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“Invent a New India Using Knowledge”

है”ह”ह

IS 6346 (1971): Method of tests for timber props for mines[CED 9: Timber and Timber Stores]

IS t 6346 5 1971

Indian Standard

METHOD OF TESTS FOR TIMBER PROPS FOR MINES

Timber Sectional Committee, BDC 9

Chairman Representing

Soar R. C. S~NI

Members

Ministry of Agriculture

SHRI Y. P. BAWA

SHR~ B. K. BHALLA SHRI G. C. DAS DEPUTY INSPECTOR GENERAL OB

FORESTS

Directorate General of Civil Aviation ( Ministry of Tourism & Civil Aviation )

The Western India Match Company Ltd, Bombay National Test House, Calcutta Ministry of Agriculture

SERI V. N. DESEPANDE DIRECTOR, NAVAL CONSTRUCTION JOINT DIRECTOR ( TIMBER ) DR JOSEPH GEORGE

Engineer-in-Chief’s Branch ( Ministry of_Defence) Naval Headquarters ( Ministry of Defence ) Ministry of Railways Indian Plywood Industries Research Institute,

Bangalore DR D. C. ROY ( Alternate)

SHRI K. S. LAULY The Federation of Indian Plywood and Panel Industry, New Delhi

SHRI K. S. NAIR ( Alternate) SHRI J. S. MATHARU

SHRI J. N. MULLICK

Directorate General of Technical Development ( Ministry of Industrial Development )

Forest Department, Government of Himachal Pradesh

SHRI BIMAL NAG Assam Railways 8s Trading Company Ltd, Margherita ( Assam )

DR A. N. NAYER SHRI U. B. KANCHAN ( Alternate)

PRESIDENT

Ministry of Defence ( R & D)

SHRI K. RAMESH RAO

DR A. V. R. RAO

DR R. S. RATRA (Alternate) MAJ G. S. SAII-~I

SHRI D. P. GHOSH (Alternate ) SHRI A. C. SEKHAR

Forest Research Institute & Colleges, Dehra Dun Forest Research Institute & Colleges (Wood

Anatomy Branch ), Dehra Dun National Buildings Organization ( Ministry of

Works & Housing)

Ministry of Defence (DGI )

Forest Research Institute & Colleges (Timber Mechanics Branch ), Dehra Dun

( Continued on page 2 )

INDIAN STANDARDS INSTITUTION MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 1

ISt6346-1971

( Continued from page 1 ) Members

SHRI N. K. SHARMA

SERI R. C. SAXENA ( Alternate ) SHRI S. M. SIBTAIN SHRI M. SWARUP SHRI D. AJITHA SIMHA,

Director ( Civ Engg )

Representing

ForegradDesphartment, Government of Madhya

Forest Department, Government of Uttar Pradesh Paharpur Timbers Private Ltd, Calcutta Director General, IS1 ( Ex-@cio Member )

SHRI K. M. MATHUR Assistant Director (Civ Engg ), IS1

Timber Testing Subcommittee, BDC 9 : 9

Convener

SHRI A. C. SEKHAR

Members

SHRI P. R. CHANDRASEKHAR SHRI F. C. SEARMA (Alternate)

SHRI G. C. DAS SHRI V. N. DESHPANDE SHRI D. P. GHOSH SHRI B. R. GUPTA

JOINT DIRECTOR ( TIMBER ) DR R. S. RATRA

SHRI P. R. ROY

Forest Research Institute & Colleges, Dehra Dun

Directorate General of Civil Aviation

National Test House, Calcutta Engineer-in-Chief’s Branch ( Ministry of Defence ) Defence Production ( DGI ) (Ministry of Defence ) Directorate of Industries & Commerce, Jammu &

Kashmir Ministry of Railways National Buildings Organization ( Ministry of

Works & Housing ) Centgianbyning Research Station ( CSIR ),

Indian Standard METHOD OF TESTS FOR

TIMBER PROPS FOR MINES

0. FOREWORD

0.1 This Indian Standard was adopted by the Indian Standards Institution on 25 November 1971, after the draft finalized by the Timber Sectional Committee had been approved by the Civil Engineering Division Council.

0.2 In order to select timber for mine ( see IS : 4424- 1967* ) ~besides limi- tation of defects, requirements in regard to minimum compressive stress, moisture content, distribution, etc, should be met with. This standard prescribes method of tests of such properties.

0.3 In order to determine the suitability of timber for use in mines for props, certain tests are required to be conducted so as to determine the suitability. This standard prescribes such method of tests which are based on the work being done in Central Mining Research Station, Dhanbad.

0.4 In the preparation of this standard considerable assistance has been rendered by Forest Research Institute and Colleges, Dehra Dun and Central Mining Research Station, Dhanbad who have supplied valuable data.

0.5 In reporting the results of a test or analysis made in accordance with this standard, if the final value, observed or calculated, is to be rounded off, it shall be done in accordance with IS : 2-196Ot.

1. SCOPE 1.1 This standard covers the method of physical and mechanical tests required for determining suitability of timber meant for use in mines.

2. TERMINOLOGY

2.1 For the purpose of this standard, the following definitions and those given in IS: 707-1968x shall apply.

*Specification for use of timber in coal mines. $-Rules for rounding off numerical values ( revised ). SGlossary of terms applicable to timber and timber products (Jirst revision ).

3

IS:6346 -1971

2.1.1 Eccentricity- Maximum deviation of the natural axis from its longitudinal axis expressed as a percentage of the length of prop (see Fig. 1 ).

2.1.2 Natural Axis -Natural axis is a line which passes through the centres of all the cross-sections of the prop ( see Fig. 1 ).

2.1.3 Longitudinal Axis -Longitudinal axis is an imaginary straight line obtained by joining the centres of the two-end cross-sections of the prop ( see Fig. 1).

LONGITUDINAL

NATURAL AXIS

FIG. 1 NATURAL AND LONGITUDINAL AXIS OF PROP

4

3.1 All the tests for timber props are divided into two categories ‘major tests’ and ‘minor tests’. The major tests are done on full size props and the minor tests on small clear specimens taken out of the butt portion of props after conducting major tests.

3.1.1 Major tests comprise the determination of following properties:

a> Compression parallel to grain,

.b) Moisture content distribution,

c> Weight of the prop,

d) Eccentricity of prop, and

e) Length/diameter ratio of the prop.

3&2 Minor tests comprise the determination of following properties:

a) Compression parallel to grain, b) Static bending, and c) Moisture content.

4.2 Distribution of Material for Test - All the props to be tested shall be distributed as follows:

a> Twenty-five percent to be tested as received from the supplier ( this test has no special significance unless it is green, that is, 25 percent above fibre saturation point);

b) Fifty percent to be tested in air dry condition (props to be kept under shade with good ventilation for a period of one month before conducting the test); and

c> Twenty-five percent to be tested in wet condition (props to be kept completely immersed under water for one month before conducting the test ) .

IS : 6346 - 1971

3. CLASSES OF TEST

4. GENERAL PROVISIONS FOR ALL TESTS

4.1 Measurements and Weights - Prior to each test, the dimensions of the specimens shall be measured to the nearest millimetre and, weighed to one decimal place of kg.

4.3 Storage -Test specimens and sample of props shall be stored under proper cover.

4.4 Rate of Loading- Test rate of loading of the testing machine used shall not vary by more than f 25 percent from the specified calculated speed for different tests.

IS t 6346 - 1971

4.5 Calibration of Apparatus - All apparatus and testing equipment used for obtaining the data shall be calibrated periodically to ensure accuracy within one percent error.

5. MAJOR TESTS

5.1 Eccentricity of the Prop - Eccentricity of the prop shall be measu- red by laying a thread under tension from end to end, in the same plane containing natural axis and longitudinal axis as shown in Fig. 1, that is, measuring the maximum distance from the prop surface to the thread to the nearest millimetre:

Eccentricity = $X 100

where

8 = deviation in mm,~ and

A = length of prop in mm.

5.2 Determination of Length/Diameter Ratio - The length and dia- meter of the prop shall be measured to the nearest millimetre and the ratio be found as follows:

Length/Diameter Ratio = -“;-

where

L = length of prop in mm, and d = average diameter of prop in mm.

5.3 Compression Parallel to Grain

5.3.1 Equipment - The test shall be conducted on any suitable compres- sion testing machine of 100 t capacity as shown in Fig. 2.

5.3.2 Procedure

5.3.2.1 The ends of the prop shall be planed accurately so as to have the end sections truly perpendicular to longitudinal axis and shall be held securely between the top and bottom platens of the machine. One of the platens of the machine shall be equipped with a hemispherical bearing to obtain uniform distribution of load along the prop length. The specimen shall be so placed that the centre of the cross-section of the specimen is vertically in line with the centres of the moving head of the machine. Before placing the prop between the platens, record shall be made of the following items on the data recording sheet:

a) The length of the prop (see 5.2 ), b) The weight of the prop ( see 5.5 ),

6

~350 mm + SPHERICAL BLOCK IS : 6346 -1971. ’

I r HANDLE

lr 350 mm + TOP BEARING BLOCK

IT+xJARD FENCE I

,- SPEC IMEN

BOTTOM BEARING BLOCK I

FIG. 2 COMPRESSION PARALLEL TO GRAIN TEST ON FULL PROPS I

IS ‘: 6346 - 1971

c) The circumference of the prop at three different places along the prop length preferably near the centre and the both ends,

d) The eccentricity of the prop ( see 5.1), and

e) The diameter of each knot and its location on the surface of the prop and any other defects.

.5.3.2.2 Rate of loading - Load shall be applied continuously during the test by the movable head of the testing machine at a constant rate of loading to be calculated by the following formula:

Jv = 0.001 5 L

where

.N = machine head speed in cm/min, and L = length of specimen in cm.

5.3.2.3 Recording of load shall be recorded.

-The final reading of the maximum load

5.3.2.4 The prop during the test shall be fenced from all sides so that no damage is caused to the machine and other equipment if the prop suddenly breaks under test.

5.3.3 Recording of Failure - To obtain satisfactory and uniform results the failure may be made to develop on the body of the specimen by continuing the machine to run for a longer time~and the kind and position of final failure shall be recorded.

53.4 Ghlations -The compressive stress at maximum load shall be calculated by the following formula:

where

F = compressive stress at maximum load in kg/cm2, P = maximum load in kg, and

A = average area of cross-section in cm2.

5.4 Moisture Distribution and Average Moisture Content

5.4.1 Immediately after the test a moisture disc approximately 2.5 cm in length and of full cross-section of the prop under test shall be taken near the $lace of failure or from the central portion of the tested prop. In no case-the moisture disc be taken from near the ends of the prop. Mois- ture distribution and average moisture content shall be determined as given in 5.4.2 to 5.4.7.

8

IS:6346 -1971

5.4.2 The moisture disc cut from each tested prop shall be cut into moisture distribution sections to present the peripheral, intermediate and core zones of cross-section as shown in Fig. 3.

FIG. 3 MOISTURE CONTENT DISTRIBUTION SECTIONS 5.4.~ the moisture distribution sections shall be so cutthateach Zone is

approximately equal to one another and represents one-third or the total cross-sectional area. This may be achieved by keeping approximately the side of central square equal to the radius of cross-section of the prop.

54.4 Moisture content of each section shall be determined by oven-dry method as given in IS : 1708-1969*.

5.4.5 Th e average value of m&m content of all dons in each zone calculated as given below shall be recorded as the moisture content of the respective zone:

a) Moisture content of peripheral = M,+iW2+W+M4

zone Mp 4

b) Moisture content of intermediate = M,+M, +M,+Ms

zone Mt 4

c) Moisture content of core zone M,

=M9

Where M followed by any suffix 1, 2, 3, etc, indicates the moisture content of the corresponding section as indicated in Fig. 3.

*Methods of testing small clear specimens of timber (first re&jcn ).

9

ISt6346-1971

5.4.6 The moisture content of the entire prop (M) shall be taken as average moisture content of all the zones at test:

M=M,+M,+M, 3

5.4.7 Where abnormal observations are made either in the failures or in the loads, the moisture contents of individual zones are taken into consi- deration. The moisture shall be considered uniformally distributed if M,, Mi and ME do not differ by more than 15 percent.

5.5 Weight of the Full Prop - Before testing, the full prop shall be weighed on a suitable weighing machine correct to one decimal place of kg. If such machine is not available, then one specimen of 20 cm length from~each end shall be taken after the test. The specimens shall be weighed to one decimal place of kg, the average of the two weights shall be taken to calculate the weight of the full prop after adjusting for the moisture content which shall be determined as in 5.4.6:

WXL Weight of the prop = 20 kg

where

W = average weight of the 20 cm specimen in kg, and L = the length of the prop in cm.

6. MINOR TESTS

6.1 After performing major tests on the props the minor tests as given below shall be conducted. The minor tests shall be carried out as prescri- bed in IS : 1708-.1969*. At least three specimens for each test from each prop shall be taken for minor tests:

Clause No. of IS : 1708-1969*

a) Compression parallel to grain b) Static bending c) Moisture content

7. REPORTING

8

6 4

7.1 All the results of the tests shall be reported in pro forma given in Appendix A which should contain signatures and designation of the testing personnel.

*Methods of testing small clear specimens of timber ( j5rst revision ).

10

IS:6346 -1971

PRO FORMA FOR TESTING OF TIMBER PROPS

(One sheet is to be used for each prop) I

1) Species of timber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2) Name of supplier ,............................................,..............................-.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3) Condition of test . . . . . . . . . Air dry/ Green / As received

4) Average dia of the . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . prop

5) Weight of the prop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6) Length/diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ratio

7) Eccentricity of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . the prop

8) Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMPRESSION PARALLEL TO %RAIN TEST ( MAJOR TEST )

PROP RATE OF Max LOAD COMPRESSIVE FAILURE REMARKS LOADING IN kg STRESSAT

Max LOAD

(1) (2) (3) 14) (5) (6)

COMPRESSION PARALLEL TO GRAIN TEST ( MINOR TEST ) ts lit

PROP LENGTH CROSS- WEIGHT MOISTURE SP SP Max COMPRES- FAILURE PIECE cm SECTION

REMARKS g

g PERCENT GR GR LOAD SIVE I cm2 AT OVEN kg STRESS ts

TEST DRY AT Max 2 a LoAD ,

(3) (4) (5) (f-5) (7) (8) (9) (10) (11) (1) (2)

STATIC BENDING ( MINOR TEST )

PIECE LENGTH WIDTH HEIGHT WEIGHT MOISTURE SP SP FIBRE MODULUS FAILURE VEMARKS No, cm cm cm g PERCENT FR

AT ZEN STRESS AT ELASTIG Ru%JRE

TEST DRI' LIMIT

(2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)

IS : 6346 - 1971

MOISTURE DISTRIBUTION AND AVERAGE MOISTURE CONTENT

i) ZONE PERIPHERAL INTERMEDIATE CORE

ii) Moisture y>rr;;-; 7-*-_,y

,5678 9 distribution section No.

iii) Moisture percentage

iv) Average moisture content of all the three zones

Name and designation of testing authority.. ........

...................................................................................

...................................................................................

Signature ( s) ...........................................................

1900-1961 Method of testing wood poles

2408-1963 Methods of static tests of timber in structural sizes

2455-1963 Method of sampling and presentation of data for timber testing

4907-1968 Method of testing timber connectors

a: ( Reaffirmed 2005 )