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This study examines the small-strain dynamic properties of mixtures composed of sandy and gravelly soils with granulated tire rubber in terms of shear modulus (G O ), and damping ratio in shear (D min ). Torsional resonant column tests are performed on dry, dense specimens of soil-rubber mixtures in a range of soil to rubber particles size 5:1-1:10 and rubber content from 0 to 35% by mixture weight. The experimental results indicate that the response of the mixtures is significantly affected by the content of rubber and the relative size of rubber to soil particles. Concering the small-strain shear modulus, an equivalent void ratio is introduced that considers the volume of rubber particles as part of the total volume of voids.Based on a comprehensive set of test results a series of equations were developed that can be used to evaluate the shear modulus and damping ratio at small shear strain levels if the confining pressure, the content of rubber by mixture weight, the grain size of soil and rubber particles, and the dynamic and physical properties of the intact soil are known.

Ð The city of Thessaloniki is located in northern Greece, close to a large seismogenic area and it has experienced several destructive earthquakes during the present century. In this paper, we focus on the de®nition of the subsurface structure of the city from a site response analysis perspective. The paper presents, together with a summary of geology and seismicity, the results of a large-scale geophysical and geotechnical survey, in order to determine and validate geometry and dynamic properties of the main soil formations. The synthesis and combination of recent results regarding the dynamic properties with those obtained from the elaboration of a large database of classical geotechnical tests led to the design of a detail geotechnical map and of various 1-D pro®les, 2-D cross sections and 3-D thematic maps for the main soil formations. These soil pro®les and maps are oriented to site eect studies and provide a comprehensive picture easily adapted to geographic information systems (GIS) for planning and design purposes. Moreover, the results of this study were correlated with macroseismic observations reported in many earlier published microzonation studies of Thessaloniki. These comparative observations revealed the complexity of surface geology of the urban area, a fact which is expected to provoke additional ampli®cation with respect to 1-D resonance.

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