×
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

Picking up a unbalanced load
4

Picking up a unbalanced load

Picking up a unbalanced load

(OP)
I've got a object (a pre-cast, reinforced concrete frame/box combo) where the center of gravity is way off-center. Nowhere near the points where you'd think they would attach for lifting. How do I go about this? Maybe lift with a spreader beam (as opposed to the slings coming to a single point)? The object is about 60' x 26' in plan view.

RE: Picking up a unbalanced load

WARose,

There's a bunch of ways - spreaders and frames certainly work. You could also vary the sling lengths from the attachment point to the hook/spreader. How many pick points? Is there a vertical height constraint (i.e., object + rigging needs to be kept under a certain height due to crane restrictions)?

RE: Picking up a unbalanced load

If you lift with a spreader beam, you could still have the whole spreader beam plus load tilting at an angle when lifted, which is presumably not the intended result.
Ideally, I'd locate lifting points in a horizontal plan, located so that the center of gravity is below the junction of the lifting points.

RE: Picking up a unbalanced load

4
I've done this a few different ways in the past. No matter what you do, the center of gravity will align itself with the crane hook - so if you can tolerate the piece hanging skewed, you can keep your COG within the bounds of your pick-points and let it hang how it hangs so to speak. If you need to pick it up dead-flat, your hook needs to align with the COG - I've done this by using a custom lifting beam with offset top-lug as shown below.

RE: Picking up a unbalanced load

(OP)
Thanks for the feedback guys.

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

3D Scanning in the Automotive Industry
With over 100 years of production history, the automotive industry has been at the forefront of manufacturing technology since its inception. Whether the transformative technology of the day was the assembly line, the integration of robotics into the manufacturing process, or the switch from steel to aluminum frame chasses, the automotive industry has consistently implemented advanced technology into its manufacturing and production workflow to improve manufacturing and product performance. Today, the same is true. Download Now
Green light on lidar: Developing low cost systems for autonomous vehicles
Lidar has been around for quite some time, but to date, it’s been custom—and expensive. Right now, there isn’t a clear-cut solution that’s suitable for all applications, such as lidar in autonomous vehicles. As they explore options, optical and mechanical engineers are forced to make choices and tradeoffs during the design process. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close