Design of gravity force-resisting systems accounting for seismic displacement demands

建筑物中的结构系统必须设计成抵抗来自重力的垂直载荷以及由风或地震作用施加的横向载荷。在结构设计中，结构框架通常由两个独立的系统组成：重力抵抗系统和侧向力抵抗系统。虽然抗震规范传统上集中在抗侧向力系统的设计要求上，但由于地震事件引起的地面震动将导致整个结构变形，即，它将在重力和抗侧向力系统中施加变形要求。在这方面，加拿大最新版的混凝土设计标准承认，重力框架的破坏是地震时建筑物倒塌的最常见原因之一。因此，该规范引入了一项新的要求，旨在确保不属于抗震系统的元件具有足够的强度和延性，但会受到地震引起的变形。传统的结构设计依赖于等效线弹性分析模型来复制建筑物中预期的非线性响应。然而，加拿大混凝土设计标准的这一新要求并没有解决如何准确地开发这种用于重力式框架抗震设计的等效线弹性分析模型。为了应对这一挑战，Glotman Simpson正与不列颠哥伦比亚省大学合作开发一种程序，该程序提供一致和可信的结果，以促进根据最新规范要求对重力式框架进行这些新的设计检查。这项工作将有助于继续提供安全和经济的设计。

The structural system in a building must be designed to resist both vertical loads from gravity, as well as lateral loads imposed by wind or seismic action. It is common in structural design for the structural frame to consist of two separate systems: a gravity force-resisting system and a lateral force-resisting system. While seismic codes have traditionally focused on the design requirements of lateral force-resisting systems, ground shaking due a seismic event will cause the entire structure to deform, i.e. it will impose deformation demands both in the gravity and the lateral force-resisting systems. In this regard, the latest edition of the concrete design standard in Canada recognizes that failure of gravity frames is one of the most common causes of building collapse during an earthquake. Thus, the code introduced a new requirements intended to ensure adequate levels of strength and ductility in elements that are not part of the seismic force-resisting system, but are subjected to seismically induced deformations. Conventional structural design relies on equivalent linear elastic analysis models to replicate anticipated nonlinear response in buildings. However, this new requirement of the concrete design standard in Canada does not address how to accurately develop this equivalent linear elastic analysis model for the seismic design of gravity frames. To address this challenge, Glotman Simpson is partnering with the University of British Columbia to develop a procedure that provides consistent and trustworthy results to facilitate these new design checks of gravity frames per the latest code requirements. This work will facilitate the continued delivery of safe and economical designs.