Performance of mid-ply wood shear walls with openings

受强烈地震或强风影响地区对强大的抗侧力系统需求不断增长的推动，中层剪力墙于20世纪90年代在加拿大首次开发。测试表明，中间层墙具有约两到三倍的传统木剪力墙的横向能力。2014年，加拿大木材设计标准CSA O86首次实施了中层剪力墙系统的设计规定。随着业主越来越青睐开放空间概念和大型玻璃幕墙，结构剪力墙和大开口很少，近年来，坚固的中层剪力墙进一步吸引了设计师的注意力。这是一个全球趋势，正在发生在北美以及海外国家进口加拿大木材产品用于建筑。近年来，木结构建筑的允许建筑高度从低层（最多4层）增加到中层（6层），这使得人们对这种坚固的木剪力墙越来越感兴趣，以解决更高的设计荷载，特别是在中层建筑的低层。在这种情况下，最近提出了一个关键问题，即窗和门经常需要的开口对中间层墙的刚度和强度性能的影响。本项目旨在解决这一问题。具体的目标是开发框架细节在中间层墙的开口，以尽量减少开口的强度和刚度的组件的影响，并评估相对大小和位置的开口的强度和刚度的中间层墙的影响。这项研究将导致设计指南，以解决中间层墙开口以及周围的开口，将允许中间层墙开口段保持可接受的刚度和强度水平的施工细节。拟议研究的成功将有助于增加加拿大木材和人造板在国内和海外市场的使用。

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.