Modelling the Material Resistance of Wood—Part 3: Relative Resistance in above- and in-Ground Situations—Results of a Global Survey

et al. 2021

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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.

Section: In-ground Contactmentioning

confidence: 99%

“…The exposure dose can then be described as a function of wood temperature, which may be determined by modelling the soil temperature. Using the same assumption, the material-inherent resistance dose is determined independent of moisture dynamics and focused on soil-contact decay tests either under laboratory or field conditions [36].…”

Section: In-ground Contactmentioning

confidence: 99%

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

Niklewski

Niekerk

et al. 2021

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“…In this study, the aims were to: 1. compare the material resistance and moisture performance of the three European reference wood species (Norway spruce, European beech and Scots pine sapwood) with conversion factors as the primary output (this paper), 2. collecting data from durability tests for validating and optimizing the 'Meyer-Veltrup model' for material-resistance [7] and Part 2 of this publication [19], and 3. surveying wood durability test data, utilize them for implementation in a material resistance model, and generate a database for service life prediction of wood products in above and in-ground situations, Part 3 of this publication [20].…”

Section: Introductionmentioning

confidence: 99%

Modelling the Material Resistance of Wood—Part 1: Utilizing Durability Test Data Based on Different Reference Wood Species

Alfredsen

Marais

et al. 2021

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To evaluate the performance of new wood-based products, reference wood species with known performances are included in laboratory and field trials. However, different wood species vary in their durability performance, and there will also be a within-species variation. The primary aim of this paper was to compare the material resistance against decay fungi and moisture performance of three European reference wood species, i.e., Scots pine sapwood (Pinus sylvestris), Norway spruce (Picea abies), and European beech (Fagus sylvatica). Wood material was collected from 43 locations all over Europe and exposed to brown rot (Rhodonia placenta), white rot (Trametes versicolor) or soft rot fungi. In addition, five different moisture performance characteristics were analyzed. The main results were the two factors accounting for the wetting ability (kwa) and the inherent protective properties of wood (kinh), factors for conversion between Norway spruce vs. Scots pine sapwood or European beech for the three decay types and four moisture tests, and material resistance dose (DRd) per wood species. The data illustrate that the differences between the three European reference wood species were minor, both with regard to decay and moisture performance. The results also highlight the importance of defined boundaries for density and annual ring width when comparing materials within and between experiments. It was concluded that with the factors obtained, existing, and future test data, where only one or two of the mentioned reference species were used, can be transferred to models and prediction tools that use another of the reference species.

“…They represent a wide range of aspects related to performance modeling of wood and wood products and give timely examples of research activities that can be observed around the globe. Several authors reported on engineering approaches to predict and plan the service lives of buildings and structures made of wood [1][2][3], models focusing on material properties such as material resistance against decay agents [3][4][5][6][7], basic wood properties and their distribution in trees [8], and new methods of monitoring performance-related parameters [9]. The link between exposureinduced dosage and material-inherent resistance were established for a variety of use conditions, such as soil contact and different above-ground scenarios [2][3][4][5]7,10,11].…”

mentioning

confidence: 99%

“…Several authors reported on engineering approaches to predict and plan the service lives of buildings and structures made of wood [1][2][3], models focusing on material properties such as material resistance against decay agents [3][4][5][6][7], basic wood properties and their distribution in trees [8], and new methods of monitoring performance-related parameters [9]. The link between exposureinduced dosage and material-inherent resistance were established for a variety of use conditions, such as soil contact and different above-ground scenarios [2][3][4][5]7,10,11]. Finally, even a model describing the performance of media presenting wood-based products is presented [12].…”

mentioning

confidence: 99%

Modeling the Performance of Wood and Wood Products

2021

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