Numerical Analyses Of Centrifuge Models Of The Bart Transbay Tube,
2010
University of California, Davis, CA
Numerical Analyses Of Centrifuge Models Of The Bart Transbay Tube, Jui-Ching Chou, Bruce L. Kutter, Thaleia Travasarou
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Centrifuge model tests were performed to study the stability and uplift mechanisms of the BART Transbay Tube. The tube is a cut-and-cover subway tunnel located in a highly seismic area. The low relative density of the backfill material around the tunnel and the low unit weight of the tunnel might make tunnel suffer uplift movement due to buoyancy forces caused by liquefaction of the backfill material during an earthquake. Three uplift mechanisms were observed in the centrifuge model tests: (1) a cyclic ratcheting mechanism of sand moving under the tunnel associated with cyclic lateral deformations of the tunnel;(2) flow of …
Using Tactile Pressure Sensors To Measure Lateral Spreading Induced Earth Pressures Against A Large, Rigid Foundation,
2010
University of Illinois at Urbana-Champaign, IL
Using Tactile Pressure Sensors To Measure Lateral Spreading Induced Earth Pressures Against A Large, Rigid Foundation, Scott M. Olson, Mark R. Muszynski, Carmine Polito, Youssef M. A. Hashash, Camilo Phillips
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Two centrifuge tests were performed at the NEES facility at Rensselaer Polytechnic Institute (RPI) to observe lateral earth pressures mobilized against a rigid foundation element during liquefaction-induced lateral spreading, as part of a larger NEESR study aimed at developing novel approaches to mitigate the effects of seismically-induced ground failures on large, rigid foundation elements. Models were constructed in a laminar box to allow unimpeded downslope soil displacement, and the sand in the model was liquefied during the centrifuge test. Lateral pressures prior to, during, and after shaking and liquefaction were directly measured using a novel device: tactile pressure sensors. Prior …
A Practical Approach For Implementing The Probability Of Liquefaction In Performance Based Design,
2010
Tufts University, Medford, MA
A Practical Approach For Implementing The Probability Of Liquefaction In Performance Based Design, Thomas Oommen, Laurie G. Baise
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Empirical Liquefaction Models (ELMs) are the usual approach for predicting the occurrence of soil liquefaction. These ELMs are typically based on in situ index tests, such as the Standard Penetration Test (SPT) and Cone Penetration Test (CPT), and are broadly classified as deterministic and probabilistic models. The deterministic model provides a “yes/no” response to the question of whether or not a site will liquefy. However, Performance-Based Earthquake Engineering (PBEE) requires an estimate of the probability of liquefaction (PL) which is a quantitative and continuous measure of the severity of liquefaction. Probabilistic models are better suited for PBEE but …
Application Of Concave-Up P-Y Elements In Static Analysis Of Piles In Laterally Spreading Ground,
2010
University of California, Los Angeles, CA
Application Of Concave-Up P-Y Elements In Static Analysis Of Piles In Laterally Spreading Ground, Pirooz Kashighandi, Scott J. Brandenberg
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Concave-up p-y behavior in liquefied sand has been observed by many researchers due to the dilatant tendency of sand that is dense of its critical state being suppressed in undrained loading. However, static analysis method often scale down the concave-down p-y curves that characterize drained loading, thereby missing the potentially important influence of concave-up behavior on pile response. For lateral spreading problems, large shear strains are typically assigned to the liquefied layer, which presupposes that the liquefied sand is soft and weak. This assumption is incompatible with the strengthening, stiffening concave-up p-y material. This paper presents a static lateral spreading …
Compaction Grouting For Seismic Mitigation Of Sensitive Urban Sites,
2010
C.T. Male Associates, P.C., Latham, NY
Compaction Grouting For Seismic Mitigation Of Sensitive Urban Sites, Richard C. Wakeman, Alan Evenson, Thomas Morgan, Joseph Pastore, J. Tanner Blackburn
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
For moderately loaded structures founded on liquefiable soils, spread footings on improved ground can provide considerable cost savings over deep foundation options. Liquefaction mitigation by ground improvement must be properly designed and executed; and should include a field verification program. Although densification is the most effective method of achieving verifiable mitigation of liquefaction susceptible soils, vibro-densification methods are often disregarded for urban sites due to concern for adjacent structures and utilities. An alternative to vibratory methods is compaction grouting, which can achieve densification of cohesionless materials while avoiding excessive vibration of adjacent structures. Recently, compaction grouting was successfully applied to …
Determination Of The Proper Thickness Of Sublayers For Analyzing Post-Liquefaction Deformation Associated With Seepage Of Pore Water After Earthquake,
2010
Tokyo Metropolitan University, Japan
Determination Of The Proper Thickness Of Sublayers For Analyzing Post-Liquefaction Deformation Associated With Seepage Of Pore Water After Earthquake, Ramez Alchamaa, Mitsutoshi Yoshimine
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The estimation of the large flow deformation in the liquefiable layered ground and its effects on a variety of civil structures and infrastructures is considered to be a significant concern in recent earthquakes. This paper proposes a new practical approach for estimating the appropriate thickness of sub-layers within a soil profile (soil element size) for simulating the post-liquefaction deformation considering the seepage flow of pore water after an earthquake. The findings of recent numerical analysis and extensive series of triaxial tests were utilized to develop the ability to analyze such fundamental issue. The study was conducted based on to the …
Liquefaction Potential Evaluation Based On Site Classes – A Performance Based Approach,
2010
Indian Institute of Science, India
Liquefaction Potential Evaluation Based On Site Classes – A Performance Based Approach, T. G. Sitharam, K. S. Vipin
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Lots of research work is being carried out in evaluating the liquefaction susceptibility. The main objectives of these studies are to identify the regions which are vulnerable to liquefaction. In the present study, an attempt has been made to predict the liquefaction susceptibility based on corrected SPT values required to prevent the liquefaction for given return periods. The evaluation of liquefaction susceptibility requires the calculation of two parameters, seismic loading and the soil resistance. In most of the studies, the seismic loading will be evaluated based on probabilistic methods and the evaluation of soil resistance will be done based on …
Calibrated 3d Computational Modeling Of Soil-Structure Systems And Liquefaction Scenarios,
2010
University of California San Diego, La Jolla, CA
Calibrated 3d Computational Modeling Of Soil-Structure Systems And Liquefaction Scenarios, Ahmed Elgamal
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Three-dimensional (3D) computational simulation is increasingly allowing for insights into the mechanics of seismic soil-structure system response. Calibration is being facilitated by field, full-scale, and centrifuge model laboratory data. Computational algorithms and scenario-specific graphical user-interfaces are gradually permitting the routine adoption of such geometrically realistic simulation environments. This paper presents an overview of salient recent 3D soil-foundation-structure earthquake response simulations. Developments related to graphical user-interfaces (OpenSeesPL, http://cyclic.ucsd.edu/openseespl) are summarized, demonstrating the current and evolving capabilities towards performance-based earthquake engineering (PBEE). From an OpenSeesPL-generated lateral push-over analysis of a large pile-group, it is shown that corner piles may shoulder a significantly …
Case Histories And Energy-Based Evaluation On Travel Distance Of Slope Failures During Recent Earthquakes,
2010
Chuo University, Japan
Case Histories And Energy-Based Evaluation On Travel Distance Of Slope Failures During Recent Earthquakes, Takaji Kokusho, Tomohiro Ishizawa
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
An energy approach evaluating travel distance of debris in slope failures is proposed here, in which earthquake energy and gravitational potential energy are dissipated in flow deformations. Shake table model tests of dry sand slopes are carried out in which the earthquake energy dissipated in slope failure can be successfully quantified. The model tests indicate that measured slope displacements can be reliably evaluated by the proposed energy approach based on a rigid block model if an appropriate friction coefficient of the slope is specified. The energy approach is then applied to a number of slopes failed during recent earthquake in …
Estimation Of Displacement Demand For Seismic Design Of Bridges With Rocking Shallow Foundations,
2010
University of California, Davis, C
Estimation Of Displacement Demand For Seismic Design Of Bridges With Rocking Shallow Foundations, Bruce L. Kutter, Lijun Deng, Sashi Kunnath
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Rocking foundations provide many desirable characteristics for a yielding dynamic system; they are economical, they provide a ductile (energy dissipating) moment limiting hinge, and they have a natural re-centering tendency. In order to take advantage of these characteristics in routine practice, simplified design procedures for bridge systems with rocking foundations are required. Two performance targets for deterministic seismic bridge design are: collapse should not occur during the “Maximum Credible Earthquake”, and, the serviceability of the bridge should not be compromised during smaller events that are expected during the lifetime of the structure (Functional Evaluation Earthquakes). The crux of the design …
Integrated Earthquake Resistant Design Of Structure-Foundation Systems,
2010
University of Auckland, New Zealand
Integrated Earthquake Resistant Design Of Structure-Foundation Systems, Michael J. Pender
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In this paper the case is made for an integrated approach to the earthquake resistant design of structure-foundation systems. Emphasis is placed on the need to analyse the response of a system that has the foundation and structure modelled with comparable levels of sophistication. The paper gives examples which illustrate what can be achieved with simplified models that represent the essence of the structural and foundation behaviour. However, to achieve a truly integrated structure-foundation design the investigation of the soil in which the foundation will be constructed needs to receive effort comparable to that expended in modelling the structurefoundation system. …
Modeling The Observed Site Response From Istanbul Strong Motion Network,
2010
Bogaziçi University, Turkey
Modeling The Observed Site Response From Istanbul Strong Motion Network, Atilla Ansal, Gökçe Tönük, Aslı Kurtuluş, Mustafa Erdik, Stefano Parolai
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
An extensive site investigation study was carried out in the European side of Istanbul as part of the large-scale microzonation project for the Istanbul Metropolitan Municipality. 2912 borings mostly down to 30m depth with approximately 250m spacing were conducted within an area of 182 sqkm to investigate local site conditions. 55 stations of the Istanbul Rapid Response Network and Ataköy vertical array are located in this area. There have been few small earthquakes in the recent years with local magnitude slightly over M=4. One of these earthquakes took place on 12/3/2008 in Yalova with local magnitude of M=4.8. Vertical array …
Seismic Response Of Deep Foundations Subjected To Liquefaction-Induced Lateral Spreading: Integrated Research And Practical Implications,
2010
Rensselaer Polytechnic Institute, Troy, NY
Seismic Response Of Deep Foundations Subjected To Liquefaction-Induced Lateral Spreading: Integrated Research And Practical Implications, Ricardo Dobry, Tarek Abdoun
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Integrated research is described on the response of pile foundations subjected to lateral ground deformations associated with sand liquefaction. Field evidence, experiments and analysis have indicated that pile bending and other response aspects depend on a complex manner on – and are very sensitive to - several parameters including the specific foundation and structural system, the free field ground deformation, and soil aspects such as layering and properties of nonliquefied and liquefied soil strata. The research presented focuses on sites where the liquefiable soil reaches the ground surface (especially important to bridge foundations), showing that in this case the permeability …
Architecture As An Expression Of Identity: Abbas Hilmi Ii And The Neo-Mamluk Style,
2010
School of Oriental and African Studies, Germany
Architecture As An Expression Of Identity: Abbas Hilmi Ii And The Neo-Mamluk Style, Nadania Idriss
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper examines the religious architecture that was built at the end of the nineteenth, beginning of the twentieth century, during the rule of Abbas Hilmi II (1892-1914). The architecture is examined in light of the political and cultural climate of the time period. European influences brought new tastes for building styles, and the Neo-Mamluk became popularized for mosque architecture.
Sand Plasticity Model For Nonlinear Seismic Deformation Analyses,
2010
University of California, Davis, CA
Sand Plasticity Model For Nonlinear Seismic Deformation Analyses, Ross W. Boulanger
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A sand plasticity model for nonlinear seismic deformation analyses is presented. The model follows the basic framework of the stressratio controlled, critical state compatible, bounding surface plasticity model for sand presented by Dafalias and Manzari (2004). Modifications to the model were implemented to improve its ability to approximate the stress-strain responses important to geotechnical earthquake engineering applications; in essence, the model was calibrated at the equation level to provide for better approximation of the trends observed across a common set of experimentally- and case history-based design correlations. An overview of the model formulation and example simulations of element loading tests …
Liquefaction-Induced Movements Of Buildings With Shallow Foundations,
2010
University of California Berkeley, Berkeley, CA
Liquefaction-Induced Movements Of Buildings With Shallow Foundations, Jonathan D. Bray, Shideh Dashti
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Seismically induced settlement of buildings with shallow foundations on liquefiable soils has resulted in significant damage in recent earthquakes. In Adapazari, Turkey multi-story buildings punched into, tilted excessively, and slid laterally on softened ground. The state-of-the-practice still largely involves estimating building settlement using empirical procedures developed to calculate postliquefaction consolidation settlement in the free-field. This approach cannot possibly capture shear-induced and localized volumetricinduced deformations in the soil underneath shallow mat foundations. Geotechnical centrifuge experiments were performed recently to identify the dominant mechanisms involved in liquefaction-induced building settlement. The centrifuge tests revealed that considerable building settlement occurs during earthquake strong shaking. …
Recent Advances In Non-Linear Site Response Analysis,
2010
University of Illinois at Urbana-Champaign, Urbana, Illinois-USA 61801
Recent Advances In Non-Linear Site Response Analysis, Youssef M. A. Hashash, Camilo Phillips, David R. Groholski
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Studies of earthquakes over the last 50 years and the examination of dynamic soil behavior reveal that soil behavior is highly nonlinear and hysteretic even at small strains. Non-linear behavior of soils during a seismic event has a predominant role in current site response analysis. The pioneering work of H. B. Seed and I. M. Idriss during the late 1960’s introduced modern site response analysis techniques. Since then significant efforts have been made to more accurately represent the non-linear behavior of soils during earthquake loading. This paper reviews recent advances in the field of non-linear site response analysis with a …
Recent Advances In Seismic Design Of Geosynthetically-Lined Waste Containment Facilities,
2010
Geosyntec Consultants, Huntington Beach, CA
Recent Advances In Seismic Design Of Geosynthetically-Lined Waste Containment Facilities, Neven Matasovic
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Geosynthetic materials are essential elements of almost all modern landfill barrier systems. Materials such as geomembranes and geosynthetic clay liners are widely used as resistive barrier elements while geotextiles, drainage nets, and geocomposites are widely employed in modern composite barrier systems for both landfill liners and covers. The ability of these geosynthetic elements to maintain their integrity when subject to deformations due to waste settlement and seismic loading is a major uncertainty with respect to the performance of modern landfills. Over past years, advances have been made in understanding of material behavior under cyclic loading, modeling of modern landfill response …
Zero-Gravity Triaxial Shear Tests On Mechanical Properties Of Liquefied Sand And Performance Assessment Of Mitigations Against Large Ground Deformation,
2010
University of Tokyo, Japan
Zero-Gravity Triaxial Shear Tests On Mechanical Properties Of Liquefied Sand And Performance Assessment Of Mitigations Against Large Ground Deformation, Ikuo Towhata, Trinh Thi Lan Anh, Suguru Yamada, Ramin Motamed, Yoshikazu Kobayashi
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper concerns prediction of liquefaction-induced large deformation of geotechnical structures that will play major roles in practice of seismic performance design. To do this prediction, it is essential to establish a mechanical model for liquefied sand in which effective stress is null or extremely low. Although past model tests suggested that liquefied sand behaves similar to viscous liquid, there is an opinion against it that pore water pressure distribution in embedded structures produces an apparent rate-dependent behavior. This opinion was examined precisely and quantitatively by analyzing a full-scale model test to find that the pore pressure theory cannot account …
Geotechnical Aspects Of Recent Pakistan Earthquakes,
2010
NUST Institute of Civil Engineering, Pakistan
Geotechnical Aspects Of Recent Pakistan Earthquakes, Sarfaraz Ali, Liaqat Ali, Muhammad Ammar
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Geologically, Kashmir and northwestern areas of Pakistan are located in most active seismic zones of sub-continent. In Kashmir area, earthquakes had been triggered by a continuous subduction phenomenon of Indian plate under Eurasian plate; a collision zone that created Himalaya Mountain range and still giving it a rise of 1 cm each year. The Quetta earthquake occurred on part of the left-lateral Chaman Fault System and was measured 8.1 on Richter scale with focal depth of 17 km. The earthquake completely devastated the city of Quetta, leaving 35000-60000 dead and injuring thousands of people in affected areas. The Kashmir earthquake …
