huangyhg

crane design information
anybody have information regarding asce rail design for crane end truck wheels? i have a crane (50 metric tons), span = 118 feet, bogie end trucks (4 wheels, 20" dia), wheel load is 50 kips. i have an old whiting crane manual that discusses rail design based on a formula:
d x w x 1400 (class d)
d x w x 1200 (class a-c)
d = wheel diameter
w = width of top of crane rail
1400 or 1200 = ????
the width of the actual wheel on the end truck is 3 inches while sitting on a asce 60# rail (1.25 inches wide) at the top of the rail.
is this too much tolerance? is a 60# rail too small? please advise.
thanks,
alumpkin
check out our whitepaper library.
check aist.org, or asme site for the information you are seeking.
the aisc has a reasonably good excel spreadsheet for prelim design...
dik
also check out
the crane manufacturer should give you a rail size, or at least a head width.
an asce 60# rail has a head width of 2 3/8", not 1 1/4".
thanks for the comments. i have checked all of the resources above but have not doownload the iso guideline for the design of crane rails as yet.
true the head width for an asce 60# rail is 2-3/8", the flat part at the top less the radius' is only 1.25 inches. that is what is shown in the old whiting crane design manual as well.
i was looking for someone familiar with the rail design process other than the crane manufacturer. we may have a problem so i want some outside assessment and backup for my benefit.
additional comments are welcome.
the width of crane wheel usually is wider than the rail to allow for lateral movement, considering the rail would not be perfect straight. check the proper sources for the tollerances on rail alignment.
several other aspects of wheel/rail design:
-class of service (duty cycle)
-wheel hardness - (big part of wheel/rail design)
-crane speed
-crane span to wheelbase ratio
-tapered or flat treads (flat being common these days - but this maybe proving to be a bad idea)
-indoor or outdoor service
-thermal expansion of crane girder vs runway system
-tight wheel/rail float demands properly aligned rails - and make sure the same tool and people measure the crane's span and rail span.
all those thoughts aside -
i confirm that 60# asce has a 2-3/8" head, ignore the 1-1/4" contact area - thats getting too scientific,
that leaves 5/8" float - this seems a bit tight to me
under general circumstances.
we too have had some problems in the past which evolved into very very detailed evaluation of the cranes and runways. there are a large number of variables all of which can easily lead you to different conclusions.
alignment issues with crane runways are normally with the runway beams themselves rather than the rails. the tolerances have to be tight, much more so than normal building steel. you can't solve runway alignment problems by adjusting the rails, that just causes more problems, premature wear issues, etc.

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