2021 Chapter Meetings
Lifeline Infrastructure System Functional Recovery and Operability
Dr. Craig Davis, Ph.D., PE, GE, 2021 EERI Distinguished Lecturer
Followed by a Panel Discussion
Panelists:
Dr. Craig Davis, Los Angeles Department of Water and Power
Dr. Stephen Potts, Geologist, U.S. Army Corps of Engineers
Tirzah Shakespeare, Public Utilities Engineer, Massachusetts Department of Public Utilities
Wednesday November 10, 2021, 2:30-4:00 PM (Eastern), 11:30 AM-1:00 PM (Pacific)
Register for FREE at: HERE
Abstract: Historically, seismic design and building codes have focused primarily on ensuring safety in the event of an earthquake, with less attention to the state of structures and infrastructure systems in the aftermath. However, an increasing focus on resiliency in recent years has brought new attention to the concept of designing for functional recovery: a post-earthquake state in which capacity is sufficiently maintained or swiftly restored to support pre-earthquake functionality. As detailed in the January 2021 FEMA/NIST report “Recommended Options for Improving the Built Environment for Post-Earthquake Reoccupancy and Functional Recovery Time,” this means considering not only safety and recovery time for buildings, but ensuring recovery-based design, upgrade, and maintenance of a lifeline infrastructure systems as well. In this webinar, co-hosted by the EERI New England Regional Chapter and the University of Massachusetts at Amherst Student Chapter, EERI 2021 Distinguished Lecturer Craig Davis will present a short lecture on Lifeline Infrastructure System Functional Recovery and Operability, followed by a live panel with speakers from the US Army Corps of Engineers and the Massachusetts Department of Public Utilities. They will speak on the role, preparedness, and plans of their organizations to mitigate damage and restore service of critical lifeline systems after a disaster, and join Dr. Davis for a Q&A session with the webinar audience.
Biography: In his three-decade-long career at the Los Angeles Department of Water and Power, Dr. Davis worked as the Departmental Chief Resilience Officer, Seismic Manager, and Geotechnical Engineering Manager, and developed a comprehensive L.A. Water System resilience program. He has served on professional committees, including the Building Seismic Safety Council, the National Earthquake Hazards Reduction Program Advisory Committee on Earthquake Hazards Reduction, and ASCE Infrastructure Resilience Division. Dr. Davis has published more than 150 technical papers and investigated numerous earthquakes.
Davis has been honored with the ASCE 2016 Le Val Lund Award for Practicing Lifeline Risk Reduction, the 2020 Charles Martin Duke Lifeline Earthquake Engineering Award, and the EERI Distinguished Lecture Award. The annual Distinguished Lecture Award is awarded to EERI members to recognize and encourage communication of outstanding professional contributions of major importance for earthquake hazard mitigation.
Determination of Undrained Strength for Contractive Coal Combustion Residuals for Seismic Assessment
Seda Gokyer Erbis, Ph.D., P.E. & Ryan Lavorati, M.Sc., P.E., Geocomp
EERI, New England Chapter, Lecture Series
Wednesday October 20, 2021, 1:00 – 2:00 PM (Eastern Time)
Register for FREE at: HERE
Abstract: The evaluation of slope stability for Coal Combustion Residuals (CCR) impoundments is becoming increasingly important as multiple failures involving undrained behavior of granular materials have recently occurred. Seismic loading is a load case where undrained behavior can be triggered that causes a rapid increase in mobilized shear stress or a rapid decrease in effective stress if contractive saturated materials are present. This rapid loading can trigger liquefaction within a CCR layer which would require considering the residual shear strength for the CCR material. Undrained strength parameters for CCR materials can be highly variable. Cone penetration tests (CPTs) are simple and relatively inexpensive, however CPT measurements is an indirect
measurement which must be converted to strength through semi-analytical-empirical correlations. Such correlations are reasonably well understood for natural clays and sands but there exists only limited correlation data for CCR materials. To improve our understanding of the shear strength of CCR materials, a program was developed to collect CPT data from five CCR impoundments and companion “undisturbed” tube samples for laboratory strength testing Laboratory testing was done to measure both monotonic and post-cyclic undrained strength in direct simple shear devices. All the laboratory tests showed contractive behavior. CPT data were also used to estimate the peak and residual strength of the CCR material using available correlations. Generally, reasonable agreement was obtained by the two independent approaches but with significant scatter. This study summarizes the approaches used to apply Best Applicable Practices to make a reliable determination of peak and residual undrained shear strength of CCR materials and provides recommendations on improving available methods to determine undrained shear strength of contractive materials.
Biographies: Seda Gokyer Erbis is a Project Engineer/Assistant Project Manager for Geocomp Corporation – Massachusetts Consulting Group. She has been with Geocomp for six years, holding a doctoral degree in Geotechnical Earthquake Engineering. She has been leading the project management and technical efforts for one of Geocomp’s largest consulting projects on seismic assessment of coal ash impoundments. She has over seven years of experience in geotechnical earthquake engineering, especially in advanced laboratory testing. She has authored and co-authored several publications in peer-reviewed ASCE and ASTM journals and conference proceedings.
Mr. Lavorati is a Project Engineer at Geocomp Corporation – Massachusetts Consulting Group. He is responsible for a range of project activities including geotechnical design, laboratory testing, data management, computer-based modeling, field investigations, and project management. He has been involved with different aspects of engineering work, from litigation review to design analysis to information research. He has extensive modeling experience in a variety of geo-structural and presentation software packages, including AutoDesk, GeoStudio, Rocscience, DEEPSOIL, and FLAC, amongst many others.
Assessing the Influence of Epistemic Uncertainties on Earthquake Loss Estimates for California
Edward (Ned) H. Field, Research Geophysicist, USGS
EERI, New England Chapter, Lecture Series
Tuesday April 27, 2021, 12:00 – 1:00 PM (Eastern Time)
The Zoom Seminar is FREE!
For registration, please visit: HERE
Abstract: To aid in setting scientific research priorities, we assess the potential value of removing each of the epistemic uncertainties currently represented in the US Geological Survey California seismic-hazard model, using average annual loss (AAL) as the risk metric of interest. Given all the uncertainties, represented with logic-tree branches, we find a mean AAL of $3.94 billion. The modal value is 17.5% lower than the mean, and there is a 78% chance that the true AAL value is more than 10% away from the mean, and a 5% chance that it is a factor 2.1 greater or lower than the mean. We quantify the extent to which resolving each uncertainty improves the AAL estimate. The most influential branch is one that adds additional epistemic uncertainty to ground motion models, but others are found to be influential as well, such as the rate of M ≥ 5 events throughout the region. We discuss the broader implications of our findings, and note that the time dependence caused by spatiotemporal clustering can be much more influential on AAL than the epistemic uncertainties explored here.
Biography: Edward (Ned) Field has been a research geophysicist with USGS since 2000. He specializes in the development of earthquake-forecast models, which are one of the two main modeling components used in modern seismic-hazard analysis (the other being ground-motion models). His focus area has mainly been California, which due to an abundance of scientific talent and data constraints, has enabled the forging of state-or-the-art methodologies. Ned has led the development of the Third Uniform California Earthquake Rupture Forecast (UCERF3), representing both multi-fault ruptures and spatiotemporal clustering (e.g., aftershocks); the relevance of both these effects was dramatically exemplified in a recent sequence of damaging earthquakes in New Zealand. These forecast models influence a variety of risk mitigation activities, including building codes and catastrophe models used by insurance industry. Important themes he is focused on nowadays include: a better quantification of uncertainties; the use of more physics-based approaches; and the need to add “valuation” to verification and validation protocols. Ned has also led the development of OpenSHA, which is an open-source, and platform-independent computational framework for conducting seismic hazard analysis, which supports loss modeling as well. He is also an active member of the planning committee of the Southern California Earthquake Center.
Are Small Earthquakes a Big Deal?
Julian J Bommer, Senior Research Investigator, Faculty of Engineering, Dept. of Civil and Environmental Engineering, Imperial College, London
Friday February 5, 2021, 12:00 PM Eastern Time (US & Canada), Virtual Event
Tufts CEE Seminar Series and Joyner Lecture at The New England Chapter of EERI Present
Abstract: Earthquake engineering has traditionally focused on protecting society against the effects of large magnitude earthquakes but in recent years there has been increasing interest regarding the impact of smaller earthquakes. This has been driven partly by the occurrence of some low-magnitude earthquakes that have been cause unexpected levels of damage and particularly by the heightened concern regarding earthquakes of anthropogenic origin. The lecture begins by re-visiting the often-misunderstood rationale behind the exclusion of smaller magnitude earthquakes from probabilistic seismic hazard analysis as being related to the risk posed by such events. A number of case histories of small magnitude events reported to have caused damage are then reviewed, highlighting in each case the specific factors contributing to the impact and in some cases arguing that the impact may have been exaggerated. This is followed by a global analysis of small-to-moderate magnitude earthquakes to ascertain the likelihood of these resulting in damage and/or injury. As well as looking at the smallest magnitude earthquakes that have caused structural damage, the question of the smallest magnitudes required to trigger liquefaction is also addressed. The lecture concludes with some insights regarding if and when smaller earthquakes should be a concern as well as discussing the challenges associated with modelling the resulting hazard and risk that such events can pose.
Please Register for Seminar: HERE
Lecture Flyer (PDF)