The Experts below are selected from a list of 1611 Experts worldwide ranked by ideXlab platform
Dov Leshchinsky - One of the best experts on this subject based on the ideXlab platform.
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two and three dimensional numerical analyses of Geosynthetic Reinforced Soil grs piers
Geotextiles and Geomembranes, 2019Co-Authors: Panpan Shen, Dov Leshchinsky, Jorge G Zornberg, Amr M Morsy, Burak F Tanyu, Chao XuAbstract:Abstract In this study, both two-dimensional (2D) and three-dimensional (3D) numerical analyses were carried out to evaluate the performance of Geosynthetic-Reinforced Soil (GRS) piers. The numerical models were first calibrated and verified against test results available in the literature. A parametric study was then conducted under both 2D and 3D conditions to investigate the influences of reinforcement tensile stiffness, reinforcement vertical spacing, and a combination of reinforcement stiffness and spacing on the performance of GRS piers under vertical loading. Numerical results indicated that the effect of reinforcement spacing was more significant than that of reinforcement stiffness. The use of closely – spaced reinforcement layers resulted in higher global elastic modulus of the GRS pier, smaller lateral displacements of pier facing and volumetric change of the GRS pier, lower and more uniformly-distributed tension in the reinforcement, and larger normalized coefficients of lateral earth pressure. This study concluded that a 2D numerical model gave more conservative results than a 3D model.
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3d effects of turning corner on stability of Geosynthetic Reinforced Soil structures
Geotextiles and Geomembranes, 2018Co-Authors: Fei Zhang, Dov Leshchinsky, Shangchuan YangAbstract:Abstract Current design procedures of Geosynthetic-Reinforced Soil Structures (GRSS's) are for walls/slopes with long straight alignments. When two GRSS segments intersect, an abrupt change in the alignment forms a turning corner. Experience indicate potential instability problems occurring at corners. The purpose of this study is to explore the effects of turning corner on the stability of Reinforced slopes. Three-dimensional (3D) slope stability analysis, based on limit equilibrium, resulted in the maximum tensile force of reinforcement. Parametric studies required numerous computations considering various geometrical parameters and material properties. The computed results produced efficient practical format of stability charts. For long-term stability of Reinforced slopes with turning corner, the influences of pore water pressure and seismic loading are also considered. Turning corner can improve the stability of Reinforced slopes by virtue of inclusion of end effects. However, localized increase of pore water pressure or directional seismic amplification may decrease locally thus stability requiring strength of reinforcement larger than in two-dimensional (2D) plane-strain. While using 2D analysis for non-localized conditions may require stronger reinforcement, it also requires shorter reinforcement than in 3D analysis; i.e., 2D analysis may be unconservative in terms of reinforcement length.
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Geosynthetic Reinforced Soil structures with concave facing profile
Geotextiles and Geomembranes, 2016Co-Authors: Farshid Vahedifard, Shahriar Shahrokhabadi, Dov LeshchinskyAbstract:Abstract This paper presents a new method to determine the optimal profile of facing elements in Geosynthetic-Reinforced Soil structures. Flexibility of some facing systems and advances in construction technology allow construction of Reinforced Soil structures with a non-planar cross section. In this study, the facing profile of a concave Geosynthetic-Reinforced Soil structure (referred to as CGRSS) is idealized by a circular arc defined by a single variable, the Mid-Chord Offset (MCO). For a given setback and elevation change, the optimal facing profile is determined by seeking the MCO which, for a given margin of safety, yields the least tensile load in the reinforcement layers. The proposed procedure for finding the optimal facing profile is incorporated into a limit equilibrium-based log spiral formulation to determine the required tensile strength of the reinforcement. Results are presented in a set of charts showing the required unfactored tensile strength, MCO, and mode of failure for various friction angles, batter angles, and seismic coefficients. It is shown that CGRSSs can decrease the required tensile strength of the reinforcement by up to 30% under static and pseudo-static conditions. This observation justifies employing concave facing profiles in practice.
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analyzing dynamic behavior of Geosynthetic Reinforced Soil retaining walls
Journal of Engineering Mechanics-asce, 2004Co-Authors: Hoe I. Ling, Victor N Kaliakin, Dov LeshchinskyAbstract:An advanced generalized plasticity Soil model and bounding surface Geosynthetic model, in conjunction with a dynamic finite element procedure, are used to analyze the behavior of Geosynthetic-Reinforced Soil retaining walls. The construction behavior of a full-scale wall is first analyzed followed by a series of five shaking table tests conducted in a centrifuge. The parameters for the sandy backfill Soils are calibrated through the results of monotonic and cyclic triaxial tests. The wall facing deformations, strains in the geogrid reinforcement layers, lateral earth pressures acting at the facing blocks, and vertical stresses at the foundation are presented. In the centrifugal shaking table tests, the response of the walls subject to 20 cycles of sinusoidal wave having a frequency of 2 Hz and of acceleration amplitude of 0.2g are compared with the results of analysis. The acceleration in the backfill, strain in the geogrid layers, and facing deformation are computed and compared to the test results. The results of analysis for both static and dynamic tests compared reasonably well with the experimental results.
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DESIGN SOFTWARE FOR Geosynthetic-Reinforced Soil STRUCTURES
Geotechnical Fabrics Report, 2002Co-Authors: Dov LeshchinskyAbstract:Over the past 3 decades, Geosynthetic Reinforced Soil structures have demonstrated safe performance while being economical. These Reinforced structures are aesthetically pleasing and designers are tempted to use them in complex applications such as multi-tiered steep slopes and walls. Multi-tiered structures alleviate the required high strength of reinforcement, thus enabling the construction of Reinforced slopes that are very high. The aim of this article is to show that pushing the design envelope can be done in a straightforward manner, extending conventional geotechnical principles and using suitable software to overcome involved and tedious computational processes.
Michael T. Adams - One of the best experts on this subject based on the ideXlab platform.
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Long-Term Behavior of a Geosynthetic Reinforced Soil Integrated Bridge System in Hawaii:
Transportation Research Record, 2019Co-Authors: Michael T. Adams, Joseph B. LawrenceAbstract:A 109.5-Ft-long Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) in Hawaii was instrumented to measure superstructure strains, vertical pressures below the footing, lateral pressures...
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deformations of Geosynthetic Reinforced Soil under bridge service loads
Geotextiles and Geomembranes, 2016Co-Authors: Jennifer Nicks, Danial Esmaili, Michael T. AdamsAbstract:Abstract This paper evaluates the results of 13 large scale Geosynthetic Reinforced Soil (GRS) column load tests, also known as performance tests (PT) or mini-pier tests, to study the effect of tensile strength (T f ), vertical reinforcement spacing (S v ), facing elements, and backfill properties on the deformations of GRS at 200 kPa, typical bridge bearing pressures, and also at 400 kPa. The results indicate that GRS performs well under service conditions. A semi-empirical expression is proposed for prescribed bearing pressures to limit vertical strain to 0.5% of the abutment height. In addition, recommendations for estimating lateral deformation for GRS bridge abutments are also provided. At 200 kPa surcharge for this series of tests, vertical settlements ranged from 8.3 to 33.9 mm (or from 0.4% to 1.7% axial strain); lateral deformations ranged from 3.0 mm to 10.1 mm (or 0.6%–2.0% lateral strain); and reinforcement strain ranged from less than 1% during construction to less than 3% during loading. The lateral deformation results indicate that the maximum displacement occurs in the top third region of the wall face. Comparing the vertical and lateral displacement data shows that most GRS models experienced negligible positive volume changes up to about 1% under typical bridge service loads.
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Thermal Activity of Geosynthetic Reinforced Soil Piers
IFCEE 2015, 2015Co-Authors: Michael T. Adams, Jennifer Nicks, Tom StabileAbstract:Four Geosynthetic Reinforced Soil (GRS) piers were constructed in 2012 to support two decommissioned 25.9 m concrete I-girders at the Federal highway Administration's (FHWA’s) Turner-Fairbank Highway Research Center in McLean, Virginia. Two of the GRS piers are built with an American Association of State Highway and Transportation Officials (AASHTO) No. 8 open-graded aggregate while two are built with an AASHTO A-1-a well-graded aggregate. Survey targets, strain gages, and pressure cells were installed on and in the piers to evaluate long term performance. Through these monitoring efforts, it was discovered that the piers with the well-graded aggregate behaved differently and experienced increased settlement after the first winter cycle. To investigate this further, one of these piers was wrapped with a warming blanket set to turn on when the ambient temperature drops to 1°C to ensure the system remained above freezing. In addition, slide wire potentiometers were installed to monitor the thermal movement of both the I-girders and the face of the walls. The relative movement between the face and the beam provides insight into the super-substructure interaction for GRS. As with the increased settlement for well-graded aggregates during thermal cycles, there is also thermal movement impacting performance. The use of well-graded backfill with any appreciable fine content, regardless of plasticity, may result in thaw weakening and increased movements. Observations also indicate that the I-girders and GRS piers move together. This paper will describe the testing, present results, and provide recommendations on the use of well-graded backfills for GRS piers.
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secondary settlement of Geosynthetic Reinforced Soil piers preliminary results
Geo-Congress 2014American Society of Civil Engineers, 2014Co-Authors: Michael T. Adams, Jennifer NicksAbstract:Four Geosynthetic-Reinforced Soil (GRS) piers, each built with different reinforcement strengths and aggregate backfill material, were constructed at the Federal Highway Administration's (FHWA's) Turner-Fairbank Highway Research Center in collaboration with the Long-Term Bridge Performance Program. The objective of the research is to assess the secondary deformation characteristics of GRS for load-bearing applications under service load conditions. The experiment consisted of axially loading the piers with 490 kN decommissioned prestressed concrete girders, resulting in an equivalent vertical applied stress of 200 kPa. The geometry of each GRS composite was 1.2 m square by 2.3 m in height, for an approximate base to height ratio of 0.5. The facing element for each GRS pier is a simple, split-faced concrete masonry unit (CMU) that is frictionally connected to the GRS composite at a nominal vertical reinforcement spacing of 0.2 m. The piers were instrumented to record reinforcement strain, earth pressures, and deformations. This paper will discuss the objectives of the experiment, explain the testing program, and share some of the vertical deformation results after almost four months in service. In addition, the results will be compared with the results of a long-term (since 1999) study on secondary settlement of a GRS abutment.
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Geosynthetic Reinforced Soil performance testing axial load deformation relationships
2013Co-Authors: Jennifer Nicks, Michael T. Adams, Tom StabileAbstract:The Geosynthetic Reinforced Soil (GRS) performance test (PT), also called a mini-pier experiment, consists of constructing alternating layers of compacted granular fill and Geosynthetic reinforcement with a facing element that is frictionally connected, then axially loading the GRS mass while measuring deformation to monitor performance. This large element load test provides material strength properties of a particular GRS composite built with unique combinations of reinforcement, compacted fill, and facing elements. This report describes the procedure and provides axial load- deformation results for a series of PTs conducted in both Defiance County, OH, as part of the Federal Highway Administration’s (FHWA) Every Day Counts (EDC) GRS Validation Sessions and in McLean, VA, at the FHWA’s Turner-Fairbank Highway Research Center as part of a parametric study. The primary objectives of this research report are to: (1) build a database of GRS material properties that can be used by designers for GRS abutments and integrated bridge systems; (2) evaluate the relationship between reinforcement strength and spacing; (3) quantify the contribution of the frictionally connected facing elements at the service limit and strength limit states; (4) assess the new internal stability design method proposed by Adams et al. 2011 for GRS; and (5) perform a reliability analysis of the proposed Soil-Geosynthetic capacity equation for LRFD calibration.
Jennifer Nicks - One of the best experts on this subject based on the ideXlab platform.
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effects of backfill constitutive behavior and Soil geotextile interface properties on deformations of Geosynthetic Reinforced Soil piers under static axial loading
Journal of Geotechnical and Geoenvironmental Engineering, 2020Co-Authors: Mahsa Khosrojerdi, Ming Xiao, Jennifer NicksAbstract:AbstractIn this research, a numerical investigation was conducted to study the effects of backfill constitutive behavior on the vertical and horizontal deformations of Geosynthetic-Reinforced Soil ...
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Effects of Backfill Constitutive Behavior and Soil–Geotextile Interface Properties on Deformations of Geosynthetic-Reinforced Soil Piers under Static Axial Loading
Journal of Geotechnical and Geoenvironmental Engineering, 2020Co-Authors: Mahsa Khosrojerdi, Ming Xiao, Jennifer NicksAbstract:AbstractIn this research, a numerical investigation was conducted to study the effects of backfill constitutive behavior on the vertical and horizontal deformations of Geosynthetic-Reinforced Soil ...
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deformations of Geosynthetic Reinforced Soil under bridge service loads
Geotextiles and Geomembranes, 2016Co-Authors: Jennifer Nicks, Danial Esmaili, Michael T. AdamsAbstract:Abstract This paper evaluates the results of 13 large scale Geosynthetic Reinforced Soil (GRS) column load tests, also known as performance tests (PT) or mini-pier tests, to study the effect of tensile strength (T f ), vertical reinforcement spacing (S v ), facing elements, and backfill properties on the deformations of GRS at 200 kPa, typical bridge bearing pressures, and also at 400 kPa. The results indicate that GRS performs well under service conditions. A semi-empirical expression is proposed for prescribed bearing pressures to limit vertical strain to 0.5% of the abutment height. In addition, recommendations for estimating lateral deformation for GRS bridge abutments are also provided. At 200 kPa surcharge for this series of tests, vertical settlements ranged from 8.3 to 33.9 mm (or from 0.4% to 1.7% axial strain); lateral deformations ranged from 3.0 mm to 10.1 mm (or 0.6%–2.0% lateral strain); and reinforcement strain ranged from less than 1% during construction to less than 3% during loading. The lateral deformation results indicate that the maximum displacement occurs in the top third region of the wall face. Comparing the vertical and lateral displacement data shows that most GRS models experienced negligible positive volume changes up to about 1% under typical bridge service loads.
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Thermal Activity of Geosynthetic Reinforced Soil Piers
IFCEE 2015, 2015Co-Authors: Michael T. Adams, Jennifer Nicks, Tom StabileAbstract:Four Geosynthetic Reinforced Soil (GRS) piers were constructed in 2012 to support two decommissioned 25.9 m concrete I-girders at the Federal highway Administration's (FHWA’s) Turner-Fairbank Highway Research Center in McLean, Virginia. Two of the GRS piers are built with an American Association of State Highway and Transportation Officials (AASHTO) No. 8 open-graded aggregate while two are built with an AASHTO A-1-a well-graded aggregate. Survey targets, strain gages, and pressure cells were installed on and in the piers to evaluate long term performance. Through these monitoring efforts, it was discovered that the piers with the well-graded aggregate behaved differently and experienced increased settlement after the first winter cycle. To investigate this further, one of these piers was wrapped with a warming blanket set to turn on when the ambient temperature drops to 1°C to ensure the system remained above freezing. In addition, slide wire potentiometers were installed to monitor the thermal movement of both the I-girders and the face of the walls. The relative movement between the face and the beam provides insight into the super-substructure interaction for GRS. As with the increased settlement for well-graded aggregates during thermal cycles, there is also thermal movement impacting performance. The use of well-graded backfill with any appreciable fine content, regardless of plasticity, may result in thaw weakening and increased movements. Observations also indicate that the I-girders and GRS piers move together. This paper will describe the testing, present results, and provide recommendations on the use of well-graded backfills for GRS piers.
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National Usage of Geosynthetic-Reinforced Soil to Support Bridges
Geo-Strata —Geo Institute of ASCE, 2015Co-Authors: Daniel Alzamora, Jennifer NicksAbstract:The Geosynthetic-Reinforced Soil Integrated Bridge System (GRS IBS) was developed by the Federal Highway Administration (FHWA) almost 20 years ago to help meet the demand for the next generation of single-span bridges in the U.S. As an alternative to conventional bridge foundations, GRS IBS is an economical solution that accelerates bridge construction while resulting in a safe, efficient design with excellent performance. By using closely-spaced, alternating layers of compacted granular fill and Geosynthetic reinforcement for the foundation and abutment support, along with an integrated approach, superstructures can bear directly on the GRS IBS substructure to create a seamless and smooth transition between the bridge and roadway without using joints, deep foundations, approach slabs, or cast-in-place concrete.
Jorge G Zornberg - One of the best experts on this subject based on the ideXlab platform.
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Geosynthetic - Reinforced Soil bridge abutments
Geotechnical Fabrics Report, 2020Co-Authors: Jorge G Zornberg, N. Abu-hejleh, Trever WangAbstract:The technology of Geosynthetic-Reinforced Soil (GRS) systems has been widely used in transportation to support the self-weight of backfill Soil, roadway structures, and traffic loads. The increased use and acceptance of Soil reinforcement is due to several factors including cost savings, aesthetics, simple and fast construction techniques, good seismic performance, and the ability to tolerate large differential settlement without structural distress. This article describes the comparatively new use of GRS systems as an integral structural component of bridge abutments and piers. The focus is on the Founders/Meadows Parkway Bridge, which crosses U.S. Interstate 25 approximately 20 miles south of downtown Denver, Colorado, and was recently opened to traffic.
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two and three dimensional numerical analyses of Geosynthetic Reinforced Soil grs piers
Geotextiles and Geomembranes, 2019Co-Authors: Panpan Shen, Dov Leshchinsky, Jorge G Zornberg, Amr M Morsy, Burak F Tanyu, Chao XuAbstract:Abstract In this study, both two-dimensional (2D) and three-dimensional (3D) numerical analyses were carried out to evaluate the performance of Geosynthetic-Reinforced Soil (GRS) piers. The numerical models were first calibrated and verified against test results available in the literature. A parametric study was then conducted under both 2D and 3D conditions to investigate the influences of reinforcement tensile stiffness, reinforcement vertical spacing, and a combination of reinforcement stiffness and spacing on the performance of GRS piers under vertical loading. Numerical results indicated that the effect of reinforcement spacing was more significant than that of reinforcement stiffness. The use of closely – spaced reinforcement layers resulted in higher global elastic modulus of the GRS pier, smaller lateral displacements of pier facing and volumetric change of the GRS pier, lower and more uniformly-distributed tension in the reinforcement, and larger normalized coefficients of lateral earth pressure. This study concluded that a 2D numerical model gave more conservative results than a 3D model.
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stress distribution and development within Geosynthetic Reinforced Soil slopes
Geosynthetics International, 2012Co-Authors: Kuohsin Yang, Jorge G ZornbergAbstract:ABSTRACT: Numerical methods combined with centrifuge tests are used to investigate the distribution and development of Soil stresses and reinforcement tensile loads in Geosynthetic-Reinforced Soil (GRS) structures. In this study, system stability indicated by the factor of safety (FS) of GRS slopes is calculated by limit equilibrium analysis. Stress information under various stress states is evaluated using finite element analysis. Advanced models and an integration algorithm are implemented in finite element code to enhance the simulation results. The proposed numerical models are validated by centrifuge tests of two GRS slopes with different backfill densities. Numerical results indicate that Soil stress mobilisation can be described by the Soil stress level S, which is defined as the ratio of the current stress status to peak failure criteria. For both slope models, as loading increases, backfill stresses develop and propagate along the potential failure surface. Mobilisation of Soil stress was non-uni...
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mobilization of reinforcement tension within Geosynthetic Reinforced Soil structures
2010 Earth Retention Conference - Earth Retention Conference 3, 2010Co-Authors: Kuohsin Yang, Jorge G Zornberg, Richard J BathurstAbstract:This paper examines the mobilization of reinforcement tension within Geosynthetic-Reinforced Soil (GRS) structures at working stress and at large Soil strains. Fully-mobilized reinforcement tension is assumed in most current design methods for the internal stability of GRS structures. In these methods the mobilized reinforcement tensile load is assumed to be equal to mobilized horizontal Soil forces computed using active earth pressure theory. However, comparison with reinforcement tension loads measured in the field has shown that this approach is conservative (excessively safe) by as much as a factor of two. This observation has prompted the current study in which stress data obtained from a numerical study and two instrumented large-scale GRS retaining walls were used to examine the relationship between mobilized reinforcement tensile load and mobilized Soil shear strength. The results show that the ratio of reinforcement tensile load and mobilized Soil shear strength is not constant Only when the average mobilized Soil shear strength exceeds 95%, is reinforcement tensile capacity mobilized significantly. Nevertheless, less than 30% of reinforcement strength is mobilized when the average mobilized Soil shear strength reaches peak Soil shear capacity. These results help explain why current design methods lead to computed reinforcement loads that are very high compared to measured loads under operational conditions.
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peak versus residual shear strength in Geosynthetic Reinforced Soil design
Geosynthetics International, 2002Co-Authors: Jorge G ZornbergAbstract:Current design guidelines for Geosynthetic-Reinforced Soil structures disagree over the shear strength parameters that should be selected to characterize the backfill material. Most Geosynthetic re...
Fumio Tatsuoka - One of the best experts on this subject based on the ideXlab platform.
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Geosynthetic-Reinforced Soil structures for railways and roads: development from walls to bridges
Innovative Infrastructure Solutions, 2019Co-Authors: Fumio TatsuokaAbstract:The development and construction of various types of Geosynthetic-Reinforced Soil (GRS) structures for railways, roads and others, mainly for railways, for the last 35 years in Japan is described. In the 1980s, GRS retaining wall (RW) with full-height rigid (FHR) facing was developed. The FHR facing is constructed firmly connected to reinforcement layers after the Reinforced backfill and subSoil has deformed sufficiently. In the early 1990s, GRS Bridge Abutment supporting one end of a simple girder at the top of the FHR facing was developed. In the early 2000s, GRS Integral Bridge was developed, which structurally integrates both ends of a continuous girder to the top of the FHR facings of a pair of GRS RWs. The total wall length of these GRS structures became about 185 km by June 2019 with no problematic case. The use of FHR facing, the staged construction of FHR facing and the structural integration for GRS Integral Bridge are the three major breakthroughs for the development of these GRS structure technologies.
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research and construction of Geosynthetic Reinforced Soil integral bridges
Transportation geotechnics, 2016Co-Authors: Fumio Tatsuoka, Toyoji Yonezawa, Masaru Tateyama, Kenichi Kojima, Masayuki Koda, Yoshinori Shindo, Shinichi TamaiAbstract:Abstract Geosynthetic-Reinforced Soil (GRS) integral bridge was developed to overcome several inherent serious problems with conventional type bridges comprising a simple-supported girder (or multiple girders) supported via bearings typically by RC abutments retaining unReinforced backfill (and a pier or piers for multiple girders). The problems include: (a) relatively high construction and maintenance costs with relatively long construction time resulting from the use of bearings and massive abutment structures usually supported by piles; (b) bumps immediately behind the abutments; and (c) a relatively low stability of the girders supported by roller bearings and the approach embankment against seismic and tsunami loads. For a GRS integral bridge, a pair of GRS walls (and an intermediate pier or piers if necessary for a long span) are first constructed. After the deformation of the supporting ground and the backfill of the GRS walls has taken place sufficiently, steel-Reinforced full-height-rigid (FHR) facings are constructed by casting-in-place concrete on the wall face wrapped-around with the geogrid reinforcement. Finally a continuous girder is constructed with both ends integrated to the top of the FHR facings. The girder is also connected to the top of an intermediate pier, or piers, if constructed. The background and history of the development of GRS integral bridge is described. The first four case histories, one completed in 2012 for a new high-speed train line and the other three completed in 2014 to restore a railway damaged by a great tsunami of the 2011 Great East Japan Earthquake, are reported.
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Geosynthetic-Reinforced Soil Structures for Railways in Japan
Transportation Infrastructure Geotechnology, 2014Co-Authors: Fumio Tatsuoka, Junichi Koseki, Masaru Tateyama, Toyoji YonezawaAbstract:Geosynthetic-Reinforced Soil retaining walls (GRS RWs) have been constructed for a total length of about 150 km as of June 2013 mainly for railways, including high-speed train lines. After a full-height wrapped-around GRS wall has been constructed and the major residual deformation of the backfill and supporting ground has taken place, a full-height rigid (FHR) facing is constructed by casting-in-place concrete on wrapped-around wall face in such that it is firmly connected to the reinforcement layers. A number of this type GRS RWs performed very well during the 1995 Great Kobe and the 2011 Great East Japan Earthquakes. The seismic design code for railway Soil structures has been revised taking into account such high-level seismic loads as experienced during the 1995 Kobe EQ. A number of conventional-type RWs and embankments collapsed during these and other earthquakes, heavy rains, floods, and storm wave actions. Many of them were reconstructed to this type GRS RWs and Geosynthetic-Reinforced embankments. Among a couple of new bridge types that have been developed, GRS integral bridge comprises a continuous girder of which both ends are structurally integrated without using bearings to the top of the facings of a pair of GRS RWs. The first prototype was constructed for a high-speed train line in 2011 and three more were constructed to restore bridges that fully collapsed by great tsunami during the 2011 Great East Japan EQ.
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Geosynthetic-Reinforced Soil Structures for Railways in Japan
Transportation Infrastructure Geotechnology, 2014Co-Authors: Fumio Tatsuoka, Junichi Koseki, Masaru Tateyama, Toyoji YonezawaAbstract:Geosynthetic-Reinforced Soil retaining walls (GRS-RWs) have been constructed for a total length more than 135 km mainly for railways, including high-speed train lines. A full-height rigid (FHR) facing is constructed, firmly connected to the reinforcement layers, after a full-height wrapped-around GRS wall has been constructed and the major residual deformation of the backfill and supporting ground has taken place. A number of this type GRS RWs performed very well during the 1995 Kobe Earthquake and the 2011 Great East Japan Earthquake. The seismic design code has been revised to be prepared for such level seismic loads as experienced during the 1995 Kobe EQ. A number of conventional type RWs and embankments that collapsed during these and other earthquakes, heavy rains, floods and storm wave actions were reconstructed to this type GRS RWs. A couple of new bridge types comprising GRS structures have been developed. The latest version is GRS integral bridge, which comprises a continuous girder integrated to the top of the facings of a pair of GRS RWs without using bearings. The first prototype was constructed for a high-speed train in 2012 and three others were also constructed to restore bridges that fully collapsed by great tsunami during the 2011 Great East Japan EQ. Copyright © 2014 Southeast Asian Geotechnical Society (SEAGS). All Rights Reserved.
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dynamic stability of Geosynthetic Reinforced Soil integral bridge
Geosynthetics International, 2012Co-Authors: Henry Munoz, Masaru Tateyama, Fumio Tatsuoka, Daiki Hirakawa, Hiroki Nishikiori, Ryoichi Soma, Kenji WatanabeAbstract:ABSTRACT: To evaluate the dynamic stability of different bridge types, the results from a series of shaking-table tests on small-scale models of the following bridge types were analysed within the framework of the single-degree-of-freedom theory: (1) a conventional bridge (CB), comprising a girder (i.e. deck) supported via a pair of movable and fixed bearings (i.e. shoes) by gravity-type abutments (without a pile foundation) having unReinforced backfill; (2) a GRS-RW bridge, comprising a girder supported via a pair of movable and fixed bearings by a pair of sill beams placed on the crest of a pair of Geosynthetic-Reinforced Soil-retaining walls (GRS-RWs) having a stage-constructed full-height rigid facing; (3) an integral bridge (IB), comprising a girder integrated to a pair of abutments (without bearings) and unReinforced backfill; (4) a GRS integral bridge, comprising a girder integrated to the abutments (in the same way as the IB bridge) while the backfill is Reinforced with Geosynthetic layers connect...