Built-up steel Section Using Reinforcing Steel
Built-up steel Section Using Reinforcing Steel
(OP)
I've been retained to review the design of a canopy structure. The canopy consists of multiple T-Frames (18ft O.C.) with the frames built-up of cold rolled sections; Dbl CEES 16x4x10Ga stitched welded to form a box section. The box section alone does not resist the design forces and thus needs to be reinforced/built-up (approximated design ratio of 1.7). The designer placed 4-#8 bars in each of the inside corners of the CEES by weld using a staggered intermittent (2-24) PJP Flared Grove Weld.
I've asked the designer to provide background information as follows:
1. Allowing intermittent groove welds on Built-up Members (AWS D1.1-15; 2.12)
2. Maximum Spacing of Intermittent Welds shall not exceed 24 times the thinner plate (AWS D1.1-15; 2.12.2)
3. Unpainted weathering steel steel intermittent welds shall not exceed 14 times the thickness of the thinner plate (AWS D1.1-15; 2.12.3)
I received the following response:
1. The use of intermittent PJP groove welds are allowed. See Ssection 2.7.3 of AWS D1./D.1.1M:2004
2. The Section referenced above is 2.11 for Built-up members and not a section for coldformed shapes. No plates were used in this built-up section; therefor, this does not apply
3. Again we are not using plates in are built up member
I would appreciate any comments confirming the above response or refuting comments.
Thanks
Charlie85
I've asked the designer to provide background information as follows:
1. Allowing intermittent groove welds on Built-up Members (AWS D1.1-15; 2.12)
2. Maximum Spacing of Intermittent Welds shall not exceed 24 times the thinner plate (AWS D1.1-15; 2.12.2)
3. Unpainted weathering steel steel intermittent welds shall not exceed 14 times the thickness of the thinner plate (AWS D1.1-15; 2.12.3)
I received the following response:
1. The use of intermittent PJP groove welds are allowed. See Ssection 2.7.3 of AWS D1./D.1.1M:2004
2. The Section referenced above is 2.11 for Built-up members and not a section for coldformed shapes. No plates were used in this built-up section; therefor, this does not apply
3. Again we are not using plates in are built up member
I would appreciate any comments confirming the above response or refuting comments.
Thanks
Charlie85






RE: Built-up steel Section Using Reinforcing Steel
At this point, I strongly recommend one of two things - revise the assembly to something a bit more standard (HSS) or both of you get a copy of AWS D1.3.
Have you looked into compliance with AISI S100?
RE: Built-up steel Section Using Reinforcing Steel
RE: Built-up steel Section Using Reinforcing Steel
Dear Lomarandil - Yes, weldable rebar
RE: Built-up steel Section Using Reinforcing Steel
What is the allowable stress being used for the CEE and the bar?
RE: Built-up steel Section Using Reinforcing Steel
Of course, cost is always an issue..., so then they crap up the design with a bunch of incompatible materials, details and joinery, not knowing a wit about structures and how they really work; and finally ask some willing Structural Engineer to bless their mess and act as the insurer of last resort. Let the “Designer” justify his mess, he made it. I think we really have to learn to turn down the impossible and stupid projects, for a small fee (low cost is important, remember?), the work is all done, can’t you just sign off on it? Buy the way, the design fees already went to that other guy, on the cheap, who isn’t able or qualified to really justify his mess.