Ogul Doygun Coauthored a Paper on Load-Controlled Cyclic Tests in the Soil Dynamics and Earthquake Engineering Journal
Ogul Doygun, Ph.D. (California) coauthored a paper entitled "High strain damping for sands from load-controlled cyclic tests: Correlation between stored strain energy and pore water pressure" that was published in the journal Soil Dynamics and Earthquake Engineering in volume 134 on July 2020.
Ogul's coauthor was H.G.Brandes.
Ogul Doygun is a Senior Staff Professional based in California focused on civil engineering, geotechnical engineering, and construction quality assurance. His experience also includes geotechnical design for various civil engineering projects.
The journal Soil Dynamics and Earthquake Engineering aims to encourage and enhance the role of mechanics and other disciplines as they relate to earthquake engineering by providing opportunities for the publication of the work of applied mathematicians, engineers and other applied scientists involved in solving problems closely related to the field of earthquake engineering and geotechnical earthquake engineering.
Undrained stress-controlled cyclic triaxial and direct simple shear test data on five different clean sands was analyzed in terms of dissipated and stored strain energy. A new method was developed to calculate damping ratio from undrained stress-controlled tests and its plausibility was examined with the help of pore water pressure data. Results from different methods in the literature to calculate damping ratio were also evaluated. The data analysis shows that the damping ratio results calculated with the new method were in some agreement with the damping ratio values for sands summarized by Seed & Idriss (1970)  for shear strains up to 0.4%. For shear strains larger than 0.4%, the new method provides more accurate estimates of damping ratio that are also conceptually more reasonable than those obtained with linear equivalent approximations. For strains in excess of 1%, damping ratio trends with strain obtained with the new method are clearly superior, although reliable experimental data is limited. In general, equivalent linear calculation of damping ratio can lead to an overestimation of damping for shear strains smaller than 1% and an underestimation of damping for the shear strains larger than 1%.
Learn more about the article: https://www.sciencedirect.com/science/article/pii/S0267726119315131?dgcid=author
Learn more about the journal: https://www.journals.elsevier.com/soil-dynamics-and-earthquake-engineering