Deflection of Cantilever Cross-Laminated Timber Diaphragms Under In-Plane Load

Abstract

Diaphragms are used to transmit lateral loads to the vertical elements (e.g., shear walls) of the lateral force resisting system of a structure. The extent of deflection in diaphragms can determine what mechanism needs to be considered during design for transfer of forces to the vertical elements. Current design specifications do not provide equations that engineers can use to determine the deflections in cantilever Cross-Laminated Timber (CLT) diaphragms. In this paper, the CLT shear wall equation prescribed by 2021 Special Design Provisions for Wind and Seismic (SDPWS) was adapted to get an equivalent analytical equation for cantilever CLT diaphragm deflection. A full scale 6.1 m x 6.1 m (20 ft. x 20 ft.) cantilever CLT diaphragm was tested using displacement controlled cyclic protocol and the deformations at various regions of the diaphragms were measured. Analysis of test results suggests that the modified shear wall deflection equation for a cantilever CLT diaphragm based on SDPWS overpredicts the contribution due to bending and shear deformations.

Citation

Bhardwaj, Bibek; Pang, Weichiang; Stoner, Michael; Rammer, Douglas; Pryor, Steve. 2023. Deflection of Cantilever Cross-Laminated Timber Diaphragms Under In-Plane Load. In: Proceedings of World Conference on Timber Engineering. Oslo, Norway. pp. 2792-2797. https://doi.org/10.52202/069179-0365.