With Hurricane Season Underway, What Have Engineers Learned from Previous Storms?
With hurricane season already underway and projected to be active, communities need to make sure they have learned the lessons from previous major storms so that they are prepared for the next one.
As the technical director for the Network for Earth Engineering Facility at Rensselaer Polytechnic Institute and an expert in centrifuge modeling, Tarek Abdoun can provide that insight. Abdoun led a research team that used physical models within the Rensselaer centrifuge to determine how some of the levees in New Orleans failed during Hurricane Katrina. Those findings have provided engineers with a better understanding of how levees respond to extreme floods. Abdoun is available to talk about what engineers have been able to learn since Katrina, and how that makes levees and dams safer.
Areas of Expertise
Earthquakes
Centrifuge Modeling
Soil-Structure Interaction
Data Visualization
Soil Remediation
Field Advanced Sensing
Biography
Tarek Abdoun is a professor of civil and environmental engineering, and the Technical Director of the Network for Earthquake Engineering Simulation facility at Rensselaer.
Abdoun's primary research interests are centrifuge modeling, soil-structure interaction, soil remediation, field advanced sensing, and data visualization. He has conducted, and advised other researchers on, successful high-quality centrifuge model tests conducted at the Rensselaer centrifuge. These centrifuge experiments, supplemented by high-quality reliable measurements, have been used to develop or calibrate new design or retrofit engineering methods.
Abdoun led the Rensselaer physical modelling research team that clarified the failure mechanisms of some of the New Orleans levees during Hurricane Katrina, providing critical feedback to the corresponding numerical analyses. He worked closely on this with the US Army Corps of Engineers and the corresponding U.S. National Academies Oversight Committee.
His work has been cited in news reports on national networks including CNN, NBC, Discovery, and ASCE News, and it was referenced in great detail in an article evaluating the lessons from Hurricane Katrina in the Spring 2007 issue of The Bridge, published by the National Academy of Engineering.
Abdoun has designed and developed a novel wireless shape-acceleration sensor array, taking advantage of new advances in fiber optic and MEMS sensor technologies. The sensors are capable of measuring ground acceleration and permanent deformation. Each sensor array is connected to a wireless sensor node to enable real time monitoring and informed assessment of pending failure.
He is a member of several technical committees and the editorial board of technical journals, including ASCE Geo Institute Committee for Earthquake Engineering and Soil Dynamics, ASCE Journal of Geotechnical and Geoenvironmental Engineering, Canadian Journal, etc.
Abdoun is the recipient of Rensselaer's 2004, 2006, & 2007 School of Engineering Excellence in Research & Teaching Award, and the 2004 prestigious Casimir Gzowski awarded by the Canadian Society for Civil Engineering.
He has published more than 120 publications and technical reports.
LEAP-UCD-2017 Comparison of Centrifuge Test Results
Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading
Bruce L. Kutter, Trevor J. Carey, Nicholas Stone, Bao Li Zheng, Andreas Gavras, Majid T. Manzari, Mourad Zeghal, Tarek Abdoun, Evangelia Korre, Sandra Escoffier, Stuart K. Haigh, Gopal S. P. Madabhushi, Srikanth S. C. Madabhushi, Wen-Yi Hung, Ting-Wei Liao
2019-11-16
This paper compares experimental results from every facility for LEAP-UCD-2017. The specified experiment consisted of a submerged medium-dense clean sand with a 5-degree slope subjected to 1 Hz ramped sine wave base motion in a rigid container. The ground motions and soil density were intentionally varied from experiment to experiment in hopes of defining the slope of the relational trend between response (e.g., displacement, pore pressure), intensity of shaking, and density or relative density. This paper is also intended to serve as a useful starting point for overview of the experimental results and to help others find specific experiments if they want to select a subset for further analysis. The results of the experiments show significant differences between each other, but the responses show a significant correlation, R2 ~ 0.7–0.8, to the known variation of the input parameters.
Large-Scale Modeling of Preshaking Effect on Liquefaction Resistance, Shear Wave Velocity, and CPT Tip Resistance of Clean Sand
Journal of Geotechnical and Geoenvironmental Engineering
R. Dobry, M.ASCE; S. Thevanayagam, M.ASCE; W. El-Sekelly, M.ASCE; T. Abdoun, M.ASCE
2019-10-01
The effect of preshaking and repeated liquefaction on liquefaction resistance was studied in a large-scale shaking table experiment, in which a sequence of 51 shakings was applied to the base of a 5-m uniform deposit of saturated clean Ottawa sand. Three event types were used in a very intense repeated pattern: mild preshaking Events A, stronger preshaking Events B, and extensive liquefaction Events C, with each Event C typically liquefying most or all of the deposit. Relative density, cone penetration test (CPT) tip resistance, and liquefaction resistance to Events A and B were found to increase significantly throughout the 51-shaking sequence, with the shear wave velocity (Vs) increasing slightly. However, the CPT tip resistance and liquefaction resistance decreased temporarily after each Event C, recovering rapidly with additional preshaking—presumably due to a decrease and subsequent increase in the soil lateral stresses. The results for the different shakings were compared with available CPT- and Vs-based field liquefaction charts, with and without accounting for the fact that the soil deposit was much younger than the case histories covered by the charts (age factor). The liquefaction response for Events A, B, and C was reasonably well predicted by the CPT chart when the age factor was considered, including Events A immediately after liquefaction by an Event C. The implications of the research were discussed for the geologic age, preshaking and liquefaction effects observed in the field, including reliquefaction response of the same site by milder aftershocks after the main earthquake shock.
Verification of the Repeatability of Soil Liquefaction Centrifuge Testing at Rensselaer
Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading
Evangelia Korre, Tarek Abdoun, Mourad Zeghal
2019-11-16
The Liquefaction Experiments and Analysis Projects (LEAP) is an international effort to use experimental data from physical modeling at different (international) centrifuge facilities to validate soil liquefaction numerical models and analysis tools. The goals of LEAP-2017 experimental efforts are to assess the repeatability potential at each facility, the reproducibility of centrifuge tests among different facilities, and the sensitivity of the experimental results to variation of testing parameters and conditions. A number of tests of the same (sloping deposit) centrifuge model were repeated at Rensselaer Polytechnic Institute in 2015 and 2017. This paper focuses on two specific tests to assess and demonstrate repeatability at this facility.
Uncertainty quantification and propagation in the modeling of liquefiable sands
Soil Dynamics and Earthquake Engineering
Vicente Mercado, Felipe Ochoa-Cornejo, Rodrigo Astrozac, Waleed El-Sekelly, Tarek Abdoun, Cesar Pastén, Francisco Hernández
2019-08-01
This paper combines data from laboratory, centrifuge testing, and numerical tools to highlight the predictive capabilities of the Bayesian method for uncertainty quantification and propagation. The Bayesian approach is employed to estimate uncertain parameters of a multi-yield constitutive model using data from cyclic-triaxial testing. Then, predictive capabilities of a finite element model in reproducing the dynamic response of a saturated sand deposit are investigated by drawing samples from the estimated posterior probability distributions of the constitutive model parameters. Variability of the predicted responses due to estimation uncertainty is evaluated. The response of centrifuge tests is used to assess the simulated responses.
