Developed at the turn of the 19th and 20th centuries, glulam frees design from the dimensions of the natural trunk. Thanks to mechanical grading and finger joints, beams of theoretically unlimited length are obtained.
The boards (lamellae) are first freed of defects, dried and then glued parallel to the grain direction. The European classification provides homogeneous (h) beams, made of lamellae of the same strength class, or combined (c), where the outer lamellae (subject to maximum stress) are of higher quality than the neutral central core.
The gluing technique makes it possible to pre-bend the lamellae before pressing, creating complex arches and portals for sports facilities. In fire, GLT shows exceptional resistance: surface charring (about 0.65 mm/min) creates an insulating layer that slows combustion, keeping the load-bearing capacity of the inner core unaltered.
Standards
European and international references applicable.
Physical properties
Usage environment
Optimal in Service Class 1 and 2 (covered environments). Use in Class 3 (exposed exterior) requires specific species (Larch, Chestnut) or deep preservative treatments, otherwise rapid biological degradation occurs.