Substructure methods for impact systems: Comparison with free field measurements

• Published in: Soil dynamics and earthquake engineering (1984) Vol. 13; no. 2; pp. 139 - 145
• Main Authors: Neidhart, Th, Grabe, J., Huber, G.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1994; Elsevier Science
• Subjects: Earth sciences; Earth, ocean, space; Earthquakes, seismology; Engineering and environment geology. Geothermics; Engineering geology; Exact sciences and technology; Internal geophysics; concrete; boundary element analysis; foundations; soft clays; geophones; elastic waves; digital simulation; ground motion; clastic sediments; velocity; frequency; sedimentary rocks; acceleration; amplitude; Wave propagation; propagation; non linear models; Non linear effect; earthquake engineering
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/0267-7261(94)90006-X

An excitation system, consisting of a concrete foundation and a vibrator, was placed on a gravelly top layer over a 40 m deep soft clay deposit. The excitation frequency was varied and the acceleration of the foundation was measured simultaneously. Geophones were installed to monitor the velocities inside and on the surface of the subsoil. It was observed that the soil behaved nonlinearly and that the foundation lost contact with the soil at some excitation frequencies. A one mass-spring-dashpot system with the ability to consider the temporary loss of contact is used to model the movement of the excitation system. Inside the subsoil, the wave propagation is modeled using boundary elements in the time domain. Displacements and velocities are calculated at various points with this numerical tool. The results are compared with the measurements.