Performance and Safety of Current Versus Bi-Level Design Procedures-Impact of Northridge Earthquake

9415726文氏大厦在我国的设计程序一直以在给定重现期的设计地震作用下的生命安全为目标。 它基本上是一个单层设计。 从最近的地震，特别是北岭地震中吸取的一个宝贵教训是，破坏和经济损失可能与生命安全一样重要。 在日本和新西兰等其他高地震活动性国家，已采用了一级以上地震的设计，其中明确考虑了正常使用和极限状态。 从北岭地震和南加州最近发生的其他地震中收集的大量数据为我们提供了机会，以批判性地看待当前手术与替代双水平手术的安全性和性能。 本研究的主要目的是：（1）对现行和替代设计方法下的建筑物进行性能和安全性评价和比较。 (2)评估上述设计程序的长期风险影响，并制定上述设计程序的策略含义，以及制定制定更合理、风险一致的代码程序的策略。 为了实现上述目标，以下任务是必要的：（i）分析北岭数据更新，地震风险和网站特定的地面运动模型，用于目前的可靠性评估的结构性能，其中依赖于地震源，路径和网站的特点被认为是。 (ii)根据1991 UBC和洛杉矶地区选定地点的替代双层程序设计低层（12层以下）钢和钢筋混凝土建筑。 (iii)进行建筑物的动力反应分析，并比较两种设计的反应行为和反应统计。 (iv)使用更新的地震风险和地面运动模型，根据两个程序对设计进行长期风险分析，并比较风险影响。 (v)确定替代设计程序与当前设计程序的优缺点，并提出未来规范中需要改进的地方。 该研究将为这一重要问题提供深入的见解，这一问题在美国和国外的研究和实践中具有深远的意义。 这是北岭地震项目。

9415726 Wen Building design procedures in this country have been aiming at life safety under a design earthquake of a given return period. It is basically a single-level design. A valuable lesson learned from recent earthquakes, in particular the Northridge earthquake, is that damage and economical loss may be just as an important issue as life safety. Design for more than one level of earthquake has been used in other countries of high seismicity such as Japan and New Zealand in which serviceability and ultimate limit states are explicitly considered. The extensive data collected from the Northridge and other recent earthquakes in Southern California provide and opportunity for us to take a critical look at the safety and performance of the current procedures versus alternative bi-level procedures. The research projects is under taken here with the following specific objectives: (1) To evaluate and compare the performance and safety of buildings designed in accordance with the current and alternative procedures. (2) To evaluate the long- term risk implications of the above design procedures and develop strategy implication of the above design procedures and develop strategy for formulating more rational, risk-consistent code procedures. To achieve the above objectives the following tasks are necessary; (i) Analysis of Northridge data to update, the seismic risk and the site specific ground motion models used in current reliability evaluation of structural performance in which dependence on seismic source, path, and site characteristics is considered. (ii) Design of low-rise (under 12 stories) steel and reinforce concrete buildings according to the 1991 UBC and alternative bi-level procedures at selected sites in the Los Angeles area. (iii) Perform dynamic response analyses of the building and compare response behaviors and response statistics of these two designs. (iv) Perform long-term risk analysis of designs according to the two procedures us ing the updated seismic risk and ground motion models and compare risk implications. (v) Identify advantages and shortcomings of alternative versus current design procedures and suggest areas for improvement in future codes. The research conducted will provide insight to this important problem which has a profound implication in research as well as practice in US and abroad. This is a Northridge Earthquake Project.