WP 0: Project management
WP 1: Hardwood supply chain
The establishment of a sustainable production of glued timber products such as glulam and cross-laminated timber (CLT) from European hardwoods requires knowledge of the current hardwood resource in Central Europe as well as its future development in terms of standing stocks and their availability.
Furthermore, characterization of the quality of the roundwood resource, i.e. its technical properties, is necessary to assess the feasibility of an efficient and economical production of hardwood glulam and CLT and to identify the specifications of the roundwood best suited for these products.
To provide such knowledge, research within work package 1 comprises the following three tasks:
- Information on the current standing stocks of the most important hardwood species in the participating countries Austria, France, Germany and Slovenia – beech, pedunculate and sessile oak, ash and sweet chestnut (in France) – are compiled from the latest national forest inventories of these countries available.
- Predictions of the future development of the standing stocks are performed for the case of Germany by aid of the WEHAM forest development simulation tool based on the latest forest inventory data. It is investigated whether this prognosis tool can also be applied to the forest inventory data available from the other participating countries. If this is not feasible, existing predictions of forest resource development from the respective countries will be compiled.
- Sample logs of the hardwood species considered are collected. They are evaluated non-destructively by X-ray computed tomography (CT) scanning and MOE measurements, and they are sawn into lamellas with typical dimensions for glulam and CLT. The lamellas are then sorted visually according to the current sorting rules and are available for further testing. Existing software for detection of internal wood features in CT images, originally developed for softwood logs, will be tested on the CT data of the sample logs. If possible, sawing simulations will be performed with log models derived from the CT images of the sample logs to investigate the feasibility of optimizing the sawing of hardwood logs for glulam and CLT lamellas.
WP 2: Basic hardwood strength data and grading tools
Consolidate existing data with respect to species and dimensions; consolidate grading information (visual / machine) and analyse data; complete data if necessary to allocate e.g. beech or ash from participating countries to strength classes in EN 1912.
WP 3: Adhesives for structural hardwood bonding
General: species dependent adhesive types, product dependent integrity tests designed for hardwoods, quality procedures adapted to hardwoods.
Finger-joints: consolidate finger-joint data in solid wood and laminations, investigate influence of size and finger-joint type for the different species with accomplishing test if necessary (associating bending and tension tests), influence of moisture content and curing process.
Finger-joints: consolidate finger-joint data in solid wood and laminations, investigate influence of size and finger-joint type for the different species with accomplishing test if necessary (associating bending and tension tests), influence of moisture content and curing process.
WP 4: Glulam made of hardwood or hardwood and softwood
glued laminated hardwood timber: homogeneous and inhomogeneous hardwood glulam, model of glulam strength classes derived from lamination properties manufacturing optimization (planing, bond-lines, finger joints, edge gluing in lamellae width), oak glulam for service class 3 usage due to its natural durability.
glued laminated hybrid timber: high strength hardwood laminations in outer zones compatibility between soft- and hardwood laminations hybrid gluing optimization, hardwood and softwood beams gluing.
glued laminated hybrid timber: high strength hardwood laminations in outer zones compatibility between soft- and hardwood laminations hybrid gluing optimization, hardwood and softwood beams gluing.
WP 5: Cross-laminated hybrid timber
Inner layers of low quality hardwood for improved (rolling) shear capacity, outer layers of solid and LVL hardwoods for high-strength applications (tests and verifications); adapted strength modelling with regard to in-plane and out-of-plane loading, optimisation of layer build-up, concentrated loads and openings enhanced by use of hardwoods, adapted species- / adhesive- / production optimization (is vacuum gluing possible?).