Performance of mid-ply wood shear walls with openings

在易受强烈地震或强风影响的地区对强大的横向荷载抵抗体系的需求日益增长的推动下，中层剪力墙于20世纪90年代在加拿大首次发展起来。试验表明，中层剪力墙的横向能力大约是传统木质剪力墙的两到三倍。2014年，加拿大木材设计标准CSA O86首次实施了层间剪力墙体系的设计规定。随着业主越来越青睐开放空间的概念和大玻璃幕墙，几乎没有结构剪力墙和大开口，坚固的中层剪力墙近年来进一步吸引了设计师的注意。这是一种全球趋势，正在发生在北美以及进口加拿大木制品用于建筑的海外国家。近年来，木结构建筑的允许高度从低层(最多4层)增加到中层(6层)，这使得人们对这种坚固的木质剪力墙越来越感兴趣，以解决较高的设计荷载，特别是在中层建筑的较低层。在这种情况下，最近提出了一个关键问题，即开孔对中层墙的刚度和强度性能的影响，这是门窗经常需要的。该项目旨在解决这一问题。具体目标是围绕中层墙中的洞口开发框架细节，以将洞口对组件的强度和刚度的影响降至最低，并评估洞口的相对大小和位置对中层墙的强度和刚度的影响。这项研究将产生设计指南，以解决带开口的中层墙以及围绕开口的建筑细节，使带开口的中层墙段保持可接受的刚度和强度水平。拟议研究的成功将有助于在国内和海外市场增加加拿大木材和人造板的使用。

Driven by the growing demand on strong lateral load resisting systems in regions susceptible to severe earthquakes or strong winds, the mid-ply shear wall was first developed in the 1990s in Canada. Testing has shown that mid-ply walls possess approximately two to three times the lateral capacity of conventional wood shear walls. Design provision for mid-ply shear wall systems was implemented first time in Canadian timber design standard CSA O86 in 2014. As home owners increasingly favour an open space concept and large glass façades with few structural shear walls and large openings, the strong mid-ply shear wall has further attracted the attention of designers in recent years. This is a global trend that is happening in North America as well as overseas countries that import Canadian wood products for construction. The increase of allowable building height for wood construction from low-rise (upto 4 storesy) to mid-rise (6-storey) in recent years has led to increased interest in this strong wood shear wall to address the higher design loads, especially in the lower storey of mid-rise buildings. In this context, a key question has been raised recently regarding the effects of openings, which are often required for windows and doors, on stiffness and strength properties of mid-ply walls. This project is intended to address this issue. The specific objectives are to develop framing details around an opening in mid-ply walls to minimize the impact of the opening on the strength and stiffness of the assembly and to evaluate the influence of relative size and location of an opening on the strength and stiffness of a mid-ply wall. This research will lead to design guidelines to address mid-ply walls with openings as well as construction detailing around openings that would allow segments of mid-ply walls with openings to retain an acceptable level of stiffness and strength. The success of the proposed research will help to increase the use of Canadian lumber and wood-based panels domestically as well as in overseas markets.