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Simulation of Strong Earthquake Motion with Explosive Line Source Arrays.
Abrahamson, G. R.; Lindberg, H. E.; Bruce, J. R.
National Science Foundation, Washington, D.C. Research Applied to National Needs., October 1977, 52 p.
This report describes an experimental investigation of the feasibility of simulating strong earthquake motion with contained explosive line source arrays. The technique consists of detonating a plane array of vertical line sources placed in the vicinity of the structure to be tested. In a full-scale test the array might measure 100 x 30 feet, consist of 10 to 20 vertical bore holes 30-feet deep spaced on 5- to 10-foot centers, placed about 30 feet from the structure to be tested. Reusable hardware was developed for producing contained explosions in a 1/3-scale source, instrumentation was incorporated for hardware diagnostics and output measurements, reasonable acceleration and frequencies were obtained in soil with the 1/3-scale source, and repeatable results were demonstrated. Estimates based on the authors' current experiments show that in a 100- x 30-foot array, a 5-Hz pulse with a 0.5-g peak acceleration can be produced with less than 100 lb of explosive. A complete train of oscillations typical of strong earthquake motion, with a total duration of 10 s and peak accelerations reaching 1 g, is estimated to require about 500 lb of explosive, fired in 10 detonations.
Earthquake resistant structures; Explosive charges; Seismic waves; Earth movements; Ground motion; Earthquake engineering; Simulation; Earthquakes