Deflection limits...
Deflection limits...
(OP)
Hi!,
Any ones knows a book, a web page or reference that recomendate deflections limits for different types of strutures? (ie. buildings, bridges, industrial storages, etc.)
Any ones knows a book, a web page or reference that recomendate deflections limits for different types of strutures? (ie. buildings, bridges, industrial storages, etc.)
Diquan






RE: Deflection limits...
Try to be a bit more clear if possible.
RE: Deflection limits...
RE: Deflection limits...
RE: Deflection limits...
The structure needs to support A/C and special panels.
Now, if i design the structure to support all the equiment the structure will deflect more than 50cm (20in) at the top of roof, so the design is govern by deflection not by work.
And the question is, what is a good limit for deflection? for this types of structures?
L/120? L/150? L/200? L/240? L/300? or L/360?
So, is there book, or something that will say something for structures this high?
Diquan
Diquan
RE: Deflection limits...
RE: Deflection limits...
Is there heavy equipment on the roof?
The absolute most deflection I would allow for this type of structure is H/150 and L/200 but this would be more stringent depending on the details.
csd
RE: Deflection limits...
RE: Deflection limits...
However, for small deflection theory, you can actually have rather large linear deflections, as it is the beams radius of curvature that is the divider between small and large deflection theory.
So if you can prove that the structure is acceptable by analysis then you should be ok. However if you have to comply with certain building regs then you might be constrained somewhat.
RE: Deflection limits...
It is not just what is acceptable by small/large deflection theory. This is a serviceability consideration. You don't want the finish of the structure (whatever that may be) to crack or otherwise fail. Different materials require different drift ratios.
Diquan-
What is the finish of the structure?
RE: Deflection limits...
RE: Deflection limits...
csd72 (Structural)-> Made of foam, the air conditioner equiment is attached to the roof. You end up with that deflection based on experience?
Diquan
RE: Deflection limits...
RE: Deflection limits...
Seismic loads will have their own deformation checks, again in your building code.
Drift under wind loads is not something I have seen typically codified but you may find other sources with recommendations. The AISC has a design guide which addresses this with some recommendations.
If you have equipment on the roof, you may want to check if the vibration will be an issue.
If you have any partitions or anything that could be damaged by excessive deflection, you may also need to limit the deflection to an absolute number, in addition to limiting it to a given fraction of the span.