×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

monorail beam design

monorail beam design

monorail beam design

(OP)
I have a exsiting monorail system ,we'er planning a special lift . I have  used a recommended analysis in the past which adds 20% of the lift load as a horz. load . This lift is inside a enclosed structure ,under very controlled guidlines ,minimum speed no lateral movement.this lift is for construction related activites ,I assume the addition of the horz. component is to compensate for unknown loadings in normal use. since this is not the case I am inclined to overlook this horz, component ,the verticle lift load puts the stress levels at 1/2 that allowable ,any comments .  

RE: monorail beam design

The horizontal component is in part from acceleration and braking while moving load along the monorail.  If your plan is to move load along the rail I would not overlook the horizontal components.

RE: monorail beam design

Make sure the load is lifted vertically and not dragged transversely from the side into position. Make sure load is not "swinging".

Longitundinally, you should have an allowance for accelerating and braking as indicated above.

RE: monorail beam design

Comments & Opinion:  You may be mixing crane DESIGN requirements with crane USE requirements - they are very different.

The 20% allowance for horizontal forces, that I am familiar with, is for sizing the supporting structural steel (see AISC Manual of Steel Construction, Section A3). This has little to do with the actual use of the crane.

Crane "use" requirements are typically based on the crane manufacturer's stated lifting capacity (assuming the structural steel supports were correctly designed). In the USA, OSHA allows normal crane use up to rated capacity and even controlled condition test loads up to 125% of rated capacity.

Since your calculations indicate that the structural steel supports are adequate, suggest that you base your decision to proceed, or not, on the rated capacity of the crane. If the load exceeds the rated capacity let us know the numbers, we may be able to provide additional comments.

 

www.SlideRuleEra.net idea
www.VacuumTubeEra.net r2d2

RE: monorail beam design

Agree with the above with an additional note:

Check the deflection limitation of the equipment.  Sometimes it's L/450; sometimes it's higher.  If the slope of the bottom flange due to deflection is too great, the hoist may not be able to move along the flange.

RE: monorail beam design

(OP)
the horz. load I'm talking about is a lateral load placed at 90 degreees to the length of the monorail beam ,I have included a 10% of vertical lift load as a axial load to cover for acceleration and braking.

RE: monorail beam design

The reference that I find to the 20% horizontal load normal to the rail is for design of crane runway beams that have a trolley that travels normal to the rail.  It states:  "20% of the sum of the lifted load and the crane trolley (but exclusive of other parts of the crane)."  As this is a monorail and the hoist doesn't travel perpendicular to the rail I would not think that this applies.

My only concern in eliminating this load case would be when someone tries to lift something that is not in line with the crane rail.   

RE: monorail beam design

Our inhouse standard is to use 10% for monorails.  I believe 20% is excessive.  As H57 mentioned above the trolley in a crane runway travels normal to the rail, so 20% makes sense for crane runways.

RE: monorail beam design

I agree, 20% sounds excessive. In fact the Australian code specifies a figure as low as 4%.Braking and inertia loads are considered separately to this of course.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources