This study proposes a model using data from a scanner (X-ray and grain angle measurements) to perform strength grading. The research also includes global measurements of modulus of elasticity (obtained by vibrations and ultrasound methods), static bending stiness and bending strength of 805 boards of Douglas r and 437 boards of spruce. This model can be used in an industrial context since it requires low computational time. The results of this study show that the developed model gives better results than the global non-destructive measurements of the elastic modulus commonly used in the industry. It also shows that this improvement is particularly higher in the case of Douglas r than for spruce. The comparison has been made on both the quality of the mechanical properties assessment and on the improvement of the grading process according to the European standards by using dierent index.

18The tests revealed the influence of wood properties and manufacturing parameters on joint 19 resistance. In fact, the results showed that specific gravity and the shrinkage coefficientgreatly 20 influenced the gluing step. Indeed, wood with a medium specific gravity needed more adhesive 21 and more pressure than wood with a high specific gravity. In addition, planning and lamella 22 thicknesswere found to affect glue joint resistance. In this study, the bondability of hardwoods for glued laminated timber beams was 5 assessed in French Guiana using local wood species. The aim was to establish 6 gluing parameters affording good mechanical properties to glued laminated beams 7 manufactured in a tropical climate. Wood and adhesive properties 18In French Guiana there are almost 1,500 species listed, but wood properties and 19 industrial constraints impose a strict choice of species for glulam manufacture. 20The most important physical wood properties are specific gravity, wood Bonding durability tests 4To assess bonding efficiency, delamination and block shear tests were used in this Delamination 8The delamination test is used to assess the resistance of the glue joint after ageing 9 cycles including strong variations in wood moisture content. As wood dimensions 10 vary during use depending on changes in ambient humidity, delamination assesses 11 the resistance of the glued assembly under those variations. Depending on the 12 service classes for which the end-product is to be used, different delamination test Delamination was measured to an accuracy of 0.1 mm. This value was compared 27 to the upper limit allowed by the European standards, i.e. 10% for tropical 28 hardwoods. 30 Block shear strength and wood failure. 31The block shear test is used to assess the shear mechanical resistance parallel to Experimental procedure 21In this study, 92 glulam beams composed from three wooden slats were 22 manufactured and tested. Depending on the lamellae thickness (e), the size of the 23 beams was 3ex100x700 mm³. Beams were manufactured from boards, air-dried in 24 the local atmosphere until they had reached a balanced moisture content MC. The 25 balanced MC observed on the guianensis species was 14, 16 and 17% (± 2%) for