RAPID: Confirmation of Structural Dynamics Concepts for Urban Structures Subjected to Adjacent Construction Blasting

该项目为推进建筑爆破振动控制提供了补充仪器，目的是降低城市建筑物和设施的建设成本。它利用正在进行的测量建筑物对高频率的反应，爆炸引起的激励在纽约市的一个建筑工地。附加的仪器将用于时间关联激励和响应运动，并测量建筑法规不要求的附加响应。通过这种补充仪器的部署实现的测量将用于测试城市结构不像通常假设的那样受到干扰的假设，因此可以安全地减少振动控制。在人口密集的城市地区，旧的和现代的高层建筑可以共存于同一街区。进行岩石挖掘的项目业主和承包商都面临着严格的振动限制，这些限制针对的是被指定为历史建筑、“地标”或脆弱的、需要修复的旧建筑。对于爆破项目，单个建筑物的存在被认为是“脆弱的”，可能会因振动而导致表面开裂，这严重限制了允许的振动极限，并限制了岩石的清除效率，从而降低了整体生产率，延长了项目的持续时间。所有这些负面的施工后果可能会不必要地增加施工成本。潜在的经济效益是巨大的。仅在纽约市，目前超过170亿美元的交通项目涉及在岩石中开挖和隧道的施工爆破。为了进一步了解城市结构在高频激励下的响应，需要进行时间相关的岩石激励和结构响应测量。沿着结构的这些测量的时间相关性将允许提高建筑物应变计算的准确性，这些应变负责表面开裂，这是法规控制的对象。目前的法规和理解是基于住宅的响应测量，1至2层的单户结构，当受到低频激励。通过响应谱分析将这些观测结果扩展到受高频地面运动激励的高层结构需要得到验证。在地震工程、防爆设计和结构动力学中发展起来的基于激励频率和应变的分析技术应该适用于这些城市情况；然而，由于难以找到全面的测试地点，通过测量进行验证还没有发生。这个地点和这些仪器提供了这样的机会。

This project provides supplementary instrumentation to advance the state-of-the-art of construction blast vibration control, with the objective of reducing the cost of constructing urban buildings and facilities. It leverages ongoing measurements of building response to high frequency, blast induced excitation at a construction site in New York City. The additional instruments will be used to time correlate excitation and response motions, and to measure additional responses not required by construction regulations. Measurements enabled by this deployment of supplemental instruments will be used to test the hypothesis that urban structures are not perturbed as greatly as typically assumed, and thus vibration controls may be safely reduced. In dense urban areas old and modern high-rise buildings can coexist on the same street block. Project owners and contractors performing rock excavation are faced with restrictive vibration limits targeted for older buildings designated as historic, "Landmark", or fragile and in need of repair. For blasting projects, the presence of a single building perceived as "vulnerable" to cosmetic cracking from vibrations can severely restrict allowable vibration limits and constrain rock removal efficiency, thereby lowering overall productivity and extending the duration of the project. All of these negative construction consequences may unnecessarily increase construction costs. The potential economic benefit is large. In New York City alone over $17 billion in current transit projects involve construction blasting for excavations and tunneling in rock.Time correlated rock excitation and structure response measurements are needed to advance the understanding of the response of urban structures to high frequency excitation. Time correlation of these measurements along a structure will allow increased accuracy in the calculation of building strains that are responsible for cosmetic cracking, the object of control by regulation. Current regulations and understanding are based upon measurements of the response of residential, 1 to 2 story single family structures when subjected lower frequency excitation. Extension of these observations by response spectrum analysis to taller structures when excited by higher frequency ground motions needs to be validated. Excitation frequency and strain based analytical techniques developed in Earthquake Engineering, Blast Protective Design, and Structural Dynamics should be applicable to these urban situations; however, validation by measurement has not occurred because of the difficulty of finding full-scale test sites. This site and these instruments provide that opportunity.