Download or read book Assessment of In situ Corrosion Conditions at Nevada Mechanically Stabilized Earth Wall Sites written by Nelson Pearson and published by . This book was released on 2015 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inability of soil to provide sufficient tensile strength presents challenges for soils being used as a structural building material. However, it is possible to improve the structural performance with the inclusion of a reinforcing system. The development of these systems has been a major advancement of the civil engineering practice. Mechanically stabilized earth (MSE) wall systems typically consist of a: concrete facing panel, specified backfill, reinforcing elements, and the retained fill. The interaction of the backfill with the reinforcements, and the reinforcements with the facing panels, produces a system that when properly designed, can be a cost effective engineering solution. In Nevada there are over 150 MSE walls that have been constructed using metallic reinforcements (Thornley 2009). Corrosion of metallic elements a naturally occurring electrochemical process is irreversible an inevitable. The rate of metal loss (corrosion) is a function of the environmental conditions and metal type. For MSE walls key parameters include the backfill's: salt content, organic content, saturation level, as well as the metal type of the reinforcements. Nevada has two previous corrosion investigations, an extensive site investigation at I-515/ Flamingo Rd. and a statistical analysis of as-built soil records along with a preliminary investigation for I-15/ Cheyenne Blvd. These studies form the foundation for this investigation of in-situ corrosion conditions. Seven MSE wall sites were investigated using electrochemical backfill characterization and linear polarization resistance (LPR) corrosion rate monitoring. Evaluation of electrochemical backfill characteristics has resulted in the discovery of six sites that fail current NDOT/ AASHTO MSE wall backfill requirements. The in-situ soil samples collected and analyzed more than doubled the available data used to describe the corrosiveness of the backfill. Linear polarization resistance corrosion rates were obtained for more than 200 different elements. These data suggest that despite the aggressive nature of the backfill, most elements are preforming well and are below the anticipated rates. However, several elements were discovered with corrosion rates in excess of five times the design model. The use of the LPR corrosion monitoring has concluded that the conditions at I-15/ and Cheyenne Blvd. are equivalent to or worse than the conditions evaluated in 2004 at the I-515/ Flamingo Rd. complex. The discoveries at Flamingo Rd. led to remediation of the largest wall at the complex. Through the use of electrochemical backfill characteristics and LPR corrosion rates, the seven sites investigated have been ranked. The rankings are dependent on several factors such as backfill electrochemical conditions and comparison of corrosion rates data with design models. This study has confirmed that observations of conditions along the exterior of the wall are not sufficient when determining the condition of the soil reinforcements. Routine corrosion monitoring is required to monitor the depletion of the soil reinforcements and should be incorporated into a Long-term Corrosion Monitoring and Asset Management Plan (LCMAMP). It is anticipated that a program will be integrated into Nevada's current asset management systems. The development and implementation of LCMAMP, directly reflects the federal initiative for systematic detailed evaluation of critical assets, MAP-21.
Download or read book Assessing the Long term Performance of Mechanically Stabilized Earth Walls written by Travis M. Gerber and published by Transportation Research Board. This book was released on 2012 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Mechanically stabilized earth (MSE) walls are an important class of infrastructure assets whose long-term performance depends on various factors. As with most all other classes of assets, MSE walls need periodic inspection and assessment of performance. To date, some agencies have established MSE wall monitoring programs, whereas others are looking for guidance, tools, and funding to establish their own monitoring programs. The objective of this synthesis project is to determine how transportation agencies monitor, assess, and predict the long-term performance of MSE walls. The information used to develop this synthesis came from a literature review together with a survey and interviews. Of the 52 U.S. and 12 Canadian targeted survey recipients, 39 and five, respectively, responded. This synthesis reveals that unlike bridges and pavements, MSE walls and retaining walls in general are often overlooked as assets. Fewer than one-quarter of state-level transportation agencies in the United States have developed some type of MSE wall inventory beyond that which may be captured as part of their bridge inventories. Fewer still have the methods and means to populate their inventories with data from ongoing inspections from which assessments of wall performance can be made. In the United States, there is no widely used, consistently applied system for managing MSE walls. Wall inventory and monitoring practices vary between agencies. This synthesis examines existing practices concerning the nature, scope, and extent of existing MSE wall inventories. It also examines the collection of MSE wall data, including the types of performance data collected, how they are maintained in wall inventories and databases, the frequency of inventory activities, and assessment practices relevant to reinforcement corrosion and degradation. Later parts of this synthesis discuss how MSE wall performance data are assessed, interpreted, and used in asset management decisions. This synthesis finds that the most well-implemented wall inventory and assessment system in the United States is the Wall Inventory Program developed by FHWA for the National Park Service. However, this system, like some others, uses 'condition narratives' in a process that can be somewhat cumbersome and subjective. Other systems use more direct numeric scales to describe wall conditions, and an advantage of such systems is that they are often compatible with those used in assessments of bridges. As experience with MSE walls accumulates, agencies will likely continue to develop, refine, and better calibrate procedures affecting design, construction, condition assessment, and asset management decisions. One portion of this synthesis is dedicated to summarizing the actions taken thus far by survey respondents to improve the long-term performance of their MSE walls. Many agencies prescribe the use of a pre-approved wall design and/or wall supplier. Other actions or policies frequently focus on drainage-related issues."--Summary.
Download or read book Measuring Corrosion Conditions in Mechanically Stabilized Earth Walls written by Robert L. Parsons and published by . This book was released on 2021 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: KDOT extensively utilizes mechanically stabilized earth (MSE) walls, typically with coarse aggregate backfill. Previous projects K-TRAN: KSU-15-6 and K-TRAN: KU-15-5 tested the aggregate material from MSE walls under construction. KU identified that several of the clean aggregate samples contained some fines, likely from crushing of the aggregate, and two of the walls contained over 10% fines. Aggregate backfill is specified because it allows for free drainage, limiting the pore water pressure buildup behind the wall. There is the potential for these fines to migrate towards the base of the wall over time. This migration of fines would not only increase the potential for water retention, but it would also increase the localized corrosion potential of the backfill. This joint project measured the backfill corrosion conditions of 12 MSE walls selected by KDOT. Walls were surveyed using a variety of non-destructive resistivity arrays and by cutting through the wall face, sampling the backfill, and inspecting reinforcing strap conditions. Multiple walls with potentially corrosive backfills (low resistivity) were identified, and several walls had reinforcement with visible corrosion in progress. The resistivity survey method and the physical sampling method were generally consistent in identifying backfills with low resistivity. The results support the potential of using a modified four-electrode electrical resistivity measurement to identify corrosive environments in MSE walls. If used by KDOT, this will improve KDOT’s geotechnical asset management of MSE walls. Results from the physical testing of backfills showed that the finest fraction of the backfill (D10) was strongly correlated with low resistivity values, particularly with the sand backfills. High chloride concentrations were also measured in the three samples with the lowest resistivity. These results support the current recommendation that the percentage of fines (material smaller than the #200 sieve) be limited to a maximum of 5%, and encourages the consideration of an additional specification that the percentage passing the #100 sieve be limited to 10%.
Download or read book Recommendations for Design and Analysis of Earth Structures using Geosynthetic Reinforcements EBGEO written by Deutsche Gesellschaft für Geotechnik and published by John Wiley & Sons. This book was released on 2012-01-09 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The completely revised and extended Recommendations deal with all questions relevant to the planning and dimensioning of geosynthetics-reinforced earth structures. In addition to the demands on materials and analysis principles, the applications of geosynthetics in a range of foundation systems, ground improvement measures, highways engineering projects, in slopes and retaining structures, and in landfill engineering are discussed. The Recommendations have been supplemented by the following sections: - reinforced earth structures over point or linear bearing elements, - foundation systems using geotextile-encased columns, - bridging subsidence, - dynamic actions of geosynthetic-reinforced systems. The remaining sections have been fundamentally revised and updated in line with current standards and codes of practice.
Download or read book Annual Meeting written by Association of Engineering Geologists and published by . This book was released on 2002 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Soil and Rock Properties written by P. J. Sabatini and published by . This book was released on 2004-10-01 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document presents state-of-the-practice information on the evaluation of soil and rock properties for geotechnical design applications. This document addresses the entire range of materials potentially encountered in highway engineering practice, from soft clay to intact rock and variations of materials that fall between these two extremes. Information is presented on parameters measured, evaluation of data quality, and interpretation of properties for conventional soil and rock laboratory testing, as well as in situ devices such as field vane testing, cone penetration testing, dilatometer, pressuremeter, and borehole jack. This document provides the design engineer with information that can be used to develop a rationale for accepting or rejecting data and for resolving inconsistencies between data provided by different laboratories and field tests. This document also includes information on: (1) the use of Geographical Information Systems (GIS) and Personal Data Assistance devices for the collection and interpretation of subsurface information; (2) quantitative measures for evaluating disturbance of laboratory soil samples; and (3) the use of measurements from geophysical testing techniques to obtain information on the modulus of soil. Also included are chapters on evaluating properties of special soil materials (e.g., loess, cemented sands, peats and organic soils, etc.) and the use of statistical information in evaluating anomalous data and obtaining design values for soil and rock properties. An appendix of three detailed soil and rock property selection examples is provided which illustrate the application of the methods described in the document.
Download or read book Recommendations for Prestressed Rock and Soil Anchors written by and published by . This book was released on 1993 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pile Design and Construction Practice written by Willis H. Thomas and published by CRC Press. This book was released on 2007-12-06 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Earth Retention Systems Handbook written by Alan Macnab and published by McGraw Hill Professional. This book was released on 2002-04-09 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Corrosion atlas a collection of illustrated case histories 2 Stainless steels and non ferrous materials 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 Rock Foundations written by United States. Army. Corps of Engineers and published by . This book was released on 1994 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book EPA 570 9 written by and published by . This book was released on 1982-10 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Techniques for Corrosion Monitoring written by and published by Elsevier. This book was released on 2008-02-01 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion monitoring techniques play a key role in efforts to combat corrosion, which can have major economic and safety implications. This important book starts with a review of corrosion fundamentals and provides a four-part comprehensive analysis of a wide range of methods for corrosion monitoring, including practical applications and case studies. The first part of the book reviews electrochemical techniques for corrosion monitoring, such as polarization techniques, potentiometric methods, electrochemical noise and harmonic analyses, galvanic sensors, differential flow through cells and multielectrode systems. A second group of chapters analyses the physical or chemical methods of corrosion monitoring. These include gravimetric, radioactive tracer, hydrogen permeation, electrical resistance and rotating cage techniques. Part II also includes a chapter on the innovative nondestructive evaluation technologies that can be used to monitor corrosion. Part III examines corrosion monitoring in special environments such as microbial systems, concrete and soil, and remote monitoring and model predictions. A final group of chapters includes various case studies covering ways in which corrosion monitoring can be applied to engine exhaust systems, cooling water systems, pipelines, equipment in chemical plants, and other real world systems. With its distinguished editor and international team of contributors, Techniques for corrosion monitoring is a valuable reference guide for engineers and scientific and technical personnel who deal with corrosion in such areas as automotive engineering, power generation, water suppliers and the petrochemical industry. Provides a comprehensive analysis of the range of techniques for corrosion monitoring Specific case studies are included to highlight the main issues A valuable reference guide for engineers, scientific and technical personnel who deal with corrosion
Download or read book Ground Anchors and Anchored Systems written by Federal Highway Administration and published by . This book was released on 2006-08-01 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents state-of-the-practice information on the design and installation of cement-grouted ground anchors and anchored systems for highway applications. The anchored systems discussed include flexible anchored walls, slopes supported using ground anchors, landslide stabilization systems, and structures that incorporate tiedown anchors. This book draws extensively in describing issues such as subsurface investigation and laboratory testing, basic anchoring principles, ground anchor load testing, and inspection of construction materials and methods used for anchored systems. This book provides detailed information on design analyses for ground anchored systems. Topics discussed include selection of design earth pressures, ground anchor design, design of corrosion protection system for ground anchors, design of wall components to resist lateral and vertical loads, evaluation of overall anchored system stability, and seismic design of anchored systems. Also included in this book are two detailed design examples and technical specifications for ground anchors and for anchored walls.
Download or read book Ralph B Peck Educator and Engineer written by Ralph Brazelton Peck and published by . This book was released on 2006 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In Situ Treatment of Hazardous Waste contaminated Soils written by and published by Noyes Publications. This book was released on 1991-01-01 with total page 533 pages. Available in PDF, EPUB and Kindle. Book excerpt: State of the art information on in situ treatment technologies for hazardous waste-contaminated soils is presented. Describes for each technology: wastes amenable to treatment, ease of application, potential level of treatment available, reliability, secondary impacts and equipment and reagents required.
Download or read book Foundation Analysis and Design written by Joseph E. Bowles and published by . This book was released on 1997 with total page 1175 pages. Available in PDF, EPUB and Kindle. Book excerpt: The revision of this best-selling text for a junior/senior course in Foundation Analysis and Design now includes an IBM computer disk containing 16 compiled programs together with the data sets used to produce the output sheets, as well as new material on sloping ground, pile and pile group analysis, and procedures for an improved anlysis of lateral piles. Bearing capacity analysis has been substantially revised for footings with horizontal as well as vertical loads. Footing design for overturning now incorporates the use of the same uniform linear pressure concept used in ascertaining the bearing capacity. Increased emphasis is placed on geotextiles for retaining walls and soil nailing.
