Feasibility of Seismic Retrofit Using an Energy Dissipating Cladding System

在第四地震区，有许多老旧的既有建筑不符合1991年《统一建筑规范》的侧向强度、漂移控制和延性细节要求。一项使用假想建筑的初步研究表明，通过一种非侵入性的改造方案可以提供额外的强度、刚度和能量耗散，包括用结构(钢)板替换现有的覆层和耗能的覆层与框架的连接。为详细研究这项翻新计划，我们会研究两幢较旧的现有楼宇。首先将进行初步设计，其中包括：(1)关于现有框架和覆层系统对翻新建筑系统的相对结构贡献的设计决定；(2)对于覆层系统，设计了实用的覆层-框架连接及其附件，并制定了覆层面板的设计程序。这种抗震加固方案的可行性将通过对改造后的周长框架施加一组具有峰值地面加速度、主要频率和持续时间范围的地震动来进行分析评估。这项研究将从两个方面推进结构被动控制的最新进展：(1)通过确定覆层和覆层-框架连接的结构特征在哪些条件下可以有效和高效，以及(2)为为现有薄弱建筑或新设计建筑的消能覆层系统设计制定合理的指导方针提供基础。

In Seismic Zone 4, there are many older, existing buildings that do not meet the lateral strength, drift control, and ductile detailing requirements of the 1991 Uniform Building Code. A preliminary study using hypothetical buildings indicates the additional strength, stiffness, and energy dissipation can be provided by a non-invasive retrofit scheme involving the replacement of the existing cladding with structural (steel) panels and energy dissipating cladding-to-frame connections. To examine this retrofit scheme in detail, two older, existing buildings will be studied. A preliminary design will be done first, which includes: (1) design decisions regarding the relative structural contributions of the existing frames and the cladding system to the retrofit building system; and (2) for the cladding system, design of practical cladding-to-frame connections and their attachments, and development of a design procedure for the cladding panels. The feasibility of this seismic retrofit scheme will be assessed analytically by subjecting the retrofit perimeter frames to a set of ground motions with ranges of peak ground accelerations, predominant frequencies, and durations. The research will advance the state-of-the-art in passive control of structures in two ways: (1) by identifying conditions under which the structural characteristics of cladding and cladding-to-frame connections can be effective and efficient, and (2) by providing a foundation for the development of rational guidelines for the designs of energy dissipating cladding systems for either existing weak buildings or newly designed buildings.