NEHRP Clearinghouse

Title
Simulation of Strong Earthquake Motion with Contained-Explosion Line Source Arrays, Single-Source and Array Tests at Camp Parks.
File
PB80201445.pdf
Author(s)
Bruce, J. R.; Lindberg, H. E.; Abrahamson, G. R.
Source
National Science Foundation, Washington, DC. Div. of Problem-Focused Research Applications., December 1979, 155 p.
Abstract
The development of a technique using explosives to simulate strong level, earthquake-like ground motion is described. The long range objective is in-situ testing of soil-structure interaction and of structures with complex internal equipment systems. The technique can be applied to buildings, nuclear reactors, pipelines, power lines, dams, bridges, and tunnels. It produces ground motion by simultaneous firing of a planar array of vertical line sources. The controlled release of high-pressure explosion products within each source allows controlled pressurization of the surrounding soil. Tests were performed with an array of ten 1/3-scale sources. Tests were also performed with single sources, both in 1/3-scale and full-scale. A quasistatic theory was developed to predict both single source and array response. The 1/3-scale array test results, when compared to 1/3-scale single source test results, showed a more than order magnitude increase in ground motion. The quasistatic theory predicted this result and compared favorably with both the single-source and array tests. Extrapolation of these results to full-scale showed an 80 x 40 ft. array can produce accelerations of 0.6 g, velocities of 1 ft./s, and displacements of about one inch at frequencies of 3 to 5 hz, a useful level of ground motion for structural testing.
Keywords
Ground motion; Earthquake resistant structures; Seismic design; Soil structure interactions; Explosive charges; Simulation; Finite element analysis; Soil properties; Earth movements; Arrays; Dynamic structural analysis