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Why do steel bridges need to be painted?
The primary cause of corrosion of steel bridges is the exposure of the steel to atmospheric conditions. This corrosion is greatly enhanced due to marine (salt spray) exposures and industrial environments. The only corrosion prevention method for these structures is to provide a barrier coating (paint).
How long does bridge paint last?
These old- technology coatings were expected to last about eight to ten years before requiring some level of maintenance intervention.
Why is painting often used to protect bridges from rusting?
On bridges, corrosion is most often caused when steel is exposed to atmospheric conditions, such as salt, moisture, and oxygen. Therefore, before the bridge painter applies the protective coating to either new steel or a rehabilitated bridge, the surface needs to be evaluated for cleanliness.
How often do bridges need to be painted?
Some say once every seven years, others say from end-to-end each year. Actually, the Bridge was painted when it was originally built. Until 1965, only touch up was required.
How do you stop bridges from rusting?
Like barrier coatings, galvanizing – the application of zinc metal to steel – protects the underlying metal from corrosion by taking on the effects of corrosion itself. Hot-dip galvanizing is considered the most effective way to prevent corrosion on unusually-shaped parts such as those used in hanger systems.
Why do bridges not need to be painted?
And when new steel bridges are constructed, they’re made out of weathering steel, which develops a protective red-rust coating and doesn’t need to be painted. Paint, according to Bottenberg, is as much for maintenance as aesthetics. And if it’s not necessary, it’s not used.
How are steel bridges supposed to look like?
Think about it: steel bridges can look light and airy or solid and stable. They can be formed into any shape, from a simple straight line to a complex curve. The surface of steel may be detailed in countless ways and painted a full range of colors.
Do you need to re-paint a steel bridge?
On the other hand, the few clients of ours that own pedestrian bridges are constructed of weathering steel and do not require re-painting. What I am hoping for is that someone on here has some very, very general method of cost estimating this type of work.
Why are Bridges painted green in the northwest?
ODOT Green is well-suited to the Northwest: its special coating cures best in damp weather. In a place like Arizona, the paint would never dry. But the color is noticeably absent on Oregon’s newer bridges. “Nowadays we favor concrete bridges, because you don’t have to paint them” Bottenberg said.