Probabilistic design of timber joints

森林业是加拿大经济的关键驱动力，但山松甲虫疫情(导致木材供应过剩)和美国房地产市场低迷(大幅减少木材出口)等逆境正在挑战该行业。因此，需要创新的解决方案，将木材的使用扩大到传统的基于轻型框架的住宅建筑之外。非住宅建筑部门代表着结构材料的巨大市场，但木材相对较少，部分原因是缺乏适当的设计工具。拟议的研究将通过开发木材接头的新设计工具来填补这一空白。节点在木结构设计中起着至关重要的作用。从业者有一系列连接承重元件的方法：机械紧固件、通过直接接触传递载荷和粘接。所有这些方法都会导致产生复杂的多轴应力奇异性的几何形状，而传统的确定性设计不能安全有效地应用于这些奇异性。 这项研究的长期目标是开发可靠、坚固和可实施的工具来设计各种连接，包括两个木材构件之间，以及木材和其他材料之间的连接。这些工具将基于对所应用的所有材料以及所涉及的降解和失效机制的概率力学描述。这项研究建立在我之前开发的木材接缝在静态短期载荷下的概率设计方法，并将其应用到实际设计程序中，并通过与木工和胶接接缝的测试进行直接比较来确定基准。在接下来的五年里，我的团队将为涉及金属紧固件和其他相关加载条件的木材接头开发概率设计工具。最终，研究方案的成功实施将对木材的结构性使用产生决定性影响，并增加其在各种应用中的市场份额。

Forest industries are key drivers of the Canadian economy, but adversities like the Mountain Pine Beetle epidemic (which causes an oversupply of timber) and the downturn of the US housing market (which significantly reduced timber exports) are challenging the sector. As a consequence, innovative solutions are required to expand the use of timber beyond traditional light-frame based residential construction. The non-residential construction sector represents a substantial market for structural materials, yet it is relatively untapped by timber, partly because of a lack of appropriate design tools. The proposed research will fill that gap by developing novel design tools for timber joints. Joints play a crucial role in the design of timber structures. Practitioners have at their disposal a series of methods to connect load bearing elements: mechanical fasteners, load transmission through direct contact, and adhesive bonding. All of these methods result in geometries that generate complex multi-axial stress singularities for which traditional deterministic design cannot be applied in a safe and efficient manner. The long-term goal of the research is to develop reliable, robust and implementable tools to design a wide range of joints, both between two timber members, and also between timber and other materials. The tools will be based on a probabilistic mechanical description of all materials applied and the involved degradation and failure mechanisms. The research builds on a probabilistic design method for timber joints under static short term loading that I have developed previously, implemented into a practical design routine, and benchmarked by a direct comparison with tests on carpentry and adhesively bonded joints. Within the next five years, my team will develop probabilistic design tools for timber joints involving metal fasteners and for other relevant loading conditions. Ultimately, the successful implementation of the research programme will have a decisive impact on the structural use of timber, and increase its market share in a variety of applications.