Problem Solving Forum
September 8 - September 11, 2020
What is the service life of a painted weathering steel bridge, compared to a painted carbon steel bridge in the same service environment?
cameron jewell of Gemstone,LLC on
September 10, 2020:
I think the question this gentleman is asking is w ...read more I think the question this gentleman is asking is what life can one expect with the combined paint and weathering steel together. My answer would be you would get 10 to 15 years life out of the paint system and then whatever additional years the weathering steel provides when the coating sytem begins to fail. So my answer is you would get an additional 10 to 15 years life out of your weathering steel or more- probably a good investment.
Mike Beitzel of Modjeski and Masters on
September 10, 2020:
The service life of the bridge coating system with ...read more The service life of the bridge coating system with all application criteria being equal, the coating system over weathering steel would generally be expected be longer in more moderate service environments as undercutting corrosion would be less severe and the percentage of area corroded lower. In more aggressive service environments such as marine the coating system service life is likely to be equal as corrosion rates would be comparable.
Jaime Marcos of Profesional independiente on
September 9, 2020:
If the environmental conditions are respected, the ...read more If the environmental conditions are respected, there should be no difference. But the reality is that in the works that are carried out on site, due to the deadlines and the need to finish the work, the ideal environmental conditions are not respected, so the quality is lower, and the useful life of the coating as well. The works carried out on site require greater control and maintenance. The ISO 12944 Standard defines the Durability of a system, depending on the corrosivity category, regardless of where the work is carried out. There is not a number of years difference that can be set for the useful life, depending on the place where the work is carried out.
jack goodwyn of Southwest Technical Services on
September 8, 2020:
There should be no difference. The key is cleanin ...read more There should be no difference. The key is cleaning to SSPC-SP10 with steel grit and use of a zinc primer (I/O or epoxy). The surface should be primed in less than 4 hours of blasting. Top coats of siloxane or urethane suggested.