EN 26891:1991

Timber structures - Joints made with mechanical fasteners - General principles for the determination of strength and deformation characteristics (ISO 6891:1983)

Applies to joints made with mechanical fasteners used in statically loaded timber structures. Covers the conditioning of test specimens and explains the apparatus to be used for measuring the geometry of the test specimens, their moisture content and other characteristics. Details the loading procedure and specifies the details to be included in the test report.

Holzbauwerke - Verbindungen mit mechanischen Verbindungsmitteln - Allgemeine Grundsätze für die Ermittlung der Tragfähigkeit und des Verformungsverhaltens (ISO 6891:1983)

Structures en bois - Assemblages réalisés avec des éléments mécaniques de fixation - Principes généraux pour la détermination des caractéristiques de résistance et de déformation (ISO 6891:1983)

La présente Norme internationale spécifie des principes généraux pour la détermination des caractéristiques de résistance et de déformation (glissement) des assemblages réalisés avec des éléments mécaniques de fixation.
La présente Norme internationale est applicable aux assemblages réalisés avec des éléments mécaniques de fixation, utilisés pour les structures en bois soumises à des charges statiques. Des modes opératoires détaillés, appropriés aux assemblages réalisés avec des éléments de fixation spécifiques, seront fournis dans des Normes internationales particulières. Le principe de ces méthodes peut aussi être appliqué à l'essai d'autres sortes d'assemblages. Il est reconnu que pour certains types particuliers d'assemblages non couverts par des Normes internationales, des modifications du mode opératoire d'essai peuvent être nécessaires.

Lesene konstrukcije - Stiki, izdelani z mehanskimi veznimi sredstvi - Splošna načela za ugotavljanje nosilnosti in deformacijskih karakteristik (ISO 6891:1983)

General Information

• Status: Published
• Publication Date: 20-Feb-1991
• ICS: 91.080.20 - Timber structures
• Technical Committee: CEN/TC 124 - Timber structures
• Drafting Committee: CEN/TC 124 - Timber structures
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 19-Feb-2007
• Completion Date: 19-Feb-2007
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Directive: 89/106/EEC - Construction products
• Mandate: M/112 - Mandate to CEN/CENELEC concerning the execution of standardization work for harmonized standards on structural timber products
• Ref Project: SIST EN 26891:1997 - Timber structures - Joints made with mechanical fasteners - General principles for the determination of strength and deformation characteristics (ISO 6891:1983)

Overview

EN 26891:1991, titled Timber structures - Joints made with mechanical fasteners - General principles for the determination of strength and deformation characteristics (ISO 6891:1983), is a European standard developed by CEN. It provides general principles and guidelines for testing the strength and deformation behavior of timber joints made with mechanical fasteners under static loading conditions. This standard is essential for designers, engineers, and testing laboratories involved in the construction and assessment of load-bearing timber structures.

The scope of EN 26891:1991 includes conditioning of test specimens, specifying measurement apparatus, and outlining loading procedures to determine key strength and slip characteristics of timber joints reliably and reproducibly.

Key Topics

• Test Specimen Conditioning
  Ensures timber joints and specimens replicate real-life moisture content and environmental conditions to reflect realistic structural performance. Standard atmospheres, such as 20°C and 65% relative humidity per ISO 554, are recommended for consistent conditioning.

• Test Specimen Geometry and Dimensions
  Specifies that specimen forms and sizes must realistically represent joints in service. Detailed specimen dimensions for specific fasteners are covered in related standards.

• Measurement Equipment and Accuracy
  Requires precise devices for measuring load (±1%) and slip (±1%, or ±0.02 mm for small slips under 2 mm). Equipment must prevent measurement errors caused by eccentricities or twisting during testing.

• Loading Procedure
  Describes a staged loading and unloading cycle starting at 0.4 times the estimated maximum load, holding loads for 30 seconds to simulate realistic conditions, followed by controlled increase to ultimate failure or a slip of 15 mm. Loading rates are specified for different phases, facilitating consistent and comparable data.

• Slip and Load Measurement
  Defines the recording of slip values at multiple points on the joint and associates these with load increments. These measurements enable calculation of key characteristics like maximum load, slip modulus, joint settlement, and elastic slip.

• Calculations and Adjustments
  Guidance on processing raw test data to yield meaningful parameters related to joint performance. Procedures for adjusting estimated maximum load during ongoing testing ensure accuracy of results.

• Test Reporting
  Specifies essential information for comprehensive reporting, including timber species, density, fastener types and coatings, joint geometry, conditioning details, loading procedures, and failure modes observed.

Applications

• Structural Timber Joint Design
  Engineers use the principles in EN 26891 to evaluate joint strength and deformation characteristics, facilitating safe, reliable timber structure designs where mechanical fasteners are employed.

• Material and Component Testing
  Laboratories assessing the performance of new fasteners or joint configurations apply the standard's principles to generate comparable, validated results.

• Quality Control in Timber Construction
  Builders and inspectors utilize test results based on EN 26891 to verify compliance with strength requirements and ensure structural integrity.

• Research and Development
  Academics and industry researchers employ this standard's test methods as a foundation for developing improved timber joints and fasteners.

Related Standards

• ISO 6891:1983
  This International Standard forms the basis of EN 26891 and provides the original detailed framework for testing timber joints with mechanical fasteners.

• ISO 554
  Defines standard atmospheres for conditioning and testing timber specimens, crucial for reproducible measurement conditions.

• Future International Standards for Specific Fasteners
  Separate standards are being developed for particular fastener types such as punched metal plate fasteners, nails, and staples, which will provide complementary detailed testing procedures.

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Keywords: EN 26891, timber structures, mechanical fasteners, joint strength, deformation characteristics, load testing, slip measurement, specimen conditioning, timber joint testing, structural timber, ISO 6891, timber construction standards

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Holzbauwerke - Verbindungen mit mechanischen Verbindungsmitteln - Allgemeine Grundsätze für die Ermittlung der Tragfähigkeit und des Verformungsverhaltens (ISO 6891:1983)Structures en bois - Assemblages réalisés avec des éléments mécaniques de fixation - Principes généraux pour la détermination des caractéristiques de résistance et de déformation (ISO 6891:1983)Timber structures - Joints made with mechanical fasteners - General principles for the determination of strength and deformation characteristics (ISO 6891:1983)91.080.20Lesene konstrukcijeTimber structuresICS:Ta slovenski standard je istoveten z:EN 26891:1991SIST EN 26891:1997en01-oktober-1997SIST EN 26891:1997SLOVENSKI
STANDARD
International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.ME)I(LLYHAPO~HAR OPTAHH3AWlfI fl0 CTAH~APTM3AWWWORGANISATlON INTERNATIONALE DE NORMALISATION Timber structures - Joints made with mechanical fasteners L General principles for the determination of strength and deformation characteristics Structures en bois - Assembfages r&alistk avec des Mments mhcaniques de fixation - Principes ghhraux pour la dh termina tion des carac terls tiques de resls tance et de dt5forma tion First edition - 1983-05-01 U DC 624.011 .l : 674.028 : 620A7 Ref. No. ISO 6891-1983 (EI Descriptors : timber construction, joints (junctions), fasteners, tests, determination, deformation, mechanical strength, specimen preparation, test equipment, loading, computation, test results. Price based on 4 pages SIST EN 26891:1997

Foreword ISO (the International Organization for Standardization) is a worldwide federation of national Standards bodies (ISO member bodies). The work of developing International Standards is carried out through ISO technical committees. Every member body interested in a subject for which a technical committee has been authorized has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 6891 was developed by Technical Committee ISO/TC 165, 77mber structures, and was circulated to the member bodies in January 4982. lt has been approved by the member bodies of the following countries : Australia Egypt, Arab Rep. of Austria France Belgium Germany, F. R. China India Czechoslova kia Ireland Denmark New Zealand Norway Portugal Romania South Africa, Rep. of Sweden United Kingdom The member body technical grounds of the following country expressed disapproval of the document on Canada 0 International Organization for Standardization, 1983 Printed in Switzerland SIST EN 26891:1997

INTERNATIONAL STANDARD ISO 68914983 (E) Timber structures - Joints made with mechanical fasteners - General principles for the determination of strength and deformation characteristics 0 Introduction Developments in the field of load-bearing timber structures re- quire that joints made with mechanical fasteners be tested to obtain information about their strength and deformation (Slip) characteristics. This International Standard lays down general principles which should be followed in Order to achieve comparability of results from investigations carried out in different laboratories. Stan- dard rules for the determination of characteristic strengths for particular types of mechanical fasteners will be given in separate International Standards. This International Standard is based on Joint Recommenda- tions from Working commission W18, Timber Structures, of CIB1) and Co mmittee 3TT, Timber Testing, of RlLEM*), who will also prepare the basis for the above-mentioned supplemen- tary International Standards. 1 Scope This International Standard lays down general principles for the determination of the strength and deformation (Slip) charac- teristics of joints made with mechanical fasteners. 2 Field of application This International Standard is applicable to joints made with mechanical fasteners used in statically loaded timber struc- tures. Detailed procedures appropriate to joints made with specific fasteners will be given in separate International Standards. The principles tan also be used for the testing of other joints. lt is recognized that for some special types of joints not covered by International Standards, modification of the test procedure may be necessary. 3 Reference ISO 554, Standard atmospheres for conditioning and/or testing - Specifica Gons. 1) International Council for Building Research, Studies and Documentation. 2) International Union of Testing and Research Laboratories for Materials and Structures. SIST EN 26891:1997

ISO 6891-1983 (EI 4 Symbols F: applied load, in newtons F est : estimated maximum load, in newtons F MaX : maximum load, in newtons k: Slip modulus, in newtons per millimetre v: joint Slip, in millimetres Subscripts for the joint Slip, and are defined in clause 8. V, relate to load Points in figure 2 5 Conditioning of test specimens b) equipment to measure joint Slip under load with an ac- curacy of + 1 % or better, or for Slips of less than 2 mm with an accuracy of + 0,02 mm. The equipment shall en- sure that eccentricities, twist, etc. have no influence on the measurements.2) , 8 Loading procedure 8.1 Estimation of maximum load Attention should be paid to the conditioning of the timber before the manufacture of the joint and also to the conditioning of the joints as a whole before testing. The conditioning should be conducted in such a way that the test conditions correspond in a realistic manner to the condi- tions in joints in structures as regards the influence of t
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