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

This is a request for rapid response funding to leverage a just initiated program of measurements of building response to high frequency, blast induced excitation. The requested funds would be employed to pay for additional instruments to time correlate excitation and response motions and to provide additional building response sites. A GOALI proposal would be written to analyze the data at a later date. A confluence of factors presents a unique opportunity to measure response of tall (> 4 stories) building response to close-in, high frequency ( > 100 Hz) blasting vibrations. Currently the developer, adjacent building owners, consultants, and regulatory officials in New York City have just (April 2014) begun to measure excitation and building response motions during fragmentation for a block wide, 80 foot deep excavation. The project, while meeting compliance regulations and incorporating many transducers, could provide much needed scientific building response information if the excitation and building response motions were time correlated. Since excavation is scheduled to be complete within six months there is not sufficient time to write a full proposal for this activity. It is critical that this instrumentation be purchased and installed immediately. First, the additional transducers and wiring are much easier to install before the excavation becomes too deep. Secondly, shallow close in blasts are closest to the structures and produce some of the higher amplitude motions. Only supplementary equipment is necessary for time correlation. Owners have already purchased, placed, and paid for archiving of time histories and use of some advanced, regulatory seismographic equipment.