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Crane Beams and Rails
- Thread starter dik
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racookpe1978
Nuclear
How long a crane rail, and how are you propose holding it up in the air?
"Accommodating" thermal movement depends on where the piece of steel is fixed, how many places it is fixed at, where the expansion "wants" to go, and the amount of relative expansion between the rail (in this case) and some other (assumed non-mobile!) object that is not expanding.
If a long rail is in mid-air with long vertical supports, there is no relative motion problem: everything expands and the vertical at each end go (slightly) out of vertical. If each each vertical is slightly canted inward in cold weather, then the end verticals move more towards "straight" up and down as the assembly heats up.
"Accommodating" thermal movement depends on where the piece of steel is fixed, how many places it is fixed at, where the expansion "wants" to go, and the amount of relative expansion between the rail (in this case) and some other (assumed non-mobile!) object that is not expanding.
If a long rail is in mid-air with long vertical supports, there is no relative motion problem: everything expands and the vertical at each end go (slightly) out of vertical. If each each vertical is slightly canted inward in cold weather, then the end verticals move more towards "straight" up and down as the assembly heats up.
madmantrapper
Electrical
I think you are only talking ~5 inches in a mile. I don't see the concern.
It's a lot more than that, manmantrapper. 0.00117 x 70/100 x 100 x 12 = about an inch in 100 ft. So 50 inches/mile.
What is normally done is to provide the longitudinal bracing near the centre of the run, and the two ends move. Requires some flexibility in the transverse bracing.
What is normally done is to provide the longitudinal bracing near the centre of the run, and the two ends move. Requires some flexibility in the transverse bracing.
rowingengineer
Structural
and the columns are designed for the eccentricity from the expansion
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Two quick thoughts - I think that there are rail-slip details that have been developed at expansion joints.
Second - I would place your X-braces - or whatever kind of brace you use - near the center of the rail system to allow the outer reaches of the rail to expand and contract without restraint.
The worst thing you can do is design several spaced braces along the length that will fight each other as the temperature changes....or braces at each end.
Second - I would place your X-braces - or whatever kind of brace you use - near the center of the rail system to allow the outer reaches of the rail to expand and contract without restraint.
The worst thing you can do is design several spaced braces along the length that will fight each other as the temperature changes....or braces at each end.
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- #10
If you brace one bay near the middle, the thermal movement would be about 1.25". But if built when the temperature is near the midpoint of your range, the movement would be half that, in either direction. I don't see a problem in allowing the end columns to lean 0.7".
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- #12
With simple span beams mounted with slotted holes and bolted crane rail joints the thermal expansion and contraction could be accommodated internally. I think 250' is a long way to go with just a center braced bay.
If you braced at intervals along the run, it would force the thermal movements into the joints mentioned.
If you braced at intervals along the run, it would force the thermal movements into the joints mentioned.
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