Product specifications, design, and assessment by calculation and tests
Foreword
This European Standard has been prepared by Technical Committee CEN/TC 53, Temporary works equipment, the Secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by the publication of an identical text or by endorsement, at the latest by March 1999, and conflicting national standards shall be withdrawn at the latest by March 1999.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom.
Introduction
Whilst this European Standard deals with the more common types of adjustable telescopic steel props in use,
it is not intended to prevent the development of other types of props. For example, props may have hinged ends or other length adjustment devices or be made of other materials. Whilst such props cannot comply with this European Standard it is recommended that the principles of this European Standard be considered in the design and assessment of such props.
The characteristic strength values specified in this European Standard form a reference level that is unsafe for direct site use. It is a matter for a separate European Standard to relate these character strengths to safe site usage by applying suitable partial safety factors M and F. It is also a matter for a separate European Standard to specify the required level of corrosion protection and inspection.
This European Standard is a product standard primarily for use in the field of falsework and formwork.
In cases where the prop is an integral part of a system of soffit support, other design and assessment procedures may be more appropriate or even necessary.
This European Standard gives a number of alternatives, a designation of which is given in clause 5.
1 Scope
This European Standard specifies materials, design requirements, corrosion protection alternatives together with assessment methods using both calculations and testing for open thread and covered thread adjustable telescopic steel props which are intended for use on construction sites (see Figure 1).
It specifies five classes of nominal characteristic strengths for adjustable telescopic steel props each having a series of maximum extended lengths. Each has a differing endplate configuration.
This European Standard does not apply to adjustable props of different materials or construction, nor does it provide any information concerning the use of adjustable steel props.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies.
EN 74 Couplers, loose spigots, and base-plates for use in working scaffolds and falsework made of steel tubes – Requirements and test procedures
EN 729-2 Quality requirements for welding – Fusion welding of metallic materials – Part 2: Comprehensive quality requirements
EN 1562 Founding – Malleable cast irons
EN 1563 Founding – Spheroidal graphite cast irons
EN 10002-1 Tensile testing of metallic materials – Method of test at ambient temperature
EN 10025 Hot rolled products of non-alloy structural steels – Technical delivery conditions
EN 10083-1 Quenched and tempered steels – Part 1: Technical delivery conditions for special steels
EN 10083-2 Quenched and tempered steels – Part 2: Technical delivery conditions for unalloyed quality steels
EN 10083-3 Quenched and tempered steels – Part 3: Technical delivery conditions for boron steels
EN 10113-1 Hot-rolled product in weldable fine grain structural steels – Part 1: General delivery conditions
EN 10113-2 Hot-rolled products in weldable fine grain structural steels – Part 2: Delivery conditions for normalized/normalized rolled steels
EN 10113-3 Hot rolled products in weldable fine grain structural steels – Part 3: Delivery conditions for thermomechanical rolled steels
EN 10155 Structural steels with improved atmospheric corrosion resistance – Technical delivery conditions
EN 10204: 1991 Metallic products – Types of inspection documents
EN 10210-1 Hot finished structural hollow sections of nonalloy and fine grain structural steels – Part 1: Technical delivery requirements
EN 10210-2 Hot finished structural hollow sections of non-alloy and fine grain structural steels – Part 2: Tolerances, dimensions, and sectional properties
EN 10219-1 Cold formed structural hollow sections of non-alloy and fine grain structural steels – Part 1: Technical delivery requirements
EN 10219-2 Cold formed structural hollow sections of non-alloy and fine grain structural steels – Part 2: Tolerances, dimensions, and sectional properties
EN 39Steel tubes for tube and coupler scaffold structures – Technical delivery conditions
EN 1993-1-1 Eurocode 3: Design of steel structures – Part 1-1: General rules and rules for buildings
EN ISO 9001 Quality systems – Model for quality assurance in design, development, production, installation, and servicing (ISO 9001)
EN ISO 9002 Quality systems – Model for quality assurance in production, installation, and servicing (ISO 9002)
ISO 2937 Plain end seamless steel tubes for mechanical application
ISO 3304 Plain end seamless precision steel tubes – Technical conditions for delivery
ISO 3305 Plain end welded precision steel tubes – Technical conditions for delivery
ISO 3306Plain end as-welded and sized precision steel tubes – Technical conditions for delivery
3 Definitions and symbols
For the purposes of this European Standard, the following definitions and symbols apply.
- adjustable telescopic steel prop: Compression member normally used as temporary vertical support in construction works. A prop consists of two tubes that are telescopically displaceable within each other. A prop has a coarse adjustment with a pin inserted into holes in the inner tube and a means of fine adjustment using a threaded collar (see Figure 1).
- endplate: Plate which is fixed at right angles to one end of the inner or outer tube.
- forkhead: Endplate with lateral projections to locate a beam.
- collar nut: Nut which incorporates at least one handle and has one face which supports the pin and is internally threaded to provide fine length adjustment to the prop.
- inner tube: The smaller diameter tube provided with holes for the coarse adjustment of the prop.
- outer tube: The larger diameter tube one end of which is threaded externally.
- length adjustment device: Device consisting of a pin, collar nut, holes in the inner tube, and a threaded outer tube.
NOTE: The forces from the endplate are transferred to the pin inserted in the inner tube holes and to the collar nut which transfers the forces to the outer tube thread. In some prop designs, an additional loose washer is used between the pin and the collar nut.
- pin: The part of the length adjustment device which is inserted through the inner tube holes and is secured to the prop.
- length at maximum extension: The distance measured between the outside faces of the endplates when the prop is in the fully extended position.
NOTE: The prop extension is called “fully open” if the pin is in the hole farthest away from the inner tube endplate and the collar nut is in the uppermost position. The prop extension is called “fully closed” if the pin is in the hole nearest the inner tube endplate and the collar nut is in the lowest position.
main symbols: Symbols are given in Table 1
4 Classification
An adjustable telescopic steel prop shall be classified according to its nominal characteristic strength Ry,k and its maximum length Imax gave in Table 2.
For classes A, B, and C props the nominal characteristic strength given in Table 2 shall apply to the maximum extension length. For classes D and E props the nominal characteristic strength given in Table 2 shall apply to all possible extension lengths.
Table 2 — Classification
| Class | Length at maximum extension IPD[ m | Nominal characteristic strength (see clause 8) R\ N kN |
| A 25 | 2,50 | 20,4 |
| A 30 | 3,00 | 17,0 |
| A 35 | 3,50 | 14,6 |
| A 40 | 4,00 | 12,8 |
| B 25 | 2,50 | 27,2 |
| B 30 | 3,00 | 22,7 |
| B 35 | 3,50 | 19,4 |
| B 40 | 4,00 | 17,0 |
| B 45 | 4,50 | 15,1 |
| B 50 | 5,00 | 13,6 |
| B 55 | 5,50 | 12,4 |
| C 25 | 2,50 | 40,8 |
| C 30 | 3,00 | 34,0 |
| C 35 | 3,50 | 29,1 |
| C 40 | 4,00 | 25,5 |
| C 45 | 4,50 | 22,7 |
| C 50 | 5,00 | 20,4 |
| C 55 | 5,50 | 18,6 |
| D 25 | 2,50 | 34,0 |
| D 30 | 3,00 | |
| D 35 | 3,50 | |
| D 40 | 4,00 | |
| D 45 | 4,50 | |
| D 50 | 5,00 | |
| D 55 | 5,50 | |
| E 25 | 2,50 | 51,0 |
| E 30 | 3,00 | |
| E 35 | 3,50 | |
| E 40 | 4,00 | |
| E 45 | 4,50 | |
| E 50 | 5,00 | |
| E 55 | 5,50 |
5 Designation
Designation of a prop in accordance with EN 1065, class: “B 25”, with a minimum extended length: “13” dm, with shaped: “SH” and plain: “O” endplates and a length adjustment device with open thread: “DO”, completely hot-dip galvanized with corrosion protection: “F4” and suitable for attaching EN 74 couplers with steel tubes in accordance with prEN 39 with nominal wall thickness greater than “3” mm and with an ongoing production inspection level “M”:
6 Materials
6.1 General
Materials shall have good resistance to, and/or be protected against atmospheric corrosion and shall be free of any impurities and defects which might affect their satisfactory use. Steels of deoxidation type FU (rimming steels) are not permitted.
Materials should be selected from the relevant existing European and International Standards and,whenever applicable, shall be in accordance with the following standards:
Material standards: EN 10025, EN 10113-1, EN 10113-2, EN 10113-3, EN 10155
Tube standards: EN 10210-1, EN 10219-1, prEN 39
Bar standards: EN 10083-1, EN 10083-2, EN 10083-3
Casting standards: EN 1562, EN 1563
6.2 Modification by cold working
Steel for tubes conforming basically to EN 10025 and modified by cold working may be used provided that
- the modified yield strength conforms to one of the yield strengths given in EN 10025 or
- the yield strength amounts to 315N/mm2 or 395N/mm2 and
- the elongation of the modified steel is not less than 18 %
- the process used can be shown to guarantee these values.
NOTE: Cold working modifies the structural properties by strain hardening.
6.3 Corrosion protection
Props shall be protected against corrosion by one of the methods given in Table 3.
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Table 3 — Methods of corrosion protection
7 Configuration
7.1 Tubes
The cross-sections of the tubes should be selected from the relevant existing European or International Standards and, whenever applicable, shall be in accordance with the following standards:
EN 10210-1, EN 10210-2, EN 10219-1, EN 10219-2, prEN 39
ISO 2937, ISO 3304, ISO 3305, ISO 3306
For classes B, C, D, and E props the nominal wall thickness of any tube used shall be at least 2,6 mm. For class A props the minimum wall thickness shall be not less than 2,3 mm after taking tolerances into account.
For the purposes of assessment, the method of making holes shall be stated on the drawings.
NOTE: The preferred method of forming holes is by drilling (see 9.2.4.1).
It is permissible to either, locally expand the diameter of the tube adjacent and welded to the endplate or, add an additional larger diameter tube adjacent and welded to the endplate to increase the stiffness of the connection (see
also 9.2.3.1).
7.2 Welding
The welding shall be carried out in accordance with EN 729-2.
All fillet welds produced by the metal arc process shall have a minimum throat thickness of 2,5 mm.
Where alternative means of welding are employed (for example friction, or projection welding), the resulting connection shall have an equal or greater weld strength to that produced by the metal arc process.
7.3 Length adjustment device
- 7.3.1 The nominal minimum wall thickness in the threaded part, 4r, shall be 2,3 mm (see Figure 2).
- 7.3.2 After taking into account the tolerances the bearing depth of the thread (see Figure 3) shall be:
≥ 0,5 mm for a concentric configuration;
≥ 0,01 mm for an eccentric configuration
7.3.3When a prop is assembled with all of its component parts and in the fully extended position, the collar nut shall have a torsional resistance of at least 100 Nm against unintentional disengagement from the outer tube thread.
In any position of a prop, the collar nut shall engage the outer tube thread with at least 30 mm effective axial thread length and for
–class A props with at least three complete turns of the thread in the collar nut,
–classes B, C, D, and E props with at least four complete turns of the thread in the collar nut.
7.3.4The nominal pin diameter DP shall not be less than 13 mm.
7.3.5Where props have a length adjustment device that meets the following dimensional requirements (see Figure 2) then verification of the characteristic load-carrying capacity of the pin and its supports shall be carried out according to 9.4.2.3:
–The thickness 4u of the collar nut flange or the thickness 4w of the welded washer shall not be less than 5 mm (see Figure 2).
–The width Iw of the collar nut flange or the width Iw of the welded washer shall not be less than 8 mm.
–The nominal pin diameter DP shall not be less than 14 mm for 4u ≤ 7 mm.
–With the fine adjustment threads in a Figure 3a) concentric configuration, the unsupported radial length (Dm – Di) / 2 between the external diameter of the inner tube Di and the collar nut major thread diameter Dm shall not be greater than the half pin diameter dp. For covered thread props, the same requirement is valid. If they have a washer welded to the top of the collar nut the unsupported radial length may be calculated by reducing 4w from the collar nut thread diameter Dm.
Where props have a length adjustment device that does not meet these requirements then verification of the characteristic load-carrying capacity of the pin and its supports shall be carried out to 9.4.2.4.
7.3.6The pin shall be attached to the prop so that it cannot be detached unintentionally, for example by having a cable or chain, or by a special shape.
7.3.7Adjustment of the prop by fine adjustment device shall also be possible when the distance between the axis of the prop and a plane wall is only 100 mm.
7.4Permanent prevention against unintentional disengagement
The inner and outer parts of a prop shall be prevented permanently from being separated except by intentional action.
7.5Endplates
7.5.1Endplates shall either be square (SQ) or, for identification purposes, be shaped (SH) in accordance with Figure 4.
Endplates shall have at least two holes for connection purposes.
If a central hole (see Figure 1) is required in the endplates it shall have a minimum diameter of 28 mm.
7.5.2Plain endplates shall be made of a material having a minimum yield strength of 235 N/mm 2 and shall have a minimum thickness:
6 mm for classes A, B, and D props; 8 mm for classes C and E props.
Profiled endplates shall have a spring stiffness and a bending resistance at least equal to that of plain endplates.
7.5.3 It shall be possible to draw the following circles on endplates: 110 mm diameter for class A props;
120 mm diameter for class B, C, D, and E props.
At corners that would otherwise be sharp the radius shall be 5 mm ≤ r ≤ 10 mm.
7.6 Props with fixed forkheads
For props having a forkhead welded to the end of the inner tube, the dimensions and alternative configuration of the forkhead shall be as given in Figure 5 and Table 4. Forkheads shall be manufactured from steel having a minimum yield strength of 235 N/mm2. The rigidity of each side upright of type 1 (square) forkhead and of each
pair of post uprights of type 2 (rectangular) forkhead shall have a minimum bending resistance of 22 kN × cm.
NOTE: The minimum bending resistance is based on a pair of 14 mm diameter rods having a yield strength of 235 N/mm2.
7.7Anti hand trap
When the prop is fully closed without the pin inserted, there shall remain at least 100 mm clearance between the endmost part of the outer tube or the collar nut in the case of a covered thread and the inside of the endplate or forkhead of the inner tube.
7.8Minimum extended length
The distance between the fully open and fully closed prop shall be not less than 1,00 m.
The minimum extended length for the fully closed prop shall be stated by the manufacturer (see clause 5).
7.9Overlapping length
There shall be an overlapping length between the outer and inner tube, I0, of at least 300 mm when the prop is fully open (see Figure 6).
7.10Data required from the manufacturer
The prop manufacturer shall record the following data:
–shape,
–class,
–minimum extended length,
–essential dimensions with tolerances,
–material characteristics of all components,
–profile of endplate, forkhead,
–type of welding,
–corrosion protection,
–method of hole production,
–marking details,
–type of quality control.
8Nominal characteristic strength
According to the class and to the length at maximum extension, a prop shall have the nominal characteristic strength calculated in accordance with the equation below (see also clause 4 and Table 2).
RA,k = 51,0 lmax ≤ 44,0 kN (1)
RB,k = 68,0 lmax ≤ 51,0 kN (2)
RC,k = 102,0 lmax ≤ 59,5 kN (3)
RD,k = 34,0 kN (4)
RE,k = 51,0 kN (5)
where:
Ry,k is the nominal characteristic strength for the prop class y in kilonewtons
Imax is the length at maximum extension in metres
I is the actual extension length in metres.
9Verification
9.1General
NOTE: Table 5 lists the main steps in the verification.
The actual characteristic strength of a prop shall either be verified by calculation (see 9.2) or by tests (see 9.3) at the manufacturer’s discretion.
The characteristic strength of a prop having a plain endplate at each end shall be verified both with the outer tube at the bottom and with the inner tube at the bottom.
The characteristic strength of a prop having a fixed forkhead shall only be verified with the forkhead at the top.
The actual characteristic strength of a prop, Ry, act, shall be verified at maximum extension, for the classes A, B, or C at the fully closed extension and the most unfavorable extension in between also. The most unfavorable extension is the length with the smallest quotient Ry, act / Ry,k.
For all extended lengths, the actual characteristic strength of a prop shall be at least equal to the nominal characteristic strength in accordance with one of the equations (1 through 5) in accordance with clause 8.
9.2Verification of the actual characteristic strength by calculation
9.2.1General
Calculations shall be carried out in accordance with this European Standard and with ENV 1993-1-1: 1992, Eurocode 3, in cases where this European Standard gives no requirements.
The global analysis to determine the internal forces and moments shall use elastic analysis design principles assuming that the behavior of the material is linear at all stress levels. The resistances of cross-sections may be calculated by using plastic stress distributions. For the global analysis, the second-order theory shall be used, taking into account the influence of the deformations of the structure on the internal forces and moments.
9.2.2Static system
Characteristic strength calculations shall be carried out using the structural model given in Figure 6, taking into account 9.2.3, 9.2.4, and annexes A and B.
The deformation of the inner tube in the overlap zone shall be taken into account.
Additional contact points which occur when the looseness between the inner and outer tube has been taken up may also be allowed for.
9.2.3Imperfections
9.2.3.1Eccen4rici4ies a4 4he ends
The following eccentricities shall be assumed (see Figure 6):
At the top of the prop: et = 10 mm
NOTE: This model makes allowance for a possibly greater eccentricity combined with some elastic restraint resulting from the loading condition at the top of the prop.
At the base of a prop (see Figure 6 detail X, Figure 7 and 9.2.4.2): eb,0 = 0,40 × D1
eb,core = – 0,25 × D1 eb,limit = – 0,50 × D1
where:
D1 is the effective diameter at the base in millimetres.
The effective diameter is the outer diameter of the tube welded to the endplate (excluding weld), for plain endplates the thickness of plate 4 may be taken into account additionally (D + 2 × 4).
9.2.3.2AngIe of incIina4ion
The angle of inclination φ0 (see Figure 6) caused by the clearance between the tubes in the overlap zone shall be determined from the nominal dimensions of the components.
9.2.3.3PrefIexure
In addition to the angle of inclination, a sine-shaped preflexure of the prop as a whole with a maximum offset of I/500 shall be assumed, where I is the extended length considered.
9.2.4Rigidity
9.2.4.1If the holes in the inner tube are made by drilling, the reduction of the flexural rigidity due to the holes shall be calculated in accordance with annex A.
If the holes are not produced by drilling the resultant deformations of the tube shall be measured and the sectional properties of the deformed tube calculated.
9.2.4.2The relation between the moment of the spring Spring (see detail X of Figure 6) and rotation at the base of the prop shall be taken as shown in Figure 7.
NOTE: For the base of the prop a structural model with load-dependent mechanical properties is analyzed (see Figure 7). First hinged support with an initial eccentricity eb,0 is assumed. When the rotation reaches φb = 1° any additional rotation will be prevented until the quotient Mt/Nt reaches the core
eccentricity eb, core. For higher values of the quotient, Mt/N4 a spring s4iffness ct = 3 × 107 N mm/rad is assumed
until the value of the quotient reaches the limit eccentricity eb, limit. For higher values of the quotient than be, limit
the load-carrying capacity of the prop is assumed to be exhausted.
9.2.5Resistances of tubes
The moment capacity Mpl, N shall be determined taking into account the effects of axial forces. This capacity, Mpl, N, shall be calculated from the equation:
Mpl,N = Mpl × cos((л/2) × (N/Npl)) (6)
where
N is the axial force;
Mpl, N is the reduced plastic resistance moment allowing for axial force;
Mpl is the moment resistance of the cross-section;
Npl is the compression resistance of the cross-section.
Equations for determining the structural properties of a perforated tube are to be taken into account in accordance with annex A.
9.2.6Verification of strength
The actual calculated strength, Ry, act, shall be compared with the nominal characteristic value, Ry,k, specified in clause 8, for a prop with the same class and extension. Ry, the act shall not be less than Ry,k.
9.3Verification of the actual characteristic strength by testing
When tested in accordance with 10.2, the actual characteristic value obtained from 10.1.3, Ry, act, shall be compared with the nominal characteristic value specified in clause 8, Ry,k, for a prop of the same class and extension. Ry, the act shall not be less than Ry,k.
Eight props shall be subjected to these tests for each of the extended lengths specified in 9.1. The most unfavorable extended length may be established by a preliminary series of tests on up to seven single-props at seven different intermediate extensions. The length increments between each of these tests shall be equal.
9.4Verification of the strength of adjustment device
9.4.1Fine adjustment device
NOTE 1: The screw-nut connection does not need to be assessed.
NOTE 2: It may be assumed that a length adjustment device conforming to 7.3 results in safe construction.
9.4.2The pin and its supports
9.4.2.1GeneraI
For the purpose of verification in accordance with 9.4.2.2 and 9.4.2.3, the characteristic strength given in clause 8
shall be increased by a factor of 1,14.
NOTE: The factor 1,14 takes into account a higher partial safety factor щМ2 = 1,25 for the pin connection resulting from the quotient щМ2/щМ1 wherein щМ1 = 1,1 is the general partial safety factor for steel structures.
For the purpose of verification in accordance with 9.4.2.4, the characteristic strength given in clause 8 shall be increased by a factor of 1,27.
NOTE: The factor 1,27 takes into account a higher partial safety factor щМ2 = 1,40 for the pin connection resulting from the quotient щМ2/щМ1 wherein щМ1 = 1,1 is the general partial safety factor for steel structures.
9.4.2.2Inner 4ube
The bearing capacity of the inner tube shall always be verified by calculation. It may be assumed that half of the axial force acts at either side of the tube. The bearing resistance of the tube shall be calculated in accordance with B.2.
9.4.2.3Pin and suppor4s conforming 4o 7.3.5
The sheer capacity of the pin shall be verified by calculation. It may be assumed that half of the axial force acts at either end of the pin. The shear resistance shall be calculated in accordance with B.1.
9.4.2.4Pin and suppor4s no4 conforming 4o 7.3.5
Specimens shall be tested in accordance with 10.3 and shall be verified by comparison with the modified value given in 9.4.2.1.
9.5Verification of the prevention against unintentional disengagement
When a prop is tested three times in accordance with 10.4 the inner tube and outer tube shall remain attached to each other.
10Test methods
10.1General
10.1.1Sampling
The required number of specimens (see 9.3) to form the sample shall be chosen at random from a batch of at least
- The batch shall either be taken from current production, or from stock.
10.1.2Method of loading
The test load on the specimen shall be applied either in steps not exceeding 20 % of the anticipated failure load, or increasing uniformly at a rate not exceeding 20 % per minute of the anticipated failure load.
When an adjustment of the load application velocity becomes necessary to establish the orderly deformation behavior in the plastic zone, this adjustment shall be achieved in the prop strength test by:
–using a deformation controlled test machine; or
–by measuring at each load step the horizontal deflection at the middle of the prop and at the length adjustment device.
The deflections shall be recorded either step by step or autographically.
10.1.3Statistical evaluation
Analyze the values R’s from the set of tests (see 10.2.6) statistically to establish the 5 % quantile values with a confidence level of 75 % either
–in accordance with Annex C with a log-normal distribution; or
–by assuming a normal distribution.
Annex C may also be used when assuming a normal distribution. In this case, the transformations according to equations (C.1) and (C.5) are not applicable.
10.2Test method for the prop strength
10.2.1General
Test procedure sees 9.1.
10.2.2Material properties
The mechanical properties of the tubes from six of the tested props shall be established by testing in accordance with EN 10002-1 to determine:
a)yield strength fy
b)tensile strength fu
c)elongation u
For the reduction of test results in accordance with 10.2.6:
d)the average of the material test results shall be taken, when the variance of the six test results is not greater than 10 %; otherwise
e)the individual relevant material properties shall be determined for each prop tested.
10.2.3Test set-up
Set up the prop in a compression testing machine at the required extension (see Figure 8).
The prop shall be tested in the upright position. Where a horizontal testing machine is used, a compensating upwards force equal to half the prop weight may be applied in the mid-length position of the prop.
At the base of the prop, position plane support of steel or concrete which allows the adjustment of an angle of 1 ° (± 0,1°) relative to the plane normal to the axis of the adjacent tube which is already inclined by the angle φb,1 due to the angle of inclination φ0 (see Figure 6 and 9.2.3.2).
At the head of the prop, position a ball joint in accordance with Figure 9 and an eccentricity of et = 10 mm (± 0,5 mm). This ball joint shall be on the same side of the prop as the line of contact at the base of the prop. The friction of the ball joint shall be minimized by lubrication.
Rotate the prop until the transverse direction of the pin is as indicated in Figure 8 and the principal pre-deflection of the prop is away from the line of the axis through the ball joint. The natural set-up of the prop shall not be improved by the use of wedges or other means.
10.2.4Deflection measurement
Set up gauges to record horizontal deflections at the middle of the prop and at the middle of the length adjustment device.
10.2.5Failure load
The rate of loading shall ensure that accurate recording of the horizontal deflections and the prop failure load, Ru, are both possible.
The load shall be increased until the prop fails or the load cannot be increased further.
The prop failure load, Ru, shall be recorded and analyzed in accordance with clause 10.2.6. The plotted load-deflection graphs shall be included in the test report.
10.2.6Reduction of test results, R’u
10.3Test of a pin and its supports
10.3.1Principle
This test establishes the characteristic strength value for the combination of the pin and its supports.
10.3.2Arrangement of test
Cut the section of the prop which forms the adjustment device to the dimensions shown in Figure 11. Apply the platens of a compression testing machine to the cut ends. Set up gauges to record the displacement of the inner tube with reference to the outer tube.
10.3.3Procedure
Apply the load in accordance with 10.1.2. The displacement readings shall be recorded at each step. Increase the load until it cannot be increased further. Record the maximum load.
10.3.4Reduction of test results
The maximum load at failure, Ru, shall be reduced in the proportion of nominal to the actual tensile strength of that component that controls the failure.
The results shall be evaluated in accordance with 10.1.3.
NOTE: See also 9.4.2.1.
10.4Test of the prevention against unintentional disengagement
Suspend the prop vertically by its endplate with the outer tube uppermost. Raise the inner tube until the prop is in a fully closed position. Allow it to fall under gravity.
11Test report
The results of all tests and calculations on the props submitted for assessment shall be recorded in a test report and shall include the following:
a)name of the test laboratory and the supervising engineer;
b)designation according to clause 5 of the tested props, and trademark or name of the manufacturer;
c)all information provided by the manufacturer (e. g. drawings, sizes, material characteristics);
d)information about the test equipment and about the test procedure;
e)the measured dimensions and deviations from nominal values stated in the manufacturer’s prop data;
f)a confirmation that the mechanical properties of materials conform to the manufacturer’s prop data;
g)all measured values, calculations, and verification results. The stiffness behavior shall be presented by graphical means;
h)significant information, such as plastic deformations.
12Marking
The marking shall be impressed or embossed on the prop or be on a steel plate welded to the prop, and shall be legible after the protective coating has been applied. The height of the characters shall be at least 4 mm and their depth shall be at least 0,2 mm.
The position of the marking shall not be obscured when the prop is in the upright position with the outer tube at the bottom.
Props shall be marked with the following information, in the sequence given:
– EN 1065;
–name or trademark of the prop manufacturer;
–year of manufacture (last two digits);
–classification (see Table 1);
–inspection level (see Annex E), if annex E (informative) is applied;
–sign of the independent certification system (for inspection level M only), if annex E (informative) is applied;
e.g. EN 1065 Europrops 97 B 30 L.
Props utilizing tubes conforming to prEN 39 shall be marked with “3” indicating that couplers conforming to EN 74 may be attached.
