Mass Timber Construction Journal <p>The Mass Timber Construction Journal is a peer-reviewed international online journal, dedicated to high quality research in Mass Timber Construction (MTC). The journal was created to fill an identified gap in the research publishing market. The editors found it difficult to publish MTC research in other journal publications due to a lack of concentrated peer-reviewers, editorial staff and researchers who are the leaders in the MTC field.</p> Mass Timber Construction Journal en-US Mass Timber Construction Journal 2209-2579 <p>The Author (on behalf of any and all co-authors) hereby assigns to MTCJ (hereafter known as the Publisher) the copyright to the Contribution named above; whereby the Publisher shall have the exclusive international rights to publish in any and all media the said Contribution and translations of it wholly or in part throughout the World under the provisions of this agreement. These rights include without limitation mechanical, electronic and visual reproduction; electronic storage and retrieval; and all other forms of electronic publication or any other types of publication including all subsidiary rights.</p> <p>&nbsp;</p> Filling the Knowledge Gaps in Mass Timber Construction. <p class="p2">As mass timber construction evolves from a niche product to a mainstream, there is an urgent need for focused research activities to support the industry and avoid duplication or overlap of work being done internationally. To identify and prioritise the future of mass timber research agenda, this article pursues responses to the following questions: What is the current state of knowledge and where are the remaining research needs in mass timber construction? For example, newcomers to mass timber often believe it is imperative to research fire performance, fire resistance, or sound transmission when these areas have been extensively explored and are now widely seen as resolved. Consequently, the focus has shifted, towards answering new research questions, including explorations of carbon storage, and life cycle analysis durability. There is already a growing research activity in mass timber, involving several research centres worldwide, that would benefit from some guidance on research needs. Thus, defining new trends and research gaps that help avoid replicating research. A more nuanced discussion on knowledge gaps and industry research needs is also timely, to truly capture and disseminate information on the full potential of engineered-wood products as an innovative construction material, which helps reduce the use of carbon-intensive conventional building materials. To answer the above-mentioned research questions, this study has consulted experts at an international conference, and seven key research areas have been identified and presented as the results.<span class="Apple-converted-space">&nbsp;</span></p> Steffen Lehmann Paul D Kremer ##submission.copyrightStatement## 2023-07-14 2023-07-14 6 1 1 10 Evaluating the Effect of Inner Layer Grain Orientation on Dimensional Stability in Hybrid Species Cross- and Diagonal-Cross-laminated Timber (DCLT) <p>Wood deformation due to moisture adsorption and desorption in the cell wall components challenges the dimensional stability of multi-layer wood-based panels. This is a common issue in timber products with single board products and parallel glued layers (such as Glued-laminated Timber; GLT). Orienting the inner layers of timber products at an angle, like plywood and Cross-laminated Timber (CLT), with the perpendicular (90°) orientation of the inner layers, helps minimize overall shrinkage and swelling of the composite panel. However, due to the perpendicular orientation of the layers, Cross-laminated Timber (CLT) exhibits a lower out-of-plane bending stiffness than a parallel-layered Glued-laminated Timber (GLT) panel. An optimized modified orientation of the inner layers in a diagonal direction could improve dimensional stability compared to GLT while developing a better structural performance than CLT. This study evaluates the dimensional stability of small specimens of four-layer Diagonal-Cross-laminated Timber (DCLT) with a hybrid layup consisting of a high-density hardwood species, black locust, in the top and bottom layers, and a low-density softwood species, eastern white pine, in the asymmetric inner layers. The results show that increasing the inner layer fiber orientation angle improves the dimensional stability of the panels. While the dimensional change in the length of the panel (longitudinal) is negligible, by varying the inner layer angle-ply from 0° to 90°, the percentage changes in width (tangential), thickness (radial), and volume reduced respectively from 3% to 0.8%, 1.6% to 0.4% and 5.1% to 1.3%. Since the dimensional tolerances of the CLT due to the moisture content in the manufacturing process and the in-service conditions have already been established in the design and building standards, the result of this study can be helpful for the construction industry to predict the potential dimensional change (%) and corresponding required tolerances for DCLT panels when used in building structures.</p> Shaghayegh Kurzinski Paul Crovella William Smith ##submission.copyrightStatement## 2023-08-11 2023-08-11 6 1 11 16 Quantifying MEPFP Mass-Timber Trade Efficiency Through Vertical Mechanical Fastener Analysis <p>Touted attributes of mass-timber structures include its efficiency in both erection and labor productivity. These efficiencies are a result of differing methods, induced by varying contractors, and are impacted by site specific variables. This study explores efficiency related to overhead fastener applications installed by MEPFP trades. Fastener installation time in an overhead rebar reinforced concrete beam is compared to that installed in a mass-timber structural beam to determine efficiency disparities (if any). Two sets of fasteners are compared in the differing materials: one for heavy and the other for light duty applications. A total of sixty fasteners were installed, consisting of two sets of fasteners, installed in both concrete and mass-timber. Results were analyzed with two independent t-tests to determine statistical significance and mean difference between fastener and material type. The study found that heavy-duty conventional overhead concrete fastener installation takes significantly longer (Fastener A-Conc. M=12.82 seconds) than mass-timber fastener installation (Fastener A-MT. M=1.01 seconds), t(26)=38.72, p=&lt;.001. Additionally, light-duty fasteners share similar results in concrete (Fastener B-Conc. M=12.18 seconds) compared to mass-timber (Fastener B-MT M=2.32 seconds) conditions; t(23)=33.56, p=&lt;.001. This study provides evidence that mass-timber offers significant time savings per each overhead fastener installation, when compared to traditional concrete structures. These results can be used for construction planning, productivity rates databases, and cost analysis.</p> Lameck Onsarigo Anthony Michael Mirando ##submission.copyrightStatement## 2023-12-29 2023-12-29 6 1 17 23