Any welding limitation to steel structural member of a bldg of 1956

[SKJ25POL]

I am wondering if there is anything that prevents us of welding cover plates and reinforcing steel to the steel memebers of a steel structure that was built 1956-7ish.

The steel structure connections are rivited.
My question is in my repair plan is okay that I connect the new reinforment members to the old existing steel structure by welding?


Appreciate your guidance.

 

[TehMightyEngineer]

With that age of steel it might not be that easy to weld to it as that was prior to A36 becoming standardized. You'll also want to make sure that your heat affected zone doesn't cause structural issues. Also, remember that reinforcing a loaded structural member is not the same as reinforcing an unloaded structural member.

Maine EIT, Civil/Structural.

 

[Ron]

TME makes some good points.

By the 1950's AWS and ASTM were well established in construction.
Weldable structural shapes in A7 and A373(later A36) were commonly available. Even so, it would be wise to cut a small coupon from a low stress area (neutral axis, low or no shear)to check the metallurgy and mechanical properties. Not that expensive and worth the money.

 

[paddingtongreen]

Back in that era, most people were avoided welding because there was no experience background in structural work, no lore. The expertise was in shipbuilding and other war materiel. I didn't mind, I quite enjoyed laying out the rivets for some very large plate girders. By the early sixties we had switched to welding and high strength bolts.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[SKJ25POL]

Does any one know any publication or specification by AISC or AWS or industry tell us how to deal in this sitaution?
I believe I am not the first one facing this issue of welding to a old structural steel?
What may happen if the welding get done?

I appreciate some directions.

 

[TehMightyEngineer]

AISC design guide 21 and little in design guide 15 discuss welding to older structures. David Ricker's 1988 paper Field Welding to Existing Structures is also a great reference. From these I've come up with two conclusions.

First, a quick test can be performed welding a plate with a single sided fillet weld to a part of the existing structure. Impact loads with a heavy hammer can be applied to the plate putting the weld in tension. If the plate can be bent over without fracturing the weld then it's generally weldable steel. The plate should then be hammered the other way putting the weld root in tension where it will fracture, allowing you to observe the fracture plane. This is detailed in design guide 21 and Ricker's paper.

Second, you will likely have to do testing regardless of the above field test to determine the chemical composition of the steel from a series of samples cut from the existing steel. This will allow you to find the tensile yeild and fracture and chemical composition. From there you can go into AWS D1.1 and establish a welding procedure and if pre or post-weld heat treatment is required.

Maine EIT, Civil/Structural.

 

[SlideRuleEra]

Another source of information on welding to old steel is the database for AISC's magazine "Modern Steel Construction". You can search it at this link:

http://search.aisc.org/queryMSC.htm...d+existing+steel&charset=iso-8859-1&style=msc

One example of the info there is the answer to this question "Is steel in older existing structures weldable?"

The answer confirms what Ron, paddingtongreen, and TME have advised:

"Possibly. If the chemical properties of steel to be welded are known, either by valid mill certification or by laboratory sample testing, its weldability can be judged by computing the carbon equivalent value. A more obvious approach would be to examine the existing structure for evidence of original welding. Alternatively, an on-site investigation could be performed to address weld ductility and base-metal hardening. Other factors should also be considered, such as past history of the structure, the nature of the loads, weather conditions, and whether the members to receive welds are loaded."

Here is a link the landmark paper, "Field Welding to Existing Structures" by Ricker, that TME recommended:

https://engineering.purdue.edu/CE/A...les/FieldWeldingtoExistingSteelStructures.pdf

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[TehMightyEngineer]

One thing to note is that according to Ricker the A7 steel you're probably looking at is generally considered weldable but not always. Thus, don't assume it's not weldable because it likely is, just make sure you verify this assumption.

Maine EIT, Civil/Structural.

 

[JAE]

One other small (but could be important) point is to verify that the steel is not painted prior to welding. Some steel looks like...well..plain steel but may have paint still on it.
And back in those days paint had lead in it. During welding operations the welders can get exposed to lead fumes.



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[SKJ25POL]

Dear TehMightyEngineer (Structural), Ron (Structural, paddingtongreen (Structural) and SlideRuleEra (Structural) thank you so so very much for all valiuable information.
I appreciate it very much, especially Mr. SlideRuleEra (Structural)thank you so very much for the refrence documents, I greatly appreciate it. The article was good as well as the Structural Magazine.

Thank you all,
Have a wonderful day

Sincerely,
Your Colleague.