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Estimation of shear moduli and damping factors of earth dam materials
Author(s) -
Lin JeenShang,
Chao BiingKuen
Publication year - 1990
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290190609
Subject(s) - superposition principle , nonlinear system , hysteresis , crest , geotechnical engineering , geology , acceleration , moduli , soil water , structural engineering , shear (geology) , engineering , mathematics , physics , mathematical analysis , classical mechanics , quantum mechanics , soil science , petrology
Abdel‐Ghaffar and Scott developed a procedure for extracting the shear moduli and damping factors of soils based upon strong motion records from earth dams. It is a very efficient procedure for earth dams that exhibited predominantly first mode response along the upstream‐downstream direction. In their approach, they employed digital band‐pass filters on the crest and abutment acceleration records, and constructed the hysteresis loops of soils by treating these filtered records as the input‐output to a non‐linear SDOF structure. In the process an important superposition assumption was implicitly introduced. This study looked into the implications of this linear superposition assumption on presumed nonlinear systems. Specifically, numerical simulations were conducted in finding out whether or not such a procedure is capable of extracting a known input dynamic behaviour of soils. It was found that the hysteresis loops were generally distorted, and to minimize errors only those loops of larger strain amplitudes should be used. Simple guidelines were suggested accordingly. Applications to real records from two dams were carried out following the proposed guidelines. Results of such applications were explored.