gas station canopy 2

[deereman]

An architect is wanting me to design a drive thru that has only 2 posts, similar to the structures they install over gas pumps. Has anyone ever designed one of these? Are the columns designed as a cantilevered column to resist lateral loads? It seem this is a very unstable structure. I've noticed that alot of the new canopies have 4 columns and the ones that have 2 columns have alot bigger columns than the older ones.

 

[Lion06]

I should clarify that it was the roof that was moving up and down 1.5'. The roof itself looked like a blanket being shaken at the beach (and this was only a 30-40 mph wind). To be honest, I didn't even look at the column drift, but that's because I was so surprised (and focused on) by the amount of movement of the roof.

 

[structuresguy]

I'm sorry StructuralEIT, but are you saying FEET or INCHES?

If it is feet, then my only advice would be RUN!!!!!

 

[Lion06]

FEET! It really was crazy, that's why I called.

 

[JLNJ]

Was it a two-post structure?

I checked one of these one time where it was not really stable - sort of a teeter-totter in one direction. The designer inadvertantly was relying on load-symmetry to "balance" things out. Otherwise they might have seen the deflections you are describing.

 

[Lion06]

Yes, it had only two columns.