Bsi bs en 00380 1993 (1999)

00316811 PDF BRITISH STANDARD BS EN 380 1993 Timber structures — Test methods — General principles for static load testing The European Standard EN 380 1993 has the status of a British Standard UDC 69[.]

BRITISH STANDARD BS EN

380:1993

Timber structures —

Test methods —

General principles for

static load testing

The European Standard EN 380:1993 has the status of a

British Standard

UDC 694.04:624:011:1:624.04

This British Standard, having

been prepared under the

direction of Technical

Committee B/518, was

published under the

authority of the Standards

Board and comes

into effect on

15 November 1993

© BSI 12-1999

The following BSI references

relate to the work on this

standard:

Committee reference B/518/1

Draft for comment 90/15570 DC

ISBN 0 580 22318 3

Cooperating organizations

The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries

Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y

France Association française de normalisation Germany Deutsches Institut für Normung e.V

Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland

Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portuguès da Qualidade Spain Asociación Española de Normalización y Certificación Sweden Standardiseringskommissionen i Sverige

Switzerland Association suisse de normalisation United Kingdom British Standards Institution

Amendments issued since publication

Amd No Date Comments

BS EN 380:1993

Contents

Page

National annex NA (informative) Committees responsible Inside back cover

ii © BSI 12-1999

National foreword

This British Standard has been prepared under the direction of Technical Committee B/518, Structural timber It is the English language version of

EN 380:1993 Timber structures — Test methods — General principles for static

load testing published by the European Committee for Standardization (CEN).

No existing British Standard is superseded

A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application

Compliance with a British Standard does not of itself confer immunity from legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6, an inside back cover and a back cover

This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 380

July 1993

UDC 694.04:624:011:1:624.04

Descriptors: Timber construction, mechanical tests, static loads, breaking loads

English version

Timber structures — Test methods — General principles

for static load testing

Structures en bois — Méthodes d’essais —

Principes généraux d’essais par chargement

statique

Holzbauwerke — Prüfverfahren — Allgemeine Grundsätze für die Prüfung unter statischen Belastungen

This European Standard was approved by CEN on 1993-07-15 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

Up-to-date 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,

Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,

Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and

United Kingdom

CEN

European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

© 1993 Copyright reserved to CEN members

Ref No EN 380:1993 E

© BSI 12-1999 2

Foreword

This European Standard was prepared by

CEN/TC 124 “Timber structures” It was approved

for the CEN final voting by the TC on 9th

December 1991

This standard is one of a series of standards for test

methods for building materials and components It

was prepared by a working group under the

convenorship of NSAI

NOTE It is considered desirable to maintain the same clause

numbers consistently throughout this series of standards

Consequently, some clauses are void in this edition of this

standard, but it is envisaged that future editions may need to

include a text in these clauses.

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

January 1994, and conflicting national standards

shall be withdrawn at the latest by January 1994

The standard was approved and in accordance with

the CEN/CENELEC Internal Regulations, the

following countries are bound to implement this

European Standard: Austria, Belgium, Denmark,

Finland, France, Germany, Greece, Iceland,

Ireland, Italy, Luxembourg, Netherlands, Norway,

Portugal, Spain, Sweden, Switzerland,

United Kingdom

No existing European Standard is superseded

Contents

Page

6 Test methods for static loading 3

Figure 1 — Schematic loading procedures 4 Table 1 — Basic loading procedure 4

EN 380:1993

1 Scope

This standard specifies the general principles to be

adopted for static load testing of timber structures

It is intended for use where it is necessary to verify

by test that a structure complies with stated

criteria Relevant parts may be used for proof

loading or for the testing of structures in service

This standard is not intended to be used for testing

of individual pieces of timber, individual joints or

structural scaled models

2 Normative references

None

3 Definitions

For the purposes of this standard, the following

definitions apply

3.1

maximum load

load at failure; or load where substantial

deformation continues without further increase in

load; or the maximum load achieved up to a

specified deformation or strain

3.2

timber structure

member or assembly of members forming the whole

or a part of a load bearing element of construction

(e.g a joist or a truss or a floor panel or a wall panel)

4 Symbols

5 General requirements

Materials and workmanship in the structure shall

be, as far as practicable, of the minimum quality and dimensions allowed by the relevant

specification The manufacture and assembly of the timber structure shall be representative of the production process likely to be used The moisture and temperature conditions at the time of test shall

be representative of the likely in-service conditions Deviations may, however, be required for structures composed of materials with different

time-dependent properties to obtain the same failure mode as in practice

6 Test methods for static loading

6.1 Principle

The principle of these test methods involves applying a stated regime of loading to a timber structure, over a stated period of time, and of observing the corresponding deformations and reporting the test results

6.2 Number of tests

Wherever possible several identical structures of the same design shall be tested to permit the assessment of the variability of the test results NOTE The number of structures to be tested and their method

of selection will depend on the probable variability in manufacture, the required level of confidence and the number of loading conditions to be applied.

6.3 Apparatus

The accuracy of loading and of deflection and load measurement shall be within ± 3 %

The test loading shall be both applied and resisted

in a manner approximating to the actual service conditions Eccentricities, other than those necessary to simulate service conditions, shall be avoided at points of loading and reaction, and care shall be taken to ensure that no inadvertent restraints are present

6.4 Preparation

Determine the density and moisture content of the materials in the structure

When testing is carried out in a laboratory it shall

be normally maintained at a relative humidity

of (65 ± 5) % and a temperature of (20 ± 2) °C, unless required otherwise by the normal in-service condition of the test structure

Departures from the required values shall be reported

When testing is carried out other than in a laboratory e.g in situ, the environmental conditions

of temperature and relative humidity existing during the test shall be reported

F load, in newtons

Fmax maximum load, in newtons

Fmax,est estimated maximum load, in newtons

G1 self weight of the structure, in

newtons

G2 applied permanent load, in newtons

Q characteristic value of variable load,

in newtons

T loading time, in seconds

Tr recovery time, in seconds

½ factor of less than unity modifying

Fmax,est

4 © BSI 12-1999

6.5 Procedures

6.5.1 Basic loading procedure

The basic loading procedure consists of the

procedural steps (0 – 7) described in Table 1 A

diagrammatic representation of the loading

procedure is given in Figure 1

Table 1 — Basic loading procedure

6.5.2 Maximum load — procedure 1

Procedure 1 consists of the basic loading steps (0 – 7) concluding by increasing the load up to

the maximum load Fmax (step 7 – 8 in Figure 1.)

If considerable deformation occurs during the application of the load, reduce the rate of loading

6.5.3 Proof loading — procedure 2

Procedure 2 consists of the basic loading steps (0 – 7); the load is removed after a prescribed

load ½Fmax,est(½ < 1) has been reached and the test ended (step 7 – 9 in Figure 1)

NOTE This procedure is intended for proof loading and the case when the capacity at more than one load combination is tested The value of ½ depends on the confidence required in estimating the maximum load capacity.

Procedural

step Loading procedure Time, in seconds

0

0 – 1

1 – 2

2 – 3

3 – 4

4 – 5

5 – 6

6 – 7a

Only G1 acting, and

F = 0

Apply F = G2

Maintain F = G2

Apply F = G2+ 0,5 Q

Remove 0,5 Q

Apply F = G2+ Q

Maintain F = G2+ Q

Increase F until ½Fmax,est

is reached

U 120

U 120

U 120

U 240

U 1 200

U 600

a The maximum loading rate shall not exceed 0,25 Q per 60 s.

Figure 1 — Schematic loading procedures

EN 380:1993

6.5.4 Long-term deformation — procedure 3

Procedure 3 consists of the basic loading

steps (0 – 7); the load ½Fmax,est is kept constant for a

chosen period of time T The load is then removed

and the recovery is measured during a chosen period

Tr (steps 7 – 10 – 11 – 12 in Figure 1)

6.5.5 Capacity after long-term loading —

procedure 4

This follows procedure 3 but in this case the

structure is reloaded to failure

(steps 7 – 10 – 11 – 12 – 13 in Figure 1)

NOTE Procedures 3 and 4 are intended for the study of

deformation at long-term loading and maximum load capacity

after long-term loading.

6.6 Results

The deformation (e.g deflection) shall be measured

at the number of points prescribed or as necessary to

estimate the performance of the structure A

minimum requirement is that the deformation is

measured at the point of expected maximum

deformation

Measurements of load and deformation shall be

recorded, preferably continuously A minimum

requirement is that load and deformation is

recorded at each load application or removal

(i.e at the points marked by circles in Figure 1) and,

additionally, at loading increments of

above 0,1 Fmax,est

During constant load, time and deformation shall

normally be recorded continuously Where this is

not possible it shall be recorded at least five times

during the period of constant load (three points in

between the starting and final points)

6.7 Test report

The test report shall include the following

a) Sampling procedure

b) Quality of materials: species or type, grade, density and moisture content Deviations from specifications

c) Specifications of design Deviations from specification

d) Conditions of testing, including methods, distribution of loading and of measuring loads and deformations Support conditions

e) Test results Maximum load and deformation Load/deformation curves; deformation/time curves

f) Type and position of fractures

g) Nature and size of defects in the materials which contributed to failure

h) A note of deviations from the general requirements for structures composed of materials with different time-dependent properties

i) Information as to the environmental conditions

of temperature and relative humidity and resultant changes in moisture content in the test structure, if relevant

BS EN 380:1993

© BSI 12-1999

National annex NA (informative)

Committees responsible

The United Kingdom participation in the preparation of this European Standard was entrusted by Technical Committee B/518, Structural timber, to Subcommittee B/518/1, Test methods, upon which the following bodies were represented:

Department of the Environment (Building Research Establishment)

Institution of Civil Engineers

Institution of Structural Engineers

Timber Research and Development Association

Wood Panel Products Federation

389 Chiswick High Road

London

W4 4AL

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