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


X Cranes?

X Cranes?

X Cranes?

Hello everybody,

I was looking at some videos on the construction of the Golden State Warriors' new arena in SF and I noticed that apart from a large number of tower cranes, at the phase of construction shown in the link below, there are two "x cranes". More accurately they are like large construction machines (like a bulldozer) bearing a huge steel boom that crosses another one to form a giant X. They have cables on them but I have never seen anything like that and couldn't really figure out what their function might be. Anyone know?

You can see them most clearly around the 2 min mark.


RE: X Cranes?

They are just two large mobile/crawler cranes facing each other. One with a large red main boom, facing right at 2:00 o’clock in the video, and the other with a large blue main boom, facing left at 2:00 o’clock in the video. These main booms will be near vertical when the cranes are in operation. The two cranes booms are being erected at the moment, just finished being assembled and rigged. The large white booms are long reach jibs (luffing booms or luffing jibs). At the moment, they are resting on their outer tips. During assembly both booms are laid out in line, on the ground. The two smaller white lattice structures on each crane boom, generally pointing upward, are jib struts. Their angles will be manipulated to raise the long reach jibs, to adjust its reach (working radius) and angle w.r.t. horiz. (luffing). After boom assembly and rigging, they put the outer tip of the jib on a rolling dolly and start lifting the main boom. This caused the jib outer tip to end up as you see them resting in the video. Now, they are ready to start lifting the jibs, and the main booms further, to put the cranes in operating condition.

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!


White Paper - Effects of AIA Quick Guide to UL 489 or UL 1077
The function of a circuit breaker is to provide overload (thermal) and short-circuit (magnetic) protection to a circuit and its downstream components. A circuit breaker functions like an airbag in a car, protecting circuit components and people by tripping the circuit to interrupt the current flow if it detects a fault condition in the control system. Download Now
White Paper - Guide to Integrate Large-Format Additive
As with any new technology, getting into large-format 3D printing begins with investigation. The first question may be a simple one: what does “large-format” mean? For 3D printers, “large” is a relative term. Many extrusion-based (FFF) 3D printers are referred to as desktop machines, because they fit on table space. Some of these have very respectable build volumes – but when it comes to “large-format,” the machines will need their own dedicated floor space. Large-format 3D printers have significant build volumes and are most often found in professional settings, like manufacturing facilities and R&D centers. 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