ABSTRACT
A chief concern in shake table tests is the difficulty in pro ducing a uniform acceleration field within the confines of the test region. This problem is very pronounced especially when the test medium is soil, since the horizontally applied base acceleration gets amplified along the depth of the soil. This acceleration simpli fication depends upon the stress-strain behavior of the soil and the applied dynamic base motion. Simplifying assumptions are often re quired to assess the approximate acceleration histories along the
depth of the medium. Another problem frequently encountered in shake table tests involving semi-infinite media such as soil is the proper modeling of boundaries. Often, the test boundaries do not imitate field conditions. The relative rigidity of the test boundaries with respect to the soil tends to create entirely different acceleration fields compared to those assumed.
