Development and characterization of efficient connections for multi-storey timber buildings

在过去的几年里，木材工业和加拿大政府以及其他森林资源丰富的国家都在推动多层木材建筑。这一趋势是合理的，原因是生态原因(减少了环境足迹、可持续性)、建筑吸引力(美学、健康、舒适性)以及适合建造中高层建筑的新工程木制品的开发，例如大量木质板材。由于其重量轻，木结构在用于抵抗地震力时可以发挥优势。然而，要使多层木结构成为主流，应开发高效和经济高效的结构体系，并将具体指导纳入设计规范。 木结构体系的结构性能主要取决于节点抵抗水平荷载(风和地震)的性能特征，而这一点在设计规范中没有得到很好的研究，也没有得到充分的考虑。在多层建筑中，有效的结构连接应该提供足够的刚度来抵御大风，并提供足够的弹性来抵御严重的地震，同时将结构的破坏降到最低。然而，目前还没有一个统一的方法来评估连接性能，设计阻力值也不是基于可靠性原则。新型工程木制品，如交错层合板(CLT)的连接设计指南还很初级，不能满足设计者的需求。这些缺点降低了设计解决方案的效率，减缓了设计进程，并阻碍了多层建筑使用木材。 拟议研究计划的主要目标是开发有效的连接和表征它们的方法，以满足多层木结构的需要。重点研究了大型木结构建筑的抗侧向荷载体系的连接，提出了可靠性原则和低损伤抗震设计思想。节点的性能特性将通过试验进行评估，以模拟其滞回性能，然后将其整合到整个结构的设计模型中，并通过实验室试验进行验证。 这项研究计划将有助于多层建筑木结构设计原则的发展，使设计者能够以较低的成本选择最有效和最可靠的解决方案。这些结果在设计规范中的实施将增加加拿大中高层建筑的竞争力和木材的使用。反过来，这将有利于加拿大木材行业，从而促进可持续未来的发展，从而有利于加拿大经济和社会。

During the last few years, multi-storey timber construction has been promoted by the wood industry and by the governments in Canada and in other countries with abundant forest resources. This trend has been justified for the ecological reasons (reduced environmental footprint, sustainability), architectural attractiveness (aesthetics, health, comfort) and development of new engineered wood products, such as mass timber panels, suitable for construction of mid-rise and tall buildings. Because of their light weight, timber structures may take advantage when used to resist seismic forces. However, to turn the multi-storey timber construction into the main stream, efficient and cost effective structural systems should be developed and specific guidance included into the design codes. The structural performance of timber systems primarily depends on the performance characteristics of the connections resisting lateral loads (wind and seismic), which are not well studied and are not sufficiently covered in the design codes. The efficient structural connections in multi-storey buildings should provide enough stiffness to resist high winds and enough resiliency to resist severe earthquakes with the minimum damage of the structure. However, there is not a unified approach to the evaluation of the connection properties, and the design resistance values are not based on reliability principles. The design guidance for the connections of new engineered wood products, such as cross-laminated timber (CLT), is rudimentary and is not satisfying the needs of the designers. These drawbacks reduce the efficiency of the design solutions, slow down the design process and discourage the use of wood in multi-storey buildings. The main goal of the proposed research program is to develop efficient connections and methods of their characterization meeting the needs of multi-storey timber construction. Particular attention will be given to the connections for the lateral load resisting systems in mass timber buildings advancing the reliability principles and the low damage seismic design philosophy. The performance characteristics of the connections will be evaluated experimentally to model their hysteretic behaviour, which then will be integrated into the design models of the whole structures and validated via laboratory tests. This research program will contribute to the development of the design principles of timber structures for multi-storey buildings enabling the designers to choose the most effective and reliable solutions at a lower cost. Implementation of these results in the design codes will increase the competitiveness and the use of timber in the mid-rise and tall building construction in Canada. In turn, this will benefit the Canadian wood industry and, therefore, the Canadian economy and society by contributing to the development of the sustainable future.