Adda Athanasopoulos Zekkos

University of California, Berkeley | UCB · Department of Civil and Environmental Engineering

Developing empirical correlations between the shear-wave velocity (V s) and the standard penetration test (SPT) blow count has been a long-term practice for sandy, silty, and clayey soils. However, the existing correlations are not suitable for gravelly soils because the SPT is not particularly reliable for gravelly soils due to the interference of...

Excess pore pressure generation of uniform gravel and gravel-sand mixtures was evaluated in this study. Comparisons were made with existing relationships for pore pressure generation of sands and show that gravel and gravel-sand mixtures can exhibit different pore pressure responses. The influence of liquefaction definition, gravel particle angular...

Evaluating the liquefaction potential of gravelly soils using in-situ testing remains a challenge in geotechnical engineering practice. The Chinese Dynamic Cone Penetration (DPT) test provides an alternative for in-situ testing in gravelly soils to Becker Penetration Test (BPT) and the Standard Penetration test (SPT). The Chinese DPT was recently c...

Results of a parametric finite element study are presented regarding the seismic response of gravity earth retaining walls with backfill possessing cohesion (c-φ soil). The response of the “wall-backfill” system was studied for the cases of a 4.0 m and 7.5 m walls under both harmonic and actual (recorded) earthquake base excitations of varying inte...

Liquefaction assessment has primarily been performed using in situ penetration testing, but this practice has become problematic for gravelly soils. For example, standard penetration test (SPT)- or cone penetration test (CPT)-based correlations can become unreliable owing to interference with large gravel particles, while the Becker Penetration Tes...

The National Science Foundation funded the Geotechnical Women Faculty (GTWF) Project in 2016 to promote gender parity amongst geotechnical engineering professors in the United States. The GTWF Project has, as part of its efforts, built a database of tenured and tenure-track faculty. This database was first created in 2016 at the start of the GTWF p...

On May 19, 2020, after several days of heavy precipitation, two earth dams failed (Edenville and Sanford) and two other dams were damaged (Secord and Smallwood), north of the town of Midland, MI. The failures resulted in about $100M in damages and the evacuation of about 11,000 people during the COVID-19 pandemic. In response to this destructive ev...

Following the Cephalonia, Greece, 2014 earthquake sequence (Mw=6.1 and Mw=6.0), liquefaction of gravelly earthfill materials at the ports of Lixouri and Argostoli resulted in the manifestation of ground cracking and coarse-grained soil ejecta, while the quay walls in these ports exhibited lateral ground displacements ranging from 0.1 m to 1.5 m. To...

The work of the GEER Association is based in part on work supported by the National Science Foundation through the Geotechnical Engineering Program under US NSF Grant No. CMMI-1266418. Any opinions, findings, and conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF....

The User Forum is a Natural Hazards Engineering Research Infrastructure (NHERI)-wide group focused on providing the NHERI Council with independent advice on community user satisfaction, priorities, and needs relating to the use and capabilities of NHERI. The User Forum has representation across NHERI activities, including representatives working di...

Available also at: https://www.michigan.gov/mdot/0,4616,7-151-9622_11045_24249-533554--,00.html

Sloping ground conditions, such as those found in dams and levees, as well as buildings, result in an initial horizontal static shear stress in the ground, affecting its cyclic resistance. When liquefaction triggering is a concern, the Kα correction factor is used to account for this initial static stress in a simplified manner. Laboratory testing...

Traditionally, geotechnical engineers have used continuum numerical methods coupled with complex constitutive models to analyze soil response. This approach, however, does not explicitly consider the particle-scale interactions underlying the macro-scale behavior. Given the advances in computational power, particle-based discrete element methods ha...

Pile installation by applying an impact to the top of a pile appears to be a simple construction process but analysis of that process is complicated as it involves a source of energy, the structural member (pile), and the ground into which the pile is driven. Codes and regulatory standards suggest some basic guidance to analysis but much is still u...

Pile installation by applying an impact to the top of a pile appears to be a simple construction process, but analyzing that process is complicated because it involves a source of energy, the structural member (pile), and the ground into which the pile is driven. Codes and regulatory standards suggest some basic guidance for analyses but much is st...

Constant volume direct simple shear testing is one of the most common tests used to characterize the cyclic response of earth materials. It is especially used to assess liquefaction susceptibility of a soil. Constant volume conditions are typically considered equivalent to undrained conditions, but are dependent on minimal volumetric strain during...

The sequence of two major earthquakes with moment magnitudes of 6.0 and 6.1 that hit the island of Cephalonia in Greece in 2014, resulted in significant liquefaction of gravelly soils. Two of the island's main ports, Lixouri and Argostoli, were impacted by lique-faction of gravel-size fills and experienced significant lateral displacements (up to 1...

Highways consist of many large structures requiring vigilant inspection and maintenance. While significant research attention has been focused on the health management of bridges, comparatively less attention has been paid to other highway structures, including retaining walls. In the United States, there has been a recent emphasis on extending the...

The number of women in the geotechnical engineering profession has increased exponentially in the past 30 years. Even so, women only comprise about 20% of the geotechnical faculty in the U.S. This case study describes a recent project to create an enduring network of geotechnical engineering faculty colleagues and collaborators, both women and men....

Understanding the factors that affect the monotonic and cyclic response of gravelly soils during earthquake events is critical to infrastructure design. In this study a large-size Cyclic Simple Shear (CSS) device was utilized to perform monotonic and cyclic shear tests on mixtures of either subrounded 9 mm Pea Gravel or angular 8 mm Crushed Limesto...

The application of the Structure-from-Motion (SfM) methodology, as enabled by the growth of Unmanned Aerial Vehicle (UAV) technology, is expected to have significant impact in geotechnical engineering research and practice. SfM outputs are presented using selected geotechnical projects as examples, and include orthophotos, 3D point clouds, and thre...

Following the November 14 2016 Mw7.8 Kaikoura earthquake, field expeditions were undertaken using Unmanned Aerial Vehicles (UAVs) to map 25 sites of scientific interest with a plan area of 7.2 km2. A total of 23,172 images collected by the UAVs were used as input in Structure-from-Motion (SfM) to create 3D models of the target areas with a focus on...

Empirical equations to predict ground motions during construction operations have been suggested by various researchers. These empirical correlations were developed after measuring particle velocities on the ground surface during pile installation or other construction activities. When waves travel through the soil and away from the impact source,...

This case study addresses the advancements of women geotechnical engineering faculty in the United States over the past 30 years. In 1989, there were just eight women geotechnical faculty in the United States. Today, we estimate that there are more than 80. Since 1989, there have been various efforts to increase the number and visibility of women g...

Ground vibrations due to impact pile driving operations can become a major concern when affecting nearby structures and underground utilities. In an effort to better understand the transmission and dissipation of energy into the ground during impact pile installation, reduced-scale pile driving tests were conducted in an indoor cylindrical (6.5 m d...

Direct simple shear (DSS) testing, despite its limitations, is one of the most common laboratory element tests in geotechnical engineering practice. The development and validation of a 300-mm diameter DSS device as well as test data generated for two materials with oversized particles, specifically pea gravel and municipal solid waste, are presente...

The generation of pore pressures in soils during earthquake loading is important to understand for designing earthquake resistant structures. Pore pressure generation of sands and sand-silt mixtures has been investigated, however less data is available for gravelly soils. A large-size cyclic simple shear (CSS) device was utilized in this study to p...

The magnitude Mw7.8 'Kaikōura' earthquake occurred shortly after midnight on 14 November 2016. This paper presents an overview of the geotechnical impacts on the South Island of New Zealand recorded during the post-event reconnaissance. Despite the large moment magnitude of this earthquake, relatively little liquefaction was observed across the Sou...

Tens of thousands of landslides were generated over 10, 000 km2 of North Canterbury and Marlborough as a consequence of the 14 November 2016, MW7.8 Kaikōura Earthquake. The most intense landslide damage was concentrated in 3500 km2 around the areas of fault rupture. Given the sparsely populated area affected by landslides, only a few homes were imp...

This paper presents the results of large-size cyclic simple shear testing on three uniform gravels (Pea Gravel, 8-mm Crushed Limestone, and 5-mm Crushed Limestone), which varied in particle size and angularity. Monotonic, cyclic, and postcyclic shear response was assessed for these materials at two relative densities and initial vertical effective...

Earthquake science is critical in reducing vulnerability to a broad range of seismic hazards. Evidence-based studies drawing from several branches of the Earth sciences and engineering can effectively mitigate losses experienced in earthquakes. Societies that invest in this research have lower fatality rates in earthquakes and can recover more rapi...

Soil softening and soil liquefaction have long been a significant aspect of seismic risk, including at sites with gravelly soils. However, the performance of gravelly soils during and after earthquake events is still not well understood. A prototype large-size cyclic simple shear (CSS) device is used in this research to perform monotonic and cyclic...

A robust social network, defined as a group of individuals and organizations with career-related and/or personal relationships with one another, is essential for operating successfully in today's business and research environments. Geotechnical engineering as a defined discipline forms such a group. Faculty in geotechnical engineering form a smalle...

On the evening of April 16 th , 2016, a moment magnitude Mw7.8 earthquake struck northern Ecuador, offshore of its west coast. The earthquake was named Muisne after the city of its epicenter, located about 29 km south-southeast of the town of Muisne, in the province of Manabí, at a hypocentral depth of 21 km. In the first 24 hours, over 135 aftersh...

On the evening of April 16 th , 2016, a moment magnitude Mw7.8 earthquake struck northern Ecuador, offshore of its west coast. The earthquake was named Muisne after the city of its epicenter, located about 29 km south-southeast of the town of Muisne, in the province of Manabí, at a hypocentral depth of 21 km. In the first 24 hours, over 135 aftersh...

A 30-m long railroad embankment failure that occurred on May 25 2011 in the city of Ann Arbor, Michigan, is presented. Emphasis is given on the field observations of the failure, the characterization of the site conditions and the seepage and slope stability analyses, all of which represent important components of the training and practice of a geo...

Pile driving is a complex dynamic process where little insight has been garnered in terms of the energy transfer from the driver to the soil and surrounding structures. Ground motion measurements during driving of full-scale steel H-piles with diesel hammers are presented. The key feature of this work is the in-depth sensor installation starting ve...

Spectral matching, the process of modifying a seed acceleration time history in intensity and frequency content until its acceleration response spectrum matches a target spectrum, is used extensively in practice. Predictive equations that quantify the impact of spectral matching on the peak ground velocity, peak ground displacement, Arias intensity...

Results are presented of numerical parametric analyses on the phase difference between seismic earth thrust and wall inertia, in the case of non-yielding earth retaining structures under earthquake loading. The FEM is used for modelling gravity, non-yielding walls with heights 4.0 m and 7.5 m, supporting horizontal cohesionless backfill with varyin...

Guidelines for selecting ground motions for evaluation of seismic slope displacements for earthen levees are proposed. These guidelines were developed based on results from two-dimensional equivalent-linear dynamic analyses of characteristic earthen levee cross sections using a wide range of ground motions (∼1;500). The effect of a number of ground...

The impact of different modification techniques on ground motion characteristics and results of seismic geotechnical analyses is investigated for a site in California. Twenty-eight motions were selected and scaled and also modified using both time domain (TD) and frequency domain (FD) techniques. PGV and PGD of the TD-modified motions are found to...

Two types of vibration damage caused by driving piles have been reported in the literature: direct structural damage and damage due to settlement. Direct damage results from vibratory excitation of structures at amplitude exceeding the structural tolerance. Damage from settlement is a consequence from vibratory densification of loose soils resultin...

Two types of vibration damage caused by driving piles have been reported in the literature: direct structural damage and damage due to settlement. Direct damage results from vibratory excitation of structures at amplitude exceeding the structural tolerance. Damage from settlement is a consequence from vibratory densification of loose soils resultin...

The results of an ongoing FEM parametric study are presented regarding the dependence of the resulting seismic displacements of gravity-type earth-retaining wall on backfill rigidity (j = 28°, 35°, and 42°), wall height (H = 4.0 m and 7.5 m), and shaking characteristics (ah = 0.1 g to 0.8 g). The response of the two walls was analyzed by using the...

Three gravel-sized materials are tested monotonically using a 305 mm diameter cyclic simple shear (CSS) device and then visually characterized using a translucent segregation table (TST), allowing for an assessment of the impact of particle size and morphology on the shear response of the materials. Three materials are tested to provide a range of...

An overview of past and recent developments on the subject of seismic earth pressures on yielding, gravity-type walls, retaining cohesionless backfill, is first presented, focusing on available data on the issue of phase difference that develops between the peak values of wall inertia and seismic earth thrust increment. The results of a FEM paramet...

Levees are very challenging engineering structures to study, in part because they are not typically well-engineered structures. Unfortunately, there is little to no guidance as to how to evaluate the seismic vulnerability of levees. This study focuses on systematically studying the dynamic response of levees using a wide range of input ground motio...

The work described here represents an attempt to understand the mechanisms of energy transfer from steel H-piles driven with diesel hammers to the surrounding soil and the energy attenuation through the soil by measuring ground motion vibrations in the near vicinity of the pile. Attenuation rates of vibration decay with radial distance from the dri...

Flood protection systems are complex, interconnected engineered systems, where failure at one location means the failure of the entire system. Earthen levees, the systems’ major component, are at risk from many causes of failure including seepage, overtopping, erosion and instability due to seismic loading. Levees stretch for long distances and are...

A large number of levee systems have embedded cutoff walls incorporated into their design in order to guard against instability due to excessive under and through seepage. Recent studies have indicated that these systems are vulnerable to seismic hazards and have raised the issue of seismic design of levees with cutoff walls. The seismic response o...

The effects of progressive failure on flood embankments with underlying thin layers of soft, sensitive soils are investigated. Finite element analysis allows for investigation of strain-softening effects and progressive failure in soft and sensitive soils. However, limit equilibrium methods for slope stability analysis, widely used in industry, can...

Flood protection levee systems are complex, interconnected systems, where failure at one location means failure of the entire system. Levees are formed through various geologic processes and human activities over time and information regarding soil properties is collected only at limited point locations and varies significantly both laterally and w...

Guidelines for selecting ground motions for liquefaction evaluation analysis of earthen levees are proposed. These guidelines were developed based on results from dynamic analyses of characteristic earthen levee cross sections using a wide range of ground motions (similar to 1,500). The effect of a number of ground motion parameters on the dynamic...

After more than half a century of increasing neglect, the nation's flood defenses are currently rated by the ASCE as having the very lowest levels of adequacy and reliability among all types of critical U.S. infrastructure, receiving a letter grade of straight "F" on the ASCE's Annual Infrastructure Report Card for the nation. Accordingly, the U.S....

The effects of progressive failure on flood embankments founded on soft, sensitive soils are investigated. Advances in finite element analysis have allowed for investigation of strain softening effects and progressive failure in embankments on soft and sensitive foundation soils. However, limit equilibrium methods for slope stability analysis, wide...

In areas of moderate to high seismicity, seismic loading typically controls the design of waste fills. In these areas, a reliable estimate of (strain-dependent) material properties of Municipal Solid Waste (MSW) is required for safe and economical design of waste fills. Our understanding of the dynamic properties of MSW has significantly improved s...

The effects of progressive failure on the behavior of failure surfaces through embankments with underlying thin layers of soft and sensitive soil is investigated. Finite element analysis allows for the investigation of strain softening effects and progressive failure through sensitive soils. However, limit equilibrium methods for slope stability an...

This paper examines the information provided by Homer related to the fields of engineering geology and geotechnical engineering. The information is subsequently compared against archaeological findings. The Homeric descriptions of battle scenes, of ancient cities and the geologic environment suggest that an understanding of some of the geologic pro...

In recent years, notable progress has been made with respect to the understanding of the mechanics of Municipal Solid Waste (MSW) response, and hence, generic MSW properties for static and seismic design of MSW landfills have been recommended. However, it is not clear if seismic design of MSW landfills based upon these generic material properties i...

A careful program of subsurface sampling and cone penetration test soundings was employed to characterize the geologic conditions beneath the failed portion of the 17th Street Canal levee in New Orleans, where a 150 m long section of the levee and floodwall translated up to 16 m when flood waters rose to 1 – 2 m of the wall's crest on August 29, 20...

The failure of the New Orleans regional flood protection systems, and the resultant catastrophic flooding of much of New Orleans during Hurricane Katrina, represents the most costly failure of an engineered system in U.S. history. This paper presents an overview of the principal events that unfolded during this catastrophic hurricane, and then a mo...

This paper addresses damage caused by Hurricane Katrina to the main Orleans East Bank protected basin. This basin represented the heart of New Orleans, and contained the main downtown area, the historic French Quarter, the Garden District, and the sprawling Lakefront and Canal Districts. Nearly half of the loss of life during this hurricane, and a...

The failure of the New Orleans regional flood protection systems, and the resultant catastrophic flooding of much of New Orleans during Hurricane Katrina, represents the most costly failure of an engineered system in U.S. history. This paper presents an overview of the principal events that unfolded in the central portion of the New Orleans metropo...

The failure of the levee and floodwall section on the east bank of the 17th Street drainage canal was one of the most catastrophic breaches that occurred during Hurricane Katrina. It produced a breach that rapidly scoured a flow pathway below sea level, so that after the storm surge had largely subsided, floodwaters still continued to stream in thr...

The failure of the levee and floodwall section on the east bank of the 17th Street drainage canal was one of the most catastrophic breaches that occurred during Hurricane Katrina. It produced a breach that rapidly scoured a flow pathway below sea level, so that after the storm surge had largely subsided, floodwaters still continued to stream in thr...

This paper examines the information provided by Homer related to the fields of engineering geology and geotechnical engineering. The information is subsequently compared against archaeological findings. The Homeric descriptions of battle scenes, of ancient cities and the geologic environment suggest that an understanding of some of the geologic pro...

The most populous of the four major protected areas that suffered significant flooding during Hurricane Katrina was the main Orleans East Bank (downtown) protected area. Two sets of failures and breaches admitted floodwaters to this region during hurricane Katrina: a series of failures along the Inner Harbor Navigation Channel - IHNC (as discussed...

The Inner Harbor Navigation Channel (IHNC) sits at the heart of the three main populated regions of New Orleans. As shown in Figure 1, a number of breaches of varying severity occurred along the shores of the IHNC during Hurricane Katrina, contributing to the flooding of all three of the most heavily populated protected areas flooded in this event....

The recent flooding and devastation of the greater New Orleans region during hurricane Katrina represented the most costly peace-time failure of an engineered system in North American history. Extensive investigations and analyses have been performed by several major teams in the wake of this disaster, and some very important lessons have been lear...

This report presents the results of an investigation of the performance of the New Orleans regional flood protection system during and after Hurricane Katrina, which struck the New Orleans region on August 29, 2005. This event resulted in the single most costly catastrophic failure of an engineered system in history. Current damage estimates at the...

Στην εργασία αυτή γίνεται μια παρουσίαση των Mυκηναϊκών έργων πολιτικού μηχανικού με έμφαση στη γεωτεχνική μηχανική. Aρχαιολογικά ευρήματα και αρχαία κείμενα χρησιμοποιούνται σε αυτή τη διερεύνηση. Aπό τη διερεύνηση αυτή καθίσταται προφανές ότι οι Mυκηναίοι μηχανικοί ήταν ικανοί κατασκευαστές με εκτεταμένη εμπειρία σε γεωτεχνικές κατασκευές που περ...