reaction values for metal building structure

[hapunaterp]

hello,
I am working on the foundation design for a metal building. I was given the basic column reactions (unfactored) and i am not clear on what the different categories are and there is no explanation or definition provided. I have a feeling it is obvious and my brain is just not cooperating. Reactions are given for each of the following: dead, collateral, live, snow, wind_left1, wind_right1, wind_left2, wind_right2, wind_long1, wind_long2 and then seismic and min. snow and unbalanced snow. can anyone explain what the 1 and 2 are with respect to the wind values are? I am not sure if it is referring to different cases in ASCE 7-10 or what.
I appreciate the help.

 

[mike20793]

I believe they come from the different wind load cases in ASCE 7-10 Figure 27.4-1, or any of the other applicable figures.

 

[daranguiz]

I'm mostly a EUROCODE user but I think it could be a case for Wind with postive internal pressure and another for negative internal pressure.

 

[hapunaterp]

Ah. Thank you. That seems to fit. i appreciate it.

 

[msquared48]

Might also look in the MBMA design manual.

Mike McCann, PE, SE (WA)

 

[JedClampett]

Good luck. We get the same garbage. It's very difficult to decipher the load cases. In our specifications we ask (require) the PEMB supplier to combine the loads or give us controlling uplift and downward cases and they flat out refuse. Sometimes they grudgingly give us some "maximum" uplift loads, but they never can be back calculated vs. the individual load cases.
I would almost say it's intentionally confusing to reduce their liability. That way if there's a problem, they can say "you misapplied the loads it's your fault."
Combine that with the fact that they won't design their own anchorage to the concrete and it makes me not want to use these buildings. I campaign against them when I can, but sometimes lose.
When we get the same kind of loads, we prepare an excel spreadsheet and combine them the best we can, using the ASCE 7 load factors.

 

[thaidavid40]

Our contracts for designing foundations for metal buildings provided by others (PEMBs) requires the Owner (PEMB Manufacturer) to provide maximum/minimum service-level envelope reactions for all columns. If such are not provided, then our contract allows us to create the appropriate design loads using the garbage usually fed to us, and to do that at our typical T&M rates, added on top of the original contract value. This places the cost burden on the Owner for this data. If they want to reduce our fee, they can lean on the PEMB manufacturer to provide the reactions data as specified. Otherwise, he has, by default, agreed to pay us to do the PEMB manufacturer's job for him.
Dave

Thaidavid

 

[hapunaterp]

I appreciate the information and it is good to hear others' experiences with this. We will err on the conservative side. It would be nice if things were more clear and I will have to keep trying to contact the manufacturer to get an explanation of the labels. I am going to learn a lot engineering the foundation for this. Some serious horizontal column reactions at each column.