An Analysis of Atmospheric Corrosion Tests on Low-Alloy Steels-Applicability of Test Results to Highway Bridges DIVISION OF RESEARCH AND EVALUATION, BUREAU OF STRUCTURES AND MATERIALS, STATE OF NEW JERSEY, DEPARTMENT OF TRANSPORTATION The New Jersey State Department of Transportation will be constructing sev- eral unpainted, low-alloy steel bridges in the near future. To gather infor- mation for use in evaluating the performance of these structures a literature search was conducted. Some problems related to material specifications and atmospheric corrosion testing are discussed. The data contained in severai reports on the atmospheric corrosion of many low-alloy steels are examined. Sufficient data appear to be available in published corrosion tests to allow a reasonable estimate of the amount of corrosion which will occur to un- stressed sample panels of manylow-alloy steels exposed freely to the atmo- sphere, at many locations. These estimates can be made by comparing the chemical composition of a given steel with several tested chemical composi- tions to which it is similar in percentages of the major corrosion-reducing alloying elements. Any comparisons, such as these, must be made for sim- ilar environments and test conditions. Test results from three different reports are compared for steels which were groupedin accordance with the percentages of the major corrosion- reducing alloying elements contained. Based on the information in these re- ports and other references, a tentative empirical method is proposed for predicting the depth of penetration of corrosion for bridge members. The empirical method assumes a linear long-term corrosion rate and includes an "exposure factor," "pittingfactor," anda "safety factor." The reductions in several cross-sectional properties of two wide-flange beams and various sizes of plate are computed and it is suggested that further study of this prob- lem should be made. The possible effect of loads on corrosion and of corrosion on static and fatigue load resistance are briefly discussed, and "other factors" of rel- evance to the use of unpainted bridges are listed. A proposed test pro- gram for an experimental New Jersey bridge is briefly outlined. • THE New Jersey State Department of Transportation will be constructing several unpainted, low-alloy steel bridges in the near future. These bridges have been classified as experimental, and an annual report on their performance will be submitted to the Bureau of Public Roads. The Division of Research and Evaluation has established a project (1) entitled "Bridge Construction of Unpainted ASTM A-242 Steel," and is responsible for the observation, analysis, and evaluation of these experimental structures. This paper is a report on the first phase of this project-a literature search-and includes: (a) an analysis of some atmm;pheric currusiou test data, (b) an attempt to apply these data to highway bridges, (c) a Hst mg oi some r eiaceci fac tor s which appe a1· i.u ue .i11 m:eu u.l .luith t:.i · .:>tudy, '1il u (d / Paper sponsored by Committee on Metals in Highway Structures and presented at the 46th Annual Meeting. 22
An Analysis of Atmospheric Corrosion Tests on Low-Alloy Steels-Applicability of Test Results to Highway Bridges
Jun 29, 2023
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