Wind Load on Temporary Structures
Wind Load on Temporary Structures
(OP)
I am looking for a little guidance on reducing the design wind load for a temporary structure with an approximate design life of 1 year. There is Table C6-7 of ASCE, but I am not for sure on how to use it. Do you just multiply the map wind speed from Fig 6-1 by the factor in the table corresponding to an MRI equal to the expected life span.






RE: Wind Load on Temporary Structures
RE: Wind Load on Temporary Structures
RE: Wind Load on Temporary Structures
OF course - once it blows away - it was truly temporary...
I have seen thunderstorms pop up around here that pretty much come very close to design limits - sometimes 2 or 3 times a year!!
RE: Wind Load on Temporary Structures
RE: Wind Load on Temporary Structures
I see the logic that your trying to use but dont agree with it.
Just because the structure only has a design life of 1 year doesnt mean that it will see less wind in that time. It is likely that it wont see the 1 in 50 year storm during the period that its up, but you never know when that 1 in 50 year storm will occur so i wouldnt try and reduce the wind load.
RE: Wind Load on Temporary Structures
RE: Wind Load on Temporary Structures
Firstly, the level of wind load to which we design for is not a set in stone, concrete number. It is based on statistical analysis and an approximation of the likelihood of failure that is acceptable to society. We cannot make building with zero possibility of failure, so we have been forced to pick a number.
Secondly, society does not expect that after a hurricane all temporary structures are going to remain undamaged. It is cheaper to take the risk and accept the consequences in the unlikely event that it is subject to this level of wind.
Thirdly, the shorter something is up, the less likely it is that it will be subject to that load. I would use the reduction factor for short term structures (less than 1 year) that do not have a significant life safety factor.
RE: Wind Load on Temporary Structures
RE: Wind Load on Temporary Structures
I don't know about that. A structure under construction is by definition unoccupied. You can get away with lower wind speeds because the danger of loss of life is much lower. If a storm comes during construction, I suspect the workers would not be taking refuge behind an erected, unattached panel.
The structure GoCyclones mentions is Temporary, but occupied (at least that's my interpretation). Consequently, I'd be careful about reducing the design wind speed. The probability of seeing the design wind event in any given year is exactly the same for a structure designed for a life cycle of 50 years as it is for one designed for one year.
RE: Wind Load on Temporary Structures
My point was for the OP to look at that information where wind loads are related to a relatively short life and decide if it was appropriate for use in his or her case.
RE: Wind Load on Temporary Structures
I recently attended a seminar where one of the speakers pointed out that if you include load factors into your calculations, the wind event is more along the lines of a 600 year event.. haven't looked at the numbers, but I have no reason to suspect he was lying..
RE: Wind Load on Temporary Structures
RE: Wind Load on Temporary Structures
However, Category I is limited to buildings and other structures that represent a low hazard to human life in the event of failure.
RE: Wind Load on Temporary Structures
Could you justify your choice of wind load to a commitee of your peers?
If you cant then you know what will happen if it does fall down.