Research
-
I am currently working on the liquefaction susceptibility and
cyclic strength of fine-grained soils as part of my PhD studies,
advised by Prof. Jonathan P. Stewart and Prof. Scott J.
Brandenberg at the University of California, Los Angeles (UCLA).
Moreover, as a graduate student researcher on the NGL Liquefaction
Susceptibility team, we are trying to quantify and assess the
cyclic tests conducted on fine-grained soils. This study focuses
especially on the translational soils that have the potential to
exhibit “clay-like” and “sand-like” behavior. This phenomenon is
significant because the cyclic strength of these two different
behaviors is crucial, and engineers in practice may under- or
over-design structures under seismic loading conditions as a
result.
-
As part of my M.Sc. studies, I investigated the probability of
liquefaction of gravelly soils under the advisement of Prof. Kemal
Onder Cetin at Middle East Technical University (METU). The
research focused on developing a database containing case
histories from prior earthquakes that exhibited gravelly soil
surface manifestations. As the final product of the research, a
probabilistic triggering model was developed based on the gathered
case history data.
-
On February 6, 2023, two earthquakes with magnitudes of 7.8 and
7.6 struck the southeastern region of Turkey. Many researchers
visited the site to investigate and gather crucial data after the
earthquake sequence. As part of both the METU and GEER teams, I
visited the site multiple times for reconnaissance studies,
gathering samples, observing surface manifestations, and taking
settlement and lateral spreading measurements.
Research Projects
-
Next Generation Liquefaction Susceptibility Database and Modeling (2023 - 2025)
Pacific Earthquake Engineering Research (PEER) Center
Principal Investigator (PI): Prof. Jonathan P. Stewart
Co-PI: Prof. Scott J. Brandenberg
Joined Universities: University of California, Los Angeles; Oregon State University (Prof. Armin W. Stuedlein, Dr. Amalesh Jana)
-
Aimed to update the Next Generation Liquefaction (NGL) database for the needs pointed out in 2022 PEER Workshop held on Oregon State University (OSU)
-
Traveled to Houston, TX to gather crucial dataset used for the legacy liquefaction susceptibility model
-
Coordinated with research groups involving OSU, UC Berkeley, UC Davis along with professional geotechnical engineering companies involving Geosyntec and ENGEO
-
Created and published DesignSafe datasets involving site investigation and cyclic laboratory test results to make the data publicly available to the geotechnical engineering community
-
Entered gathered datasets to the NGL database to make the data easily queried within SQL framework
-
Determined the potential issue and missing input entries in the NGL database structure for future efforts to organize and re-design
-
Create a logic tree framework to demonstrate the seismic ground failure hazard assessment and illustrated with an case history from 1999 Kocaeli earthquake
-
Next Generation Liquefaction Project Database and Model Development in Support of Improved Liquefaction Hazard Assessments (2024 - Expected 2029)
U.S. Federal Highway Administration (FHWA)
Principal Investigator (PI): Dr. Kristin J. Ulmer (SwRI), Prof. Jonathan P. Stewart (UCLA), Prof. Armin W. Stuedlein (OSU)
Co-PI: Dr. John Stamatakos (SwRI), Prof. Scott J. Brandenberg (UCLA), Prof. T. Matthew Evans (OSU)
Joined Universities and Research Institutes: Southwest Research Institute; University of California, Los Angeles; Oregon State University; University of Washington (Prof. Steven L. Kramer)
-
Aimed to use the Next Generation Liquefaction (NGL) database to create probabilistic liquefaction susceptibility models as the first step of the seismic ground failure hazard assessment
-
Worked on the quantification of the hysteresis loop metrics to identify the sand-like and clay-like behavior under cyclic loading
-
Developed a form website using HTML, CSS and JavaScript to gather expert opinions to determine the sand-like and clay-like behavior for a subset
-
Related the gathered expert opinions with the hysteresis loop metrics to create a framework to objectively assess the overall NGL database
-
Developed a framework by using Bayesian Inference to estimate soil behavior using hysteresis loop metrics considering the uncertainty in the expert judgements
-
Created a dynamic tool using Python and IPyWidgets to easily access to the cyclic test data, calculate the hysteresis loop metrics and visualize the resulting plots
-
Evaluated all the cyclic test results in the NGL database and created a protocol that helps to identify usable test in a liquefaction susceptibility of the soil body
-
Working on relating the liquefaction susceptibility with the common index parameters such as Atterberg limits that are available in almost all of the geotechnical engineering projects
-
Correlating the liquefaction susceptibility with Cone Penetration Test (CPT) results to form a separate model to provide flexibility to the engineers in practice to use the most available and reliable data that is collected within the scope of the project
-
Prepared two interim reports to FHWA to summarize the findings of the research in collaboration with the joined universities and research institutes
-
RAPID: Geotechnical Engineering and Geo-Sciences Response to the 6 February 2023 Turkiye Earthquake Sequence (2023 - 2025)
U.S. National Science Foundation (NSF)
Principal Investigator (PI): Prof. Jonathan P. Stewart
Joined Universities: University of California, Los Angeles; California Polytechnic State University (Prof. Robb Eric S. Moss); Middle East Technical University (Prof. Kemal Onder Cetin), California State University Fullerton (Prof. Sinan Akciz)
-
Aimed to perform site investigation efforts in which the information regarding the surface manifestation has been reported by the reconnaissance teams along with the strong ground motion stations to estimate the soil profile effects to the amplification/de-amplification of incoming ground motions
-
Summarized the available data and published through DesignSafe to make it publicly available and advance the current state of practice
-
Analyzed the site investigations in ground motion stations to compare them with the available models to understand their shortcomings and include them to the databases used for the newer version of the models
-
Performed liquefaction assessment by using the gathered site investigation results, and legacy models and NGL liquefaction triggering model to test their applicability and performance to the newly investigated sites
-
Completed a study starting from reconnaissance studies till the evaluation of the site investigation results to create a complete case history
-
Prepared a report for NSF to summarize the findings of this study in collaboration with the joined universities
-
Reconnaissance after February 6, 2023 Turkiye Earthquake Sequence (2023)
Geotechnical Extreme Events Reconnaissance (GEER)
Coordinators: Prof. Kemal Onder Cetin (METU), Prof. Jonathan D. Bray (UC Berkeley), Prof. J. David Frost (Georgia Tech), Prof. Robb Eric S. Moss (CalPoly), Prof. Jonathan P. Stewart (UCLA)
Joined Universities and Research Institutes: Middle East Technical University; California Polytechnic State University; Georgia Institute of Technology; Southwest Research Institute; University of California, Berkeley; Portland State University; Ohio State University; University of California, Los Angeles
-
Aimed to visit the effected sites after two major earthquakes after February 6, 2023 Turkiye earthquakes that was one of the major earthquake sequence in the past 10 years
-
Visited the site with various research teams including researchers from Middle East Technical University and Gazi University followed by GEER teams that visited the site in three phases through mid-February to end of March
-
Evaluated the performance of the support systems, dams, bridges, lifelines, ports, buildings against the seismic ground failure to understand and learn for future data collection, testing of the existing models and future model development
-
Collected samples from the soil ejecta to understand and classify the soils that are liquefied during the earthquakes
-
Took measurements from buildings that have experienced excessive settlements and locations that experienced lateral spreading including port facilities, bridges and dams
-
Throughly investigated two port facilities that one of them experienced surface manifestation and the other did not to create a complete case history and published the results in a journal paper
-
Helped preparing reconnaissance reports for the Turkish researchers and GEER efforts
