Mechanical Steel Tubing as a Structural Member
Mechanical Steel Tubing as a Structural Member
(OP)
Let me begin by pleading ignorance when it comes to Mechanical Steel Tubing.
I have client who has installed a three-story spiral staircase in a residence. They have used Mechanical Steel Tubing for the column. It appears to be a 3" pipe, but the client is uncertain how the steel was produced (AISI 1026, AISI 1020, AISI 1010).
As a structural engineer who is being asked to stamp a letter to the adequacy of this column, I am quite nervous. I work in a world of ASTM standards and it doesn't appear from other threads that the carbon content allows me to design this column as I would otherwise. I am also nervous about the welding done as part of the installation of the staircase.
Does anyone have a steel equivalent to these AISI or any advice on finding information as to whether it is advisable or not to use this type of material for structural implications. Any help would be appreciated.
I have client who has installed a three-story spiral staircase in a residence. They have used Mechanical Steel Tubing for the column. It appears to be a 3" pipe, but the client is uncertain how the steel was produced (AISI 1026, AISI 1020, AISI 1010).
As a structural engineer who is being asked to stamp a letter to the adequacy of this column, I am quite nervous. I work in a world of ASTM standards and it doesn't appear from other threads that the carbon content allows me to design this column as I would otherwise. I am also nervous about the welding done as part of the installation of the staircase.
Does anyone have a steel equivalent to these AISI or any advice on finding information as to whether it is advisable or not to use this type of material for structural implications. Any help would be appreciated.





RE: Mechanical Steel Tubing as a Structural Member
RE: Mechanical Steel Tubing as a Structural Member
Marking or other grade/spec ID on the tube.
Weld coupons for destructive testing.
Without both of those you can't evaluate the design and construction.
We all know that it is probably fine, but that isn't what they are asking you to say.
= = = = = = = = = = = = = = = = = = = =
Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net
RE: Mechanical Steel Tubing as a Structural Member
RE: Mechanical Steel Tubing as a Structural Member
Prior to posting on this site I had asked the fabricator for any and all information pertaining to the steel that has been installed. He indicated he would be providing me with said info. I am suspect at this point, but will come back if I get information.
Confused to the reference to the local building code? We are operating under the 2003 IBC. I can use this to determine the loads, but can't get far if I am unsure of the material properties.
At this point, I believe it is either AISI 1010 or AISI 1018. From what I have read, I am more nervous about the welding done than anything. Are these concerns warranted based on your expertise. I am just not at all familiar with welding techniques for these materials.
RE: Mechanical Steel Tubing as a Structural Member
There is more to the building code than materials. You need to find out what welding code or standards is required - for example AWS D1.1? Second point, you need to evaluate the weld joint details ( example - fillet welds, partial penetration groove welds, full penetration groove welds?)
In reading your post, as as observer, I would be very concerned until you answered my questions above.
RE: Mechanical Steel Tubing as a Structural Member
Based on the 2003 IBC, the reference welding code is AWS D1.1-2000. I guess I assumed this was implied based on the applicable building code.
All welding appears to be fillet welds.
Trust me, I am very concerned. Wish they would have called prior to actually installing the stair.
RE: Mechanical Steel Tubing as a Structural Member
RE: Mechanical Steel Tubing as a Structural Member
You will need to review adequacy of the fillet weld size based on the fabrication drawings and your OWN expertise..
RE: Mechanical Steel Tubing as a Structural Member
RE: Mechanical Steel Tubing as a Structural Member
= = = = = = = = = = = = = = = = = = = =
Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net