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Currently, I have an actual entire corroded bridge model in the FEM analysis in Abaqus I want to estimate the residual strength of this bridge due to corrosion from the output results in the Abaqus, I can have stress and strain values

but I was wondering how to calculate the residual strength of this corroded bridge,? is there any possibility to derive an equation to estimate the residual strength of this bridge using the results from Abaqus model?

thank you very much in advance

Cindy.Karina9
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  • Get the output results to include the actual size of the corroded elements ie reduced area etc and use those for the input to the equation. – Solar Mike Jul 28 '18 at 11:40
  • I was wondering is it okay to just make a simple relationship between the stress value from corroded structure to the yield strength of steel? – Cindy.Karina9 Jul 28 '18 at 11:46
  • Run the results and find out - hopefully you will get the correct answer before the real bridge drops people in the river... – Solar Mike Jul 28 '18 at 11:48
  • lol. the bridge already collapsed long years ago, but I used the data for my dissertation project to estimate residual strength of corroded bridge – Cindy.Karina9 Jul 28 '18 at 11:49
  • Then why not look for a correlation between years and corrosion - perhaps applied after 3 years or 5 years and also a painting quality adjustment,,, – Solar Mike Jul 28 '18 at 11:56
  • I want to know what formula to calculate residual strength from stress and yield strength value of a steel? – Cindy.Karina9 Jul 28 '18 at 12:16
  • Have you thought of including a factor of safety... – Solar Mike Jul 28 '18 at 12:17
  • yeah, I am thinking of it, but where this safety factor come from? for example, I want to make correlation between the stress value and yield strength as the limit, so the safety factor comes from the division of the two values? – Cindy.Karina9 Jul 28 '18 at 12:19
  • A factor of safety is where something is made 1.5 or 2 or 5 or more times stronger than it needs to be - so that errors, defects and perhaps "redneck" loading can be supported without failure, but cost and weight are also limiting factors... Think about why some of the "Victorian" engineering structures are still in service while some "newer" designs have failed... – Solar Mike Jul 28 '18 at 12:28
  • Is there anyway to get residual strength from abaqus? – Cindy.Karina9 Jul 28 '18 at 13:46
  • You should be able to find out - I don't even have it ... – Solar Mike Jul 28 '18 at 13:48
  • do you know which best parameter to check whether our bridge is still safety or now? – Cindy.Karina9 Jul 28 '18 at 14:12
  • This is really a discussion you should be having with your supervisor... – Solar Mike Jul 28 '18 at 14:22
  • I agree you should be having this discussion with your supervisor, but I don't like the way it is going if anyone else might take it as advice to use on a real-world structural safety investigation. For example you are completely ignoring the effects of surface finish on crack initiation, and (probably more important) the effects on the fasteners holding the parts of the bridge together. Bolts and rivets are FAR more likely to fail before the "solid" steel beams they are connecting. IMO. – alephzero Jul 28 '18 at 15:36
  • Does anyone know which stress values should we pick from all stress components in abaqus probe values? – Cindy.Karina9 Jul 28 '18 at 16:27
  • +1. As one of this site's top users in the Abaqus tag, I wonder if you've seen this question and/or if you might know the answer to it? https://mattermodeling.stackexchange.com/q/2055/5 – Nike Dattani Nov 14 '20 at 03:38

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The strength of the steel has not changed unless there is some factor you have not mentioned. You can get a good estimate of the remaining strength of the structure by putting in the minimum remaining thickness of the various sections into the program. This technique is accepted by AGA ( American Gas Association) , and I think ASME or ANSI, for determining the remaining strength of corroded line pipe. That is , if the original crossection area was 5 sq. in. and corrosion has removed 1 sq. in. of steel in the most corroded point of that member ; The strength of that member is reduced by 20 %.

blacksmith37
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