[QUESTION] Offshore structure H beam CODE check practice 2

[offshorejhlee]

Hello off-str-engineers,

As to the Rolled H section and Built-up H section, I have very basic questions about offshore topside structure design code check.

1. Is there any difference in the aspect of Code check? Especially AISC code.
There might be some differences in code check between Built-up and Rolled.

2. Is there any SACS options for Built-up and rolled beam?
In actual situation, I have never seen anyone who applies the built-up or rolled H beam.

3. Is "this sentence" correct?
"the most offshore topside structural design codes are based on AISC for H beams and API for tubulars."
I have designed about 6 offshore steel structures such as FPSO and Jackets which are installed in Africa, Asia and North Sea for 8 years. However, I have never seen other topside design codes. (Except only one Eurocode design for Aluminum structure)
Is this a normal practice? or are there any other practices?

4. Any difference for Fatigue check between Rolled and Built-up H section?

Thank you for your help in advance.

 

[KootK]

I have no experience with these structures so my ability to help will be limited. Since nobody else has showed up yet, however, I'll do what I can. At the very least, this should bump your thread.

1) A built up section would need to have all of the connections between individually plates properly designed of course. Perhaps more concern for corrosion as well depending on how the pieces are joined.

2) I would certainly expect a difference when it comes to fatigue. This kind of thing is a big deal for built-up bridge girders.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[BUGGAR]

I wanted to reply but my memory on this is bad.
AISC covers tubulars (HSS) in round, square and rectangular sections but only up to about 24" in size. Above this size, you can specify pipe under API. This pipe is suitable for gas pipelines and similar and is structural quality. We used it for piles for offshore work and for access bridges between mooring platforms. I recall the API spec was better for the seam welds than the (other large pipe spec which I forgot).