This study validated a 2D dynamic anisotropic hygrothermal simulation model for Cross-Laminated Timber (CLT), focusing on vertical water uptake and moisture dry-out processes. The simulations, compared against experimental data, showed a root mean square deviation of ≤3.3 across all locations. Variations in material properties necessitated the use of multiple material definitions. Moisture storage and liquid conductivity function had a significant impact on the results. A new two-step moisture content (MC) performance criterion was developed: MC ≤ 16 % at 30 mm and MC ≤ 25 % at 10 mm from the end grain to prevent mould growth. Sensitivity analysis suggested that validating MC30 mm is reasonable when MC10 mm exceeds 19 %. The criterion was applied to analyse moisture management strategies for CLT end-grain moisture safety. Simulations with 30-year climate data indicated a slight decrease in successful outcomes in recent years. Strategic installation timing, particularly favouring the spring season due to its relatively drier conditions in Estonia, was found to be highly beneficial. CLT end-grain protection or full-coverage weather protection is recommended to ensure a high level of moisture safety, and long construction periods should be avoided even with full-coverage protection. Including moisture dry-out periods before covering CLT is advised. However, unassisted dry-out is feasible only during spring (up to four weeks). Additional equipment is necessary for timely moisture dry-out during other seasons, including summer, due to higher precipitation loads. The use of anisotropic 2D hygrothermal simulations proved to be practical in enhancing CLT resilience to moisture-induced damage.

中文翻译：

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加强 CLT 结构 – 湿热建模、新性能标准和端纹水分安全策略


本研究验证了正交胶合木 （CLT） 的 2D 动态各向异性湿热模拟模型，该模型侧重于垂直吸水和水分干燥过程。与实验数据相比，模拟结果显示所有位置的均方根偏差为 ≤3.3。材料属性的变化需要使用多个材料定义。水分储存和液体电导函数对结果有显著影响。开发了一个新的两级含水率 （MC） 性能标准：MC 在距端纹 30 毫米处≤ 16%，MC ≤ 25 %（在距端纹 10 毫米处），以防止霉菌生长。敏感性分析表明，当 MC10 mm 超过 19 % 时，验证 MC30 mm 是合理的。该标准用于分析 CLT 端粒水分安全的水分管理策略。使用 30 年气候数据的模拟表明，近年来成功结果略有下降。研究发现，战略性的安装时间，特别是由于爱沙尼亚相对干燥的条件而有利于春季，非常有益。建议使用 CLT 端纹保护或全覆盖天气保护，以确保高水平的湿气安全，即使有全覆盖保护，也应避免长时间施工。建议在覆盖 CLT 之前包括水分干燥期。然而，只有在春季（最多四个星期）才能进行无辅助干燥。由于降水负荷较高，在其他季节（包括夏季）需要额外的设备来及时干燥水分。事实证明，使用各向异性 2D 湿热模拟在增强 CLT 对湿气引起的损伤的弹性方面是实用的。