Repair of Corroded Steel I-beam
Repair of Corroded Steel I-beam
(OP)
What are the common methods for repairing corroded steel sections? In this case I am looking at an A36 built up I-beam section where there is an approximately 1/8" loss on the lower part of the web on one side and a 1/8" gross loss with some areas penetrating 3/16" and 1/4" on the upper face of one half of the lower flange. The section has enough material to remain in service for the time being, but I'd like to know what are common methods for a future repair. Thanks!






RE: Repair of Corroded Steel I-beam
RE: Repair of Corroded Steel I-beam
RE: Repair of Corroded Steel I-beam
Assuming the added steel doesn't interfere, the web you can "Fish Plate" with original web thickness the depth of the beam on both sides of the corroded section. The flange would be a similar repair by welding a plate the same flange thickness on the outside of the flange, a depth D beyond the corroded section.
As NJL stated the web repair may not be needed but you can expect the corrosion to continue, this will put you ahead of the game.
RE: Repair of Corroded Steel I-beam
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RE: Repair of Corroded Steel I-beam
If you have a column and the web is gone, that means that the flanges are taking more of the load. If you just repair the web, you're not removing the stress from the flanges. Additional loads might cause local problems.
One other issue to think about. Be careful welding to loaded existing members. The heat of welding reduces the strength and stiffness of the existing steel.
RE: Repair of Corroded Steel I-beam
Going a little off topic, Wednesday I got sucked into redesigning and detailing about three dozen steel repairs -they're repairs at the ends of bridge stringers - because the contractor says they're unbuildable as shown (he's reasonably correct). The end diaphragms are skewed; whoever detailed them didn't realize a number of things like the proposed angle stiffeners hit the diaphragm flanges and bolting clearances exist for a reason.
RE: Repair of Corroded Steel I-beam
RE: Repair of Corroded Steel I-beam
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
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RE: Repair of Corroded Steel I-beam
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RE: Repair of Corroded Steel I-beam
My thought for using the angle goes back to my paper mill background. Most heavily corroded steel beam were due to chemical, water, or steam leaks onto the steel at specific areas. Armoring these areas with as much metal as possible was often worth it in the event the leak source wasn't easily removed.
The other thing is make sure you stress the timely application of this repair along with proactive repainting and inspecting of other areas where corrosion may exist. That amount of corrosion does not happen overnight and I usually found it was due to lax facility maintenance of uncommonly inspected areas and equipment. For example, we had one corrosion repair job where they put our engineered shoring system in for the repair but then delayed the job for 6 months at which time the corroded beam actually failed and the equipment was left hanging off of piping. This made the job 10x more expensive and involved new columns, new framework for more shoring, etc.; to say nothing of the cost had the equipment ripped out the piping, likely shutting down that side of the mill and requiring replacement of the equipment. In short, impress upon them that waiting to the last minute to perform maintenance will cost them much more down the road.
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/