Bottom flange of a monorail

[ape2010]

Hi,

When the hoist wheel loads are applied to a bottom flange of an I beam, how can I analyse the bottom flange for the local failure for bending and shear.

Thanks.

 

[apsix]

Depends where you are.
In Australia the crane code AS1418 details the procedure.

 

[steele6707]

ASME NUM - 2000 Construction of Cranes, Monorails, and Hoists (check for a later edition)contains a procedure for designing steel members. Section NUM-III-8232.3 is titled Local bending of Flanges Due to Wheel Loads. I saw this at Linda Hall Library.

 

[jike]

I believe Roark also has a formula for flange bending. Don't forget to then combine that stress with primary bending stress by Mohr's circle.

 

[jberg]

If you are in the U.S., you could also check out Crane Manufacturers Association of America, Inc. (CMAA) at

http://www.mhia.org/industrygroups/cmaa

Their spec. 70 and 74 are references I have used in the past for the effects of local flange bending.

JWB

 

[weab]

Jberg is right. CMAA is the reference to check out. Not familiar with 70 but 74 is the one I have used.

 

[george69]

The AS1418 is the most comprehensive and accurate. The bottom flange capacity "Tf" formula was determined from combining local bending stresses with longitudinal bending stresses by Von Mises criteria. The "Tf" formulas accuracy was verified in the early 70's by BHP testing a series of I beams beams with point loads on the bottom flange. The experimental results correlated extremly well with the formulas prediction on capacity.


FYI: wheel loads are applied usually 0.9 to 0.95 of the bottom flange width - That is to say the loads are virtually at the tip of the flange.

But remember to check the web capacity also and the global buckling capacity. The serviceability limit should be limited to L/500 or L/600 depending on where you are. If there is a joint between beams , say at a splice, you should have a gap of no more that 3-4mm. The flange should be locally thickened near a free edge or at a splice point - This is clearly due to the point load causing larger stresses near an unsupported edge.

take care

 

[ape2010]

Thank you very much everybody for giving me advices, I will check with those references.

Regards.