Question about temporary structural loading.
Question about temporary structural loading.
(OP)
I've got a structure I'm designing that will be in place about 4 months (only for 4 months). The thing I'm trying to decide is whether or not to use full lateral loads or something less. I know ASCE puts out a standard on this [i.e. ASCE 37]....my question is (for anyone who has this standard): does this standard address load magnitude vs. specific duration time? And (if this is addressed and you feel generous): what kind of magnitude are we talking for 4 months duration (approximately)?






RE: Question about temporary structural loading.
RE: Question about temporary structural loading.
RE: Question about temporary structural loading.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Question about temporary structural loading.
Nope. June 2010....will be down sometime in September 2010.
RE: Question about temporary structural loading.
RE: Question about temporary structural loading.
RE: Question about temporary structural loading.
So is it significantly less than the full amount for 4 months duration (if you [or anyone else reading this] have this reference)?
If it's close: the heck with it, I'll just use the full design loads. But if it's (say) half......it will justify me going out and buying the reference to read the fine print and get the load down exactly. (Where I'm working they don't have this on the shelf.....so I'm trying to brow beat my boss into getting it and this will give me ammo.)
RE: Question about temporary structural loading.
For that matter, "temporary" barracks structures for the military built in the 40's are still in service today!
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Question about temporary structural loading.
That's exactly what I was thinking of. I remember many of those structures at Ft. Jackson, Ft. Dix, and Ft. Bliss.
When the base closings were going on, I couldn't help but think about all the new buildings that would be "abandoned", compared to the old ones that had served for so many years..such a waste. Big difference in benefit to cost.
Ron
RE: Question about temporary structural loading.
BA
RE: Question about temporary structural loading.
On those plans, in bold letters, it stated that the planned service life of those structures was only five years. After that time, they were to be demolished.
The point is that things change, to include intentions.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Question about temporary structural loading.
So it kind of goes back to my question from before: for that duration, what kind of % of the max load are we talking? (Ball park for anyone that has this reference.)
RE: Question about temporary structural loading.
I'm not convinced that it applies to your case. It is moreso intended to address temporary construction loads and exposed structural conditions during construction. There is a provision that includes "temporary structures" but my interpretation of that is such temporary structures as formwork or shoring, not a completed structure that is used for a short period of time.
Further, if you are in a wind area or snow area that is significant, the time of year that the building will be used will be critical to your design.
RE: Question about temporary structural loading.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Question about temporary structural loading.
In your case, the 4 months indeed might grow to 6, 8, or 800 months.
RE: Question about temporary structural loading.
Well I appreciate it. At this point I'm starting to wonder if I'll need this to justify designing for full design forces.....(sort of the opposite that I was thinking before).
But it cannot stay up for 4 months [and really....people are already raising
RE: Question about temporary structural loading.
Garth Dreger PE
AZ Phoenix area
RE: Question about temporary structural loading.
It's really too complicated a situation to lay out here (including the scheduling of everything). The temporary structure is a steel frame to be built.....(and yet another twist in this is I'm expected [to speed things up] to use an abandoned foundation that's off to the side).
It's got more twists than a pretzel......that's why I kept my original post as simple as possible so we didn't wind up discussing less critical parts.
RE: Question about temporary structural loading.
For 4 month periods the site wind speed can be reduced by between 0 and 27%.
These obviously only apply to the UK, but going on that it would appear unlikely that you can get a "50%" reduction from your code, and if as you say your building it during storm season I would guess the reduction factor will be zero...
RE: Question about temporary structural loading.
I'd recommend buying ASCE 37-02. I don't think it is very expensive, and it will provide a lot more insight than the responses here. I'm also not sure it would apply to your temporary structure.
RE: Question about temporary structural loading.
It is not "Design Loads on Temporary Structures" for a reason.
If this structure will be used in a manner consistent with a permanent structure and we are discussing design for it as a finished product, I would not see a justification to even use 37-02.
There could be a justification for a reduced period based on the life of the strucutre, but in south GA during the summer, you run the risk of seeing the maximum events for the area, so I think you are back where you started from.
For the price of ASCE37-02 (or the new edition), it is still a document worth picking up, even if it only helps you understand what others should be doing in the construction process.
Hope it helps,
Daniel Toon
RE: Question about temporary structural loading.
ZCP
www.phoenix-engineer.com
RE: Question about temporary structural loading.
IMHO, you will find better guidance in the International Building Code. The latest edition that I have is 2003. See Table 1604.5 "Classification of Building and Other Structures for Importance Factors". Category I includes "Certain Temporary Facilities" and allows the following factors for loading:
Seismic: 1.0
Snow: 0.8
Wind: 0.87 (with a footnote about hurricane prone regions).
These numbers may give you a general idea of what reductions are considered prudent.
However, for your case (this summer) I would give serious consideration to zcp's advice.
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RE: Question about temporary structural loading.
RE: Question about temporary structural loading.
RE: Question about temporary structural loading.
However, you have to temper that thought with the fact that if the structure fails, who is first in line to take the hit? It's you. Never forget that fact either.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Question about temporary structural loading.