Temperature in exposed steel truss 2

[IJR]

I have a feeling the subject of temperature effects on exposed steel is not well covered in codes. Unless someone tells me how bad I babble

A steel truss exposed to summer temperatures of 40degs and winter temperatures of -20degs.

What temperature should I subject the truss members for summer conditions and for winter conditions?

I usually get mixed responses from friends who like me have never taken the matter seriously.

regs
IJr

 

[Hariharan]

IJR,

I am in this forum as well!

Probably the main reason why people don't bother about
thermal effects in trusses is that most trusses are statically
determinate, or the level of indeterminacy may be very low.
When all members in a statically determinate structure are
subjected to the same increase/decrease in temperature, the
members do not experience any increase/decrease in stress.
It is the redundancy which introduces stresses due to temp.
variations. And in trusses, the actual magnitude of stress, I
think, would be quite small, even if there is redundancy.

Hariharan

 

[IJR]

It is nice to see that you visit here as well, Hariharan. I do post questions here.

My question is : given winter minimum and summer high, say -20deg and 40deg, what numbers should I use in modelling element temperature


Regards

IJR

 

[Qshake]

Speaking of the AASHTO code only, when we (brigde engineers) design steel or concrete bridges we must look at a map of isothermals for a range for a particular location.

For the midwestern US and for steel structures, this amounts to a fall of say 80 degrees and a rise of 60 degrees for a datum of 60 degrees. Thus the range is 140 degrees. For concrete it is somewhat less, with a rise of 30 degrees and a fall of 40 degrees resulting in a range of 70 degrees. Again, we would design for the range. It is not uncommon, in reviewing past records, to see a range very close to this especially in the transition climates.

 

[IJR]

Qshake the Boss, long time no see. Nice to hear from you. And thanks merciful.

Qshake, so when you say you design for the range, what do you exactly mean by that. Do you want to give me an example featuring a simple application. That will probably keep the buzz off from my brain.

Regards
IJR