Download or read book The Development Testing and Reinforcement Applications of Geogrids written by James Paul and published by . This book was released on 1994 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Geogrids written by Robert M. Koerner and published by . This book was released on 1991 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Geogrids written by Robert M. Koerner and published by . This book was released on 1992 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Geogrids written by Robert M. Koerner and published by . This book was released on 1991 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geogrid Reinforcement of Piedmont Residual Soil written by Alan T. Stadler and published by . This book was released on 2001 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil-geosynthetic composites such as those used in mechanically stabilized earth (MSE) retaining walls are experiencing widespread use, particularly in transportation applications. The potential economic benefit of using "lower-quality" on-site material in MSE retaining wall applications is substantial. An experimental research program investigating soil-geosynthetic interaction was performed at the University of North Carolina at Charlotte. To study this composite behavior, the research program employed a large pullout box equipped with state-of-the-art electronic instrumentation and data acquisition. The interaction of two "lower quality" piedmont residual soils (A-2-4 and A-4) with four representative, geosynthetic reinforcement materials (rigid geogrid, flexible geogrid, high strength geotextile, and medium strength geotextile) was examined through a series of anchorage strength tests. Through these tests, insight into the load versus deformation behavior of the reinforcing materials embedded in piedmont residuum was obtained. This report describes the test methodology and presents test results.

Download or read book Applications of Geogrids written by Robert M. Koerner and published by . This book was released on 1991 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Geogrids Vol 2 Geogrid Reinforced Steep Soil Slopes written by and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quality Assessment of Geogrids Used for Subgrade Treatment written by Min Sang Lee and published by Purdue University Press. This book was released on 2012-12-31 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geogrid reinforcements have been used by the Indiana Department of Transportation (INDOT) to construct stable subgrade foundations and to provide a working platform for construction over weak and soft soils. Use of geogrid reinforcement in a pavement system ensures a long-lasting pavement structure by reducing excessive deformation and cracking. The main objectives of this research were to evaluate the mechanical interaction between a subgrade soil and an aggregate base layer with and without a geogrid in place at the interface. A series of large-scale direct shear tests were performed to investigate the effects of geogrid properties, such as geogrid aperture area, junction strength, and tensile strength, on the interface shear strength of soil-geogrid-aggregate systems. The test results showed that the aperture size and junction strength of the geogrids were relatively important factors affecting the overall interface shear strength the most. The average values for the peak interface shear strength coefficient for the three normal stresses (50 kPa, 100 kPa and 200 kPa) considered in this study ranged from 0.96 to 1.48. In addition, the test results showed that the average peak interface shear strength coefficient increases with increases in the junction strength of the geogrid. The optimum aperture area of the geogrid was found to be equal to 825 mm2 (1.4 in2) for the subgrade soil and aggregate considered in this study. There was no significant correlation between the geogrid tensile strength at 2% strain and the average peak interface shear strength coefficient. The effect of the moisture content of the subgrade soil on the peak interface shear strength coefficient was also investigated. The peak interface shear strength coefficient for the subgrade soil sample prepared at the optimum moisture content and compacted to relative compaction values of 94-96 % (Rsoil = 95-96% and Raggregate = 94-95%) and tested under a normal stress of 100 kPa was 20% less than that for the subgrade soil sample prepared at a moisture content 4% above the optimum moisture content. Based on the results of the tests performed in this study, an aperture area requirement of 825 mm2 (1.4 in2) and a junction strength requirement of 11.5 kN/m (788 lb/ft) were suggested as preliminary guidelines for subgrade reinforcement systems. These requirements are only limited to the use of Type IV geogrid (INDOT specification 207.04) for subgrade reinforcement with aggregate No. 53.

Download or read book Applications of Geogrids Vol 3 Polymeric Geogrid Reinforcement of Embankments Over Weak Soils written by and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Field and laboratory pull out tests on geogrids written by and published by . This book was released on 1901 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A técnica de reforço de solo por inclusão de materiais geossintéticos vem se consolidando de forma acelerada em todo o mundo, com aplicações diretas em estabilização de encostas e de aterros sobre solos moles. A utilização de geogrelhas como elemento de reforço apresenta-se como uma alternativa promissora, embora ainda pouco difundida no Brasil. O presente trabalho tem por objetivos avaliar a resistência ao arrancamento de diferentes tipos de geogrelhas e analisar os mecanismos de interação entre solo e geogrelha. Para tal, foi realizado um extenso programa de ensaios de arrancamento no laboratório e no campo. Os equipamentos utilizados, a preparação das amostras e as metodologias dos ensaios estão apresentados em detalhe. Os ensaios de arrancamento no campo utilizaram uma estrutura de reação fixa, específica para ensaios de arrancamento de grandes dimensões, e foram realizados no campo experimental da PUC-Rio, em Jacarepaguá. Nestes ensaios, três tipos de geogrelhas foram utilizadas para o arrancamento em aterros de solo arenoso e solo residual. Os ensaios de arrancamento no laboratório foram executados em uma caixa de arrancamento cúbica de grandes dimensões (1m de aresta), no Laboratório de Geotecnia do CEDEX, na Espanha. No programa experimental no laboratório, foram utilizados os mesmos tipos de geogrelhas e de solos, de modo a facilitar as comparações e análises dos resultados. As influências do tipo de geogrelha, do tipo de solo, da tensão confinante e dos procedimentos de ensaioforam analisadas em detalhe no que se refere à rigidez e à resistência ao arrancamento das geogrelhas.

Download or read book Development of Test Procedures and Material Properties for Evaluating Geogrids for Soil Reinforcement written by and published by . This book was released on 1988 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this study was to determine the influence of the construction and geometry of four geogrids and one geotextile on the interfacial shear strength of a granular and a cohesive soil. in addition, a modification to the standard direct shear testing apparatus was made and a testing procedure for measuring the interfacial shear strength was developed. results indicate that the interfacial shear strength of reinforced soil is less than the shear strength of the unreinforced soil. geogrids with large apertures permit a greater degree of soil to soil interaction and exhibit higher interfacial friction than woven geotextiles. it is found that geogrids do not represent significant planes of weaknesses within a compacted granular fill. geotextiles may represent a more potential sliding plane within a granular embankment that geogrids. for cohesive soil, geogrids with a high percent of open area and geotextiles with a rough surface texture can generate shearing strength approaching that of the unreinforced clay.

Download or read book Use of Geogrids in Railroad Track written by David M. Coleman and published by . This book was released on 1990 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geogrid has been defined as a deformed or nondeformed net-like polymetric material used with foundation, soil, rock, earth, or any other geotechnical engineering-related materials as an integral part of a human-made project, structure, or system. Geogrids are one of the geosynthetics that have seen increased use in railroad applications. In conjunction with design of railroad track at several military installations the question was raised as to the benefit of including a geogrid in the ballast to act as a reinforcement mechanism. The use of geogrids in railroad track applications was investigated to determine if the ballast thickness can be reduced using geogrids. Investigation was made of the advantages and disadvantages of using geogrids along with the possibility of reducing the ballast thickness through the use of a geogrid. All available technical literature applicable to the use of geogrids in railroad track was reviewed. A number of telephone calls and personal contacts were made with people in academia and in the geosynthetics and railroad industries who have been involved with the development, testing, and use of these materials in railroad track. A synopsis of the information that is currently available in relation to the use of geogrids in railroad track reinforcement is presented along with recommendations for the use of geogrids on low traffic density, low speed railroad tracks typical of those found on military installations. (edc).

Download or read book Effectiveness of Geotextiles geogrids in Roadway Construction Determine a Granular Equivalent GE Factor written by Hossein Alimohammdi and published by . This book was released on 2021 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geogrids have been widely used in roadway construction as reinforcement in pavement foundations. Geogrids have been effective in practice for reducing rutting damage, distributing traffic loads within the pavement foundation layers, increasing the resilient modulus of the base course, and stabilizing the subgrade layer. For this project, an integrated mobile accelerated test system (IMAS), an automated plate load test (APLT) device, and finite element simulation approaches were used to evaluate the effects of geogrid reinforcement. Test configurations were constructed by varying geogrid types (i.e., light-duty biaxial, heavy-duty biaxial, light-duty triaxial, and heavy-duty triaxial), geogrid locations in the base course (i.e., at the interface between the base and the subgrade or in the base course), and base aggregate thicknesses (6, 10, and 16 in) in the laboratory and in experimental field tests. The finite element method (FEM) models were calibrated based on the results from the experimental test sections. Then, the calibrated FEM models were used to determine granular equivalent (GE) values for the remaining sections. Testing results included resilient modulus, deflection, and permanent deformation of the pavement foundation to evaluate the structural benefits of geogrids as a function of the GE. The results of this research revealed that improvement in pavement performance using geosynthetic reinforcement depended on various factors and variables. A new formulation was proposed to predict the GE factor of geogrid reinforcement of flexible pavements. The products produced by this research include this report, which improves geogrid understanding, and a well-developed method to apply GE factors during pavement design. It is expected that one or more of the following benefits will be achieved during implementation: increased service life, reduced gravel and/or asphalt thickness, and reduced maintenance costs.

Download or read book A Test Fill for Geogrid Reinforcement of Cohesive Soils written by and published by . This book was released on 1988 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A geogrid reinforced cohesive soil test embankment 12 metres high with 1:1 side slopes is under construction in the province of alberta. three different types of geogrids are being evaluated at the site, including tensar sr2, signode tnx-5001, and paragrid 50s. this paper outlines the geometric layout for the test fill and the design methods currently used for this type of reinforced slope. instrumentation has been installed to monitor pore pressure responses and the deformations of both the in situ foundation soils and the compacted fill material. through the analysis of the soil-geogrid interaction performance, a rational design approach will be developed for high geogrid reinforced slopes constructed with cohesive soils. for the covering abstract of the conference see irrd 807201.

Download or read book Characteristics and Behavior of Geogrid Reinforced Aggregate Under Cyclic Load written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study is to investigate the behavior of reinforced unpaved structure under cyclic load through laboratory testing, finite element and theoretical analyses. Main focus of research was on such behavior with degradation of aggregate base layer. Fourteen laboratory large-scale cyclic load plate tests were conducted on unpaved structure sections with two base course thicknesses and several geosynthetic reinforcements placed between base layer and subgrade. Results indicated that reinforcement improved stress distribution transferred to the subgrade, and decreased degradation of base course and surface deformation accumulation. Stiffer geogrids showed better stress attenuation effect and reduced plastic surface deformation as compared with lower modulus geogrids. Degradation was related to base layer thickness and base layer/geogrid interaction. The degradation and permanent surface deformation were correlated to geogrid torsional stiffness. Performance of geogrid-reinforced test sections was simulated using the FEM program ABAQUS. FEM results indicated that geogrid reinforcement can provide lateral confinement at the bottom of the base layer by improving interface shear resistance and increasing mean stress at the bottom of the base layer. The effect of geogrid reinforcement was also shown to reduce surface deformation, improve stress distribution on subgrade layer, and reduce strain induced at the bottom of the base layer due to lateral spread. As ABC thickness decreased, or the elastic modulus ratio decreased, the benefit due to geogrid reinforcement becomes more apparent. In general, geogrid with higher tensile modulus and better interface friction coefficient enhanced the reinforcement effects. A new unpaved road design model was developed on the basis of geogrid reinforcement mechanisms, degradation of base course, and mobilization of subgrade bearing capacity. Required base course thicknesses calculated using the proposed method compared favor.

Download or read book Large Scale and Bench Scale Test Systems for Assessing Impact of Geogrids on Pavements Founded on Problematic Soils written by Steven Williams and published by . This book was released on 2019 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geogrid reinforcement is an economically viable alternative to achieve improved performance in highway pavement construction in regions with soft problematic subgrade soils. To examine the potential benefits of using geogrids in pavement foundations, measurement of permanent deformation using laboratory triaxial tests is typical practice. However, since the performance improvement of pavement foundation systems is achieved by distribution of vertical stresses at the reinforcing layer through the tensile properties of the geogrid material, it is desirable to conduct large-scale testing to more accurately monitor the behavior of the geogrid-reinforced aggregate and soil system. This article describes the development of laboratory large-scale and bench-scale pavement testing systems to evaluate the behavior of geogrid-reinforced pavement systems through wheel tests performed with problematic subgrade soils found in North Georgia. The large-scale test specimens are prepared in a 1.8 (6 ft) by 1.8 (6 ft) by 0.6 m (2 ft) metal box and consist of 305 mm (12 in.) of unbound aggregate base (UAB) overlying 305 mm (12 in.) of subgrade soil. Geogrid is placed at the interface between the subgrade soil and UAB layer. Pressure sensors are installed near the bottom of the UAB layer and near the top and bottom of the subgrade layer to monitor stress distributions within the pavement foundation system. The bench-scale system, which measures 914 (36 in.) by 203 (8 in.) by 152 mm (6 in.) is also described. This system is advantageous because not only does it expedite rapid testing but also allows for relative micro- and macroscale comparisons of aggregate-geogrid behavior. This article presents test results showing vertical stress variations obtained experimentally in the UAB and subgrade soils under simulated traffic tire loading. The two systems are shown to be effective in establishing the influence of geogrid reinforcement in pavement systems.

Download or read book Geosynthetic Reinforcement of Flexible Pavements written by Steven W. Perkins and published by . This book was released on 1999 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the course of the last 17 years, approximately 12 different studies have shown the potential for the use of geosynthetic materials (geogrids and geotextiles) as a reinforcement inclusion in the base course aggregate layer of flexible pavements. The attraction of this application lies in the possibility of reducing the thickness of the base course layer such that a roadway of equal service life results or in extending the service life of the roadway. While several existing studies have provided data that aid in describing mechanisms of reinforcement, detailed information required to understand the mechanisms by which geosynthetics reinforce flexible pavements is lacking. In the absence of this information, it has historically been difficult to create mechanistic based models that adequately describe the process. As such, efforts to establish design solutions have been based largely on empirical data and considerations. Existing design solutions have not been met with open acceptance due to their inability to predict performance for conditions other than those established in the experiments for which the solution was based. This research was undertaken to provide experimental data that could be used to further establish the mechanisms of geosynthetic reinforcement that lead to enhanced pavement performance. Subsequent work will involve the use of these data in developing numerical models and design solutions for this application. Pavement test sections have been constructed in a laboratory based pavement test facility. The facility consists of a large concrete box in which field scale pavement layers can be constructed. Loading is provided through the application of a cyclic, 40 kN load applied to a stationary plate resting on the pavement surface. The test sections have been instrumented with an extensive series of stress and strain cells. Test section variables have included geosynthetic type (two biaxial geogrid products and one woven geotextile), subgrade type and strength, placement position of the geosynthetic in the base course layer and base course layer thickness. The results have shown that the inclusion of a geosynthetic provides a significant reinforcement effect. The geosynthetic is shown to have an influence on the amount of lateral spreading that occurs in both the bottom of the base course layer and in the top of the subgrade. Reinforcement is also seen to produce a more distributed vertical stress distribution on the top of the subgrade. As a result of these effects, reinforcement limits the vertical strain developed in the base and subgrade layers, leading to less surface deformation. Given that these mechanisms result from the development of shear interaction between the base and the geosynthetic, the combination of these effects is termed a mechanism of a shear resisting interface. These effects are seen to be most significant for a soft subgrade where substantial improvement in pavement performance has been observed. Geosynthetic type, strength, stiffness and placement position are also seen to influence observed improvement.