Crane failures 8

[enginesrus]

https://www.youtube.com/watch?v=nvQuFBMUko4

At the 3:22 area, what sort of material does that look like?
I wonder how many such failures have happened due to the use of the wrong size and type of materials used to construct the crane system?

 

[Cool_Controls]

I agree a brake failure would not typically cause a shaft to disappear.

 

[spsalso]

Yes, the sound from the biginning of the "drop" segment is different. And it stayed that way for about a second, until something failed, and the load dropped.

That sound could have been made by an element that was GONNA fail in about a second. Or it could have been ambient noise unrelated to the drop.

There WAS a loud snap noise when the fail physically happened. It's easy to pick out in the slo-mo versions.


spsalso

 

[Brian Malone]

FacEngrPE - isn't the failure of the crane at Russellville different from the Harculo incident?

https://www.osha.gov/sites/default/files/2019-12/2013_r_04.pdf

https://www.osha.gov/news/newsreleases/region6/09272013

Russellville crane accident:
1. Temporary crane was brought in for this job and insufficient/incomplete lateral bracing was in place for the load conditions.
2. EOR signed off no need to load test system based on historical use but new installation was not an exact replica of previous use. And new beam sections were installed with no weld inspections.
3. Crane company EOR and team did not properly analyze the lift conditions and the utility and construction engineering teams did not question the crane capacity and installation calculations.
4. Utility and construction contractor engineers agreed to skip the required load tests.

The Russellville incident appears to me to be a case of procedural shortcuts and overconfidence added to create a failure.

Harculo incident:
1. On-site crane probably is sized with capacity for the rotor used in turbine hall. The crane capacity has not documented but it seems somewhat unlikely the turbine hall crane would not be sized to carry the loads expected for the equipment used.
2. Rotor weight is unknown so this may not have been an over- capacity lift - just titles in videos state the rotor weight - but reasonably, the rotor being installed would be a known value that would not change radically from any initial conditions of the installation facility. Unless the recommissioning of the facility changed out the turbine housing, the rotor being installed cannot be bigger than the rotor that was removed and the crane should have been designed for.

The Harculo incident seems to me (from the failure modes that been described using the limited available info) to be a mechanical failure that may have been hard to forsee.

The Russellville incident, unfortunately workers were allowed to be too close to the lift zone and one died and many were injured - the Harculo incident, two workers were lucky that they got out of the danger zone before tragedy struck.

 

[FacEngrPE]

Russellville incident
The crane was designed for 100% of the lifted load, not 125% as required by the crane standard. The crane was not proof tested in the configuration it was to be loaded in, and some parts were not load tested at all. In this case the failure was structural stability (the crane fell over sideways).

In both cases the lift did not match the requirements of the standard so it is considered an "engineered lift" per the ASME crane standard. OSHA found fault with the engineers design.

I am unsure how Netherlands/EU standards would treat the situation. The legal landscape works differently in the EU, and the website is Dutch which I do not read.

https://osha.europa.eu/en/about-eu-osha/national-focal-points/netherlands[/URL]]The Netherlands OSH
In the Netherlands, it is the employer and employees within a company who have primary responsibility for occupational health and safety policy.

I have a copy of FEM. It is quite detailed in applying load cycle analysis to design, with the intent that the result is fit to task, but not over designed. The risk is that if the crane designer misses the mark, or any of the components are under strength there is no "builders margin".

 

[Brian Malone]

Wow - building 'to fit task' seems to be risky!

 

[Cool_Controls]

FEM is very detailed, my only issue with it is that it was orginally written in French and most of the English versions I have used had typos (sometimes in equations) and poor translations.