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Author : Tony L. Beckham
Publisher :
ISBN 13 :
Total Pages : 29 pages
Book Rating : 4.:/5 (247 download)
Download or read book Corrosion Evaluation of Mechanically Stabilized Earth Walls written by Tony L. Beckham and published by . This book was released on 2005 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Christopher L. Raeburn
Publisher :
ISBN 13 :
Total Pages : 42 pages
Book Rating : 4.3/5 (555 download)
Download or read book Evaluation of Corrosion of Metallic Reinforcements and Connections in MSE Retaining Walls written by Christopher L. Raeburn and published by . This book was released on 2008 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanically Stabilized Earth (MSE) retaining walls have become the dominant retained wall system on ODOT projects. The permanent MSE walls constructed on ODOT projects, in recent years, use metallic reinforcements and facing connections buried directly in the backfill soil. Accelerated deterioration of these structural elements would have serious financial and safety impacts for the Department. Classical MSE wall design incorporates an estimate of deterioration of reinforcement by corrosion. Monitoring of actual corrosion performance, however, is an important element of managing the current inventory of MSE walls. Monitoring could answer key questions that can provide for the best management of the existing walls, and provide feedback to the design process for future installations. This report details a literature review of methods for estimating and measuring deterioration of structural reinforcing elements in both concrete and MSE walls. It also presents a selected history of metallic reinforcement design specification and utilization. A listing of the MSE walls that can be identified in the ODOT Bridge Data System is included.
Author : Travis M. Gerber
Publisher : Transportation Research Board
ISBN 13 : 0309223741
Total Pages : 211 pages
Book Rating : 4.3/5 (92 download)
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.
Author : Brandon Seth Berke
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (436 download)
Download or read book Long Term Corrosion of Reinforcing Strips in Mechanically Stabilized Earth Walls written by Brandon Seth Berke and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 : Nelson Pearson
Publisher :
ISBN 13 :
Total Pages : 286 pages
Book Rating : 4.:/5 (12 download)
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 286 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.
Author :
Publisher :
ISBN 13 :
Total Pages : 154 pages
Book Rating : 4.:/5 (794 download)
Download or read book Corrosion/degradation of soil reinforcements for mechanically stabilized earth walls and reinforced soil slopes written by and published by . This book was released on 2009 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Robert L. Parsons
Publisher :
ISBN 13 :
Total Pages : 79 pages
Book Rating : 4.:/5 (126 download)
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%.
Author : Victor Elias
Publisher :
ISBN 13 :
Total Pages : 94 pages
Book Rating : 4.:/5 (155 download)
Download or read book Corrosion/degradation of Soil Reinforcements for Mechanically Stabilized Earth Walls and Reinforced Soil Slopes written by Victor Elias and published by . This book was released on 2000 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual is intended to provide criteria for evaluating corrosion losses when using coated or uncoated steel reinforcements, and for determining aging and installation damage losses when using geosynthetic reinforcements. Monitoring methods for in situ corrosion rates for steel reinforcements are evaluated and remote methods using electrochemical methods are recommended. Monitoring methods for determinations of in situ aging of geosynthetics are evaluated and protocols for implementation are recommended.
Author : Travis M. Gerber
Publisher :
ISBN 13 :
Total Pages : 74 pages
Book Rating : 4.:/5 (1 download)
Download or read book Assessing Corrosion of MSE Wall Reinforcement written by Travis M. Gerber and published by . This book was released on 2010 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this study was to extract reinforcement coupons from select MSE walls and document the extent of corrosion. A secondary objective of this project was to develop and assess techniques for removal of coupons on two-stage MSE walls.
Author : U.s. Department of Transportation
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781724239112
Total Pages : 156 pages
Book Rating : 4.2/5 (391 download)
Download or read book Corrosion/Degradation of Soil Reinforcements for Mechanically Stabilized Earth Walls and Reinforced Soil Slopes written by U.s. Department of Transportation and published by Createspace Independent Publishing Platform. This book was released on 2018-07-25 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion/degradation of soil reinforcements for mechanically stabilized earth walls and reinforced soil slopes /
Author : Randall J. Scott
Publisher :
ISBN 13 :
Total Pages : 228 pages
Book Rating : 4.:/5 (48 download)
Download or read book Corrosion Rate of Reinforcing Strips in Mechanically Stabilized Earth Walls written by Randall J. Scott and published by . This book was released on 1998 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Daniel T. Pond
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (9 download)
Download or read book Alternative Steel Reinforcement in Mechanically Stabilized Earth (MSE) Walls written by Daniel T. Pond and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 : Victor Elias
Publisher :
ISBN 13 :
Total Pages : 104 pages
Book Rating : 4.:/5 (368 download)
Download or read book Corrosion/degradation of Soil Reinforcements for Mechanically Stabilized Earth Walls and Reinfirced Soil Slopes written by Victor Elias and published by . This book was released on 1996 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Noreen Poor
Publisher :
ISBN 13 :
Total Pages : 355 pages
Book Rating : 4.:/5 (913 download)
Download or read book Distribution of Chloride, PH, Resistivity, and Sulfate Levels in Backfill for Mechanically-stabilized Earth Walls and Implications for Corrosion Testing written by Noreen Poor and published by . This book was released on 2015 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate goals of this research were to improve quality, speed completion, and reduce risk in mechanically-stabilized earth (MSE) wall projects. Research objectives were to assure (1) that variability in the corrosion properties of soil (pH, minimum resistivity, chloride, and sulfate levels) due to sampling and analytical technique was much lower than variability in these levels within and between soil sources and types and thus did not inflate the risk of emplacing a corrosive soil as MSE wall backfill, (2) that the number of soil type samples analyzed prior to acceptance of a backfill was appropriate, based on the expected distribution of corrosion properties within the backfill, and (3) that the corrosion properties of backfill material did not change appreciably over time, especially after emplacement and over the design lifetime of an MSE wall. Corrosion properties of soil were tested with Florida Methods (FMs) 5-550, 5-551, 5-552, and 5-553 for pH, minimum resistivity, water-soluble chloride, and water-soluble sulfate, respectively. Changes to the quality assurance (QA) plan for acceptance quality characteristics (AQC) of backfill corrosion properties were recommended based on research outcomes. These changes had as their focus an improvement in the buyers statistical power to accept good backfill material through reductions in test error associated with material properties, sample processing, and laboratory procedures. Recommended changes included (1) proposed revisions to the FMs for pH, minimum resistivity, chloride, and sulfate, (2) an increase in the number of independent samples tested for pH and minimum resistivity, (3) a revised acceptance limit for minimum resistivity, (4) method operator training and independent audits, (5) an inter-laboratory study post-implementation of the revised methods, and (6) re-evaluation of the need for chloride and sulfate testing for backfill above a pre-determined minimum resistivity. Geochemical modeling with the U. S. Geological Survey (USGS) model PHREEQC for a conservative case of a low ionic strength and poorly buffered sandy backfill revealed that in a few years time the pore water of emplaced backfill could equilibrate with infiltrating rainfall. The model results suggested that a soils buffering capacity might be important consideration when metal is used as reinforcement in MSE wall backfill. Field and laboratory testing of candidate sands to calibrate the model were recommended ahead of any proposed changes to the QA plan based on model results.
Author : Michael Watts Esfeller (Jr)
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (69 download)
Download or read book Electrochemical Assessment and Service-life Prediction of Mechanically Stabilized Earth Walls Backfilled with Crushed Concrete and Recycled Asphalt Pavement written by Michael Watts Esfeller (Jr) and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A Mechanically Stabilized Earth (MSE) wall is a vertical grade separation that uses earth reinforcement extending laterally from the wall to take advantage of earth pressure to reduce the required design strength of the wall. MSE wall systems are often prefabricated to reduce construction time, thus improving constructability when compared with conventionally cast-in-place reinforced wall systems. However, there is a lack of knowledge for predicting the service-life of MSE retaining wall systems when recycled backfill materials such as Recycled Asphalt Pavement (RAP) and Crushed Concrete (CC) are used instead of Conventional Fill Material (CFM). The specific knowledge missing is how these recycled materials, when used as backfill in MSE wall systems, affects the corrosion rate of the reinforcing strips. This work addresses this knowledge gap by providing recommendations for MSE wall systems backfilled with CC or RAP, and provides a guide to predict the service-life based on corrosion rate test data obtained from embedding steel and galvanized-steel earth reinforcing strips embedded in MSE wall systems backfilled with CC, RAP, and CFM. Experimental data from samples emulating MSE wall systems with steel and galvanized-steel reinforcing strips embedded in CC and RAP were compared to samples with strips embedded in CFM. The results of the testing provide data and methodologies that may, depending on the environmental exposure conditions, justify the use of RAP and CC for the construction of MSE walls. If these backfill materials are obtained from the construction site, this could provide a significant cost savings during construction.
Author : Juan Pedro Rossi
Publisher :
ISBN 13 :
Total Pages : 454 pages
Book Rating : 4.:/5 (361 download)
Download or read book The Corrosion Behavior of Galvanized Steel in Mechanically Stabilized Earth Wall Structures written by Juan Pedro Rossi and published by . This book was released on 1996 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Tanit Chalermyanont
Publisher :
ISBN 13 :
Total Pages : 238 pages
Book Rating : 4.:/5 (89 download)
Download or read book Reliability Analysis of Mechanically Stabilized Earth (MSE) Walls written by Tanit Chalermyanont and published by . This book was released on 2002 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
