Terex RT665 Boom Bend While Lifting

From the above information? The crane was being asked to do more than the maximum of which it was capable.

Was anyone hurt/killed?

Load limits on cranes are pointless. Go ahead and lift more then the crane is rated for, it will be ok.

14.5 > 12. Duh.

Did it make the regional television news?

There are too many variables that could cause the problem. Not being on site for the failure. I would just be throwing out maybes. One thing I do know is if the boom is bent get a qualified tech to service it. He maybe able to determine the cause.

Never been in a Terex RT-665. If by computer it has an on board one. That computes the load. One of the sensors maybe bad or need calibrated.

Could be the load was stuck in the mud. Like I said throwing out guesses.

http://www.scribd.com/doc/140892378/Terex-Rt-665-Tabla-de-Capacidad

Wind Shear?

You can't possibly be serious!

The crane was overloaded, by some idiot.

Can you possibly fire yourself, please?

14.5/12, 21% overload should not be enough to fail any crane.

There is something odd though, when I search for a Terex RT-665, I find they are rated for 60 or 65 tons.

Typical example

Up close at no boom extension they are rated for 65 tons but at full extension and a low boom angle they are rated for far less.

Bending the boom is a solid sign that too much was being lifted at a position that was not rated for it. In this case 14+ tons at a position and extension rated for 12 tons would easily do it.

I don't question your answer, it just looked too tight a margin compared with the stresses we use in buildings etc. I think the highest we go is still 2/3 of the yield stress at the extreme fibers. Even yield stress at the extreme fibers does not bring member failure.

Check the crane chart....what's the boom length? Load radius? Sounds like the load is still attached to ground....

http://www.bigge.com/crane-charts/rough-terrain-crane-charts/RT600LC.pdf

Well assuming you you are asking why your load monitoring system is not working and not why your boom is bent then its this.

The most likely answer is the wire harness that runs from your computer in the cab through the cable reel on the side of your boom up to the tip has been damaged. This happened because your operator lifted too great a load which caused the boom to deflect further than the maximum length of the wire harness will allow.

That's a pretty round about way to just say, "You lifted too much weight and it broke."

But, after noticing your name, Tribune, it all makes sense.

So it was a maximum bending moment.....why does that sound familiar....oh yeah....

"and the load came to zero" ????

Does this mean the load was lifted up, and then lowered automatically, or did it never leave the ground ?

There are a number of inputs to the crane's operating system that could result in a 'no lift' problem. A couple of these are the SLI and OPD (Safe Load Indicator and Overload Protection Device) ie When safe load conditions are exceeded, the crane will not lift, and probably just cut out. You stated that the computer showed 14.5t (2.5t over the safe limit). Either the computer is correct (likely), or your estimate of the load is not.

Some inputs to the computer to perform it's safety calculations are:

• Dead end Tensiometers
• Running Line Tensiometers
• Load sensing pins
• Boom length sensor (for telescopic boom crane applications)
• Boom angle sensor
• List angle sensor
• Anti-two-block
• Wind Speed Monitor
• Slew / Swing sensors

When in doubt, check the crane's service history (it is not impossible that the safety system requires a calibration check), but it seems to me that the crane did exactly what it was supposed to do.

It would be interesting to know when the crane last had an insurance examination, and when the operatives involved last had a crane lifting competency assessment.

Maybe it just needs a boombox to support it.

I gotta go scratch my head a bit more. It must be too early and no coffee.

No one would ever try to lift 14 tons with a 12 ton crane he mutters walking down the hall towards the coffee machine. Gotta be a typo.

Does "top boom" = "jib"?