ISO 19993-2020 pdf free.Timber structures — Glued laminatedtimber — Face and edge joint cleavage test.
1.Scope.This document specifies methods of evaluating the effectiveness of glued laminated timber face andedge bonds within a manufacturing plant by cleaving of the glue line in both dry and wet conditions.lt is not intended that it be used for initial type testing where cyclic delamination or block shear ispreferred. lt is based on the principle that, provided minimum wood failure percentages are met, thenthe bond strength exceeds the perpendicular to the grain tension strength of the under-lying substrateand therefore the bond is not the weak element limiting the integrity of a glulam assembly.
2.Normative references:There are no normative references in this document.
3.Terms and definitions:For the purposes of this document, the following terms and definitions apply.
3.1.wood failure:area of wood fibre remaining on the bond line following completion of the cleavage(3.2) test expresseas a percentage of the total test area excluding any areas of wood defect (gum vein and similar)
3.2.cleavage:rupture parallel to the wood grain of a glulam face or edge joint bond line or the adjacent adherend bythe application of normal stress
4.Principle:A specimen consisting of a full cross-section of laminated timber is cleaved apart in the plane of thebond lines and wood failure is assessed after wet or dry conditioning.Cleavage is achieved by cutting a saw kerf that straddles the bond line then using a chisel, usuallybricklayer’s bolster, that is placed in the saw kerf and is struck with a hammer to produce stressesperpendicular to the grain, in other words, to induce cleavage. If there is sufficient wood failure itmeans that the adhesive bond is stronger than that of the wood and that there is no loss of strengperpendicular to the grain at the interface between laminations.A member to be tested shall be manufactured to a slightly longer length than specified to allow forrepresentative specimen or specimens to be removed at the end of the member. The specimen(s) shabe removed from the off-cut portion at the end of the member after trimming to length.Each specimeshall be marked to identify the member from which it is cut.
The specimens shall include the full cross-section of the laminated timber to be tested, perpendicularto the grain of the wood and 50 mm long measured along the grain.Each bond line of the specimenshall be cut uniformly the full width of the specimen to a depth of 10 mm from one cross-cut face.Forconvenience, the specimen may be divided into smaller parts, provided the cuts are perpendicular to orwell away from the bond lines and that all parts are tested (see Figure 1).ISO 19993 pdf download.