Beam Deflection due to temperature
Beam Deflection due to temperature
(OP)
I am a Geotechnical Engineer and need some guidance.
A 40 foot long steel beam (415) is fixed at one end and other end is simply supported. Will there be any deflection (vertical) in the beam due to change in temperature. The beam is allowed to move at one end. I have a dial gauge with precision of 1000th of an inch.
I think beam will deflect under its own weight. How about deflection with temperature. Will there be any deflection I should be concern about?
A 40 foot long steel beam (415) is fixed at one end and other end is simply supported. Will there be any deflection (vertical) in the beam due to change in temperature. The beam is allowed to move at one end. I have a dial gauge with precision of 1000th of an inch.
I think beam will deflect under its own weight. How about deflection with temperature. Will there be any deflection I should be concern about?






RE: Beam Deflection due to temperature
If subjected to higher temperatures, then the Young's modulus will diminish and the yield strength will also be reduced and deflection can increase substantially. By higher temperatures, I thinking in the magnitude of several hundred degrees.
Dik
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
Under normal conditions you shouldn't get any deflection due to a change in temperature... However, the beam length will change... but as long as it is free to move at one end it should not deflect except under it's own weight.
Now if the beam is at an extremely high temperature then you will get a decrease in the material properties, which would have an effect on your self-weight deflection.
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
What if the temperature difference be about 25 degrees over a period of 24 hours. Also, if top flange of W10 by 40 steel beam is exposed to sun and bottom flange not, is it going to make any difference. Please advise
RE: Beam Deflection due to temperature
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On the other hand, I think a vertical temperature gradient should make the beam want to bow, concave-cold. I get a rude & crude change in arc length of a fraction of an inch, top to bottom, unrestrained, 100-deg delta. You can model it, superimposing its own weight. Coef of thermal expansion, like E, is a function of temperature, but you can treat it as a constant; for steel its pretty flat in this range.
RE: Beam Deflection due to temperature
Dik
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
On the papers I was reading by then and at bridges (don't know the scale of such bridges) I think to remember that a spanish civil engineer stated that these stresses meant in practical terms around 15 to 20 MPa of actual top values of additional stresses appearing. For a proper analysis of bridges, these self equilibrated thermal stresses should be included as a thermal hypothesis for combinations.
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
Mike McCann
MMC Engineering
RE: Beam Deflection due to temperature
That "a gnats ..." thank you very much.
It is a measurement only slightly more primative than feet and inches :)
I agree with the thermal gradient causing bending.
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
You are asking a VERY general question, and the responses you've gotten reflect the lack of information about your concerns. Would a 1 micron deflection cause a problem? Would 10, or 100? Until you can clearly define your area of concern, you're going to get a vast range in answers.
TTFN
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RE: Beam Deflection due to temperature
BA
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
Mike McCann
MMC Engineering
RE: Beam Deflection due to temperature
RE: Beam Deflection due to temperature
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Beam Deflection due to temperature
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