EN 408-2003 pdf download.Timber structures – Structural timber and glued laminated timber- Determination of some physical and mechanical properties.
15 DeterminatIon of tension strength parallel to the grain
15.1 Test piece
The test piece shell be of full structural cross section, and of sufficient length to provide a test length clear of the testing machine grips of at least nine times the larger cross-sectional dimension.
15.2 Procedure
The test piece shall be loaded using gripping devices which wlO permit as far as possible the application of a tensile load without inducing bending. The gripping devices and loading conditions actuay used shall be reported.
The loading equipment used shall be capable of measuring the load to an accuracy of 1 % of the load applied to the test p4ece.
Load shall be applied at a constant loading-head movement so adjusted that maximum load is reached within
(300 120) 8.
NOTE This rate should be determined from the results of prelinilnary tests. The objective Is that the time to reach for eadi piece is 300 S.
The hme to failure for each test piece shall be recorded and Its average reported. Any single piece diverging more than 120 s from the target of 300 s shall be reported.
15.3 ExpressIon of results
The tensile strength Is given by the equation = FI 4
The sbds are as given in clause 4.
The tens4le strength shall be calculated to an accuracy of I %.
The mode of fracture and growth characteristics at the fracture section of each test piece shall be recorded. If failure is associated with the grips, this shall be reported.
16 Determination of modulus of elasticity In compression parallel to the grain
16.1 Test piece
The test piece shall be of ui cross section, and shall have a length of six times the smaller cross-sectional dliens4on. The end surfaces shall be accurately prepared to ensure that they are plane and parallel to one another and perpendicular to the axis of the piece.
16.2 Procedure
The test piece shall be loaded concentrically using sphericaNy seated loading-heads or other devices which permit the application of a compressive load without indudng bending. After an initial load has been applied the loading- heads shall be locked to prevent angular movement. The grping devices and loading conditions actually used shall be reported.
Load shall be applied at a constant rate. The rate of movement of the loading-head shall be not greater than
0.00005 rmmis.
The loading equipment used shall be capable of measuring the load to an accuracy of I % of the load applied to thetestpiece, orforloads lessthan 10% of the appliedmaxinium load, withan accuracyofO,1 %of the rnaxmium applied load.
Defomation shall be measured over a central gauge length of four times the smaller cross-sectional dimension of the piece, Two extensometers shall be used, and shall be positioned to minimize the effects of distortion.
Deformations shal be determined with an accuracy of I % or, for deformations less than 2 mm, with an accuracy of 0.02 mm.
17.2 Procedure
The test piece shall be loaded concentrically using spherically seated loading-heads or other devices, wNch pem’dt the applacation of a compressive load without lndudng bending. After an initial load has been applied the loading- heads shall be locked to prevent angular movement. The gripping devices and loading conditions actually used shall be reported.
The loading equipment used shall be capable of measuring the load to an accuracy of 1 % of the load applied to the test piece.
Load shall be applied at a constant loading-head movement so adjusted that maximum load is reached within (300 120) a.
NOTE Tha rate should be determined from the results of prelininary tests. The objective Is that the time to reach F for each piece is 300 a.
The time to failure of each test piece shall be recorded and Its average reported. My srigle piece diverging more than 120 s from the target of 300 a shaH be reported.
17.3 Expression of results
The compressive strength Is given by the equation = IX1 A
The symbols are as given in cLause 4.
The compressive strength shaH be calculated to an accuracy of I %.
The mode of fracture and growth characteristics at the fracture section of each test piece shall be reported.
18 DetermInation of tension and compression strengths perpendicular to the grain
18.1 Requirements for test pieces
18.1.1 FabricatIon
The fabrication of the test pieces shall be such as will allow for the application of the loads to the test piece.
NOTE 1 Suitable rangemsnts are shown ki annexes A and B.
For tension tests, the test piece shall be glued to steel plates. The gluing process shall be capable of ensuring the specified position of the test piece during testing.
NOTE 2 A suitable ae&ve for fixing the steal plates to the timber test piece Is a t-p1 epoxy. Iromedialely prior to uing, the surfaces to be joined should be prepared by planing the timber test piece surfaces and sandblasbng the steel plates.EN 408-2003 pdf download.