Influence of Diaphragm Behavior on Performance of Precast Parking Garages During Northridge Earthquake

北岭地震期间隔膜行为对预制停车库性能的影响

• 批准号: 9416274
• 负责人: Richard Sause
• 金额: $ 5.21万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-15 至 1996-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9416274&HistoricalAwards=false
• 关键词: Influence; Diaphragm; Behavior; Performance; Precast

9416274 Sause Many precast parking garages were heavily damaged in the Northridge earthquake. The gravity load system of many of these structures consisted of double tee floor units supported by inverted tee girders, spandrel girders, and columns with corbels. The lateral load system consisted of a few shearwalls with diaphragms formed by the double tees with reinforced topping slabs. These two systems are usually designed as separate systems. If the diaphragm develops cracks as a result of large in-plane forces and bending moments, significant diaphragm deformation may result and the rigid diaphragm assumption may be inadequate. Yielding of diaphragm reinforcing steel would result in much large diaphragm deformation. The objectives of this project are to: (1) study the influence of diaphragm behavior on the levels of drift experienced by the gravity load systems of precast parking structures during the Northridge earthquake, (2) evaluate whether diaphragm failure contributed to the observed damage in precast parking structures, and (3) propose capacity design concepts for precast diaphragms, if appropriate. A prototype parking structure based on the damaged parking structures will be designed and detailed. The seismic force- deformation behavior of a typical diaphragm of the prototype structure will be studied analytically, using a linear model, and two nonlinear models of different levels of detail and complexity. Unidirectional and bidirectional seismic loads will be considered. The seismic force- deformation behavior of a typical shearwall will also be studied analytically. The results of this analysis will be used to assess the significance of the diaphragm deformation. If appropriate, capacity-based design concepts for diaphragms will be developed using the results of nonlinear dynamic analysis of the prototype structure. The type of construction of precast parking structures damaged in this earthquake is widely used across the country, a nd thus a substantial hazard may exist. The research undertaken in this project will evaluate the role of diaphragm behavior and new capacity-based design concepts will be proposed to avoid inadequate diaphragm behavior in new precast parking structures. This is a Northridge Earthquake project. ***

9416274 Sause 许多预制停车场在北岭地震中严重受损。 许多此类结构的重力荷载系统由双 T 形地板单元组成，由倒 T 形梁、拱肩梁和牛腿柱支撑。 横向荷载系统由一些带有隔板的剪力墙组成，隔板由带有加固顶板的双 T 形件形成。 这两个系统通常被设计为独立的系统。 如果膜片由于大的面内力和弯矩而产生裂纹，则可能导致显着的膜片变形，并且刚性膜片假设可能不充分。 隔板钢筋的屈服会导致隔板变形过大。 该项目的目标是：(1) 研究北岭地震期间隔膜行为对预制停车结构重力荷载系统所经历的漂移水平的影响，(2) 评估隔膜失效是否导致了在北岭地震中观察到的损坏。预制停车结构，以及 (3) 提出预制隔板的容量设计概念（如果适用）。 将根据受损的停车结构设计并详细设计原型停车结构。 将使用线性模型和不同细节和复杂程度的两个非线性模型对原型结构的典型隔板的地震力变形行为进行分析研究。 将考虑单向和双向地震荷载。 还将对典型剪力墙的地震力变形行为进行分析研究。 该分析的结果将用于评估隔膜变形的重要性。 如果合适，将利用原型结构的非线性动力学分析结果来开发基于容量的隔膜设计概念。 此次地震受损的预制停车结构建筑形式在全国范围内广泛使用，可能存在较大的危险。 该项目进行的研究将评估隔膜行为的作用，并将提出新的基于容量的设计概念，以避免新的预制停车结构中隔膜行为不足。 这是北岭地震项目。 ***