Evaluation of Moisture and Decay Models for a New Design Framework for Decay Prediction of Wood

Abstract

Performance-based, service-life design of wood has been the focus of much research in recent decades. Previous works have been synthesized in various factorized design frameworks presented in the form of technical reports. Factorization does not consider the non-linear dependency between decay-influencing effects, such as between detail design and climate variables. The CLICKdesign project is a joint European effort targeting digital, performance-based specification for service-life design (SLD) of wood. This study evaluates the feasibility of using a semi-empirical moisture model (SMM) as a basis for a digital SLD framework. The performance of the SMM is assessed by comparison against a finite element model (FEM). In addition, two different wood decay models (a logistic, LM, and simplified logistic model (SLM)) are compared. While discrepancies between the SMM and FEM were detected particularly at high wood moisture content, the overall performance of the SMM was deemed sufficient for the application. The main source of uncertainty instead stems from the choice of wood decay model. Based on the results, a new method based on pre-calculated time series, empirical equations, and interpolation is proposed for predicting the service life of wood. The method is fast and simple yet able to deal with non-linear effects between weather variables and the design of details. As such, it can easily be implemented as part of a digital design guideline to provide decision support for architects and engineers, with less uncertainty than existing factorized guidelines.

Mapping the biotic degradation hazard of wood in Europe – biophysical background, engineering applications, and climate change-induced prospects

“…Later on, Carll (2009) added data for Hawaii, where the SCI was > 300. Numerous authors used the SCI for decay hazard mapping of various countries and regions such as Canada (Setliff 1986), North America (Morris et al 2008), Korea (Kim et al 2011;Kim and Ra 2014), Iran (Helali et al 2021), China (Wang et al 2007), Japan (Hasegawa 1996), Australia (Wang et al 2008a), Switzerland (Brischke and Selter 2020), Norway (Lisø et al 2006;Tajet and Hygen 2017), United Kingdom (Curling and Ormondroyd 2018), Spain (Fernandez-Golfin et al 2016), Greece (Nikolitsa and Giarma 2019), Northern Europe (Niklewski et al 2016b), Slovenia (Humar et al 2021) and Europe (Brischke et al 2011;.…”

Anisotropic Tensile Characterisation of Eucalyptus nitens Timber above Its Fibre Saturation Point, and Its Application

“…Previous studies have found that timber members can reach an average MC above 70% after exposure outdoors for 2 months [15]. Moisture contents of 30-70% are associated with decay, which causes degradation and a reduction in the durability of timber structures [16,17]. This reduction in the mechanical properties of wood results from the change in wood cellulose polymers, where hydrogen bonding between the cellulose polymers is reduced because of the bound water in the cell wall [18,19].…”

Modelling temperature‐precipitation pressures on African timber heritage

“…The simplicity of the index explains its wide use, although modifications have been proposed, which for example include the addition of a term to account for high levels of condensation or dew during the morning (Fernandez-Golfin et al, 2016). More elaborate models are available that focus on moisture content, but challenges remain in using them to predict the service life of timber (Niklewski et al, 2021).…”