Most office building construction relies on steel and concrete for mid-high rise office building applications. The primary goal of this thesis is to understand the implications of CLT and mass timber construction systems for mid-high rise office buildings in Seattle by developing a prototypical office building located on a specific site. This research thesis will focus on comparing this prototypical mass timber office building design to the same/similar design using industry standard construction materials for Seattle. The criteria for comparison will include code, cost, schedule and greenhouse gas emissions.
The goal of this work was to develop material quantity estimates of a typical mid-rise office building in the Pacific Northwest and to deliver the results to the Forestry Research Team in the University of Washington (UW) College of the Environment School of Environmental and Forest Sciences. The Forestry Research Team will then use these results to develop regionally specific life cycle inventory data to support the greater study funded by the 2015 McIntire-Stennis Research Grant, which is “to assist small and medium-sized wood products companies and Native American tribal enterprises to understand and adapt to changing market conditions” (http://depts.washington.edu/sefsifr/2015-mcintire-stennis-grantwinners/).
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.
Nowadays, it is possible to build zero-energy houses or even positive energy buildings. Nevertheless, many incoherencies exists if we attach importance to the embodied energy of its constructions. The present paper lays on the logic of structural insulated panel which is used in many low-energy and passive houses and go further in order to reduce the global greenhouse gases emissions. For this purpose, cross-laminated timber is used instead of oriented strand board and the insulation used is made of wood wool. The structure, the technology and the thermal aspects are discussed as well as the fire resistance in order to show if its new product is economically and technically interesting. Results show that the embodied energy can be drastically reduced compared to the structural insulated panels. A wood consumption reduction of thirty percent can also be obtained compared to the classical cross-laminated timber construction.
In a former paper by the authors , the elastic behavior of Cross Laminated Timber (CLT) and timber panels having periodic gaps between lateral lamellae has been analyzed. A thick plate homogenization scheme based on Finite Elements computations has been applied. The predicted behavior was in agreement with experimental results. In this paper, simplified closed-form solutions are derived in order to avoid FE modeling. Both cases of narrow gaps of CLT panels and wide gaps of innovative lightweight panels are investigated. CLT and timber panels with gaps are modeled as a space frame of beams connected with wooden blocks. The contribution of both beams and blocks to the panel’s mechanical response is taken into account, leading to closed-form expressions for predicting the panel’s stiffnesses and maximum longitudinal and rolling shear stresses. The derived closed-form solutions are in agreement with the reference FE results and they can be used for practical design purposes.
Bosnia and Herzegovina is the most forested country in the Balkan area, and Sweden and Slovenia are two of the most densely forested countries in the European Union. Living habits differ considerably between these three countries, but the use of wood is very similar. This book grew out of the collaboration of three wood scientists with totally different backgrounds who met and discussed their common interest – wood. Based on the different experiences in each country, the idea was to try to find ways to increase the common knowledge base for the use of wood, achieving excellence in timber design research and education; the architect with a deep knowledge of culture based needs, the engineer with experience and knowledge of technological needs, and the practitioner who always has to find the final solution.