Mass timber (MT) slabs are increasingly used in multi-story buildings as a sustainable alternative to concrete or steel slabs, offering a reduced carbon footprint and efficient on-site assembly. MT slabs are usually modelled using a rigid diaphragm approach [1] but recent studies have shown that while the panels tend to behave rigidly, the connections exhibit significant flexibility [2]. Flexibility in MT diaphragms can be accounted using a variety of methods. Common modelling strategies for panel-to-panel (PPC) connections involve the use of homogeneous, lumped or distributed connection models. The modelling strategies vary as a function of the level of detail and can range from (1) a homogenization approach in which average stiffness properties are used to model the complete diaphragm to (2) detailed nonlinear modelling of connections or individual fasteners using uniaxial force-displacement relationships [3]. Independently of the modelling approaches used, there is a lack of full-scale experimental validation of diaphragm behaviour under dynamic loading, especially for systems other than Cross-laminated timber (CLT). Based on existing knowledge, this study presents and validates a finite element (FE) modelling approach for four MT diaphragm systems, using experimental data from a six-story shake-table testing campaign performed at Large High-Performance Outdoor Shake Table (LHPOST6) at the University of California San Diego (UCSD). The FE models are built using OpenSeesPy [4] and validated via modal features obtained from Operational Modal Analysis (OMA). Results include frequencies, and mode shapes obtained from the numerical modelling, which are compared to extracted mode shapes using the Modal Assurance Criterion (MAC). While four different MT diaphragm systems were modelled in a previous study [5], this extended abstract focuses on one of the systems, known as the Nail-laminated timber (NLT) diaphragms due to the scarce dynamic characterization data available in the literature.
Keywords: mass timber, finite element modelling, nail-laminated timber, operational modal analysis
Authors
Robin W. Karlsson
Linnaeus University, Sweden
Jacob Andlöw
Linnaeus University, Sweden
Carmen Amaddeo
Linnaeus University, Sweden
Patricio Uarac Pinto
Oregon State University, USA
Andre R. Barbosa
Oregon State University, USA
Login to download the PDF