design loads for corrugated metal panels 1

[Kris the Engineer]

I am currently involved in a project that will be a 5 story building that will be made of premanufactured containers (similar to shipping containers) that will be custom built in china and shipped over and then stacked to make the building that will be located in California. I am having the hardest time finding any relevant information for the lateral design of the building regarding the seismic parameters and the allowable load for the shear wall. The containers will be built with steel beams along the top and bottom along with steel posts at the corners and for interior bearing points. The walls/lateral system will be corrugated panels that will be welded to the top and bottom beams.

Has anyone used this type of system in the past or have any reference material on the seismic design parameters for the corrugated metal panels? For the allowable strength I was going to look at an equivalent Verco section since they have an allowable diaphragm load. Please let me know your thoughts and if I am going down the right path.

thanks.

 

[Ceinostuv]

I've seen others use Verco sections to justify container conversions; you'll be taking a risk and it will ultimately be up to the building official whether to accept or not. It isn't too difficult to poke holes in that approach and I'm not a fan of it.

The 'most correct' approaches, I gather, are to either test the units after modifications have been made or to do FEA. AISC has a seminar on the second approach.

Assuming there are no modifications (read: openings added), you might look at using the values from ISO 1496 to justify the design; again, you're at the mercy of the building official with this route and should verify the containers are, indeed, ISO containers. You'll also want to do a quality check on the containers, there is another ISO document out there for that, especially if they've been used for shipping prior to the conversion. If the units are just similar to ISO IMSC's, you may be out of luck with this route.

I believe the CBC (it might be a local Californian jurisdiction though, I don't recall) also has a prescriptive guide for container structures, but you'll essentially be building a wood structure inside; not the hardest thing to accomplish if there will be finished walls within the structure.

PS - 5 stories in California, I assume you'll have some sizable seismic forces. If I'm right, you may have issues using the values from ISO, depending on what the end use and finishes will be.

Good luck, have fun, I'll be rooting for you.

Judgement-In-Training

 

[Deker]

Take a look at this LADBS Bulletin for some design considerations for cargo container conversion to buildings. Note the excerpt below which requires quantification of the seismic response factors through testing and/or some pretty serious modeling if you're trying to utilize the corrugated siding.

Since it sounds like these will be newly fabricated modules rather than conversions, I suggest designing and detailing the corrugated siding as a facade and utilizing shear walls (could be steel plate) or braced frames (SCBF or BRBF) within the module frames.

The lateral force resisting system shall be one of the Table 12.2-1 (ASCE 7-10 as modified by 2017 Los Angeles Building Code [LABC]) systems permitted by LADBS. The contribution of the corrugated steel container sides, if left in place, to the lateral force resistance is to be neglected, unless testing and analysis is provided to demonstrate equivalency as an alternate design system in accordance with Section 104.2.6 of the 2017 LABC, to a system in Table 12.2-1 or new seismic design parameters (response modification factor, over-strength factor, deflection amplification factor, etc.) specific to this system are developed in accordance with FEMA P-795 and FEMA P-695, respectively and approved by the Department.

 

[Kris the Engineer]

Ceinostuv,
I found the ISO document the thing is that these are conversion units. these will be brand new built units. they will not have doors each end like the ISO containers do.

Decker,
You are correct that these will be brand new containers that will be built to the specifications that I tell them. We will be having metal studs for an interior finish and I was thinking of using those as shearwalls instead of messing with the corrugated panels.

 

[JLNJ]

How does one handle Special Inspections for structural steel things built in China?

 

[Kris the Engineer]

It is all part of the process we are trying to determine. Special inspections are not required as long as the shop is certified, that is what i have been thinking from the beginning but i have also heard mentioned from the architect that they have flown inspectors over to Chine before to have them do the inspections before although I'm not sure how that is going to work out with corona.

 

[r13]

For cross country project and as a structural engineer, you should pay attention to the code/standard the manufacture uses. In this case, welding standard, procedure, inspection and testing need to be addressed before manufacturing starts.