EN 16784:2016

Timber structures - Test methods - Determination of the long term behaviour of coated and uncoated dowel-type fasteners

This European Standard specifies a test method for the determination of the long duration withdrawal strength of coated and uncoated dowel-type fasteners in structural timber and timber products and wood based products for structural application.
The method applies to all types of nails, screws and staples.

Holzbauwerke - Prüfverfahren - Bestimmung des Langzeitverhaltens beschichteter und unbeschichteter stiftförmiger Verbindungsmittel

Diese Europäische Norm legt ein Prüfverfahren zur Bestimmung der Langzeit-Ausziehtragfähigkeit von beschichteten und unbeschichteten stiftförmigen Verbindungs¬mitteln in Holz, Holzprodukten und Holzwerkstoffen für tragende Zwecke fest.
Das Prüfverfahren gilt für alle Typen von Nägeln, Schrauben und Klammern.

Structures en bois - Méthodes d'essai - Détermination du comportement à long terme des éléments de fixation de type tige, revêtus ou non

La présente norme européenne définit une méthode d'essai permettant de déterminer la résistance à l'arrachement à long terme d'éléments de fixation de type tige revêtu ou non revêtu insérés dans du bois de structure, des produits en bois ou des matériaux à base de bois destinés à être utilisés dans des applications structurelles.
Cette méthode s'applique à tous les types de pointes, de vis et d'agrafes.

Lesene konstrukcije - Preskusne metode - Ugotavljanje dolgoročnega obnašanja premazanih in nepremazanih paličastih veznih sredstev

Ta evropski standard določa preskusne metode ugotavljanja dolgoročnega obnašanja premazanih in nepremazanih paličastih veznih sredstev pri nosilnih lesenih konstrukcijah (žeblji, sponke, vijaki, mozniki in sorniki z maticami).

General Information

• Status: Published
• Publication Date: 28-Jun-2016
• ICS: 91.080.20 - Timber structures
• Technical Committee: CEN/TC 124 - Timber structures
• Drafting Committee: CEN/TC 124/WG 1 - Test methods
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 08-Nov-2022
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 16784:2016 - Timber structures - Test methods - Determination of the long term behaviour of coated and uncoated dowel-type fasteners

Overview

EN 16784:2016 is a European Standard developed by CEN that establishes a comprehensive test method for determining the long-term withdrawal strength of dowel-type fasteners - both coated and uncoated - used in timber structures. This standard applies to all common dowel-type fasteners including nails, screws, and staples, and is essential for assessing their durability and safety performance in structural timber and wood-based products under sustained load conditions.

This test method enables precise evaluation of fastener withdrawal resistance over extended durations, contributing significantly to reliable timber joint design and safety assurance in construction applications.

Key Topics

• Scope & Application: EN 16784:2016 covers test procedures for assessing the long-duration withdrawal strength of mechanical fasteners in timber products, including solid timber, glued laminated timber, and wood-based panels.
• Test Specimen Preparation: Specifies dimensions, moisture conditioning, and fastener insertion methods with fastener axes either perpendicular or parallel to the grain, ensuring representative and reproducible testing conditions.
• Testing Conditions: Requires controlled environmental conditions for testing (20 ± 2 °C and 65 ± 5 % relative humidity) and considers adjustments for thermo plastic adhesive coatings tested at elevated temperatures.
• Measurement Procedure: Withdrawal force is applied in accordance with EN 26891, incrementally increasing load until a preset level is reached and held until failure or test termination; time to failure is recorded precisely.
• Load Levels & Duration Testing: Loads are applied at various percentages (20% to 80%) of reference withdrawal strength, derived per EN 1382, to generate load duration curves for different conditions.
• Data Analysis: Describes calculation of the load duration factor for withdrawal (kd,T), a key parameter reflecting how withdrawal strength decreases as loading duration increases. The factor is derived using logarithmic regression on failure time and load levels.
• Test Reporting: Mandates comprehensive documentation including specimen details, fastener types and coatings, test conditions, results, statistical analysis, and failure modes to ensure transparency and repeatability.

Applications

• Structural Timber Design: Supports engineers and designers in selecting appropriate fasteners and coatings by providing data on long-term withdrawal performance essential to Eurocode 5 (EN 1995-1-1) compliance.
• Quality Assurance: Enables manufacturers to verify the durability and adherence of mechanical fasteners to specified standards, particularly for coated versus uncoated fasteners.
• Product Development: Assists fastener producers in optimizing material and coating properties based on empirical long-term performance data.
• Safety Evaluations: Crucial for assessing joint integrity in timber structures subject to sustained or cyclic loading, helping to prevent structural failures.

Related Standards

• EN 1382: Test methods for the withdrawal capacity of timber fasteners; provides baseline withdrawal strength data for reference in EN 16784.
• EN 26891:1991: Framework for determining strength and deformation characteristics of timber joints with mechanical fasteners, referenced for testing apparatus and load application.
• EN ISO 8970: Requirements for wood density measurement in timber fastener testing, ensuring accurate specimen characterization.
• ISO 13061-1 & ISO 13061-2: Methods for determining moisture content and density of wood specimens, critical for conditioning the timber samples prior to testing.
• EN 14592: Specifications for dowel-type fasteners used in timber structures, informing fastener dimensions and mechanical properties for tests.
• EN 1995-1-1 (Eurocode 5): Design rules for timber structures, providing context for the application of load duration factors in structural calculations.

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By adhering to EN 16784:2016, stakeholders in timber construction gain access to standardized, reliable methodologies for evaluating how mechanical fasteners perform under long-term loads, ensuring safer, more durable timber assemblies and fostering innovation in fastener technologies. This standard is a fundamental resource for testing laboratories, fastener manufacturers, structural engineers, and regulatory bodies involved in timber engineering and construction.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Holzbauwerke - Prüfverfahren - Bestimmung des Langzeitverhaltens beschichteter und unbeschichteter stiftförmiger VerbindungsmittelStructures en bois - Méthodes d'essai - Détermination du comportement à long terme des éléments de fixation de type tige, revêtus ou nonTimber structures - Test methods - Determination of the long term behaviour of coated and uncoated dowel-type fasteners91.080.20Lesene konstrukcijeTimber structuresICS:Ta slovenski standard je istoveten z:EN 16784:2016SIST EN 16784:2016en,fr,de01-september-2016SIST EN 16784:2016SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16784
June
t r s x ICS
{ sä r z rä t r English Version
Timber structures æ Test methods æ Determination of the long term behaviour of coated and uncoated dowelætype fasteners Structures en bois æ Méthodes d 5essai æ Détermination du comportement à long terme des éléments de fixation de type tigeá revêtus ou non
Holzbauwerke æ Prüfverfahren æ Bestimmung des Langzeitverhaltens beschichteter und unbeschichteter stiftförmiger Verbindungsmittel This European Standard was approved by CEN on
z April
t r s xä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
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t r s x CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s x y z vã t r s x ESIST EN 16784:2016
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