Welding position and method for pipe support.

By SGC Date 02-15-2019 04:18

Hello.

Please let me have GOOD advices from specialists. ...

Backgound: Structural pipe support frames are normally "goal post", "T", Cantilever" shape of frame and they are welded to main structure above or below in offshore platform. When tubular section or square hollow section is used as structural pipe support sections, clients request the CJP welding for the joints between supports and main structure beam and welders qualified with 6GR positions. In case H-Beam or angle beam section is applied, the filler welding was sufficient, so 6GR welders are not required.

My questions are..,
1. Is there any reason or code requirement stating that the CJP welding is necessary for closed section beam like the square hollow section or tubular sections?

2. Is the requirement of 6GR welder madatory for joints described above?
Many of pipe supports are installed at deck below and there are many obstacles.

Thanks.

By 803056

Date 02-15-2019 14:27

The Engineer is responsible to determine if and where the groove welds must be CJP.

If the weld is specified as CJP on a tubular joint, yes, the welder must be qualified for the 6GR.

Al

By SGC Date 02-17-2019 23:29

Thanks.,

I am wondering how the engineer is able to determine the type of welding type among CJP, PJP, Fillet.
Is there no requirement depending on type of section i.e. tubular or H-beam or else? If the strength calculation of a fillet welding for a joint is satisfied, then the fillet welding has no problem to be applied for the tubular or square hollow section. I have experence that some of our clients request the CJP welding regardless of the strength calculation.

By 803056

Date 02-18-2019 00:33 Edited 02-18-2019 00:40

It is a lazy engineer or designer that specifies a CJP when it isn't needed.

Welding, believe it or not, gets scant coverage in most engineering curriculums. The result is many designers take the easy way out and call for CJP.

A basic static course as a freshman engineering student will determine the load at the connection. A few simple calculations is all that is needed to determine the size of the fillet weld or PJP needed to transmit the load. Yea, sometime a CJP is needed, but the detailer often times doesn't understand what it takes to make a CJP weld.

I’ve encounter way too may jobs where the detailer called for CJP when they were not needed, but it was the fast, easy way to call out the weld. Many times they will settle for a PJP or fillet when pressed. After all, detailers and engineers are human to and way too many of us are simple taking the easy way out.

Al

By yojimbo (***)

Date 02-18-2019 04:59

Amen to that.