Abstract
This paper describes measurement and interpretation of strains induced in two, multiple story, older, urban structures by ultra-high frequency rock blast excitation from contiguous excavation. These strains are obtained from relative displacements found by integrating time correlated velocity time histories from multiple positions on the structures and foundation rock. Observations are based on ten instrumented positions on the structures and in the foundation rock during eight blast events, which provided over 70 time histories for analysis. The case study and measurements allowed the following conclusions: despite particle velocities in the rock that greatly exceed regulatory limits, strains in external walls are similar to or lower than those necessary to crack masonry structures and weak wall covering materials. These strains are also lower than those sustained by single story residential structures when excited by low frequency motions with particle velocities below regulatory limits. Expected relative displacements calculated with pseudo velocity single degree of freedom response spectra of excitation motions measured in the rock are similar to those measured.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4073-4090 |
| Number of pages | 18 |
| Journal | Rock Mechanics and Rock Engineering |
| Volume | 49 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 1 2016 |
Funding
This paper is the result of an unusual set of fortuitous circumstances and the authors wish to acknowledge the organizations and special circumstances that allowed the writing of the paper. First, the New York City Fire Department for their interest in allowing this activity to further the science of blast vibration monitoring. Second, building owners and their contractors, for their cooperation and coordination given the inevitable intrusions necessary to instrument structures in the midst of complicated and compact construction foot print. Third, the members of the Aimone-Martin Associates, especially Brent Meins, for installing and maintaining the operability of the instruments during the course of the investigation. Fourth, the GGGE Program of the CMMI Division of the National Science Foundation which provided the additional funds to time correlate the instruments through the RAPID Response initiative. Finally, the US Embassy in Tunis, as well as the US Department of State, Bureau of Educational and Cultural Affairs and the Council for the International Exchange of Scholars for their assistance and support during the Fulbright Visiting Research Fellowship of Dr. Essaieb Hamdi at the Civil and Environmental Engineering Department of the Northwestern University.
Keywords
- Close-in rock blasting
- Displacements
- Peak particle velocity
- Pseudo velocity spectral analysis
- Shear and tensile strains
- Ultra-high frequency excitation
- Urban structures
ASJC Scopus subject areas
- Civil and Structural Engineering
- Geotechnical Engineering and Engineering Geology
- Geology