Implications of Measured Near-Field Ground Motion for Structural Response

测量的近场地面运动对结构响应的影响

• 批准号: 9416174
• 负责人: Wilfred Iwan
• 金额: $ 3.5万
• 依托单位: California Institute of Technology
• 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 1996-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9416174&HistoricalAwards=false
• 关键词: Implications; Measured; Near; Field; Ground

9416174 Iwan The objective of this project is to determine the nature and importance of potentially serious structural response problems associated with near-field earthquake ground motions such as those observed during the Northridge earthquake. Measured near- field ground motions from the Northridge earthquake indicate very high velocities and pulse-like ground displacements. These motions are capable of causing high levels of demand for a wide range of different types of structures including base-isolated buildings and multi-story buildings. The high velocity pulses observed in the near-field of the Northridge earthquake are of great concern for the performance of taller multi-story buildings. The stress waves in the structure that are caused by these high velocities can result in very high story drift that may, in turn, cause failure of structural elements. Preliminary indications are that story drifts induced by near-field velocity pulses during the Northridge earthquake may have significantly exceeded the code allowable values. In light of the poor performance of a number of steel moment resisting frame buildings in the earthquake, this is an issue that demands urgent resolution. In this project, simple linear shear-beam model is employed to determine the magnitude of the problem and to identify the factors that are most important in developing solutions to the problem. The results of this investigation will provide insights in to whether changes are needed in the seismic design of multi-story structures to account for the near-field effects. If changes are needed, they need to be identified as quickly as possible before more serious consequences occur. ***

9416174 Iwan 该项目的目标是确定与近场地震地面运动（例如在北岭地震期间观察到的地面运动）相关的潜在严重结构响应问题的性质和重要性。 北岭地震测量的近场地面运动表明速度非常高，地面位移呈脉冲状。 这些运动能够引起对各种不同类型结构的高需求，包括基础隔离建筑和多层建筑。 在北岭地震近场观察到的高速脉冲对于高层建筑的性能非常重要。 由这些高速引起的结构中的应力波可能导致非常高的楼层漂移，进而可能导致结构元件的失效。 初步迹象表明，北岭地震期间近场速度脉冲引起的层位漂移可能已大大超出规范允许值。 鉴于不少钢结构抗震框架建筑在地震中性能较差，这是一个亟待解决的问题。 在该项目中，采用简单的线性剪切梁模型来确定问题的严重程度，并确定在制定问题解决方案时最重要的因素。 这项调查的结果将有助于了解是否需要改变多层结构的抗震设计以考虑近场效应。 如果需要改变，需要在更严重的后果发生之前尽快确定。 ***