for bending members or width for tension members, in mm.
26Material  Standard  Service class  Loadduration class  

Permanent action  Long term action  Medium term action  Short term action  Instantaneous action  
Solid timber  EN 140811  1  0,60  0,70  0,80  0,90  1,10 
2  0,60  0,70  0,80  0,90  1,10  
3  0,50  0,55  0,65  0,70  0,90  
Glued laminated timber  EN 14080  1  0,60  0,70  0,80  0,90  1,10 
2  0,60  0,70  0,80  0,90  1,10  
3  0,50  0,55  0,65  0,70  0,90  
LVL  EN 14374, EN 14279  1  0,60  0,70  0,80  0,90  1,10 
2  0,60  0,70  0,80  0,90  1,10  
3  0,50  0,55  0,65  0,70  0,90  
Plywood  EN 636  
Type EN 6361  1  0,60  0,70  0,80  0,90  1,10  
Type EN 6362  2  0,60  0,70  0,80  0,90  1,10  
Type EN 6363  3  0,50  0,55  0,65  0,70  0,90  
OSB  EN 300  
OSB/2  1  0,30  0,45  0,65  0,85  1,10  
OSB/3, OSB/4  1  0,40  0,50  0,70  0,90  1,10  
OSB/3, OSB/4  2  0,30  0,40  0,55  0,70  0,90  
Particleboard  EN 312  
Type P4, Type P5  1  0,30  0,45  0,65  0,85  1,10  
Type P5  2  0,20  0,30  0,45  0,60  0,80  
Type P6, Type P7  1  0,40  0,50  0,70  0,90  1,10  
Type P7  2  0,30  0,40  0,55  0,70  0,90  
Fibreboard, hard  EN 6222  
HB.LA, HB.HLA 1 or 2  1  0,30  0,45  0,65  0,85  1,10  
HB.HLA1 or 2  2  0,20  0,30  0,45  0,60  0,80  
Fibreboard, medium  EN 6223  
MBH.LA1 or 2  1  0,20  0,40  0,60  0,80  1,10  
MBH.HLS1 or 2  1  0,20  0,40  0,60  0,80  1,10  
MBH.HLS1 or 2  2  –  –  –  0,45  0,80  
Fibreboard, MDF  EN 6225  
MDF.LA, MDF.HLS  1  0,20  0,40  0,60  0,80  1,10  
MDF.HLS  2  –  –  –  0,45  0,80 
NOTE: In EN 1194 values of strength and stiffness properties are given for glued laminated timber allocated to strength classes, see annex D (Informative).
where h is the depth for bending members or width for tensile members, in mm.
Material  Standard  Service class  

1  2  3  
Solid timber  EN 140811  0,60  0,80  2,00 
Glued Laminated timber  EN 14080  0,60  0,80  2,00 
LVL  EN 14374, EN 14279  0,60  0,80  2,00 
Plywood  EN 636  
Type EN 6361  0,80  –  –  
Type EN 6362  0,80  1,00  –  
Type EN 6363  0,80  1,00  2,50  
OSB  EN 300  
OSB/2  2,25  –  –  
OSB/3, OSB/4  1,50  2,25  –  
Particleboard  EN 312  
Type P4  2,25  –  –  
Type P5  2,25  3,00  –  
Type P6  1,50  –  –  
Type P7  1,50  2,25  –  
Fibreboard, hard  EN 6222  
HB.LA  2,25  –  –  
HB.HLA1, HB.HLA2  2,25  3,00  –  
Fibreboard, medium  EN 6223  
MBH.LA1, MBH.LA2  3,00  –  –  
MBH.HLS1, MBH.HLS2  3,00  4,00  –  
Fibreboard, MDF  EN 6225  
MDF.LA  2,25  –  
MDF.HLS  2,25  3.00  – 
where:
h  is the depth of the member, in mm; 
s  is the size effect exponent, refer to 3.4(5)P. 
where ℓ is the length, in mm.
NOTE 1: Preservative treatment may affect the strength and stiffness properties.
NOTE 2: Rules for specification of preservation treatments are given in EN 3502 and EN 335.
Fastener  Service class^{b}  

1  2  3  
Nails and screws with d ≤ 4 mm  None  Fe/Zn 12c^{a}  Fe/Zn 25c^{a} 
Bolts, dowels, nails and screws with d > 4 mm  None  None  Fe/Zn 25c^{a} 
Staples  Fe/Zn 12c^{a}  Fe/Zn 12c^{a}  Stainless steel 
Punched metal plate fasteners and steel plates up to 3 mm thickness  Fe/Zn 12c^{a}  Fe/Zn 12c^{a}  Stainless steel 
Steel plates from 3 mm up to 5 mm in thickness  None  Fe/Zn 12c^{a}  Fe/Zn 25c^{a} 
Steel plates over 5 mm thickness  None  None  Fe/Zn 25c^{a} 
^{a} If hot dip zinc coating is used, Fe/Zn 12c should be replaced by Z275 and Fe/Zn 25c by 2350 in accordance with EN 10147  
^{b} For especially corrosive conditions consideration should be given to heavier hot dip coatings or stainless steel. 
NOTE: Deviations from straightness and inhomogeneities are taken into account implicitly by the design methods given in this standard.
Figure 5.1 – Examples of frame analysis model elements
Figure 5.2 – Geometry of support
where h is the height of the structure or the length of the member, in m.
e = 0,0025 ℓ (5.2)
Examples of assumed initial deviations in the geometry and the definition of ℓ are given in Figure 5.3.
34Figure 5.3 – Examples of assumed initial deviations in the geometry for a frame (a), corresponding to a symmetrical load (b) and nonsymmetrical load (c)
Figure 6.1 – Member Axes
σ_{t,0,d} ≤ f_{t,0,d} (6.1)
where:
σ_{t,0,d}  is the design tensile stress along the grain; 
f_{t,0,d}  is the design tensile strength along the grain. 
σ_{c,0,d} ≤ f_{c,0,d} (6.2)
where:
σ_{c,0,d}  is the design compressive stress along the grain; 
f_{c,0,d}  is the design compressive strength along the grain. 
NOTE: Rules for the instability of members are given in 6.3.
σ_{c,90,d} ≤ k_{c,90} f_{c,90,d} (6.3)
with:
36where:
σ_{c,90,d}  is the design compressive stress in the effective contact area perpendicular to the grain; 
F_{c,90,d}  is the design compressive load perpendicular to the grain; 
A_{ef}  is the effective contact area in compression perpendicular to the grain; 
F_{c,90,d}  is the design compressive strength perpendicular to the grain; 
k_{c,90}  is a factor taking into account the load configuration, the possibility of splitting and the degree of compressive deformation. 
The effective contact area perpendicular to the grain, A_{ef}, should be determined taking into account an effective contact length parallel to the grain, where the actual contact length, ℓ, at each side is increased by 30 mm, but not more than a, ℓ or ℓ_{1}/2, see Figure 6.2.
where h is the depth of the member and ℓ is the contact length.
where h is the depth of the member and ℓ is the contact length.
Figure 6.2 – Member on (a) continuous and (b) discrete supports
where:
σ_{m,y,d} and σ_{m,z,d}  are the design bending stresses about the principal axes as shown in Figure 6.1; 
f_{m,y,d} and f_{m,z,d}  are the corresponding design bending strengths. 
NOTE: The factor k_{m} makes allowance for redistribution of stresses and the effect of inhomogeneities of the material in a crosssection.
For solid timber, glued laminated timber and LVL:
for rectangular sections: k_{m} = 0,7
for other crosssections: k_{m} = 1,0
For other woodbased structural products, for all crosssections: k_{m} = 1,0
τ_{d} ≤ f_{v,d} (6.13)
where:
τ_{d}  is the design shear stress; 
f_{v,d}  is the design shear strength for the actual condition. 
NOTE: The shear strength for rolling shear is approximately equal to twice the tensile strength perpendicular to grain.
b_{ef} = k_{cr} b (6.13a)
where b is the width of the relevant section of the member.
NOTE: The recommended value for k_{cr} is given as
k_{cr} = 0,67  for solid timber 
k_{cr} = 0,67  for glued laminated timber 
k_{cr} = 1,0  for other woodbased products in accordance with EN 13986 and EN 14374. 
Information on the National choice may be found in the National annex.
38Figure 6.5 – (a) Member with a shear stress component parallel to the grain (b) Member with both stress components perpendicular to the grain (rolling shear)
Figure 6.6 – Conditions at a support, for which the concentrated force F may be disregarded in
τ_{tor,d} ≤ k_{shape} f_{v,d} (6.14)
with
where:
τ_{tor,d}  is the design torsional stress; 
f_{v,d}  is the design shear strength; 
k_{shape}  is a factor depending on the shape of the crosssection; 
h  is the larger crosssectional dimension; 
b  is the smaller crosssectional dimension. 
where:
σ_{c,α,d}  is the compressive stress at an angle α to the grain; 
k_{c,90}  is a factor given in 6.1.5 taking into account the effect of any of stresses perpendicular to the grain. 
Figure 6.7  Compressive stresses at an angle to the grain
NOTE: To check the instability condition, a method is given in 6.3.
and
where:
λ_{y} and λ_{rel,y}  are slenderness ratios corresponding to bending about the yaxis (deflection in the zdirection); 
λ_{z} and λ_{rel,z}  are slenderness ratios corresponding to bending about the zaxis (deflection in the ydirection); 
E_{0,05}  is the fifth percentile value of the modulus of elasticity parallel to the grain. 
where the symbols are defined as follows:
where:
β_{c} is a factor for members within the straightness limits defined in Section 10:
k_{m} as given in 6.1.6.
where σ_{m,crit} is the critical bending stress calculated according to the classical theory of stability, using 5percentile stiffness values.
The critical bending stress should be taken as:
where:
E_{0,05}  is the fifth percentile value of modulus of elasticity parallel to grain; 
G_{0,05}  is the fifth percentile value of shear modulus parallel to grain; 
I_{z}  is the second moment of area about the weak axis z. 
I_{tor}  is the torsional moment of inertia; 42 
ℓ_{ef}  is the effective length of the beam, depending on the support conditions and the load configuration, acccording to Table 6.1; 
W_{y}  is the section modulus about the strong axis y. 
For softwood with solid rectangular crosssection, σ_{m,crit} should be taken as:
where:
b  is the width of the beam; 
h  is the depth of the beam. 
σ_{m,d} ≤ k_{crit} f_{m,d} (6.33)
where:
σ_{m,d}  is the design bending stress; 
f_{m,d}  is the design bending strength; 
k_{crit}  is a factor which takes into account the reduced bending strength due to lateral buckling. 
Beam type  Loading type  ℓ_{ef}/ℓ^{a} 

Simply supported  Constant moment Uniformly distributed load Concentrated force at the middle of the span 
1,0 0,9 0,8 
Cantilever  Uniformly distributed load Concentrated force at the free end 
0,5 0,8 
^{a} The ratio between the effective length ℓ_{ef} and the span ℓ is valid for a beam with torsionally restrained supports and loaded at the centre of gravity. If the load is applied at the compression edge of the beam, ℓ_{ef} should be increased by 2h and may be decreased by 0,5h for a load at the tension edge of the beam. 
where:
σ_{m,d}  is the design bending stress; 
σ_{c,0,d}  is the design compressive stress parallel to grain; 
f_{c,0,d}  is the design compressive strength parallel to grain; 
k_{c,z}  is given by expression (6.26). 
where:
σ_{N}  is the axial stress; 
N  is the axial force; 
A  is the area of the crosssection. 
Figure 6.8 – Single tapered beam
At the outermost fibre of the tapered edge, the stresses should satisfy the following expression:
σ_{m,α,d} ≤ k_{m,α} f_{m,d} (6.38)
where:
σ_{m,α,d}  is the design bending stress at an angle to grain; 
f_{m,d}  is the design bending strength; 
k_{m,α}  should be calculated as: 
For tensile stresses parallel to the tapered edge:
For compressive stresses parallel to the tapered edge:
σ_{m,d} ≤ k_{r} f_{m,d} (6.41)
where k_{r} takes into account the strength reduction due to bending of the laminates during production.
NOTE: In curved and and pitched cambered beams the apex zone extends over the curved part of the beam
with:
k_{1} = 1 + 1,4 tan α_{ap} + 5,4 tan^{2} α_{ap} (6.44)
45k_{2} = 0,35  8 tan α_{ap} (6.45)
k_{3} = 0,6 + 8,3 tan α_{ap}  7,8 tan^{2} α_{ap} (6.46)
k_{4} = 6 tan^{2} α_{ap} (6.47)
r = r_{in} + 0,5 h_{ap} (6.48)
where:
M_{ap,d}  is the design moment at the apex; 
h_{ap} is the depth of the beam at the apex, see Figure 6.9;  
b  is the width of the beam; 
r_{in}  is the inner radius, see Figure 6.9; 
α_{ap}  is the angle of the taper in the middle of the apex zone, see Figure 6.9. 
where
r_{in}  is the inner radius, see Figure 6.9; 
t  is the lamination thickness. 
σ_{t,90,d} ≤ k_{dis} k_{vol} f_{t,90,d} (6.50)
with
where:
k_{dis}  is a factor which takes into account the effect of the stress distribution in the apex zone; 
k_{vol}  is a volume factor; 
f_{t,90,d}  is the design tensile strength perpendicular to the grain; 
V_{0}  is the reference volume of 0,01m^{3}; 
V  is the stressed volume of the apex zone, in m^{3}, (see Figure 6.9) and should not be taken greater than 2V_{b}/3, where V_{b} is the total volume of the beam. 
where:
τ_{d}  is the design shear stress; 
f_{v,d}  is the design shear strength; 
σ_{t,90,d}  is the design tensile stress perpendicular to grain; 
k_{dis} and k_{vol} are given in (6). 
or, as an alternative to expression (6.54), as
where:
p_{d}  is the uniformly distributed load acting on the top of the beam over the apex area; 
b  is the width of the beam; 
M_{ap,d}  is the design moment at apex resulting in tensile stresses parallel to the inner curved edge; 
with:
k_{5} = 0,2 tan α_{ap} (6.57)
k_{6} = 0,25  1,5 tan α_{ap} + 2,6 tan^{2} α_{ap} (6.58)
k_{7} = 2,1 tan α_{ap}  4 tan^{2} α_{ap} (6.59)
Note: The recommended expression is (6.54). Information on the national choice between expressions (6.54) and (6.55) may be found in the National annex.
47Figure 6.9 – Double tapered (a), curved (b) and pitched cambered (c) beams with the fibre direction parallel to the lower edge of the beam
48Figure 6.10 – Bending at a notch: a) with tensile stresses at the notch, b) with compressive stresses at the notch
where k_{v} is a reduction factor defined as follows:
k_{v} = 1,0 (6.61)
where:
49i  is the notch inclination (see Figure 6.11a); 
h  is the beam depth in mm; 
x  is the distance from the line of action of the support reaction to the corner of the notch, in mm; 
Figure 6.11 – Endnotched beams
NOTE: For roof trusses with a maximum centre to centre distance of 1,2 m it may be assumed that tiling battens, purlins or panels can transfer the load to the neighbouring trusses provided that these loaddistribution members are continuous over at least two spans, and any joints are staggered.
Figure 6.12 – System strength factor k_{sys} for laminated deck plates of solid timber or glued laminated members
NOTE: In EN 26891 the symbol used is k_{s} instead of K_{ser}.
Fastener type  K_{ser} 

Dowels Bolts with or without clearance^{a} Screws Nails (with predrilling) 
ρ_{m}^{1,5} d/23 
Nails (without predrilling)  ρ_{m}^{1,5}d^{0,8}/30 
Staples  ρ_{m}^{1,5}d^{0,8}/30 
Splitring connectors type A according to EN 912 Shearplate connectors type B according to EN 912 
ρ_{m} d_{c}/2 
Toothedplate connectors:

1,5 ρ_{m}d_{c}/4 ρ_{m}d_{c}/2 
^{a} The clearance should be added separately to the deformation. 
–  w_{c}  is the precamber (if applied); 
–  w_{inst}  is the instantaneous deflection; 
–  w_{creep}  is the creep deflection; 
–  w_{fin}  is the final deflection; 
–  w_{net,fin}  is the net final deflection. 
Figure 7.1 – Components of deflection
w_{net,fin} = w_{inst} + w_{creep} − w_{c} = w_{fin} − w_{c} (7.2)
NOTE: The recommended range of limiting values of deflections for beams with span ℓ is given in Table 7.2 depending upon the level of deformation deemed to be acceptable. Information on National choice may be found in the National annex.
w_{inst}  w_{net,fin}  w_{fin}  

Beam on two supports  ℓ/300 to ℓ/500  ℓ/250 to ℓ/350  ℓ/150 to ℓ/300 
Cantilevering beams  ℓ/150 to ℓ/250  ℓ/125 to ℓ/175  ℓ/75 to ℓ/150 
and
v ≤ b^{(f1ζ−1)} m/(Ns^{2}) (7.4)
where:
w  is the maximum instantaneous vertical deflection caused by a vertical concentrated static force F applied at any point on the floor, taking account of load distribution; 
v  is the unit impulse velocity response, i.e. the maximum initial value of the vertical floor vibration velocity (in m/s) caused by an ideal unit impulse (1 Ns) applied at the point of the floor giving maximum response. Components above 40 Hz may be disregarded; 
ζ  is the modal damping ratio. 
NOTE: The recommended range of limiting values of a and b and the recommended relationship between a and b is given in Figure 7.2. Information on the National choice may be found in the National annex.
Figure 7.2 — Recommended range of and relationship between a and b
where:
m  is the mass per unit area in kg/m^{2}; 
ℓ  is the floor span, in m; 
(EI)_{ℓ}  is the equivalent plate bending stiffness of the floor about an axis perpendicular to the beam direction, in Nm^{2}/m. 
where:
v  is the unit impulse velocity response, in m/(Ns^{2}); 
n_{40}  is the number of firstorder modes with natural frequencies up to 40 Hz; 
b  is the floor width, in m; 
m  is the mass, in kg/m^{2}; 
ℓ  is the floor span, in m. 
The value of n_{40} may be calculated from:
where (EI)_{b} is the equivalent plate bending stiffness, in Nm^{2}/m, of the floor about an axis parallel to the beams, where (EI)_{b}< (EI)_{ℓ}.
F_{v,ef,Rk} = n_{ef} F_{v,Rk} (8.1)
where:
F_{v,ef,Rk}  is the effective characteristic loadcarrying capacity of one row of fasteners parallel to the grain; 
n_{ef}  is the effective number of fasteners in line parallel to the grain; 
F_{v,Rk}  is the characteristic loadcarrying capacity of each fastener parallel to the grain. 
NOTE: Values of n_{ef} for rows parallel to grain are given in 8.3.1.1(8) and 8.5.1.1(4).
F_{v,Ed} ≤ F_{90,Rd} (8.2)
with
where:
F_{90,Rd}  is the design splitting capacity, calculated from the characteristic splitting capacity F_{90,Rk} according to 2.4.3; 
F_{v,Ed,1,} F_{v,Ed,2}  are the design shear forces on either side of the connection. (see Figure 8.1). 
where:
and:
F_{90,Rd}  is the characteristic splitting capacity, in N; 
w  is a modification factor; 
h_{e}  is the loaded edge distance to the centre of the most distant fastener or to the edge of the punched metal plate fastener, in mm; 
h  is the timber member height, in mm; 
b  is the member thickness, in mm; 
w_{pl}  is the width of the punched metal plate fastener parallel to the grain, in mm. 
Figure 8.1 – Inclined force transmitted by a connection
with
where:
F_{v,Rk}  is the characteristic loadcarrying capacity per shear plane per fastener; 
t_{i}  is the timber or board thickness or penetration depth, with i either 1 or 2, see also 8.3 to 8.7; 
f_{h,i,k}  is the characteristic embedment strength in timber member i; 
d  is the fastener diameter; 
M_{y,Rk}  is the characteristic fastener yield moment; 
β  is the ratio between the embedment strength of the members; 
F_{ax,Rk}  is the characteristic axial withdrawal capacity of the fastener, see (2). 
NOTE: Plasticity of joints can be assured when relatively slender fasteners are used. In that case, failure modes (f) and (k) are governing.
– Round nails  15 % 
– Square and grooved nails  25 % 
– Other nails  50 % 
– Screws  100% 
– Bolts  25% 
– Dowels  0 % 
If F_{ax,Rk} is not known then the contribution from the rope effect should be taken as zero.
For single shear fasteners the characteristic withdrawal capacity, F_{ax,Rk} is taken as the lower of the capacities in the two members. The different modes of failure are illustrated in Figure 8.2. For the withdrawal capacity, F_{ax,Rk}, of bolts the resistance provided by the washers may be taken into account, see 8.5.2(2).
Figure 8.2 – Failure modes for timber and panel connections.
where:
F_{v,Rk}  is the characteristic loadcarrying capacity per shear plane per fastener; 
f_{h,k}  is the characteristic embedment strength in the timber member; 
t_{1}  is the smaller of the thickness of the timber side member or the penetration depth; 
t_{2}  is the thickness of the timber middle member; 
d  is the fastener diameter; 
M_{y,Rk}  is the characteristic fastener yield moment; 
F_{ax,Rk}  is the characteristic withdrawal capacity of the fastener. 
NOTE 1: The different failure modes are illustrated in Figure 8.3 
Figure 8.3 – Failure modes for steeltotimber connections
NOTE: A method of determining the strength of the fastener group is given in Annex A (informative).
t_{1} is:
the headside thickness in a single shear connection;
the minimum of the head side timber thickness and the pointside penetration in a double shear connection;
t_{2} is:
the pointside penetration in a single shear connection;
the central member thickness in a double shear connection.
where:
M_{y,Rk}  is the characteristic value for the yield moment, in Nmm; 
d  is the nail diameter as defined in EN 14592, in mm; 
f_{u}  is the tensile strength of the wire, in N/mm^{2}. 
f_{h,k} = 0,082 ρ_{k}d^{0,3} N/mm^{2} (8.15)
f_{h,k} = 0,082(10,01 d)ρ_{k} N/mm^{2} (8.16)
where:
ρ_{k}  is the characteristic timber density, in kg/m^{3}; 
d  is the nail diameter, in mm. 
Figure 8.4  Definitions of t_{1} and t_{2} (a) single shear connection, (b) double shear connection
Figure 8.5  Overlapping nails
n_{ef} = n^{kef} (8.17)
where:
n_{ef}  is the effective number of nails in the row; 63 
n  is the number of nails in a row; 
k_{ef}  is given in Table 8.1. 
Spacing^{a}  k_{ef}  

Not predrilled  Predrilled  
a_{1} ≥ 14d  1,0  1,0 
a_{1} = 10d  0,85  0,85 
a_{1} = 17d  0,7  0,7 
a_{1} = 4d    0,5 
^{a} For intermediate spacings, linear interpolation of k_{ef} is permitted 
Figure 8.6  Nails in a row parallel to grain staggered perpendicular to grain by d
Note 1: An example of a secondary structure is a fascia board nailed to rafters.
64Note 2: The recommended application rule is given in 8.3.1.2(3). The National choice may be specified in the National annex.
a_{1}  is the spacing of nails within one row parallel to grain; 
a_{2}  is the spacing of rows of nails perpendicular to grain; 
a_{3,c}  is the distance between nail and unloaded end; 
a_{3,t}  is the distance between nail and loaded end; 
a_{4,c}  is the distance between nail and unloaded edge; 
a_{4,t}  is the distance between nail and loaded edge; 
α  is the angle between the force and the grain direction. 
Spacing or distance (see Figure 8.7)  Angle α  Minimum spacing or end/edge distance  

without predrilled holes  with predrilled holes  
ρ_{k} ≤ 420 kg/m^{3}  420 kg/m^{3} < σ_{k} ≤ 500 kg/m^{3}  
Spacing a_{1} (parallel to grain)  0° ≤ α ≤ 360°  d < 5 mm: (5+5 cos α )d d ≥5 mm: (5+7 cos α)d 
(7+8 cos α)d  (4+ cos α)d 
Spacing a_{2} (perpendicular to grain)  0° ≤ α ≤ 360°  5d  7d  (3+ sin α)d 
Distance a_{3,t} (loaded end)  90° ≤ α ≤ 90°  (10+ 5 cos α) d  (15 + 5 cos α) d  (7+ 5cos α) d 
Distance a_{3,c} (unloaded end)  90° ≤ α ≤ 270°  10d  15d  7d 
Distance a_{4,t} (loaded edge)  0° ≤ α ≤ 180°  d < 5 mm: (5+2 sin α) d d ≥ 5 mm: (5 + 5 sin α) d 
d < 5 mm: (7+2 sin α) d d ≥ 5 mm:(7 + 5 sin α) d 
d < 5 mm: (3 + 2 sin α) d d ≥ 5 mm: (3 + 4 sin α) d 
Distance a_{4,c} (unloaded edge)  180° ≤ α ≤ 360°  5d  7d  3d 
where:
t  is the minimum thickness of timber member to avoid predrilling, in mm;65 
ρ_{k}  is the characteristic timber density in kg/m^{3}; 
d  is the nail diameter, in mm. 
Expression (8.19) may be replaced by expression (8.18) for edge distances given by:
a_{4} ≥ 10 d for ρ_{k} ≤ 420 kg/m^{3}
a_{4} ≥ 14 d for 420 kg/m^{3} ≤ ρ_{k} ≤ 500 kg/m^{3}.
Note: Examples of species sensitive to splitting are fir (abies alba), Douglas fir (pseudotsuga menziesii) and spruce (picea abies). It is recommended to apply 8.3.1.2(7) for species fir (abies alba) and Douglas fir (pseudotsuga menziesii). The National choice may be specified in the National annex.
Figure 8.7 – Spacings and end and edge distances (a) Spacing parallel to grain in a row and perpendicular to grain between rows, (b) Edge and end distances
f_{h,k} = 0,11 ρ_{k} d^{−0,3} (8.20)
where:
f_{h,k}  is the characteristic embedment strength, in N/mm^{2}; 
ρ_{k}  is the characteristic plywood density in kg/m^{3}; 
d  is the nail diameter, in mm; 
f_{h,k} = 30 d^{−0,3} t^{0,6} (8.21)
where:
f_{h,k}  is the characteristic embedment strength, in N/mm^{2}; 
d  is the nail diameter, in mm; 
t  is the panel thickness, in mm. 
f_{h,k} = 65 d^{0,7} t^{0,1} (8.22)
where:
f_{h,k}  is the characteristic embedment strength, in N/mm^{2}; 
d  is the nail diameter, in mm; 
t  is the panel thickness, in mm. 
NOTE: The following definition of threaded nails is given in EN 14592: Nail that has its shank profiled or deformed over a part of its length of minimum 4,5 d (4,5 times the nominal diameter) and that has a characteristic withdrawal parameter f_{ax,k} greater than or equal to 6 N/mm^{2} when measured on timber with a characteristic density of 350 kg/m^{3} when conditioned to constant mass at 20 °C and 65 % relative humidity.
where:
f_{ax,k}  is the characteristic pointside withdrawal strength; 
f_{head,k}  is the characteristic headside pullthrough strength; 
d  is the nail diameter according to 8.3.1.1; 
t_{pen}  is the pointside penetration length or the length of the threaded part in the pointside member; 
t  is the thickness of the headside member; 
d_{h}  is the nail head diameter. 
where:
ρ_{k} is the characteristic timber density in kg/m^{3};
Figure 8.8 – (a) Nailing perpendicular to grain and (b) slant nailing
where:
F_{ax,Rd} and F_{v,Rd} are the design loadcarrying capacities of the connection loaded with axial load or lateral load respectively.
M_{y,Rk} = 240 d^{2,6} (8.29)
where:
M_{y,Rk}  is the characteristic yield moment, in Nmm; 
d  is the staple leg diameter, in mm. 
Figure 8.9 – Staple dimensions
Figure 8.10 – Definition of spacing for staples
70Spacing and edge/end distances (see Figure 8.7) 
Angle  Minimum spacing or edge/end distance 

a_{1}(parallel to grain for θ ≥ 30° for θ < 30° 
0° ≤ α ≤ 360°  (10 + 5cos α d (15 + 5cos α d 
a_{2} (perpendicular to grain)  0° ≤ α ≤ 360^{0°}  15 d 
a_{3,t} (loaded end)  90° ≤ α ≤ 90°  (15 + 5cos α d 
a_{3,c} (unloaded end)  90° ≤ α ≤ 270°  15 d 
a_{4,t} (loaded edge)  0° ≤ α ≤ 180°  (15 + 5sin α d 
a_{4,c} (unloaded edge)  180° ≤ α ≤ 360°  10 d 
M_{y,Rk} = 0,3 f_{u,k} d^{2,6} (8.30)
where:
M_{y,Rk}  is the characteristic value for the yield moment, in Nmm; 
f_{u,k}  is the characteristic tensile strength, in N/mm^{2}; 
d  is the bolt diameter, in mm. 
f_{h,0,k} = 0,082(1−0,01 d)ρ_{k} (8.32)
where:
and:
f_{h,0,k}  is the characteristc embedment strength parallel to grain, in N/mm^{2}; 
ρ_{k}  is the characteristic timber density, in kg/m^{3}; 
α  is the angle of the load to the grain; 
d  is the bolt diameter, in mm. 
Spacing and end/edge distances (see Figure 8.7) 
Angle  Minimum spacing or distance 

a_{1} (parallel to grain)  0° ≤ α ≤ 360°  (4 +  cos α  d 
a_{2} (perpendicular to grain)  0° ≤ α ≤ 360°  4 d 
a_{3,t} (loaded end)  90° ≤ α ≤ 90°  max (7 d; 80mm) 
a_{3,c} (unloaded end)  90° ≤ α < 150° 150° ≤ α < 210° 210° ≤ α ≤ 270° 
(1 + 6 sin α)d 4 d (1 + 6 sin α) d 
a_{4,t} (loaded edge)  0° ≤ α ≤ 180°  max [(2 + 2 sin α) d; 3d] 
a_{4,c} (unloaded edge)  180° ≤ α ≤ 360°  3d 
where:
a_{1}  is the spacing between bolts in the grain direction; 
d  is the bolt diameter 
n  is the number of bolts in the row. 
For loads perpendicular to grain, the effective number of fasteners should be taken as
n_{ef} = n (8.35)
For angles 0° < α < 90° between load and grain direction, n_{ef} may be determined by linear interpolation between expressions (8.34) and (8.35).
f_{h,k} = 0,11 (1  0,01 d) ρ_{k} (8.36)
where:
ρ_{k}  is the characteristic plywood density, in kg/m^{3}; 
d  is the bolt diameter, in mm. 
f_{h,k} = 50 d^{−0,6} t^{0,2} (8.37)
where:
d  is the bolt diameter, in mm; 
t  is the panel thickness, in mm. 
Spacing and edge/end distances (see Figure 8.7) 
Angle  Minimum spacing or edge/end distance 

a_{1} (parallel to grain)  0° ≤ α ≤ 360°  (3 + 2 cos α) d 
a_{2} (perpendicular to grain)  0° ≤ α ≤ 360°  3d 
a_{3,t}(loaded end)  90° ≤ α ≤ 90^{0°}  max (7 d; 80 mm) 
a_{3,c} (unloaded end)  90^{0°} ≤ α < 150° 150° ≤ α < 210° 210° ≤ α ≤ 270° 
max(a_{3,t}  sin α) d; 3d) 3 d max(a3,t  sin α) d; 3d) 
a_{4,t} (loaded edge)  0° ≤ α ≤ 180°  max([2 + 2 sin α) d; 3d) 
a_{4,c} (unloaded edge)  180° ≤ α ≤ 360°  3 d 
Minimum screw spacing in a plane parallel to the grain a_{1} 
Minimum screw spacing perpendicular to a plane parallel to the grain a_{2} 
Minimum end distance of the centre of gravity of the threaded part of the screw in the member a_{1,CG} 
Minimum edge distance of the centre of gravity of the threaded part of the screw in the member a_{2,CG} 

7d  5d  10d  4d 
Figure 8.11a – spacings and end and edge distances
where
d  is the outer thread diameter; 
d_{1}  is the inner thread diameter 
the characteristic withdrawal capacity should be taken as:
where:
75F_{ax,α,Rk}  is the characteristic withdrawal capacity of the connection at an angle a to the grain, in N; 
f_{ax,k}  is the characteristic withdrawal strength perpendicular to the grain, in N/mm^{2}; 
n_{ef}  is the effective number of screws, see 8.7.2(8); 
ℓ_{ef}  is the penetration length of the threaded part, in mm; 
ρ_{k}  is the characteristic density, in kg/m^{3}; 
α  is the angle between the screw axis and the grain direction, with α ≥ 30°. 
NOTE: Failure modes in the steel or in the timber around the screw are brittle, i.e. with small ultimate deformation and therefore have a limited possibility for stress redistribution.
where
f_{ax,k}  is the characteristic withdrawal parameter perpendicular to the grain determined in accordance with EN 14592 for the associated density ρ_{a}; 
ρ_{a}  is the associated density for f_{ax,k}, in kg/m^{3} 
and the other symbols are explained in (4).
where:
F_{ax,α,Rk}  is the characteristic pullthrough capacity of the connection at an angle a to the grain in N, with α ≥ 30° 
f_{head,k}  is the characteristic pullthrough parameter of the screw determined in accordance with EN 14592 for the associated density ρ_{a}; 
d_{h}  is the diameter of the screw head in mm 
and the other symbols are explained in (4).
F_{t,Rk} = n_{ef} f_{tens,k} (8.40c)
where
f_{tens,k}  is the characteristic tensile capacity of the screw determined in accordance with EN 14592; 
n_{ef}  is the effective number of screws, see 8.7.2(8). 
n_{ef} = n^{0,9} (8.41)
where:
n_{ef}  is the effective number of screws; 
n  is the number of screws acting together in a connection. 
xdirection  main direction of plate; 
ydirection  perpendicular to the main plate direction; 
α  angle between the xdirection and the force (tension: 0° ≤ γ < 90°, compression: 90° ≤ γ < 180°); 
β  angle between the graindirection and the force; 
γ  angle between the xdirection and the connection line; 
A_{ef}  area of the total contact surface between the plate and the timber, reduced by 5 mm from the edges of the timber and by a distance in the grain direction from the end of timber equal to 6 times the fastener’s nominal thickness; 
l  dimension of the plate measured along the connection line. 
f_{a,0,0}  the anchorage capacity per unit area for α = 0° and β = 0°; 
f_{a,90,90}  the anchorage capacity per unit area for α = 90° and β = 90°; 
f_{t,0}  the tension capacity per unit width of plate for α = 0°; 
f_{c,0}  the compression capacity per unit width of plate for α = 0°; 
f_{v,0}  the shear capacity per unit width of plate in the xdirection; 
f_{t,90}  the tension capacity per unit width of plate for α = 90°; 
f_{c,90}  the compression capacity per unit width of plate for α = 90°; 
f_{v,90}  the shear capacity per unit width of plate in the ydirection; 
k_{1},k_{2},α_{o}  constants. 
Figure 8.11 – Geometry of punched metal plate connection loaded by a force F_{Ed} and moment M_{Ed}
f_{a,α,β,k} = f_{a,0,0,k} − (f_{a,0,0,k} − f_{a,90,90,k})sin(max(α,β)) for 45° < β ≤ 90° (8.43)
The constants k_{1}, k_{2} and α_{0} should be determined from anchorage tests in accordance with EN 1075 and derived in accordance with the procedure given in EN 14545 for the actual plate type.
with:
where:
F_{A,Ed}  is the design force acting on a single plate at the centroid of the effective area (i.e. half of the total force in the timber member); 
M_{A,Ed}  is the design moment acting on a single plate on the centroid of the effective area; 
dA  is the segmental area of the punched metal plate fastener; 
r  is the distance from the centre of gravity of the plate to the segmental plate area dA; 
A_{ef}  is the effective plate area. 
with:
where:
h_{ef} is the maximum height of the effective anchorage area perpendicular to the longest side.
where:
F_{Ed}  is the design axial force of the chord acting on a single plate (compression or zero); 
M_{Ed}  is the design moment of the chord acting on a single plate; 
h  is the height of the chord. 
F_{x,Ed} = F_{Ed} cos α ± 2 F_{M,Ed} sin γ (8.53)
F_{y,Ed} = F_{Ed} sin α ± 2 F_{M,Ed} cos γ (8.54)
where:
F_{Ed}  is the design force in a single plate (i.e. half of the total force in the timber member) 
F_{M,Ed}  is the design force from the moment on a single plate (F_{M,Ed} = 2 M_{Ed}/ℓ) 
where:
F_{x,Ed} and F_{y,Ed}  are the design forces acting in the x and y direction, 
F_{x,Rd} and F_{y,Rd}  are the corresponding design values of the plate capacity. They are determined from the maximum of the characteristic capacities at sections parallel or perpendicular to the main axes, based upon the following expressions for the characteristic plate capacities in these directions 
with
where γ_{0} and k_{v} are constants determined from shear tests in accordance with EN 1075 and derived in accordance with the procedure given in EN 14545 for the actual plate type.
where:
F_{v,0,Rk}  is the characteristic loadcarrying capacity parallel to the grain, in N; 
d_{c}  is the connector diameter, in mm; 
h_{e}  is the embedment depth, in mm; 
k_{i}  are modification factors, with i = 1 to 4, defined below. 
Figure 8.12 – Dimensions for connections with split ring and shear plate connectors
where:
a_{3,t} is given in Table 8.7.
For other values of α, k_{2} = 1,0.
where ρ_{k} is the characteristic density of the timber, in kg/m^{3}.
with:
k_{90} = 1,3 + 0,001 d_{c} (8.68)
where:
F_{v,0,Rk}  is the characteristic loadcarrying capacity of the connector for a force parallel to grain according to expression (8.61); 
d_{c}  is the connector diameter, in mm. 
Spacing and edge/end distances(see figure 8.7)  Angle to grain  Minimum spacings and edge/end distances 

a_{1} (parallel to grain)  0° ≤ α ≤ 360°  (1,2 + 0,8  cos α ) d_{c} 
a_{2} (perpendicular to grain)  0° ≤ α ≤ 360°  1,2 d_{c} 
a_{3,t} (loaded end)  90° ≤ α ≤ 90°  1,5 d_{c} 
a_{3,c} (unloaded end)  90° ≤ α < 150°  (0,4 + 1,6  sin α ) d_{c} 
150° ≤ α < 210°  1,2 d_{c}  
210° ≤ α ≤ 270°  (0,4 + 1,6  sin α ) d_{c}  
a_{4,t} (loaded edge)  0° ≤ α ≤ 180°  (0,6 + 0,2  sin α ) d_{c} 
a_{4,c} (unloaded edge)  180° ≤ α ≤ 360°  0,6 d_{c} 
where:
k_{a1}  is a reduction factor for the minimum distance a_{1} parallel to the grain; 
k_{a2}  is a reduction factor for the minimum distance a_{2} perpendicular to the grain. 
Figure 8.13 – Reduced distances for connectors
k_{R,red} = 0,2 + 0,8 k_{s,red} (8.70)
where:
n_{ef}  is the effective number of connectors; 83 
n  is the number of connectors in a line parallel to grain. 
where:
F_{v,Rk}  is the characteristic loadcarrying capacity per toothedplate connector, in N. 
k_{i}  are modification factors, with i = 1 to 3, defined below. 
d_{c}  is:

where:
t_{1}  is the side member thickness; 
t_{2}  is the middle member thickness; 
h_{e} is the tooth penetration depth. 
with
84where:
d  is the bolt diameter, in mm; 
d_{c}  is explained in (2) above. 
with
where:
d  is the bolt diameter in mm; 
d_{c}  is explained in (2) above. 
where ρ_{k} is the characteristic density of the timber, in kg/m^{3}.
Spacing and edge/end distances(see figure 8.7) 
Angle to grain  Minimum spacings and edge/end distances 

a_{1} (parallel to grain)  0° ≤ α ≤ 360°  (1,2 + 0,3  cos α ) d_{c} 
a_{2} (perpendicular to grain)  0° ≤ α ≤ 360°  1,2 d_{c} 
a_{3,t} (loaded end)  90° ≤ α ≤ 90°  2,0 d_{c} 
a_{3,c} (unloaded end)  90° ≤ α < 150°  (0,9 + 0,6  sin α ) d_{c} 
150° ≤ α < 210°  1,2 d_{c}  
210° ≤ α ≤ 270°  (0,9 + 0,6  sin α ) d_{c}  
a_{4,t} (loaded edge)  0° ≤ α ≤ 180°  0,6 + 0,2 sin α ) d_{c} 
a_{4,c} (unloaded edge)  180° ≤ α ≤ 360°  0,6 d_{c} 
Spacing and edge/end distances(see figure 8.7) 
Angle to grain  Minimum spacings and edge/end distances 

a_{1} (parallel to grain)  0° ≤ α ≤ 360°  (1,2 + 0,8  cos α ) d_{c} 
a_{2} (perpendicular to grain)  0° ≤ α ≤ 360°  1,2 d_{c} 
a_{3,t} (loaded end)  90° ≤ α ≤ 90°  2,0 d_{c} 
a_{3,c} (unloaded end)  90° ≤ α < 150°  (0,4 + 1,6  sin α ) d_{c} 
150° ≤ α < 210°  1,2 d_{c}  
210° ≤ α ≤ 270°  (0,4 + 1,6  sin α ) d_{c}  
a_{4,t} (loaded edge)  0° ≤ α ≤ 180°  (0,6 + 0,2 sin α ) d_{c} 
a_{4,c} (unloaded edge)  180° ≤ α ≤ 360°  0,6 d_{c} 
σ_{f,c,max,d} ≤ f_{m,d} (9.1)
σ_{f,t,max,d} ≤ f_{m,d} (9.2)
σ_{f,c,d} ≤ k_{c} f_{c,0,d} (9.3)
σ_{f,t,d} ≤ f_{t,0,d} (9.4)
where
σ_{f,c,max,d}  is the extreme fibre flange desing compressive stress; 
σ_{f,t,max,d}  is the extreme fibre flange design tensile stress; 
σ_{f,c,d}  is the mean flange desing compressive stress; 
σ_{f,t,d}  is the mean flange design tensile stress; 
k_{c}  is a factor which takes into account lateral instability. 
Figure 9.1 – Thinwebbed beams
where:
ℓ_{c}  is the distance between the sections where lateral deflection of the compressive flange is prevented; 
b  is given in Figure 9.1. 
If a special investigation is made with respect to the lateral instability of the beam as a whole, it may be assumed that k_{c} = 1,0.
σ_{w,c,d} ≤ f_{c,w,d} (9.6)
σ_{w,t,d} ≤ f_{t,w,d} (9.7)
where:
σ_{w,c,d} and σ_{w,t,d}  are the design compressive and tensile stresses in the webs; 
f_{c,w,d} and f_{t,w,d}  are the design compressive and tensile bending stresses of the webs; 
h_{w} ≤ 70 b_{w} (9.8)
and
where:
F_{v,w,Ed}  is the design shear force acting on each web; 
h_{w}  is the clear distance between flanges; 
h_{f,c}  is the compressive flange depth; 
h_{f,t}  is the tensile flange depth; 
b_{w}  is the width of each web; 
f_{v,0,d}  is the design panel shear strength. 
where:
τ_{mean,d}  is the design shear stress at the sections 11, assuming a uniform stress distribution; 
f_{v,90,d}  is the design planar (rolling) shear strength of the web; 
h_{f}  is either h_{f,c} or h_{f,t}. 
b_{ef} = b_{c,ef} + b_{w} (or b_{t,ef} + b_{w}) (9.12)
b_{ef} = 0,5 b_{c,ef} + b_{w} (or 0,5 b_{t,ef} + b_{w}) (9.13)
The values of b_{c,ef} and b_{t,ef} should not be greater than the maximum value calculated for shear lag from Table 9.1. In addition the value of b_{c,ef} should not be greater than the maximum value calculated for plate buckling from Table 9.1.
Flange material  Shear lag  Plate buckling 

Plywood, with grain direction in the outer plies:  

0,1ℓ 0,1 ℓ 
20h_{f} 25 h_{f} 
Oriented strand board  0,15ℓ  25h_{f} 
Particleboard or fibreboard with random fibre orientation 
0,2ℓ  30h_{f} 
where:
τ_{mean.d}  is the design shear stress at the sections 11, assuming a uniform stress distribution; 
f_{v,90,d}  is the design planar (rolling) shear strength of the flange. 
For section 11 of a Ushaped crosssection, the same expressions should be verified, but with 8h_{f} substituted by 4h_{f}.
σ_{f,c,d} ≤ f_{f,c,d} (9.15)
σ_{f,t,d} ≤ f_{f,t,d} (9.16)
where:
σ_{f,c,d}  is the mean flange design compressive stress; 
σ_{f,t,d}  is the mean flange design tensile stress; 
f_{f,c,d}  is the flange design compressive strength; 
f_{f,t,d}  is the flange design tensile strength. 
Figure 9.2 – Thinflanges beam
s_{ef} = 0,75 s_{min} + 0,25 s_{max} (9.17)
NOTE: A method for the calculation of the loadcarrying capacity of mechanically jointed beams is given in Annex B (Informative).
NOTE: A method for the calculation of the loadcarrying capacity of I and boxcolumns, spaced columns and lattice columns is given in Annex C (Informative).
– in an outer bay:  0,8 times the bay length; 
– in an inner bay:  0,6 the bay length; 
– at a node:0,6  times the largest adjacent bay length; 
– at the beam end with moment:  0,0 (i.e. no column effect); 
– in the penultimate bay:  1,0 times bay length; 
– remaining bays and nodes:  as described above for continuous beams without significant end moments; 
For the strength verification of members in compression and connections, the calculated axial forces should be increased by 10 %.
91F_{r,d} = 1,0 + 0,1 L (9.18)
where:
F_{r,d}  is in kN; 
L  is the overall length of the truss, in m. 
Figure 9.3 – Moment diagrams and effective lengths in compression (a) No significant end moments (b) Significant end moments
σ_{m,d} ≤ 0,75 f_{m,d} (9.19)
Figure 9.4 – Diaphragm loading and staggered panel arrangements
NOTE: The recommended procedure is method A given in 9.2.4.2. National choice may be given in the National annex.
F_{v,Rd} = Σ F_{i,v,Rd} (9.20)
where F_{i,v,Rd} is the design racking loadcarrying capacity of the wall panel in accordance with 9.2.4.2(4) and 9.2.4.2(5).
where:
F_{f,Rd}  is the lateral design capacity of an individual fastener; 
b_{i}  is the wall panel width; 94 
s  is the fastener spacing. 
and
where:
b_{0} = h/2  
h  is the height of the wall. 
Figure 9.5 – Forces acting on:
a) wall panel;
b) framing;
c) sheet
where h is the height of the wall.
Figure 9.6 – Example of the assembly of wall panels containing a wall panel with a window opening and a wall panel of smaller width
where:
b_{net}  is the clear distance between studs; 
t  is the thickness of the sheet. 
Figure 9.7 – Example of wall assembly consisting of several wall panels
F_{v,Rd} = ΣF_{i,v,Rd} (9.24)
where:
F_{i,v,Rd}  is the design racking strength of a wall in accordance with (3) below. 
where:
F_{f,Rd}  is the lateral design capacity of an individual fastener; 
b_{i}  is the wall length, in m; 
s_{0}  is the basic fastener spacing, in m, see (4) below; 
k_{d}  is the dimension factor for the wall, see (4) below; 
k_{i,q}  is the uniformly distributed load factor for wall i, see (4) below; 
k_{s}  is the fastener spacing factor, see (4) below; 
k_{n}  is the sheathing material factor, see (4) below. 
where:
s_{0}  is the basic fastener spacing, in m; 
d  is the fastener diameter, in mm; 
ρ_{k}  is the characteristic density of the timber frame, in kg/m^{3}; 
where h is the height of the wall, in m;
where q_{i} is the equivalent uniformly distributed vertical load acting on the wall, in kN/m, with q_{i} ≥ 0, see (5) below;
98where s is the spacing of the fasteners around the perimeter of the sheets;
where:
F_{i,v,Rd,max}  is the design racking strength of the stronger sheathing; 
F_{i,v,Rd,min}  is the design racking strength of the weaker sheathing. 
where:
a  is the horizontal distance from the force F to the leeward corner of the wall; 
b  is the length of the wall. 
Figure 9.8 – Determination of equivalent vertical action q_{i}, and reaction forces from vertical and horizontal actions
99where h is the height of the wall.
These external forces can be transmitted to either the adjacent panel through the vertical paneltopanel connection or to the construction above or below the wall. When tensile forces are transmitted to the construction below, the panel should be anchored with stiff fasteners. Compression forces in the vertical members should be checked for buckling in accordance with 6.3.2. Where the ends of vertical members bear on horizontal framing members, the compression perpendicular to the grain stresses in the horizontal members should be assessed according to 6.1.5.
where:
b_{net}  is the clear distance between vertical members of the timber frame; 
t  is the thickness of the sheathing. 
where:
k_{s}  is a modification factor; 
N_{d}  is the mean design compressive force in the element; 
a  is the bay length (see Figure 9.9). 
NOTE: For k_{s}, see note in 9.2.5.3(1)
where k_{f,1} and k_{f,2} are modification factors.
NOTE: For k_{f,1} and k_{f,2} see note in 9.2.5.3(1)
Figure 9.9 – Examples of single members in compression braced by lateral supports.
where:
The value of k_{crit} should be determined from 6.3.3(4) for the unbraced beam, and M_{d} is the maximum design moment acting on the beam of depth h.
where:
N_{d}  is the mean design compressive force in the member; 101 
ℓ  is the overall span of the stabilizing system, in m; 
k_{f,3}  is a modification factor 
Figure 9.10 – Beam or truss system requiring lateral supports
NOTE: The values of the modification factors k_{s}, k_{f,1}, k_{f,2} and k_{f,3} depend on influences such as workmanship, span etc. Ranges of values are given in Table 9.2 where the recommended values are underlined. The National choice may be given in the National annex.
Modification factor  Range 

k_{s}  4 to 1 
k_{f,1}  50 to 80 
k_{f,2}  80 to 100 
k_{f,3}  30 to 80 
d_{c}  is the connector diameter, in mm; 
d  is the bolt diameter, in mm 
d_{1}  is the diameter of centre hole of connector. 
Type of connector EN 912  d_{c}  d minimum  d maximum 

mm  mm  mm  
A1 – A6  ≤ 130  12  24 
A1, A4, A6  > 130  0,1 d_{c}  24 
B  d_{1}1  d_{1} 
NOTE 1: The control of the construction is assumed to include:
NOTE 2: A control program is assumed to specify the control measures (inspection maintenance) to be carried out in service where longterm compliance with the basic assumptions for the project is not adequately ensured.
NOTE 3: All the information required for the use in service and the maintenance of a structure is assumed to be made available to the person or authority who undertakes responsibility for the finished structure.
Figure 10.1 – Example of connection of panels not supported by a joist or a rafter
Figure 10.2 – Panel fixings
Note: Requirements for the fabrication of trusses are given in EN 14250.
Note: The recommended range of a_{bow,perm} is 10 to 50 mm. The National choice may be given in the National annex.
Note: The recommended range of a_{dev,perm} is 10 to 50 mm. The National choice may be given in the National annex.
(Informative)
with
A_{net,t} = L_{net,t} t_{1} (A.2)
and
where
F_{bs,Rk}  is the characteristic block shear or plug shear capacity; 
A_{net,t}  is the net crosssectional area perpendicular to the grain; 
A_{net,v}  is the net shear area in the parallel to grain direction; 
L_{net,t}  is the net width of the crosssection perpendicular to the grain; 
L_{net,v}  is the total net length of the shear fracture area; 
ℓ_{v,i,} ℓ_{t,i}  are defined in figure A.1; 
t_{ef}  is the effective depth depending of the failure mode of the fastener, see Figure 8.3; 
t_{1}  is the timber member thickness or penetration depth of the fastener; 
M_{y,Rk}  is the characteristic yield moment of the fastener; 108 
d  is the fastener diameter; 
f_{t,0,k}  is the characteristic tensile strength of the timber member; 
f_{v,k}  is the characteristic shear strength of the timber member; 
f_{h,k}  is the characteristic embedding strength of the timber member. 
NOTE: The failure modes associated with expressions (A.3), (A.6) and (A.7) are shown in Figure 8.3.
Figure A.1 – Example of block shear failure
Figure A.2 – Example of plug shear failure
(Informative)
Figure B.1 – Crosssection (left) and distribution of bending stresses (right). All measurements are positive except for a_{2} which is taken as positive as shown.
111using mean values of E and where:
A_{i} = b_{i} h_{i} (B.2)
γ_{2} = 1 (B.4)
where the symbols are defined in Figure B.1;
K_{i} = K_{ser,i}  for the serviceability limit state calculations; 
K_{i} = K_{u,i}  for the ultimate limit state calculations. 
For Tsections h_{3} = 0
where:
112i = 1 and 3, respectively;
s_{i} = s_{i}(x) is the spacing of the fasteners as defined in B.1.3(1).
113(Informative)
σ_{c,0,d} ≤ k_{c} f_{c,0,d} (C.1)
where:
where:
A_{tot}  is the total crosssectional area; 
k_{c}  is determined in accordance with 6.3.2 but with an effective slenderness ratio λ_{ef} determined in accordance with sections C.2  C.4. 
with
where (EI)_{ef} is determined in accordance with Annex B (informative).
A_{tot} = 2 A (C.6)
A_{tot} = 3 A (C.8)
115Figure C.1 – Spaced columns
where:
λ  is the slenderness ratio for a solid column with the same length, the same area (A_{tot}) and the same second moment of area (I_{tot}), i.e., 
λ_{1}  is the slenderness ratio for the shafts and has to be set into expression (C.10) with a minimum value of at least 30, i,e. 
n  is the number of shafts; 
η  is a factor given in Table C.1 
Packs  Gussets  

Glued  Nailed  Bolted^{a}  Glued  Nailed  
Permanent/longterm loading  1  4  3,5  3  6 
Medium/shortterm loading  1  3  2,5  2  4,5 
^{a} with connectors 
Figure C.2 – Shear force distribution and loads on gussets or packs
where:
λ_{tot}  is the slenderness ratio for a solid column with the same length, the same area and the same second moment of area, i.e. 
μ  takes the values given in (3) to (6) below. 
where(see Figure C.3):
e  is the eccentricity of the joints; 
A_{f}  is the area of the flange; 
I_{f}  is the second moment of area of the flange; 
ℓ  is the span; 
h  is the distance of the flanges. 
Figure C.3 – Lattice columns: (a) Vtruss, (b) Ntruss
where:
n  is the number of nails in a diagonal. If a diagonal consists of two or more pieces, n is the sum of the nails (not the number of nails per shear plane); 119 
E_{mean}  is the mean value of modulus of elasticity; 
K_{u}  is the slip modulus of one nail in the ultimate limit state. 
where:
n  is the number of nails in a diagonal. If a diagonal consists of two or more pieces, n is the sum of the nails (not the number of nails per shear plane); 
K_{u}  is the slip modulus of one nail for the ultimate limit states. 
(Informative)
EN 338  Structural timber – Strength classes 
EN 1194  Glued laminated timber – Strength classes and determination of characteristic values 