Author: Richard A. Jobes
Publisher:
ISBN:
Category : Iron and steel bridges
Languages : en
Pages : 140
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Some states have reported problems with excessive corrosion of unpainted A588 weathering steel bridges. Considerable savings in initial and life cycle costs are anticipated when using weathering steel, but only if good long range performance is attained. The Idaho Transportation Department conducted its first in-depth study of a representative group of 12 weathering steel bridges to determine their present condition. Weathering steels develop a protective oxide coating that shields the underlying steel base from further corrosion when certain conditions are met. All weathering steel bridges in Idaho were identified and current inspection reports were reviewed. Data collected from the field inspections include: visual observations of the condition of the protective oxide coating (color, texture, adherence), conditions and details that cause corrosion problems, and plate thickness measurements with an ultrasonic gage. Samples of the oxide coating were tested for chlorides.
Author: Theodore Hopwood (II)
Publisher:
ISBN:
Category : Iron and steel bridges
Languages : en
Pages : 75
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Author: R. L. McCrum
Publisher:
ISBN:
Category : Iron and steel bridges
Languages : en
Pages : 157
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Author: Wayne Lander
Publisher:
ISBN:
Category : Iron and steel bridges
Languages : en
Pages :
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Author: Douglas D. Crampton
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 40
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Weathering steel is commonly used as a cost-effective alternative for bridge superstructures, as the costs and environmental impacts associated with the maintenance/replacement of paint coatings are theoretically eliminated. The performance of weathering steel depends on the proper formation of a surface patina, which consists of a dense layer of corrosion product used to protect the steel from further atmospheric corrosion. The development of the weathering steel patina may be hindered by environmental factors such as humid environments, wetting/drying cycles, sheltering, exposure to de-icing chlorides, and design details that permit water to pond on steel surfaces. Weathering steel bridges constructed over or adjacent to other roadways could be subjected to sufficient salt spray that would impede the development of an adequate patina. Addressing areas of corrosion on a weathering steel bridge superstructure where a protective patina has not formed is often costly and negates the anticipated cost savings for this type of steel superstructure. Early detection of weathering steel corrosion is important to extending the service life of the bridge structure; however, written inspection procedures are not available for inspectors to evaluate the performance or quality of the patina. This project focused on the evaluation of weathering steel bridge structures, including possible methods to assess the quality of the weathering steel patina and to properly maintain the quality of the patina. The objectives of this project are summarized as follows: -- Identify weathering steel bridge structures that would be most vulnerable to chloride contamination, based on location, exposure, environment, and other factors. -- Identify locations on an individual weathering steel bridge structure that would be most susceptible to chloride contamination, such as below joints, splash/spray zones, and areas of ponding water or debris. -- Identify possible testing methods and/or inspection techniques for inspectors to evaluate the quality of the weathering steel patina at locations discussed above. -- Identify possible methods to measure and evaluate the level of chloride contamination at the locations discussed above. -- Evaluate the effectiveness of water washing on removing chlorides from the weathering steel patina. -- Develop a general prioritization for the washing of bridge structures based on the structure's location, environment, inspection observations, patina evaluation findings, and chloride test results.
Author: A. Raman
Publisher:
ISBN:
Category : Iron and steel bridges
Languages : en
Pages : 178
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Author: American Iron and Steel Institute. Task Group on Weathering Steel Bridges
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 32
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Author:
Publisher: Transportation Research Board National Research
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 116
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Author: J. T. Rupp
Publisher:
ISBN:
Category :
Languages : en
Pages : 270
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Book Description
The long-term performance of uncoated weathering steel (UWS) bridges in the United States is being assessed to update the current FHWA technical advisory regarding the use of UWS in highway bridges. The main purpose of the larger research project, to which the research described in this thesis contributed, is to develop quantitative recommendations about environmental conditions and maintenance practices that may be the most suitable for UWS highway bridges. Prior work included the development of a national UWS GIS database in order to quantify environments. This database was used to strategically select 21 UWS bridges for field evaluations in 7 states in order to qualitatively assess the performance of rust patinas and collect rust samples for assessment using quantifiable metrics. Rust samples were assessed by evaluating data from clear tape adhesion tests and ion chromatography analyses. Part of this research also included collecting and analyzing maintenance data collected from state highway agencies throughout the United States. This data included information from 34 state highway agencies' bridge maintenance manuals and bridge washing practices from 33 state highway agencies. Deicing agent usage data was also obtained from 39 state highway agencies and existing databases. Correlations between the different data types that were collected were assessed to investigate any trends in UWS bridge performance based on environmental conditions and maintenance practices. The most significant finding from this research involved differences in UWS performance as quantified by chloride concentrations and rust particle sizes of surface rust based on interior, sheltered girder locations and exterior, exposed girder locations. Quantifiable data obtained from this research will be useful for evaluating UWS bridge performance trends with a larger dataset in order to update national specifications and maintenance practices involving UWS bridges.
Author:
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 552
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