Performance-based design of multi-story timber-steel hybrid structures under extreme hazards

木钢混合结构是可持续的多层建筑的一种新的解决方案。钢框架与工程木板和墙板的组合导致了整体建筑重量的减轻，同时允许减少与建筑相关的排放。这种创新的结构系统展示了尖端的工程壮举，但也容易受到来自自然和人为危害的日益增加的威胁。缺乏对这一新系统抵御极端事件的结构性能的全面了解，对生命安全和重大经济损失构成危险。尽管有研究兴趣，但由于这些知识差距而在行业中普遍存在的沉默阻碍了混合木结构系统在北美的采用。最近的研究对木钢混合结构的地震反应进行了研究。然而，对于可靠的工业应用，还没有系统的框架可用。此外，关于火灾下全球结构行为的信息也不多。需要进行深入的研究，特别是在研究层叠的多种危险情况下的结构行为时，例如地震后的火灾。对于基于代码的指导方针仍处于萌芽状态的结构，基于性能的设计方法是一个有吸引力的替代方案。这需要评估结构在现实危险情况下的反应，以及对整体结构性能的风险进行彻底量化。拟议的研究计划将寻求为地震、火灾和多种危险情况下的多层木-钢混合结构建立一个稳健的基于性能的设计和评估框架。通常，木结构的地震风险被量化为：风险=危险×暴露×易损性。系统的风险评估包含了与该模型的每个组成部分相关的不确定性。这项研究计划将遵循类似的方法来描述木材-钢结构混合结构的真实地震、火灾和级联危险。将对场地和占用情况的具体危险强度措施进行描述。将进行详细的分析和实验分析，以校准在表征的危险下的结构行为。将为每个装载场景建立损害评估指标。此外，这项研究将在响应和恢复时间以及此类建设的维修成本方面表征系统级的弹性。高素质人才的培训将是研究计划的首要重点。对研究界和加拿大来说，将有两方面的好处：第一，更好地了解混合木钢结构的整体性能将有助于改进设计实践，确保更好的生命安全；第二，新知识将提高加拿大在混合木结构方面的地位，导致林业部门的潜在增长和随之而来的经济效益。

Timber-steel hybrid structures are a novel solution towards sustainable multi-story construction. The combination of steel framing with engineered wood slabs and wall panels leads to overall building weight reduction, while allowing for a decrease in construction-related emissions. This innovative structural system presents cutting-edge feats of engineering, but is also susceptible to increasing threats from natural and man-made hazards. Lack of comprehensive knowledge regarding structural performance of this new system against extreme events poses a danger to life safety and substantial economic loss. Despite research interest, reticence prevalent in the industry due to these knowledge gaps has impeded the adoption of hybrid timber structural systems in North America. Recent studies have investigated seismic response of timber-steel hybrid structures. However, no systematic framework is available for reliable industrial applications. Additionally, not much information is available regarding global structural behavior under fire. In-depth research is needed, particularly for investigating structural behavior under cascading multi-hazard scenarios, such as fire following an earthquake. For structures where code-based guidelines are still nascent, performance-based design methodologies are an attractive alternative. This requires the evaluation of structural response under realistic hazards, coupled with a thorough quantification of risks for overall structural performance. The proposed research program will seek to establish a robust performance-based design and assessment framework for multi-story timber-steel hybrid structures under earthquake, fire, and multi-hazard scenarios. Typically, seismic risk for wooden structures has been quantified as: risk = hazard x exposure x vulnerability. Systematic risk assessment incorporates uncertainties associated with each of the components of this model. This research program will follow a similar approach to characterize realistic earthquake, fire and cascading hazards for hybrid timber-steel structures. Site- and occupancy- specific hazard intensity measures will be characterized. Detailed analytical and experimental analyses will be conducted to calibrate structural behavior under the characterized hazards. Damage assessment metrics will be established for each loading scenario. Additionally, this research will characterize system-level resilience in the shape of response and recovery times and repair costs for such construction. Training of highly qualified personnel will be a prime focus of the research program. Benefits to the research community and Canada will be two-fold: first, better understanding of overall performance of hybrid timber-steel structures will help improve design practice ensuring better life safety; and secondly, the new knowledge will advance Canada's standing in terms of hybrid wood construction, leading to potential growth of the forestry sector and ensuing economic benefits.