An increased environmental conscientiousness in society and the abundance of timber in Canada has inevitably led to the desire for more timber construction. In order to increase the opportunity for timber products in construction, novel building systems such as post-tensioned (PT) timber have been developed. Limited development on numerical modelling has been done on PT timber systems for the optimization of design for fire performance. In industry, there is need for a modelling software capable of approximating complex timber system behaviours that is accessible to practitioners. This research program serves to evaluate the current capabilities or shortcomings of modelling PT timber in both ambient and fire conditions, and to develop a methodology for analyzing the performance of the system. Several numerical models of PT timber beam tests are developed and validated using general purpose FEM software ABAQUS. This software is a good research tool and the lessons learned may be used to refine an accessible model for practitioners. Various material definitions are compared including isotropic and orthotropic models. The numerical models show highly promising results for demonstrating the loading and failure behaviour of PT timber beams. Material property directionality is paramount, captured best with the use of Hill’s Potential Function for non-elastic behaviour. Ambient beam tests are modelled with accurately demonstrated load–deflection behaviour and peak loads are computed to within 5% of experimentally recorded values. For PT timber beam standard fire furnace tests, beam failure times are modelled within 3 min of experimental beam failure times for various fire exposure durations (about 5%), and load–deflection behaviour and failure mechanisms are accurately demonstrated. Thermal gradients align with the recorded thermocouple readings and char depths are computed within 4 mm of the observed layers.

中文翻译：

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环境和火灾条件下后张木梁的有限元建模

社会环境意识的增强和加拿大木材的丰富不可避免地导致了对更多木材建筑的渴望。为了增加木材产品在建筑中的机会，已经开发了新型建筑系统，例如后张 (PT) 木材。在 PT 木材系统上对用于优化防火性能设计的数值建模进行了有限的开发。在工业中，需要一种建模软件，能够模拟从业者可以访问的复杂木材系统行为。该研究计划用于评估在环境和火灾条件下模拟 PT 木材的当前能力或缺点，并开发一种分析系统性能的方法。使用通用 FEM 软件 ABAQUS 开发和验证了 PT 木梁测试的几个数值模型。该软件是一个很好的研究工具，所获得的经验教训可用于为从业者改进可访问的模型。比较了各种材料定义，包括各向同性和正交各向异性模型。数值模型显示出非常有希望的结果，可以证明 PT 木梁的加载和破坏行为。材料属性方向性是最重要的，最好使用希尔势函数来处理非弹性行为。环境梁测试通过精确演示的载荷-挠度行为建模，峰值载荷计算为实验记录值的 5% 以内。对于 PT 木梁标准火炉测试，对于各种火灾暴露持续时间（约 5%），梁失效时间在实验梁失效时间的 3 分钟内建模，并准确地证明了载荷挠度行为和失效机制。热梯度与记录的热电偶读数一致，焦炭深度在观察层的 4 毫米内计算。