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2010

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Articles 2281 - 2310 of 5375

Full-Text Articles in Engineering

Dynamic Winkler Modulus For Axially Loaded End-Bearing Piles, George M. Anoyatis, George E. Mylonakis May 2010

Dynamic Winkler Modulus For Axially Loaded End-Bearing Piles, George M. Anoyatis, George E. Mylonakis

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

The problem of dynamic pile-soil interaction and its modeling through the concept of a Dynamic Winkler Foundation are revisited. It is shown that depth-dependent Winkler springs and dashpots, obtained by dividing the complex-valued soil shear tractions and the corresponding displacements along the pile, may faithfully describe pile-soil interaction, contrary to common perception that the Winkler model is always approximate. A theoretical wave model is then derived for analyzing the response of axially loaded endbearing piles embedded in a homogeneous viscoelastic soil medium. Closed-form solutions are obtained for: (i) the displacement field in the soil and along the pile; (ii) the …

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Effect Of Uplift Modelling On The Seismic Response Of Shallow Foundations, Liam Wotherspoon, Michael Pender May 2010

Effect Of Uplift Modelling On The Seismic Response Of Shallow Foundations, Liam Wotherspoon, Michael Pender

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

This paper presents the development and response of a numerical model for the representation of uplift and reattachment of shallow foundations using the Ruaumoko non-linear dynamic analysis software. Vertical loads carried by the foundation were used to control the rotational and horizontal characteristics, as the stiffness of all degrees of freedom must reduce as the footing progressively detaches from the underlying soil. This culminates in the representation of total uplift, where the foundation provides no stiffness in any degree of freedom until vertical loads become compressive again. Through extension of the capabilities of Ruaumoko, this response was able to be …

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Estimation Of Lateral Load Capacity Of Short Piles Under Earthquake Force, Indrajit Chowdhury, Shambhu P. Dasgupta May 2010

Estimation Of Lateral Load Capacity Of Short Piles Under Earthquake Force, Indrajit Chowdhury, Shambhu P. Dasgupta

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

Lateral load induced in piles (both long and short) under earthquake is a problem of serious complexity that has been plaguing professional engineers and researchers alike for quite some time. The practice in vogue is to ensure that fixed base shear of the column does not exceed static shear load capacity of the piles. Inertial and stiffness effects of pile are usually ignored in dynamic earthquake analysis. The present paper proposes a method where, based on modal response or time history analysis, load on short piles may be estimated under earthquake considering its stiffness, inertia, effect of material and geometric …

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Effects Of Soil-Structure Interaction On Stress Distribution Within A Pile Group Under Multi-Dimensional Loading, Hiroko Suzuki, Kohji Tokimatsu May 2010

Effects Of Soil-Structure Interaction On Stress Distribution Within A Pile Group Under Multi-Dimensional Loading, Hiroko Suzuki, Kohji Tokimatsu

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

To investigate inertial and kinematic effects on stress distributions within a pile group, physical model tests were conducted at EDefense, one of the largest shaking table facilities in the world. A 3x3 steel pile group supporting a foundation with a superstructure was set in a dry sand deposit prepared in a cylindrical laminar box with a height of 6.5 m and a diameter of 8.0 m. Natural periods of superstructures were variable in the tests. The tests were conducted under one-, two- or three-dimensional shaking. The test results have shown that pile stresses were mainly controlled by the inertial force …

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Influence Of Soil-Structure Interaction On Seismic Response Of Shear Buildings, Stefano Renzi, George Mylonakis, Giovanni Vannucchi, Claudia Madiai May 2010

Influence Of Soil-Structure Interaction On Seismic Response Of Shear Buildings, Stefano Renzi, George Mylonakis, Giovanni Vannucchi, Claudia Madiai

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

The beneficial or detrimental effect of dynamic Soil-Structure Interaction (SSI) is a controversial issue. With reference to an idealized R/C shear building, a comprehensive comparison between the results obtained with a classical fixed-base analysis and a complete SSI analysis is provided in the present paper. The shear-type structure is modeled as generalized Single Degree Of Freedom (SDOF) system using the principle of virtual displacements. The foundation consists of surface square foundations resting on different soil conditions, consistent with the provisions of EC8-part I. SSI effects in the far-field of earthquakes was evaluated by direct application of the elastic pseudo-acceleration/displacement design …

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Interaction Between Superstructure And Substructure In Railways, Konstantinos Giannakos May 2010

Interaction Between Superstructure And Substructure In Railways, Konstantinos Giannakos

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

The railway track superstructure undertakes the forces that develop during train movement and distributes them towards its seating. The track panel (sleepers with their fastenings or slab with the fastenings) plays a key role in terms of load distribution, while at the same time it ensures the stability of the geometrical distance between the rails. Earthworks and ballast (if it exists) undergo residual deformations, settlements and lateral displacements, directly influencing the deterioration of the so-called geometry of the track, which can be nevertheless described much more specifically as quality of the track. In this paper, a parametric investigation of the …

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Nonlinear Soil-Pile Interaction Under Vertical And Coupled Motion, Bappaditya Manna, Dilip Kumar Baidya May 2010

Nonlinear Soil-Pile Interaction Under Vertical And Coupled Motion, Bappaditya Manna, Dilip Kumar Baidya

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

This paper presents the test results of single (L/d = 15) and 2 x 2 group piles (L/d = 15 and s/d = 2, 3, 4) subjected to strong vertical and coupled vibration. The observed response curves display marked nonlinearity as the natural frequencies decreases with increasing intensity of excitation. The measured response is compared with the results obtained by using the continuum approach of Novak with dynamic interaction factor. To account for the nonlinear response of the piles, provisions are made for yielding of soil around the piles by introducing the weak boundary zone effect concept in the model. …

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Numerical Analysis Of Disconnected Spread Footing On Soft Soil During Strong Earthquake, Sascha Richter, Roberto O. Cudmani May 2010

Numerical Analysis Of Disconnected Spread Footing On Soft Soil During Strong Earthquake, Sascha Richter, Roberto O. Cudmani

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

For the design of the Golden Ears approach bridge in Vancouver (Canada) a disconnected spread footing (DSF) was considered as alternative to a conventional pile foundation. In a DSF, a spread footing rests on natural ground improved by piles. Footing and piles are separated by a layer of coarse grained material. The mechanisms governing the behavior of the DSF during strong earthquake events have been investigated in a numerical finite element (FE) analysis using a (visco-)hypoplastic constitutive relationship. The FE model consists of a soil column (height 45 m) which includes the concrete piles. The superstructure is represented by a …

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Pile-In-Tube Foundations With Reserve Switch-Off Elements And Other Systems For Seismic Response Adaptive Control, J. M. Eisenberg May 2010

Pile-In-Tube Foundations With Reserve Switch-Off Elements And Other Systems For Seismic Response Adaptive Control, J. M. Eisenberg

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

Predominant ground motion frequencies and spectra could differ sufficiently at different earthquakes on one site. The reasons of the differences are the epicenter distance, the focal depth, and many others. As it is well known, the frequency spectral configuration and predominant frequency values influence the structural seismic response and seismic behavior of structures (Mexico earthquakes 1957, 1962; Bucharest, 1977, Spitak, Armenia, 1988 and other). The maximum seismic response depends of how close the fundamental frequency values of the structure are to the predominant ground motion frequencies. Seismoisolation as an effective approach to seismic response control became popular recent decades in …

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Seismic Analysis Of Pile Group Using Pseudostatic Approach, H. Elahi, M. Moradi, H. G. Poulos, A. Ghalandarzadeh May 2010

Seismic Analysis Of Pile Group Using Pseudostatic Approach, H. Elahi, M. Moradi, H. G. Poulos, A. Ghalandarzadeh

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

This paper evaluates a simple approximate pseudostatic method for estimating the maximum internal forces and horizontal displacements of pile group subjected to lateral seismic excitation. The method involves two main steps. At first the free-field soil movements caused by the earthquake are computed. Then the response of the pile group based on the maximum free-field soil movements which considered as static movements as well as a static loading at the pile head, which depends on the computed spectral acceleration of the structure being supported is analyzed. The methodology takes into account the effects of group interaction and soil yielding at …

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Seismic Response Of Barrage Raft Floor Under Heterogeneous Soil Medium, Kumar Venkatesh, A. D. Pandey, N. K. Samadhiya May 2010

Seismic Response Of Barrage Raft Floor Under Heterogeneous Soil Medium, Kumar Venkatesh, A. D. Pandey, N. K. Samadhiya

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

Seismic analyses of a barrage raft floor resting on homogeneous and heterogeneous subsoil condition were carried out by means of finite element modeling and analysis. Three dimensional models considering soil-raft-structure system were developed for both circumstances. The soil continuum, cut-off, pier, beam and abutment were modeled using eight noded brick element whereas raft floor was modeled using four noded plate bending element. The relevant amount of soil around and bottom of the barrage raft foundation has been modeled to find the effect of homogeneous and heterogeneous soil media on the seismic behavior of barrage raft floor. The seismic analysis was …

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Seismic Response Of Inelastic Pile Foundations: A New Performance Based Design Philosophy, Nikos Gerolymos, Vassilis Drosos, George Gazetas May 2010

Seismic Response Of Inelastic Pile Foundations: A New Performance Based Design Philosophy, Nikos Gerolymos, Vassilis Drosos, George Gazetas

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

While seismic codes do not allow plastic deformation of piles, the Kobe earthquake has shown that limited structural yielding and cracking of piles may not be always detrimental. This paper focuses on the influence of soil compliance, pile-to-pile interaction, intensity of seismic excitation, pile diameter, above–ground height of the pile, location of plastic hinges (above or below ground development), on the seismic response of pile supported bridge structures. Evaluation of the bridge pier behaviour is achieved through key performance measure indices, as is: the displacement (global) and curvature (local) ductility demands and the maximum drift ratio. It is shown that …

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Soil-Structure Interaction Analysis For Bridge Caisson Foundation, Zhao Cheng, Hubert Law, Yang Jiang May 2010

Soil-Structure Interaction Analysis For Bridge Caisson Foundation, Zhao Cheng, Hubert Law, Yang Jiang

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

In the practical seismic analysis for the project of South Park Bridge Replacement, the caisson foundations are modeled as Winkler springs in the global bridge model. The global bridge model is then excited by depth-varying ground motions acting along the height of the caisson. The foundation model would entail Winkler springs distributed over the surfaces of caisson to represent the soil continuum underlying the foundation and passive soil pressure acting on the sides. The soil springs are nonlinear for consideration of yielding of localized soil. In addition, gapping elements can also be implemented in series with the soil springs to …

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Structure-To-Soil-Structure Interaction Analysis: A Case Study, Lisa M. Anderson, Tarek Elkhoraibi May 2010

Structure-To-Soil-Structure Interaction Analysis: A Case Study, Lisa M. Anderson, Tarek Elkhoraibi

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

Current industry codes, such as ASCE 4-98 recommend consideration of Structure-to-Soil-Structure Interaction (SSSI) only when it is determined to have a significant effect on local results. In some cases, it is not computationally feasible, or too costly, to analyze an explicit model including a complex of all contributing structures. The significance of SSSI is dependent upon several variables, namely the characteristics of the soil, structures, and ground motion, as well as the spatial distance between structures. The SSSI effect is most significant for lighter structures adjacent to more massive structures that are founded on soil sites. The Hanford Waste Treatment …

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Times-History Finite Element Dynamic Analysis - Soil Nail Wall - San Manuel Casino - Highland, California, Pirooz Barar, Qing Liu May 2010

Times-History Finite Element Dynamic Analysis - Soil Nail Wall - San Manuel Casino - Highland, California, Pirooz Barar, Qing Liu

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

The site of the proposed Phase II Parking Facility at the San Manuel Resort Casino, Highland, California, is on a sloped terrain where there is a 35 ft. grade differential from the north to the south end of the planned structure. PB&A, Inc. was selected to design a 12,000 square foot Soil-Nailed wall with a maximum height of 37 ft. to protect the Parking Structure from the soil pressures resulting from sloping ground conditions at the site. The project site is located within 100 feet of the San Andreas Fault in the highly seismic Southern California region, characterized by numerous …

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Wave-Induced Strength Weakening Of Soft Clay Below A Prefabricated Caisson Dike, Shuwang Yan, Jian Chu, Qijin Fan May 2010

Wave-Induced Strength Weakening Of Soft Clay Below A Prefabricated Caisson Dike, Shuwang Yan, Jian Chu, Qijin Fan

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

A case history of constructing offshore guide dikes on soft clay is presented in this paper. The guide dikes were constructed near the Shanghai Port, China, for deepening of navigation channel along the Yangtze Estuary. The guide dikes were designed as gravity retaining structures using prefabricated, semi-circular shaped concrete caissons. Some sections of the guide dikes were installed on a thick layer of soft soils. During the construction, the caissons in one section failed under a heavy storm. The causes of failure were investigated by running dynamic triaxial tests on undisturbed soil samples taken from the construction site, associated with …

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Soft Soil Effect On Soft Storey Response, Tahmeed M. Al-Hussaini, Kamruzzaman Khan May 2010

Soft Soil Effect On Soft Storey Response, Tahmeed M. Al-Hussaini, Kamruzzaman Khan

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

Multi-storied reinforced concrete frame (RCF) buildings with open first storey to provide parking space is common in Dhaka city, the capital of Bangladesh. Such buildings are likely to produce soft storey action when subjected to earthquake loadings. Bangladesh building code places Dhaka in a moderate earthquake zone with a zone coefficient (Z) value of 0.15. Several soft soil sites exist in the city, most of which have been created by filling up of low lands and water bodies without proper compaction. Such soft soil sites are likely to produce major site amplification effects during earthquakes. One-dimensional wave propagation using the …

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The Variable Damping Concept In Pile Capacity Prediction By Wave Equation Analysis, Mark R. Svinkin May 2010

The Variable Damping Concept In Pile Capacity Prediction By Wave Equation Analysis, Mark R. Svinkin

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

A wave equation method is applied for pre-driving analysis of driveability calculations and capacity prediction of driven piles. For the majority of piles, there are substantial differences between predicting results and pile capacities determined from static or dynamic tests. Correct calculations of the dynamic resistance are important for accurate prediction of the pile capacity. The dynamic resistance depends on the pile velocity and the damping coefficient, but both of them cannot reflect time-dependent changes of the pile-soil system after the end of driving. Variation of the pile-soil system after pile installation can be taken into account with a variable damping …

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A Review Of Seismic Lrfd (Load-And-Resistance Factor Design) Method For Mse (Mechanically Stabilized Earth) Walls, Fransiscus S. Hardianto, Kim M. Truong, John E. Sankey May 2010

A Review Of Seismic Lrfd (Load-And-Resistance Factor Design) Method For Mse (Mechanically Stabilized Earth) Walls, Fransiscus S. Hardianto, Kim M. Truong, John E. Sankey

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

The introduction of AASHTO’s LRFD (load-and-resistance factor design) method for the design of MSE (mechanically stabilized earth) walls in 2004 has gradually replaced conventional state-of-the-practice seismic ASD (allowable stress design) method in some states, and by FHWA mandate should completely replace the ASD method by 2010. Limit equilibrium analyses based on Mononabe- Okabe (M-O) pseudo-static method had been the standard method of estimating the seismic external thrust and inertia force for MSE walls. Considering the flexible nature of MSE walls that allow deformation without compromising structural integrity, in the LRFD method, the displacement based pseudo-static method that was developed from …

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Application Of Vertical Reinforcement For Performance Enhancement Of Reinforced Soil Under Seismic Loading, Binod Shrestha, Hadi Khabbaz May 2010

Application Of Vertical Reinforcement For Performance Enhancement Of Reinforced Soil Under Seismic Loading, Binod Shrestha, Hadi Khabbaz

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

Reinforced soils have been widely used in geotechnical structures as a result of their satisfactory performance and cost effectiveness. A number of investigations have been carried out to find out the seismic deformation modes of reinforced soil walls with conventional horizontal inclusions. This study puts forward a new concept of soil reinforcement, applying vertical reinforcement together with conventional horizontal reinforcement. A key difference between the general practice and after insertion of vertical reinforcement is that the latter not only provides passive resistance against shearing due to making intact layers but also increases the strength and stability of the reinforced soil. …

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Effects Of Internal Gas Explosion On An Underwater Tunnel Roof, Omar Al-Farouk Salem Al-Damluji, Akram Younis Thannon Al-Sa'aty, Rafi' Mahmoud Sulaiman Al-Nu'aimy May 2010

Effects Of Internal Gas Explosion On An Underwater Tunnel Roof, Omar Al-Farouk Salem Al-Damluji, Akram Younis Thannon Al-Sa'aty, Rafi' Mahmoud Sulaiman Al-Nu'aimy

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

An underwater reinforced concrete tunnel roof is subjected to an internal gas explosion. Dynamic analyses are performed for three cases, namely, (1) an uncoupled solution, (2) class II coupling analysis and (3) full model with class I and II couplings. Three load cases are considered, dead (gravity) load, uniformly distributed vertical loads from sand and water and finally an internal pressure gas explosion. Linear and non-linear constitutive relationships are considered for the materials constituting the gas explosion problem. Results include time deflection of tunnel roof, time histories of stresses in vertical reinforcing bars and contours of concrete stresses for tunnel …

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Effects Of Wall-Soil-Structure Interaction On Seismic Response Of Retaining Wall, Aditya Parihar, Navjeev Saxena, D. K. Paul May 2010

Effects Of Wall-Soil-Structure Interaction On Seismic Response Of Retaining Wall, Aditya Parihar, Navjeev Saxena, D. K. Paul

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

Retaining walls have suffered damages under past earthquakes. Usually the analyses do not consider the retained soil’s interaction with the wall, which takes place during dynamic conditions. The consideration makes the wall-soil system more flexible than the wall alone. The conditions of separation of wall (during interactions) again change the dynamic characteristics of the assumed wall-soil system that needs to be addressed. The paper presents a study on the behavior of the retaining wall under static as well as seismic conditions considering above aspects. The wall-soil interaction model incorporates the modeling of interface between them. The system is idealized as …

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Numerical Simulation Of The Performance Of Cantilever Walls Subjected To Seismic Loading, Alberto Pettiti, Dominic Assimaki, Sebastiano Foti May 2010

Numerical Simulation Of The Performance Of Cantilever Walls Subjected To Seismic Loading, Alberto Pettiti, Dominic Assimaki, Sebastiano Foti

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

The design of flexible earth retaining structures against seismic loading is a challenging geotechnical problem, and it is typically conducted using pseudo-static approaches, which do not adequately represent the transient loading conditions of earthquake motions. Numerical analyses of designed walls with simplified material models showed high stresses in the structure when subjected to both dynamic and pseudo-static conditions, and a very large amount of reinforcement would be required to avoid the formation of plastic hinges. On the other hand, detailed simulations with inelastic material behaviour would yield more realistic estimations of the retaining structural response and improve the efficiency of …

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A Comparison Of Local Site Conditions With Passive And Active Surface Wave Methods, Arif Mert Eker, Haluk Akgün, Mustafa Kerem Koçkar May 2010

A Comparison Of Local Site Conditions With Passive And Active Surface Wave Methods, Arif Mert Eker, Haluk Akgün, Mustafa Kerem Koçkar

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

This study encompasses dynamic soil characterization and seismic hazard mapping of the Plio-Quaternary and especially Quaternary alluvial sediments of the Çubuk district and its close vicinity that is situated towards the north of Ankara. The project site is located at a region which has a potential of being seriously affected by a possible earthquake occurring along the Çubuk Fault Zone that is thought to be a continuation of the Dodurga Fault Zone and a sub-fault belt of the North Anatolian Fault System that is one of the most prominent fault systems in Turkey with significant earthquake potential. Non-invasive seismic methods …

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An Alternative Method For Probabilistic Seismic-Hazard Assessment: A Case Study Of Three Cities, Hing-Ho Tsang, Saman Yaghmaei-Sabegh, P. Anbazhagan, M. Neaz Sheikh, T. G. Sitharam, J. S. Vinod May 2010

An Alternative Method For Probabilistic Seismic-Hazard Assessment: A Case Study Of Three Cities, Hing-Ho Tsang, Saman Yaghmaei-Sabegh, P. Anbazhagan, M. Neaz Sheikh, T. G. Sitharam, J. S. Vinod

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

The conventional source-based method of probabilistic seismic-hazard assessment is considered difficult to conduct for regions lacking adequate information on the source characteristics, or with a paucity of recorded strong ground motion data. Meanwhile, the historic method is unreliable in estimating the hazard at low probability. This paper proposes a midway approach, derived from the source-based method, yet does not require the characterization of seismic sources. While the method possesses the simplicity of the historic method, it is extended to account for large events that have not been observed historically, in order to improve the reliability of hazard calculation at low …

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Gis-Based Identification Of Topographic Sites In Italy With Significant Ground Motion Amplification Effects, Vera Pessina, Emilia Fiorini, Roberto Paolucci May 2010

Gis-Based Identification Of Topographic Sites In Italy With Significant Ground Motion Amplification Effects, Vera Pessina, Emilia Fiorini, Roberto Paolucci

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

Surface topography can significantly affect earthquake ground motions, as suggested by many examples of unexpected damage suffered by buildings located on the top of hills, on ridges or along slopes. European and Italian seismic codes suggest topographic aggravation factors in the 1 – 1.4 range to be applied to seismic actions, depending not only on simple morphologic parameters (average slope angle, width and height of the relief) but also on the type of relief (isolated cliff or ridge) and on the location of the site relative to the relief. Furthermore, strongly irregular topographies should be dealt with by a specific …

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Preparation The Site Specific Spectrum For Civil Regions Of Zagross Mountains, Kaveh Andisheh, Seydeh Sara Hossini, Mortaza Taghizadeh May 2010

Preparation The Site Specific Spectrum For Civil Regions Of Zagross Mountains, Kaveh Andisheh, Seydeh Sara Hossini, Mortaza Taghizadeh

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

In this paper the site specific spectra for a region of the Zagros Mountains containing 5 cities in Kurdistan province of Iran is prepared. For this purpose, all the occurred earthquakes, containing both historical and instrumental events, in each 5 city have been gathered then main earthquakes was prepared by elimination the aftershocks, foreshocks, and the incorrect reported events from the data and main earthquakes were taken into consideration to calculate the seismic parameters by Kijko [2000] method considering uncertainty in magnitude and incomplete earthquake catalogue. All seismic sources of the region are modeled and recurrence relationship is established. After …

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Ground Motion Study On Dumbarton Toll Bridge, Te-Chih Ke, Hubert Law, Po Lam, Brian Maroney, Saba Mohan, Jason Weinstein May 2010

Ground Motion Study On Dumbarton Toll Bridge, Te-Chih Ke, Hubert Law, Po Lam, Brian Maroney, Saba Mohan, Jason Weinstein

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

The existing Dumbarton Toll Bridge was built in 1982, connecting the cities of Newark and East Palo Alto in the San Francisco Bay Area. The initial vulnerability studies conducted by California Department of Transportation (Caltrans) in 2004 indicated that the performance of the bridge during a maximum credible earthquake was uncertain. Earth Mechanics, Inc. (EMI) has carried out the necessary study for the seismic evaluation of the bridge. An extensive field investigation was undertaken both on-land and over-water at the site to develop the idealized subsurface profile along the bridge alignment. According to the probabilistic and deterministic seismic hazard analyses …

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Ground Improvement By Dynamic Compaction At A Tailings Disposal Facility, Howard D. Plewes, Robert W. Chambers, Rick Friedel, Terence K. Jibiki, Alex Sy May 2010

Ground Improvement By Dynamic Compaction At A Tailings Disposal Facility, Howard D. Plewes, Robert W. Chambers, Rick Friedel, Terence K. Jibiki, Alex Sy

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

This paper presents two case histories of ground improvement by dynamic compaction (DC) at the Myra Falls mine in Vancouver Island, British Columbia, Canada. Dynamic compaction was employed to densify soils at two sites within the operating mine: a waste rock dump beneath a new processing plant to reduce settlements beneath the structure foundations (Site A); and coarse fluvial and colluvial soils at the toe of an existing tailings embankment to improve seismic resistance against liquefaction (Site B). At Site A, the variable plant loadings required variable compaction energy to achieve uniform foundation performance. At Site B, the foundation soils …

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Numerical Study Of The Seismic Response Of An Urban Overpass Support System, Juan M. Mayoral, Francisco A. Flores, Miguel P. Romo, Manuel J. Mendoza May 2010

Numerical Study Of The Seismic Response Of An Urban Overpass Support System, Juan M. Mayoral, Francisco A. Flores, Miguel P. Romo, Manuel J. Mendoza

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

A strategic urban overpass is to be built in the so-called transition and hill zones in Mexico City. The subsoil conditions at these zones typically consist on soft to stiff clay and medium to dense sand deposits, randomly interbedded by loose sand lenses, and underlain by rock formations that may outcrop in some areas. Several critical supports of this overpass are going to be instrumented with accelerometers, inclinometers and extensometers to assess their seismic performance during future earthquakes and to generate a database to calibrate soil-structure-interaction numerical models. This paper presents the seismic performance evaluation of one of these supports. …

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