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2010

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Articles 511 - 540 of 1220

Full-Text Articles in Civil and Environmental Engineering

The Effect Of Step Load Moving On The Surface Of A Cylindrical Cavity Using Neural Networks, Hamed Saeidi, Mansour Nikkhah-Bahrami May 2010

The Effect Of Step Load Moving On The Surface Of A Cylindrical Cavity Using Neural Networks, Hamed Saeidi, Mansour Nikkhah-Bahrami

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Potential functions and Fourier series method in the cylindrical coordinate system are employed to solve the problem of moving loads on the surface of a cylindrical bore in an infinite elastic and isotropic medium. The steady state dynamic equations of medium are uncoupled by applying potential functions. The medium responses are obtained by using an appropriate numerical method of Laplace transform inversion. The solution has an integral form; therefore, a feedforward backpropagation neural network is designed and trained using the response evaluated numerically in a finite set of random points to approximate stress and displacement components in the medium. It …

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Numerical Modeling Of Buried Pipeline Crossing A Fault, Chaudhari Vasudeo Govind, Ramancharla Pradeep Kumar May 2010

Numerical Modeling Of Buried Pipeline Crossing A Fault, Chaudhari Vasudeo Govind, Ramancharla Pradeep Kumar

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Pipelines are common transportation means for oil and natural gas, which act as an important lifeline facility for any nation. Often the design of these pipelines is a difficult task because they commonly are installed underground passing through different types of soil media. Many of these existing pipelines run through the faulted area, which continuously exposed to considerable risk of failure due to movement along the fault. In this paper, a numerical study is carried out to understand stress development in buried pipeline subjected to fault motion with Mundra-Delhi pipeline as a case study. For this purpose, a 3D finite …

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Response Spectrum Estimation Using Support Vector Machines, Jale Tezcan, Qiang Cheng, Lincoln Hill May 2010

Response Spectrum Estimation Using Support Vector Machines, Jale Tezcan, Qiang Cheng, Lincoln Hill

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This study investigates the applicability and efficiency of support vector machines for the problem of estimating the earthquake response spectra from the Fourier amplitude spectra of the ground motion acceleration. Two methods are commonly used for this purpose: time domain simulations, and the random vibration theory. The use of time domain simulations offers high accuracy at high computational cost, while the use random vibration theory, although not computationally intensive, requires knowledge of the statistical distribution of the response amplitudes. This study treats the task of estimating response spectra from the Fourier spectra as a nonlinear regression problem, and constructs a …

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Analysis Of Aseismic Reliability Considering The Uncertainties Both Structural Parameters And Earthquake Loadings For The Gravity Type Earth-Retaining Wall, Zhiqiang Li, Jinbei Li, Yaping Kong May 2010

Analysis Of Aseismic Reliability Considering The Uncertainties Both Structural Parameters And Earthquake Loadings For The Gravity Type Earth-Retaining Wall, Zhiqiang Li, Jinbei Li, Yaping Kong

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A simple numerical deterministic approach for evaluating stochastic properties of structural systems with uncertain parameters under random seismic excitations (“double-random problem”) is presented. The method is based on the impulse response function method, the perturbation law and random central differential law. On the other hand, the equivalent linear model is used to account for the nonlinearity of soil. On the basis of the above random response analysis method, the aseismic reliability of earth-retaining wall is calculated and the analysis flow of dynamic reliability under the stationary random seismic action is also presented. From the above analysis, we can see that …

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Dynamic Response Of Cantilever Retaining Walls Considering Soil Non-Linearity, Leuzzi Francesco, S. Foti, R. Lancellotta, G. Mylonakis May 2010

Dynamic Response Of Cantilever Retaining Walls Considering Soil Non-Linearity, Leuzzi Francesco, S. Foti, R. Lancellotta, G. Mylonakis

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

For many decades the analysis of earth retaining structures under dynamic or seismic conditions has been carried out by means of standard limit equilibrium (Coulomb, M-O) or elastic methods (Wood, Veletsos and Younan). These approaches are simplified, as they make use of considerable approximations which are often applicable only under particular conditions. A different and perhaps more realistic approach is possible using established computer codes, which integrate numerically the governing equations of the soil and wall media. Since these problems may involve significant levels of strain in the backfill, material non-linearity should be taken into account to realistically simulate the …

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Seismic Analysis And Fragility Curves Of Gravity Waterfront Structures, Kalliopi Kakderi, Kyriazis Pitilakis May 2010

Seismic Analysis And Fragility Curves Of Gravity Waterfront Structures, Kalliopi Kakderi, Kyriazis Pitilakis

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The aim of the study is to propose adequate fragility curves for waterfront/ retaining structures for ground shaking without the presence of liquefaction, using available data from past earthquakes’ damages in Europe and worldwide and numerical analysis of typical cases. Existing fragility curves and damage states are evaluated and their shortcomings and/or limitations are assessed. Typical waterfront structures, with different geometry, foundation soil conditions and seismic excitations, are studied using appropriate numerical modeling. The corresponding damage levels are estimated with respect to the induced residual displacements and the seismic response of the soil-structure system. Considering aleatory uncertainties of the parameters …

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Seismic Analysis Of Retaining Wall Structures, Mohammadreza Abbasi Garavand, Alireza Saberi, Mona Salimi Ghezelbash May 2010

Seismic Analysis Of Retaining Wall Structures, Mohammadreza Abbasi Garavand, Alireza Saberi, Mona Salimi Ghezelbash

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper describes 3-D finite element dynamic analysis of retaining wall structures with consideration of the soil-structure interaction. Purpose of this study is to reduce damages due to earthquake in such structures. For this reason, finite element program ANSYS has been used. The analysis data is based on 1995 Kobe earthquake report and the results have been verified with some retaining walls were damaged in that earthquake. To take into account the non-linearity of soil-structure surface, surface to surface contact element is used. One of the most important problems in dynamic analysis is modeling of infinite media. If hinge or …

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Seismic Lateral Earth Pressures On Retaining Structures, A. Murali Krishna May 2010

Seismic Lateral Earth Pressures On Retaining Structures, A. Murali Krishna

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Various methods are available to estimate seismic earth pressures on soil retaining structures which cane be grouped to experimental, analytical and numerical methods. 1G model shaking table studies or high-g level centrifuge model shaking studies give some insight on the variation of seismic earth pressures along height of the retaining structure. In the simple analytical methods, M-O method based pseudo-static analysis is extensively used to evaluate seismic earth pressure variation and its probable resultant location. Pseudodynamic analysis method based analyses are also developed and are in progress for the same. Besides, these experimental and analytical methods, FEM or FDM based …

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Seismic Response Of Reinforced Soil Retaining Walls With Block Facings, Anitha Nelson, P. K. Jayasree May 2010

Seismic Response Of Reinforced Soil Retaining Walls With Block Facings, Anitha Nelson, P. K. Jayasree

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Reinforced soil walls have become very popular in seismic areas owing to their flexible nature and cost effectiveness when compared to the conventional retaining structures. Although the use of reinforced soil walls with modular block facings and gabion facings is growing world wide at a rapid rate, the seismic response of these walls is yet to be analyzed. This paper discusses the response of these walls in terms of lateral facing deflection, reinforcement tensile force and crest surface settlement when subjected to seismic loading simulated by means of a variable amplitude harmonic vibration using the finite element analysis package, PLAXIS …

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Seismic Soil Pressures On Rigid Walls With Sloped Backfills, Guoxi Wu May 2010

Seismic Soil Pressures On Rigid Walls With Sloped Backfills, Guoxi Wu

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Wood (1973) provided analytical solutions for the response of a rigid wall retaining elastic uniform soil backfill of finite length subjected to harmonic base excitation. Wu and Finn (1999) proposed a modified shear beam solution and derived closed-form formulations for computing dynamic soil pressures under harmonic loading. However, for rigid walls retaining sloped backfills, analytical solutions are not available for computing seismic soil pressures against the walls. In the current study, seismic soil pressures on rigid walls retaining 2H:1V (27°) sloped backfills have been computed using a total of eight acceleration time histories recorded in past large earthquakes. These records …

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An Upgrade Of The Microzonation Study Of The Centre Of Tirana City, Llambro Duni, Luljeta Bozo, Neki Kuka, Enkela Begu May 2010

An Upgrade Of The Microzonation Study Of The Centre Of Tirana City, Llambro Duni, Luljeta Bozo, Neki Kuka, Enkela Begu

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

An attempt was made in this paper to present an upgrade of the seismic microzonation of a part of the Tirana City. Some results of the previous, complete study performed in the late 80-s were used in this paper. The new aspect of this study is related to the probabilistic assessment of the ground motion parameters. Using gridded seismicity methodology, the PGA and the uniform response spectrum at the base rock corresponding to the 475-years return period were estimated. Based on them, five acceleration time histories are selected, which are later used to assess the response of the geotechnical models …

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Analysis Of Earthquake Site Response And Site Classification For Seismic Design Practices, Gloria M. Estrada May 2010

Analysis Of Earthquake Site Response And Site Classification For Seismic Design Practices, Gloria M. Estrada

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

In general, seismic provisions worldwide present different criteria for site classification, based on specific soil and rock properties, in order to determine representative design spectra for seismic design. On the other hand, results of site–specific analysis and seismic microzonation studies have shown not only the main properties of soil-rock profile that have marked influence on site response, but also site characteristics where it is necessary to carry out detailed and particular studies of earthquake ground response. This paper analyzes and compares site classification for seismic design of some seismic codes worldwide, with results of site-specific analysis and seismic microzonation studies. …

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Characterization Of The Elastic Displacement Demand: Case Study - Sofia City, Ivanka Paskaleva, Mihaela Kouteva, Franco Vaccari, Giuliano F. Panza May 2010

Characterization Of The Elastic Displacement Demand: Case Study - Sofia City, Ivanka Paskaleva, Mihaela Kouteva, Franco Vaccari, Giuliano F. Panza

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The results of the study on the seismic site response of a part of the metropolitan Sofia are discussed. The neo-deterministic seismic hazard assessment procedure has been used to compute realistic synthetic waveforms considering four earthquake scenarios, with magnitudes M=3.7, M=6.3 and M = 7.0. Source and site specific ground motion time histories are computed along three selected cross sections, making use of the hybrid approach, combining the modal summation technique and the finite differences scheme. Displacement and acceleration response spectra are considered. These results are validated against the design elastic displacement response spectra and displacement demand, recommended in Eurocode …

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Comparison Of Liquefaction Potential Evaluation Based On Different Field Tests, Syed M. Ali Jawaid May 2010

Comparison Of Liquefaction Potential Evaluation Based On Different Field Tests, Syed M. Ali Jawaid

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The lowlands of India are vulnerable to possible future large earthquakes. The liquefaction strength is estimated using in-situ tests and the factor of safety against liquefaction by comparing the liquefaction strength with cyclic shear stress ratio developed in the deposit during an earthquake. Standard Penetration test (SPT) and Cone Penetration test(CPT) have been most commonly used in-situ tests for characterization of liquefaction resistance. In this study, liquefaction potential is evaluated based on SPT as well as CPT data obtained from the three different locations situated in alluvial lowlands. A large difference in factor of safety against liquefaction is found based …

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Geotechnical And Seismic Risk Evaluation In Urban Areas, Piera Paola Capilleri, Michele Maugeri, Erminia Raciti May 2010

Geotechnical And Seismic Risk Evaluation In Urban Areas, Piera Paola Capilleri, Michele Maugeri, Erminia Raciti

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Seismic and geotechnical hazard problems are widespread all over the world and they can cause natural disasters, damaging properties or causing human lives losses. Italian municipalities are not yet organised either to deal with the phenomena consequences, or to plan risk mitigation actions. A clear knowledge of the location and of the space and time evolution of the phenomena is needed for a vulnerability mitigation in the probably involved areas. Geo-hazard can be related with the consequences for exposed people and man made work by a microzonation. GIS technologies could play a crucial role in analysing large areas, but a …

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Geotechnical Preconditions For Skyscrapers Construction In Bulgaria And Seismic Risk Aspect, Chavdar V. Kolev, Martina G. Perikliyska May 2010

Geotechnical Preconditions For Skyscrapers Construction In Bulgaria And Seismic Risk Aspect, Chavdar V. Kolev, Martina G. Perikliyska

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Parallel to the economic development of Bulgaria in the last nine – ten years there is a rapid raise in construction as well. This increase has been a good precondition for invest in some very high buildings with application of the newest technological achievements. These buildings are situated in the centrums of the largest Bulgarian cities: Sofia, Plovdiv, Varna and Bourgas. The Paper describes the geotechnical preconditions for construction of this type of buildings from seismic risk aspect. These preconditions are divided in four groups: geological, urban, technological and economical. The paper renders an account of the preconditions which are …

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The Meaning Of Eurocode 8 And Induced Seismicity For Earthquake Engineering In The Netherlands, J. W. R. Brouwer, T. Van Eck, F. H. Goutbeek, A. C. W. M. Vrouwenvelder May 2010

The Meaning Of Eurocode 8 And Induced Seismicity For Earthquake Engineering In The Netherlands, J. W. R. Brouwer, T. Van Eck, F. H. Goutbeek, A. C. W. M. Vrouwenvelder

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The Netherlands is one of the few European countries where seismic loading is not a dominant part of the national codes. Only for very special structures, earthquakes are regarded as a separate loading case. Until now, Eurocode 8 (EC8) is not part of Dutch building laws nor is there an official Dutch translation. Tectonic seismicity mainly occurs in the southern part of The Netherlands. The Dutch code NEN 6702 has a zonation map which shows horizontal peak accelerations of 0.01g to 0.1g for a return period of 5000 years. However, this seismic zonation map is yet not coherent with the …

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Seismic Microzonation Of The Texcoco Lake Area, Mexico, Luis Osorio Flores, Juan M. Mayoral Villa, Miguel P. Romo May 2010

Seismic Microzonation Of The Texcoco Lake Area, Mexico, Luis Osorio Flores, Juan M. Mayoral Villa, Miguel P. Romo

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper presents some of the most relevant results obtained from field, laboratory and analytical investigations aimed at characterizing the seismic environment prevailing at the Texcoco lake region, in the Valley of Mexico, with the goal of developing a microzonation. In particular, this study focuses on an area of 19.0 by 5.5 km2, which has been instrumented with four seismological stations: TXSO, TXS1, TXS2 and TXCH that have recorded ground motions for at least 15 years. Field investigations were conducted to define the subsoil conditions underneath each station. Dynamic testing in these high plasticity clays was carried out to establish …

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Application Of High-Power Electrical Sparks For Dynamic Compaction Of Soil, Kh. A. Dzhantimirov, S. A. Rytov, S. A. Kryuchkov May 2010

Application Of High-Power Electrical Sparks For Dynamic Compaction Of Soil, Kh. A. Dzhantimirov, S. A. Rytov, S. A. Kryuchkov

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The paper describes an electrical discharge technology, applied for soil compaction around a borehole, filled with hardening grout, in operations for erection of micropiles, cast piles, soil anchors and soil nails. The technology consists in that 150-250 microsecond long electrical sparks are generated with 6-second period in borehole. The sparks have 30-40 kJ energy, which is roughly of the same order of magnitude as a pile drop hammer. But a single electrical spark has 200-250 MW because of its short duration. Such pulses compact the contact layer of soil and thus increase bearing capacity of piles, anchors or soil nails …

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Floatation Of Tunnel In Liquefiable Soil, S. C. Chian, S. P. G. Madabhushi May 2010

Floatation Of Tunnel In Liquefiable Soil, S. C. Chian, S. P. G. Madabhushi

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Underground structures such as tunnels have a lower unit weight than the surrounding soil and are commonly deemed to be susceptible to floatation in liquefiable soil. In the process of floatation, the tunnel has to possess ample buoyancy force to shear and carry the overlying soil upwards. This is aided by soil liquefaction resulting from the increase in water pressure with number of earthquake loading cycles. With onset of liquefaction, effective stress decreases which lead to a reduction in the shear strength of soil, hence assisting the floatation of tunnel. Conversely, the total stress exerted by the overburden soil suppresses …

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The Influence Of Irregularity On The Values Of Demand Modifier Factor In Asce 41-06, M. R. Malek Mohammad May 2010

The Influence Of Irregularity On The Values Of Demand Modifier Factor In Asce 41-06, M. R. Malek Mohammad

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

In the past two decades, many investigations have been made on the methods related to the seismic retrofitting of the structures. As the real nonlinear behaviors of the elements are considered in these methods, the values of internal forces determined in the members are equal to the real ones. In the structural seismic linear analysis methods the elements behaviors are still assumed linear. In this regard, the passage of structure through yield point borders and the displacement increasing are correspondent to the forces elevation. In FEMA codes, the factors such as demand modifier (m) or increasing capacity ones are presented …

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Comparison Of Erosional Features By Tsunami And Wind Waves, B. K. Pal, M. K. Panda May 2010

Comparison Of Erosional Features By Tsunami And Wind Waves, B. K. Pal, M. K. Panda

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The erosion features from tsunami wave and wind wave are different according to the characteristics of the two kinds of waves. The tsunami wave is a shallow water wave, even in Deep Ocean, with very long wavelength and relatively high especially near shore. It does not break when attacking the shore. It composed of run-up and run-down. The waves which can scour the offshore sea bottom and deposit the sediment mostly sand on the coast called storm or tsunami over washes. The erosion features from storm wave are caused by the breaking waves and wind-driven currents. However, the erosion features …

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Vibro Replacement And Soil Mixing Ground Improvements At A Shopping Mall Site In San Diego, California, Usa, Lisheng Shao, Jack Kinley May 2010

Vibro Replacement And Soil Mixing Ground Improvements At A Shopping Mall Site In San Diego, California, Usa, Lisheng Shao, Jack Kinley

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A 230,000 ft2 (21,367 m2) addition was planned for construction at the Plaza Bonita shopping mall in San Diego, CA. The soil profile at the site consisted of fill soils underlain by alluvial deposits followed by San Diego Formation. The saturated loose sand layers were liquefiable and would result in significant settlement under the site design earthquake. In addition, soft clay layers would undergo excessive settlement under heavy building column loads. The geotechnical contractor proposed soil treatment with vibro replacement stone columns to mitigate the site liquefaction and to reduce static settlement under building column loads. Building …

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Assessment Of Rock Pressure For Tunnels In The Himalayan Region — A Case History, A. K. Dube May 2010

Assessment Of Rock Pressure For Tunnels In The Himalayan Region — A Case History, A. K. Dube

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Since early sixties numerous tunnels had been planned and constructed for hydro-electric power generation in the Himalayan Region of India. The mountain chain is of very recent origin geologically and is believed to be still active tectonically. The geology is complex and tunneling under such circumstances had been a real challenge. It was a tough task to predict the geotechnical behaviour of the tunneling media. Beginning with the classical approach of Terzaghi (1925-46) many rock pressure estimation theories had been evolved for prediction and estimation of rock pressure for designing competent and stable tunnel supports. The author has made an …

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Experimental Investigation Of Plastic Demands On Piles During Lateral Spread-Induced Loads, Barbara J. Chang, Tara C. Hutchinson May 2010

Experimental Investigation Of Plastic Demands On Piles During Lateral Spread-Induced Loads, Barbara J. Chang, Tara C. Hutchinson

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Past earthquakes have demonstrated that lateral spreading from liquefaction of the soil may cause undesirable movement and potential failure to the below ground portion of a pile foundation. For a multi-layer soil profile, the case of a dense crust layer overlying a liquefiable soil layer may create large localized plastic demands in the piles. To study this behavior and provide detailed data for use in model validation studies, a one-g shaking table experiment was conducted considering a single reinforced concrete pile embedded in a 3-layer soil system. The model pile of 10 inch diameter was tested in a sloped laminar …

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Large-Scale Shake Table Test On Lateral Spreading Of A Sheet-Pile Wall Model And Its Centrifuge Simulation, Masayoshi Sato, Kentaro Tabata, Akio Abe May 2010

Large-Scale Shake Table Test On Lateral Spreading Of A Sheet-Pile Wall Model And Its Centrifuge Simulation, Masayoshi Sato, Kentaro Tabata, Akio Abe

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The purpose of this test was to realistically reproduce soil liquefaction and the lateral spreading of saturated sand deposits behind the sheet-pile quay walls and the consequent deformation and translation of neighboring pile foundations. Therefore, a shake table test was carried out using a large-scale laminar box on the large-scale shake table in Tsukuba. The inside dimensions of the model were 11.6 m in length, 3.1 m in width and 4.5 m in depth. Next, a dynamic centrifuge test on the behavior of a sheet-pile wall and a soil pile system was conducted to simulate that of a large-scale shake …

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Numerical Analyses Of Centrifuge Models Of The Bart Transbay Tube, Jui-Ching Chou, Bruce L. Kutter, Thaleia Travasarou May 2010

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 …

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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 May 2010

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 …

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A Practical Approach For Implementing The Probability Of Liquefaction In Performance Based Design, Thomas Oommen, Laurie G. Baise May 2010

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 …

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Application Of Concave-Up P-Y Elements In Static Analysis Of Piles In Laterally Spreading Ground, Pirooz Kashighandi, Scott J. Brandenberg May 2010

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 …

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