| 项目编号: | 1424896
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| 项目名称: | Structural Monitoring of Rock Arches |
| 作者: | Jeffrey Moore
|
| 承担单位: | University of Utah
|
| 批准年: | 2013
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| 开始日期: | 2014-09-01
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| 结束日期: | 2018-08-31
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| 资助金额: | USD359251
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Earth Sciences
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| 英文关键词: | rock arch
; arch
; rock mechanic
; change
; resonant frequency
; response
; ambient vibration monitoring
; goal
; concept
; project
; structural health
; time
; long-term relative change monitoring
; natural rock feature
|
| 英文摘要: | Rock arches are dynamic natural structures that bend, sag, sway and shake in response to a variety of environmental forcings. Visitors to these features are confronted with their fragile nature, however few appreciate the dynamic life of what are often perceived as stoic geological structures. The investigators will monitor the ambient resonance of a number of prominent rock arches, as well as daily and seasonal deformation at select sites. Their goal is to understand how arches respond to changes in their environment (e.g. thermal stresses, rainfall), and ultimately be able to discern subtle changes in internal strength over time. Key to their approach is measuring how arches vibrate. Rock arches are relatively simple mechanical structures with measurable resonant frequencies and mode shapes. This project measures resonant frequencies using broadband seismometers. The researchers then generate 3D models of each arch from the analyzed field measurements and input these into a numerical simulation to predict the resonant mode shapes and frequencies, and calibrate to match field data. This multidisciplinary project combines concepts from the fields of structural dynamics, seismology, rock mechanics, and geomorphology, with the goal of establishing a new method to quantitatively evaluate changes in the dynamics and structural performance of rock arches. The research will lead to new understanding of the life-cycle of natural arches, their response to different external loads, and failure processes leading to their eventual collapse. Our project also provides an excellent opportunity for public engagement and science education. In the long-term, the envisioned outcomes may lead to new methodology for assessment of natural hazards and visitor safety.
Rock arches are spectacular natural landmarks that connect visitors with the dynamics and beauty of earth surface processes. Delicate Arch, for example, is an icon of the western United States and is as recognizable as many national monuments. However, there is currently no methodology in place to evaluate the structural health and integrity of these natural landmarks as they change through time or in the wake of a damaging event such as a strong storm or earthquake. Unlike engineered structures, the internal composition and strength of critical elements in natural rock features cannot be known a priori. The only means available to evaluate structural damage requires understanding the structure's current behavior and response to external loads, and being able to sense relative changes in performance. We propose new methodology to evaluate the dynamic behavior of natural rock arches, estimate fundamental mechanical properties, generate data for short- and long-term relative change monitoring, and ultimately provide a means to distinguish elastic and inelastic behavior and evaluate changing structural health. The project's core technique utilizes ambient vibration monitoring (i.e., measuring the resonant frequencies of an arch under weak background excitation and detecting changes through time that may be either progressive or punctuated in nature). The concept used merges three scientific disciplines: structural dynamics, seismology, and rock mechanics, building on established concepts from the field of structural health monitoring. Changes in behavior will be assessed by measuring the spectral characteristics of ambient vibrations and through time-dependent modal analysis. By sensing how an arch vibrates we can interpret its behavior and response to external loading, and detect reversible or irreversible changes in mechanical parameters. Resonant frequency shifts will be related to deformation and environmental measurements to assess driving forces and sensitivity of the monitored arches to external perturbations. The measurements are non-invasive and non-destructive, and all instruments are selected to be mobile with a small footprint. The goal is to establish a new method to evaluate the long-term structural integrity of natural rock arches, some of which are internationally recognized landmarks. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/95901
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Jeffrey Moore. Structural Monitoring of Rock Arches. 2013-01-01.
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