ДСТУ Б EN 1075:2011
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1 2 4 EN 1075:1999 Timber structures - Test methods - Joints made with punched metal plate fasteners - - - - Timber structuresTest methodJoints made with punched metal pl ate fasteners
1 - - - 2 EN 336 1 Scope
This European Standard specifies the test methods for determining the strength capacity and stiffness of joints made with punched metal plate fasteners in load bearing timber structures, being used to join two or more pieces of timber of the same thickness in the same plane The properties measured are
- load-slip characteristicsand maximum load resulting from the lateral resistance of the embedded projections, at various angles between the direction of the applied force and the axis of the fastener (load- fastener angle a)
the direction of the grain of the timber (load-grain angle ₽?)
- the tension capacity of the fastener at various angles a
- the compression capacity of the fastener at various angles a
- the shear capaci ty of the fastener at vari ous angl es a.
A nai I root test method is shown 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 336 Structural timber - Coniferous and poplar - Sizes, permissible deviations
EN 26891 EN 28970 3.1 3.3 EN 26891 Timber structures - Joints made with mechanical fasteners - General principles for the determination of strength and deformation characteristics
EN 28970 Timber structures - Testing of joints made with mechanical fasteners - Requirements for wood density.
3 Definitions
For the purposes of this standard, the following def 3.1 punched metal plate fastener: Fastener made of metal plate of nominal thickness not less than 0,9 mm and not more than 2,5 mm, having integral projections punched out in one direction and bent perpendicular to the base of the metal plate
3.2 major axis of fastener: Direction giving the highest tension capacity per unit width of the fastener. (In many cases the punching pattern of the fastener gi ves ri se to two mai n di recti ons, perpendi cul ar to each other, with different capacity properties).
3.3 effective area of fastener: The contact area of fastener and ti mber member reduced by 5 mm from the edges and by 10 mm in the grain direction from the end of the timber member, see figure 1.
2 —r -=- Figure 1: Def 3.4 3.5 5- 3.6 3.4 anchorage capacity per unit area: The maximum load resisted by the joint per effective unit area of the fastener.
3.5 characteristic density: the population 5-percentile value with the mass and volume corresponding to equilibrium moisture content at a temperature of 20 0 C and a relative humidity of 65 %.
3.6 design core thickness of fastener: nominal
4
width of fastener perpendicular to the major axis of the fastener, fastener anchorage capacity, square millimetre
fastener compression capacity, in newtons per
millimetre
fastener tension capacity, in newtons per millimetre
actual tension strength of the fastener material, in newtons per square mi 11 character! sti c tensi on strength of the fastener
materi al, fastener shear capacity, characteristic yield stress of the fastener material
load, in newtons
maximum load, in newtons
estimated maximum load, in newtons 5 5.1 5.2 6 6.1 Pi< characteristic density of the timber or timber grade, to which the test results shall be applied, in ki I ogrammes per cubi c metre
5 M aterials
5.1 Timber
The timber shall be selected in accordance with of the methods given in EN 28970 (see al so 6.6.1)
5.2 Fasteners
The fastener specification, including the relevant characteristic mechanical properties (eg., tensile strength, yield stress and elongation) of the steel used to manufacture the fasteners, determined using standard test procedures, shall be record. For the purpose of verifying such records, material shall be available which has taken from the coil used in the manufacture of the fasteners.
The ducti I ity of the fasteners at the root position of the projections shall be determined in accordance with annex A.
NOTE: The sizes (length and width) of fastener to be used for the various tests should be selected in such a way that capacity values for the complete range of sizes normally produced by the fastener manufacturer may by obtained by interpolation or extrapolation with adquate rd 6 Test methods
6.1 General
For the determination of the fastener tension capacity, the timber shall be sufficiently strong for failure to occur in the fastener. The timber used shall have a target size, see EN 336, of not less than 35 mm or twice the length of the projections plus 5 mm, whichever is the greater.
NOTE 1: In the tests specified in 6.4.1 and 6.4.2 the minimum timber thickness should be limited to mat proposed for use NOTE 2: Test data of anchorage capacity should not be applied to joints with members thinner than those tested, but may be applied to joints with thicker members.
NOTE 3: Examples of properly located transducers are given in Annex C (Informative).
If there are no special requirements, the ti mber shalI be planed; the difference in thickness between adjoining pieces shall not exceed 0,5 mm. For each test piece, the two individual members to be joined shall be cut from 6.2 6.3 adjacent positions on the same plank to ensure a test piece of balanced density. In each group of similar test pieces, the ti mber for each test piece shal I be cut from a different plank.
Timber members for the test pieces shall be cut so that the areas to which the fasteners are embedded are free from knots, local grain disturbance, fissuresand wane.
Else/vhere the members shall be free from characteristics which could lead to premature failure in the timber.
The moisture content of the ti mber and its density shal I be determined.
6.2 Conditioning
The test pieces shal I be manufactured with the ti mber at an equi I NOTE: For some hardwoods a much longer conditioning period may be necessary.
6.3 Fabrication of test pieces
Test pieces shall be made with two fasteners positioned parallel to each other and symmetrically on opposite faces of the joint. The size and geometry of the test pieces will depend upon fastener size and the property being measured.
The test pieces shall be assembled using the method (eg. press or roller) normally used with the particular fasteners in the commercial production of structural timber components and the projections of the fastener shall be fully embedded in the timber so that the contact surface of the fastener is flush with the surface of the timber. If complementary nails are used to locate fasteners dur In the case of the testing of fastener compression capacity (see 6.4.4), the test piece shal I be fabricated so that the pieces of ti mber 6.4 6.4.1 NOTE: The fastener size should be chosen so that no anchorage failure occurs in the determination of the tension, compression and shear capacity of the fastener. However, in testing for shear capacity, some buckling of the edge of the fastener may occur locally and this should be acceptable.
6.4 Preparation of test pieces
6.4.1 Anchorage capacity and load-slip characteristics of contact surface of fastener and timber: load parallel toff'ain
The maximum load due to the lateral resistance of the fastener projections and the load-slip characteristics, with the load applied in the direction parallel to the grain of the timber, shall be determined using the test pi
*—r -==- Figure2: Test piecefor anchorage capacity and load-slip characteristics of contact surface: load parallel to grain
Generally fasteners have multiple projections in a modular arrangement and it will be sufficient to test one size of fastener at each value of the angle a The size of the fastener shall be such that its dimension in the direction of the applied force is the largest for whi ch fai I ure at the embedded proj ecti ons wi 11 occur. 6.4.2 NOTE: The selection of the appropriate size of fastener may often be made on the basis of experience with similar fasteners. However, preliminary tests may someti mes be requi red.
The fasteners shal I be positioned on the members so as to mi ni mi se the effects of moment rotati on. The comers of the fastener may cross the edges of ti mber members.
NOTE: With the results of the anchorage test and the shear test, the rotational stiffness of the contact surface of the fastener with the ti mber at various angles a may be derived by calculation as shown in annex B.
6.4.2 Anchorage capacity and load-slip characteristics of contact surface of fastener and timber: load not parallel to (pain
The maximum load due to the lateral resistance of the fastener projections and the load-slip characteristics, with the load applied other than parallel to the grain of the timber, shall be determined using the test piece shown in figures.
The length of the abutting timber loaded in tension shal I be such that the end of the test machi ne gri p shal I be not I ess than 20 mm from the ends of the fasteners.
NOTE: The distance between the edge of the fastener and the edge of the support should be in the range h/4 to h.
The fasteners shal I be posi ti oned to favour fai I ure at the fastener projections embedded in the member loaded not parallel to the grain of the member, i.e in the cross member. Thi s wi 11 normal ly occur when < 12 and 1 7 <0,7h.
NOTE: The selection of the appropriate size of fastener may be made on the basis of experience with similar fasteners. However, preliminary tests may someti mes be requi red.
F
C) a =90 P =90 Figure3: Test piecefor anchorage capacity and load-