PSI - Issue 78

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 78 (2026) 1229–1236

XX ANIDIS Conference Non-destructive assessment of hybrid CLT Vittoria Borghese a, ∗ , Niels Vonk a , Jan Niederwestberg a a TNO, Building Materials and Structures, Molengraa ff singel 8, Delft, 2629 JD, Netherlands

© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of XX ANIDIS Conference organizers Abstract Cross-laminated timber (CLT) has become one of the most popular mass timber products. Its overall behaviour is strongly influ enced by the CLT layup and the properties of the layers. Existing calculation approaches reflect this through simple calculations using mean sti ff ness values. This study evaluates the validity of these simplifications for CLT panels made with a heterogeneous layup including partially reclaimed timber. Five-layer CLT panels were produced from Dutch-grown Ash and Douglas in the lon gitudinal, and reclaimed Spruce in the cross layers. Ultrasonic non-destructive testing was performed on each individual lamellae before panel assembly, yielding a detailed dataset of the longitudinal elastic moduli. Laminate locations within the CLT were recorded during assembly. Parametric finite element analysis (FEA) models were generated using Python scripting in DIANAFEA , and modal analyses were carried out. Three statistical and probabilistic approaches were investigated for assigning the elastic mod uli to lamellae to the respective layers within the model: (i) assigning the actual measured modulus to each lamella, (ii) assigning a random modulus from the dataset to each lamella, (iii) using the global mean value per layer. The results from the FEA analy ses were compared with results from experimental modal tests. The impact of each modulus assignment strategy on the dynamic response of the panels was evaluated by comparing natural frequencies, mode shapes, statistical indicators, and relative errors.

Keywords: Cross-laminated timber (CLT); Finite element analysis (FEA); Layer properties; Modal analysis; Non-destructive testing (NDT);

1. Introduction

In recent years, mass timber construction has become a widely adopted construction material (Pajchrowski et al., 2014). Modern timber construction has achieved a high prefabrication level with low tolerances, which in turn reduces assembly times and the amounts of waste on construction sites (Sutkowska et al., 2024). Due to its natural structure, timber itself has one dominant structural direction, i.e., the direction parallel to the fibre, making it most suitable for beams and columns (Senalik & Farber., 2021). Cross-laminated timber (CLT) is a multi-layered structure with layers being formed from several lamellae. The layup is usually symmetrical and has an uneven number of layers ( ≥ 3). The direction of the fibres of neighbouring layers is commonly altered by 90 ◦ , allowing the assembly of panel structures

∗ Corresponding author: Vittoria Borghese E-mail address: vittoria.borghese@tno.nl

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of XX ANIDIS Conference organizers 10.1016/j.prostr.2025.12.157