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
This volume contains the proceedings of the 12th International Conference on Geosynthetics (12 ICG), held in Roma, Italy, 17-21 September 2023. About 750 Authors - Academics, Researchers, Students, Practitioners, Contractors and Manufacturers – contributed to the peer-reviewed papers of this volume, which includes the Giroud lecture, the Bathurst lecture, the Rowe lecture, four keynote lectures and 296 technical papers. The content of these proceedings illustrates the sustainable use of geosynthetics in a variety of innovative as well as consolidated applications. After the sustainability implications in the correct use of geosynthetics, the ability to overcome the natural events effects, often related to the climate change, and to adequately afford the human activities (as the increase of pollution) forced to refer to a new keyword: Resiliency. The 12 ICG intends to become the base for the next step, hence the conference theme is 'Geosynthetics, Leading the Way to a Resilient Planet'. The conference topics, through general and parallel sessions, invited presentations and keynote lectures, address the most recent developments in geosynthetic engineering, and stimulate fruitful technical and scientific interaction among academicians, professionals, manufacturers, students. The 12 ICG proceedings contain a wealth of information that could be useful for researchers, practitioners and all those working in the broad, innovative and dynamic field of geosynthetics.
Creating a more efficient reinforcement for Mechanically Stabilized Earth (MSE) Walls is important because it will reduce the amount of material needed to construct MSE walls, and will reduce overall construction costs for companies and contractors. This thesis explores four main geometries of metallic crimped and metallic crossbar type reinforcement constructed with both, smooth steel and #4 rebar steel. Metal round bar was chosen because, compared to metallic rectangular strip reinforcements, there is less surface area in contact with the soil which will then reduce the amount of corrosion loses. Throughout testing, it was found that crimped metal round bar was able to produce the required pullout resistance but created too much extensibility (the amount of length the crimps straightened). The reinforcement made with crossbars and metal round bar were found to produce the required amount of pullout resistance with little to no extensibility.
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.
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.
This book is intended to serve as a one-stop reference on fibre-reinforced soils. Over the past 30-35 years, the engineering behaviour of randomly distributed/oriented fibre-reinforced soil, also called simply fibre-reinforced soil, has been investigated in detail by researchers and engineers worldwide. Waste fibres (plastic waste fibres, old tyre fibres, etc.) create disposal and environmental problems. Utilization of such fibres in construction can help resolve these concerns. Research studies and some field applications have shown that the fibres can be utilized in large quantities in geotechnical and civil engineering applications in a cost-effective and environmentally friendly manner. This book covers a complete description of fibres, their effects when included within a soil or other similar materials such as the fly ash, and their field applications. It gives a detailed view of fibre-reinforced soil engineering. The book will be useful to students, professional, and researchers alike, and can also serve as a text for graduate coursework and professional development programs
Includes case histories of the Dumbarton Bridge (San Francisco Bay, Calif.), the Rainier Avenue Embankment (Seattle, Wash.) and the Gallows Road Grade Separation (Fairfax, Va.)
Presents a systematic and comprehensive presentation of temporary excavation shoring and earth retention systems used to construct permanent facilities inside them. These systems are used to construct underground pipelines, tunnels, tank and storage facilities, foundations and structures. Each chapter presents a shoring system type description, how it is constructed, equipment requirements, cost analysis, etc. Safety, inspection and testing codes and methods included throughout.
This international handbook is essential for geotechnical engineers and engineering geologists responsible for designing and constructing piled foundations. It explains general principles and practice and details current types of pile, piling equipment and methods. It includes calculations of the resistance of piles to compressive loads, pile group
