On a number of occasions glued laminated timber breaks apart before the end of their service life. Examples in Germany (Frese M., Blaß H. J. ) and Denmark (Hansson, Larsen  ) show that this problem is real. In order to find the causes of the problem, extensive tests were conducted: 16 buildings with glued laminated timber were examined on the spot, calculations and laboratory work were carried out. These examinations told us that not only did the properties of the wooden material cause the damage, but the problems were also due to the wood used and the method of construction. In the calculations, the external load and residual stresses occurring in the glued laminated timber were included. Residual tensions in this timber were generated by climatic stresses and also due to the method of construction. These stresses also accumulated along with the stresses of the external load. Laboratory work was carried out to measure the delamination. We examined whether these analyses and calculations prove or disprove the results of the on- the- spot examinations.
As part of the CORRIM Phase I research, this study completed a full gate-to-gate life-cycle inventory for the production of glued-laminated timbers (glulam) produced in two regions of the United States—the Pacific Northwest (PNW) and Southeast (SE). Data collected from surveys of manufacturers are presented for energy requirements, raw materials use, and emissions to land, water, and air allocated for one cubic meter and 1000 cubic feet of glulam. The glulam manufacturers surveyed represented 70 and 43% of the region's total glulam production for the PNW and SE, respectively. From both regions, 82% of the raw material and energy inputs and emission outputs were allocated to the glulam product, leaving the remaining 18% allocated to co-products. Contributions to the glulam process included impacts for the inputs of lumber and adhesives. Results show that wood drying and adhesive manufacturing make major environmental contributions to the glulam process. In addition, fuel sources, either biomass or fossilbased, have significantly different emission impacts to the environment. Wood fuel representing wood waste and hogged fuel accounted for nearly 50% of the cumulative energy consumed, while for wood fuel used for heat energy to dry lumber represented 65% and 100% for the PNW and SE glulam models. The cumulative energy from all fuel types including wood fuel allocated for one cubic meter of glulam was 6,748 MJ/m3 when manufactured in the PNW and 7,213 MJ/m3 when manufactured in the SE.
This research investigates a new structural system based on a central core of CLT (cross-laminated timber) panels to provide more useful multi-level timber buildings that are taller and with open floor areas. Because pinus radiata is a suitable timber for the manufacture of CLT panels, the system has the potential to add value...
Project contact is Louis Gosselin at Université Laval
The volume occupied by all components between the ceiling of a floor and the floor of the upper floor (slab, ventilation duct, plumbing, etc.) is of great importance and it is best to minimize its thickness. This project aims to develop a multi-objective optimization strategy to design this sandwich type assembly according to various structural, acoustic, thermal and mass transfer criteria (Alev and Kalamees, 2017), while minimizing its volume, its size and its cost. and this, according to a given context. A case study will be conducted to assess the degree of optimality of the solutions chosen. Multidisciplinary tools facilitating the optimal design of this system will be proposed.
The Italian building heritage is aged and inadequate to the high-performance levels required nowadays in terms of energy efficiency and seismic response. Innovative techniques are generating a strong interest, especially in terms of multi-level approaches and solution optimizations. Among these, Nested Buildings, an integrated intervention approach which preserves the external existing structure and provides a new structural system inside, aim at improving both energy and structural performances. The research presented hereinafter focuses on the strengthening of unreinforced masonry (URM) buildings with cross-laminated timber (CLT) panels, thanks to their lightweight, high stiffness, and good hygrothermal characteristics. The improvement of the hygrothermal performance was investigated through a 2D-model analyzed in the dynamic regime, which showed a general decreasing in the overall thermal transmittance for the retrofitted configurations. Then, to evaluate the seismic behavior of the coupled system, a parametric linear static analysis was implemented for both in-plane and out-of-plane directions, considering various masonry types and connector spacings. Results showed the efficiency of the intervention to improve the in-plane response of walls, thus validating possible applications to existing URM buildings, where local overturning mechanisms are prevented by either sufficient construction details or specific solutions. View Full-Text