Alternative Steel Reinforcement in Mechanically Stabilized Earth (MSE) Walls PDF Download

Author: Daniel T. Pond
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Mechanically Stabilize Earth (MSE) is a method in which soil tensile strength and shear resistance is increased by using reinforcement. The traditional forms of reinforcement include bars, galvanized strips, welded wire mats or steel grids, and geosynthetics.When steel is used as reinforcement in MSE walls, it gets corroded or decayed. Certain shapes of reinforcement will have less corrosion because less surface area is exposed. Pullout resistance is the ability to resist a tensile force. This can be affected by the design and shape of the steel. This study simulates different overburden depths or pressures for pullout resistance and evaluates standard corrosion rates.

Author: Oscar Ernesto Suncar (E.)
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 198

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Book Description
Many research studies made on hundreds of MSE walls have shown that in order to get lower values of lateral earth pressure coefficients from an active condition on the backfill soil, thus lower exerted loads and stresses on the reinforcement, the wall needs to yield. This is typical of extensible polymer-based wall systems, such as geosynthetics. Steel systems, on the other hand, are very rigid and do not allow enough deformation on the wall to generate the active condition. For this research, steel reinforcement for MSE walls that behaves similar to geosynthetics was developed. This was done by using crimps on steel bars that would allow the wall to deform as the crimps straighten. A pullout box was designed and constructed, where tensile and pullout tests were performed on the crimped reinforcement. Different crimp geometries on different bar diameters were tested under a range of confining pressures. From this, force-displacement curves were developed for these crimp geometries that could be used to predict deflections on walls with crimped reinforcement. In addition, the pullout resistance of the crimps in the straighten process was evaluated. This way, the crimps would not only be used to allow the wall to yield, but also as a pullout resistance mechanism. The pullout resistances per crimp for different tensions on the crimp and under a range of overburden pressures were evaluated. By combining the pullout resistance of the crimps and the force-displacement curves, a new internal stability design method was introduced where crimped reinforcement is used to resist both pullout and rupture failure. Also presented here are the pullout resistances of round bars with improved deformations of different diameters. These were found to have the same pullout resistance of square deformed bars with the same cross-sectional area. Round bars are preferred over square bars because they are more corrosion resistant and have longer design life.

Author: Mehari T. Weldu
Publisher:
ISBN:
Category :
Languages : en
Pages : 44

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Book Description
A wide range of reinforcement-backfill combinations have been used in mechanically stabilized earth (MSE) walls. Steel strips are one type of reinforcement used to stabilize aggregate backfill through anchorage. In the current MSE wall design, pullout capacity of steel strips is evaluated to ensure internal stability of the reinforced mass. The pullout resistance of reinforcement is expressed in terms of pullout resistance factor that measures the reinforcement-backfill interaction. This pullout resistance factor is commonly determined by performing pullout tests. AASHTO (2012) LRFD Bridge Design Specifications provides default values of pullout resistance factor, F*, for strip reinforcement embedded in backfill material with a uniformity coefficient of Cu e"4, where the uniformity coefficient is defined as the ratio of the particle size at 60% finer to that at 10% finer. However, for backfill with a uniformity coefficient of Cu

Author: D. Manzanal
Publisher: IOS Press
ISBN: 1614996032
Category : Technology & Engineering
Languages : en
Pages : 3344

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Book Description
The work of geotechnical engineers contributes to the creation of safe, economic and pleasant spaces to live, work and relax all over the world. Advances are constantly being made, and the expertise of the profession becomes ever more important with the increased pressure on space and resources. This book presents the proceedings of the 15th Pan-American Conference on Soil Mechanics and Geotechnical Engineering (XV PCSMGE), held in Buenos Aires, Argentina, in November 2015. This conference, held every four years, is an important opportunity for international experts, researchers, academics, professionals and geo-engineering companies to meet and exchange ideas and research findings in the areas of soil mechanics, rock mechanics, and their applications in civil, mining and environmental engineering. The articles are divided into nine sections: transportation geotechnics; in-situ testing; geo-engineering for energy and sustainability; numerical modeling in geotechnics; foundations and ground improvement; unsaturated soil behavior; embankments, dams and tailings; excavations and tunnels; and geo-risks, and cover a wide spectrum of issues from fundamentals to applications in geotechnics. This book will undoubtedly represent an essential reference for academics, researchers and practitioners in the field of soil mechanics and geotechnical engineering. In this proceedings, approximately 65% of the contributions are in English, and 35% of the contributions are in Spanish or Portuguese.

Author: James J. Walters
Publisher:
ISBN:
Category : Retaining walls
Languages : en
Pages : 245

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Book Description
In many geotechnical design situations involving tight right-of-way constraints, Mechanically Stabilized Earth (MSE) walls are often the most cost-effective and reliable earth retention technology among available alternatives. However, few well-documented case histories with detailed material testing, instrumentation programs and construction observation of performance are available in the literature. Despite the small number of case histories, empirical design methods are used in place of more theoretically-based methods. As a result, current design methods for MSE walls result in a large amount of inaccuracy, especially when their empirical calibration limits are exceeded. This study characterizes the constitutive behavior of a sandy gravel backfill soil and ribbed steel strip reinforcement material used in the construction of two very tall MSE walls constructed during the 3rd Runway Expansion Project at the Seattle-Tacoma International Airport (SeaTac). Tension testing was performed on coupons cut from the reinforcement material in order to measure its Young's modulus and yield strength. Consolidated drained triaxial strength testing was performed to measure the stress-strain behavior of the loose, medium dense, and densely-compacted backfill materials. Then the frictional interaction between the reinforcement and densely-compacted backfill soil was evaluated by performing twenty full-scale single-strip laboratory pullout tests. Using the results from the material testing and in-situ reinforcement strain measurements taken at the SeaTac MSE walls, the accuracy of four reinforcement load prediction methods was evaluated. The pullout test results were used to develop a backfill-specific design model, as well as being combined with other pullout test results for gravels reported in the literature to develop a global gravel design model for predicting peak reinforcement pullout resistances. These newly developed pullout design models were compared to the current AASHTO design model and found to produce much more accurate predictions of peak reinforcement pullout resistance. Walls designed and constructed with the kinds of backfill evaluated herein and with the new models generated will be more cost-effective than typically accepted design models.

Author: Brandon Seth Berke
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
ABSTRACT: Mechanically stabilized earth (MSE) walls are a more advanced form of a retaining wall, often larger and able to hold back more backfill. This is achieved by reinforcing strips or meshes (most often galvanized steel) placed into the soil, which are held in place by friction. The strips mechanically stabilize the earth while undergoing tension. The wall is covered with concrete medallions that connect to the reinforcements. The medallions have only a secondary structural role in holding up the wall but provide cover that protects the soil from washing away. MSE walls are structures expected to have very long service lives (e.g. 100 years). Confirmation is needed that such durability can be achieved, especially to show that the progression of corrosion of the reinforcement is slow enough. Ten MSE walls around Florida were instrumented (electrical connections were made through the concrete covers to the buried elements) between 1996- 1998 and used to survey corrosion rates of galvanized strip or mesh soil reinforcements. Initial estimates of corrosion-related durability were obtained at that time, indicating a good prognosis for long term durability. The objective of the research in this thesis was to obtain additional indications of the durability of reinforcements in MSE walls in Florida so as to perform a more reliable projection of future performance. Corrosion behavior was measured at the same locations as the initial survey by electrochemical nondestructive tests and by destructive tests. The nondestructive testing consisted of half-cell potentials, polarization resistance measurements, and electrochemical impedance spectroscopy. Corrosion rates reported in this thesis are based upon polarization resistance measurements. The destructive testing consisted of soil extraction and hardware extraction. Hardware extraction enabled independent verification of estimates of electrochemical corrosion rate. Analysis of extracted soil verified that soil composition was within construction specifications. The data from the current survey were also used to further improve prediction of corrosion. The present series of evaluations confirm that the structures are performing as desired based upon the updated model projection of future corrosion.

Author: Robert D. Holtz
Publisher:
ISBN: 9780784412770
Category : Geotechnical engineering
Languages : en
Pages : 0

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Book Description
GSP 230 contains 39 papers on applied geotechnical engineering in soft ground construction, reinforced soils, and fundamental soil behavior presented in honor of Robert D. Holtz.

Author: Swami Saran
Publisher: I K International Pvt Ltd
ISBN: 938590972X
Category : Technology & Engineering
Languages : en
Pages : 435

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Book Description
Reinforced soil is a composite material formed by the association of frictional soil and tension-resistant elements in the form of sheets, strips, nets or mats of metal, synthetic fabrics, or fibre reinforced plastics and arranged in the soil mass in such a way as to reduce or suppress the tensile strain that might develop under gravity and boundary forces. The variety and range of applications of reinforced soil technique are unlimited. Jones (1985) identified several field applications, viz., retaining walls, abutments, quay walls, embankments, dams, hill roads, housing, foundations, railways, industry, pipe works, waterway structures and underground structures. In several countries structures have been constructed using this technique and the concept has become very popular. The book covers all the important topics like Basic Mechanism, Strength Characteristics, Frictional Characteristics, Reinforced Soil, Wall, Wall with Reinforced Backfill, Foundation on Reinforced Soil, Soil Nailing and Randomly Distributed soil. Each chapter is supported by illustrative examples for easy understanding. In this edition, chapters on Reinforced Soil Wall, Foundation on Reinforced Soil, and Randomly distributed reinforced soil have been substantially modified making the book more useful. The book would well serve and benefit undergraduate and postgraduate students, researchers and professional geotechnical engineers.

Author: Peter G. Nicholson
Publisher: Butterworth-Heinemann
ISBN: 0124078990
Category : Technology & Engineering
Languages : en
Pages : 474

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Book Description
Written by an author with more than 25 years of field and academic experience, Soil Improvement and Ground Modification Methods explains ground improvement technologies for converting marginal soil into soil that will support all types of structures. Soil improvement is the alteration of any property of a soil to improve its engineering performance. Some sort of soil improvement must happen on every construction site. This combined with rapid urbanization and the industrial growth presents a huge dilemma to providing a solid structure at a competitive price. The perfect guide for new or practicing engineers, this reference covers projects involving soil stabilization and soil admixtures, including utilization of industrial waste and by-products, commercially available soil admixtures, conventional soil improvement techniques, and state-of-the-art testing methods. - Conventional soil improvement techniques and state-of-the-art testing methods - Methods for mitigating or removing the risk of liquefaction in the event of major vibrations - Structural elements for stabilization of new or existing construction industrial waste/by-products, commercially available soil - Innovative techniques for drainage, filtration, dewatering, stabilization of waste, and contaminant control and removal

Author: Jonathan T. H. Wu
Publisher: John Wiley & Sons
ISBN: 1119375843
Category : Technology & Engineering
Languages : en
Pages : 414

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Book Description
The first book to provide a detailed overview of Geosynthetic Reinforced Soil Walls Geosynthetic Reinforced Soil (GRS) Walls deploy horizontal layers of closely spaced tensile inclusion in the fill material to achieve stability of a soil mass. GRS walls are more adaptable to different environmental conditions, more economical, and offer high performance in a wide range of transportation infrastructure applications. This book addresses both GRS and GMSE, with a much stronger emphasis on the former. For completeness, it begins with a review of shear strength of soils and classical earth pressure theories. It then goes on to examine the use of geosynthetics as reinforcement, and followed by the load-deformation behavior of GRS mass as a soil-geosynthetic composite, reinforcing mechanisms of GRS, and GRS walls with different types of facing. Finally, the book finishes by covering design concepts with design examples for different loading and geometric conditions, and the construction of GRS walls, including typical construction procedures and general construction guidelines. The number of GRS walls and abutments built to date is relatively low due to lack of understanding of GRS. While failure rate of GMSE has been estimated to be around 5%, failure of GRS has been found to be practically nil, with studies suggesting many advantages, including a smaller susceptibility to long-term creep and stronger resistance to seismic loads when well-compacted granular fill is employed. Geosynthetic Reinforced Soil (GRS) Walls will serve as an excellent guide or reference for wall projects such as transportation infrastructure—including roadways, bridges, retaining walls, and earth slopes—that are in dire need of repair and replacement in the U.S. and abroad. Covers both GRS and GMSE (MSE with geosynthetics as reinforcement); with much greater emphasis on GRS walls Showcases reinforcing mechanisms, engineering behavior, and design concepts of GRS and includes many step-by-step design examples Features information on typical construction procedures and general construction guidelines Includes hundreds of line drawings and photos Geosynthetic Reinforced Soil (GRS) Walls is an important book for practicing geotechnical engineers and structural engineers, as well as for advanced students of civil, structural, and geotechnical engineering.