The objective of this project was to quantify and compare the environmental impacts associated with alternative designs for a typical North American mid-rise office building. Two scenarios were considered; a traditional cast-in-place, reinforced concrete frame and a laminated timber hybrid design, which utilized engineered wood products (cross-laminated timber (CLT) and glulam). The boundary of the quantitative analysis was cradle-to-construction site gate and encompassed the structural support system and the building enclosure. Floor plans, elevations, material quantities, and structural loads associated with a five-storey concrete-framed building design were obtained from issued-for-construction drawings. A functionally equivalent, laminated timber hybrid design was conceived, based on Canadian Building Code requirements. Design values for locally produced CLT panels were established from in-house material testing. Primary data collected from a pilot-scale manufacturing facility was used to develop the life cycle inventory for CLT, whereas secondary sources were referenced for other construction materials. The TRACI characterization methodology was employed to translate inventory flows into impact indicators. The results indicated that the laminated timber building design offered a lower environmental impact in 10 of 11 assessment categories. The cradle-to-gate process energy was found to be nearly identical in both design scenarios (3.5 GJ/m2), whereas the cumulative embodied energy (feedstock plus process) of construction materials was estimated to be 8.2 and 4.6 GJ/m2 for the timber and concrete designs, respectively; which indicated an increased availability of readily accessible potential energy stored within the building materials of the timber alternative

Structural materials with exceptional strength and toughness are assembled through water induced hydrogen bonding among cellulose nanofibers, providing significant finding that water can serve as structural molecules to bridge natural polymers.

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This paper evaluates the performance of momentresisting bolted timber connections with self-tapping wood screws acting as perpendicular-to-grain reinforcement. Considering an unreinforced joist-tocolumn connection with slotted-in steel plates as baseline, an increase in capacity by a factor of 1 . 7 was observed when the connections were reinforced with self-tapping screws under reverse cyclic loading. This was further increased by 22 . 5% when the bolt diameter in the reinforced connection was increased from 19 . 0 to 25 . 4 mm. Reducing the edge distances of the bolts in the reinforced connection provided addition gain in capacity of 35 . 3% to a total capacity increase by a factor of 2 . 9 when compared to the unreinforced connections while maintaining very ductile behaviour. The results show that it is feasible to create ductile and high-capacity moment-resisting bolted timber connections with selftapping wood screws as reinforcements.

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Engineered wood products are structural composites that have been gaining successes in the construction industry. The mechanical and physical properties of these products depend on the interacting relationships between the quality of the resource, the manufacturing process, and the applications. In general their mechanical properties are more uniform compared with solid sawn material; hence, higher allowable properties are available in engineering design. This paper reviews the manufacturing processes, structural properties, physical attributes, and common applications of some of the major engineered wood products including: glued-laminated timber, parallel strand lumber, laminated strand lumber, laminated veneer lumber, and thick oriented strand board/rimboard.

Cross-laminated timber (CLT) panels are relatively new engineered wood products that can be used as load bearing walls, floors and roof elements in innovative and high quality modern timber structures. The fire behavior of cross-laminated timber panels requires careful evaluation to allow the expansion of CLT elements usage in buildings. A University of British Columbia study has been conducted at the Trees and Timber Institute CNR-IVALSA in San Michele all'Adige, Italy to experimentally evaluate the fire performance of Canadian CLT panels. In total, ten loaded fire tests were performed using standard fire curves (ULC/ASTM and ISO) to study the influence of different cross-section layups on the fire resistance of floor and wall elements and to investigate the influence of different anchors on the fire behavior of wall elements. This paper presents the main results of the experimental analyses and discusses in particular the charring rate, one of the main parameters in fire design.

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