Mechanical Characterization of Connections for Modular Cross-Laminated Timber Construction Using Underutilized Lumber
Publication: Journal of Structural Engineering
Volume 150, Issue 2
Abstract
This study was part of a larger project investigating the feasibility of using ponderosa pine (Pinus ponderosa, PP) harvested from forest restoration programs in the Northwestern United States for low-rise modular buildings. The panels have a standard width of 1.2 m to consider dimensions available from local manufacturers. To use these panels as walls or floors, they must be joined using in-plane connections. The stiffness and capacity of these connection systems under reversal lateral loading affect the behavior of the multipanel wall systems. Such multipanel systems are proposed for use in modular construction, with the goal of finding suitable market outlets for PP cross-laminated timber (CLT). In-plane connections within the multipanel system here play the role of the intramodular connection, while intermodular connections connect different multipanel systems to form a structure. Butt joints with 45° screws and a bolted point-type connection system were selected as intramodular and intermodular connections, respectively, due to their suitability for prefabrication and ease of installation. The aim of the study was to determine the mechanical characteristics of these two types of connections in PP CLT. Ten intramodular connections under monotonic and cyclic loading in shear and tension, and 12 intermodular connections in monotonic and cyclic in two different configurations were tested. The resulting force-displacement curves were used to extract the mechanical characteristics of the connections, which were then compared to the performance of the same type of connections in CLT panels made from other wood species. The intramodular connection showed high ductility in shear and low to medium ductility in tension, while the intermodular connection had lower initial stiffness compared to tests of commercial CLT in all tested directions except compression.
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Data Availability Statement
Some or all data, models, or code generated or used during the study are available from the corresponding author by request.
Acknowledgments
This research was funded by USDA Forest Service (wood innovation grants program 17-DG-1162765-742 and 18-DG-11062765-738). The materials for the tests were provided by Collins Lumber Co., AkzoNobel, and Rothoblaas. The CLT panels were manufactured at AA Red Emmerson Advanced Manufacturing Laboratory of Tallwood Design Institute (TDI) and the tests were conducted at the Department of Wood Science and Technology, Oregon State University (OSU). Other partners of the project are Anderson Construction, DR Johnson, Sierra Pacific, SMT Research, USNR, and Vaagen Timbers; their respective contributions are acknowledged. Support of Dr. Andrea Polastri, National Research Council (CNR), Italy, in testing methodology is acknowledged.
Author contributions: SB, EF, and MR conceived the study. SB conducted the experimental tests with input from EF, MR, and SJ. SB performed the data analysis and interpretation of results with the guidance of EF. SB led the drafting of the article with critical input from EF, MR, and LM. All authors have reviewed and agreed to the final version of the article.
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Journal of Structural Engineering
Volume 150 • Issue 2 • February 2024
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Feb 6, 2023
Accepted: Sep 27, 2023
Published online: Nov 27, 2023
Published in print: Feb 1, 2024
Discussion open until: Apr 27, 2024
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