Multihazard Performance and Design of Ecoroofs

生态屋顶的多灾种性能和设计

• 批准号: 1162616
• 负责人: Christopher Higgins
• 金额: $ 33.5万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1162616&HistoricalAwards=false
• 关键词: Multihazard; Performance; Design; Ecoroofs

The proliferation of "green roofs" or more generally, ecoroofs in the United States has increased dramatically in the last ten years and has radically expanded the historical function of a roof. Ecoroofs offer new opportunities to provide environmental, economical, and social benefits. However, ecoroofs carry higher gravity loads and must support long-duration transient fluid loading compared to traditional systems. This shift in roof design demands has outpaced building codes and regulations, and more importantly exceeded our fundamental understanding of roof structural behaviors under these nontraditional loads. Regrettably, conventionally engineered roofs account for a disproportionately large number of structural failures with over $1 billion in damages since 1990 for a single insurer. Proper design of ecoroofs to ensure structural safety and serviceability of these relatively "sensitive" structural components requires research to address these three critical questions: 1.Under earthquake induced roof shaking, does the ecoroof planting material mobilize? To what degree is the ecoroof planting material coupled to the structure? Can roof dead load imbalances be expected after an earthquake?2.During rain events, what are the load effects produced on ecoroofs and over what time-scales? How loads are distributed in ecoroofs and will traditional design approaches ensure ponding stability and prevent overloading? 3.What are the engineering properties of typical ecoroof planting materials? Which properties are most critical to achieving ecoroof performance during seismic and rain events?This project is the first to examine the structural, geotechnical, and planting interactions on ecoroof seismic performance. The research focuses on system response to demonstrate the important interactions of the design elements. An ecoroof structural simulator will be developed to test full-scale laboratory ecoroof prototypes and will be integrated with field survey and component laboratory data to produce new knowledge on fluid-structure interaction at the roof including: planting material mobility during lateral shaking, water retention and drainage characteristics, and long-term service performance. These will provide background material for development of a structural guide for ecoroof designs in seismic zones.

在过去的十年里，美国“绿色屋顶”或更普遍的生态屋顶的激增急剧增加，并从根本上扩展了屋顶的历史功能。生态屋为提供环境、经济和社会效益提供了新的机会。然而，与传统系统相比，ecoroofs承受更大的重力载荷，必须支持长时间的瞬态流体载荷。屋顶设计需求的转变已经超越了建筑规范和法规，更重要的是超出了我们对这些非传统荷载下屋顶结构行为的基本理解。令人遗憾的是，传统工程屋顶造成了不成比例的大量结构故障，自1990年以来，一家保险公司造成的损失超过10亿美元。为了确保这些相对“敏感”的结构部件的结构安全性和可使用性，生态屋顶的适当设计需要研究解决以下三个关键问题：1。在地震引起的屋顶震动下，生态屋顶种植材料是否会动员？生态屋面种植材料与结构的耦合程度如何？地震后屋顶恒载是否会出现不平衡？在降雨期间，对生态屋顶产生的荷载效应是什么？在什么时间尺度上？生态屋顶的荷载是如何分布的？传统的设计方法能否确保水池的稳定性并防止超载？3.典型的生态屋顶种植材料的工程特性是什么？在地震和降雨情况下，哪些性能对实现环保屋顶性能最为关键？该项目是第一个研究结构、岩土和种植相互作用对生态屋顶抗震性能的影响的项目。研究的重点是系统响应，以展示设计元素之间的重要交互作用。将开发一个生态屋顶结构模拟器来测试全尺寸的实验室生态屋顶原型，并将与现场调查和组件实验室数据相结合，以产生关于屋顶流体结构相互作用的新知识，包括：横向震动期间种植材料的流动性、水保持和排水特性以及长期服务性能。这些将为地震带生态屋设计结构指南的制定提供背景材料。