Load Test on a Crane

[noobrich]

I am working at a nuclear facility. Our group has changed some components on a large crane. As a result of this change we are planning to load test the crane to 125%. An engineer has challenged stating that we must complete an analysis to verify the structure is able to support the increased load. He is indicating that we have to check the structure for side load perpndicular crane.

In my experience the load test is simply completed. Further buiding analysis is not required.

I would argue that the original design utlises a live load factor of 1.5. This is controlled activity below this limit. For this reason it is acceptable to complete the test.

Please advise who is correct. Thanks for any insight.

 

[TehMightyEngineer]

I've also seen gantry cranes load tested without verifying the surrounding structure can take the additional load. I've only personally ever insisted this check occur when the crane load rating was increased or crane load path modified. Unless the structure is suspected of being deficient I'd not think a structural analysis would be required for a load test of the crane.

If anything the load test is there to find out if a problem will occur during crane use, so of course loading into the safety factor of the crane and supporting structure is normal.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com

 

[SlideRuleEra]

In the US, nuclear facilities typically comply with Department of Energy requirements which may differ somewhat from OSHA. Here is DOE Standard 1090 - Overhead and Gantry Cranes. I'm not too familiar with the document's content, but it may be a place to see if the Engineer's claim has basis. If you are not in the US, perhaps a similar agency has governing documents for nuclear facilities.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[jayrod12]

Are you changing (i.e. increasing) the design capacity for the crane? If not, and you aren't changing any of the structural connections then I would say no analysis is required. If so, then I would agree that an analysis of the support structure should be undertaken.

 

[dhengr]

Noobrich:
You said... “An engineer has challenged stating....” What engineer, who’s engineer, and what authority or jurisdiction does he have? Your research, design and calcs., etc. associated with the changes you have made should be the support you need to verify the adequacy of your changes. Of course, the crane must be able to support the increased loading, and those considerations should be part of your design package. I assume this is a bridge crane. Maybe you should/could pass your changes buy the original crane designer/manufacturer, for their review. Nobody should know their crane better than they do. It probably doesn’t require a complete redesign, if you have been diligent in your redesign/modification work. But, without some involvement on their part, in this kind of facility, you might want to consider how the changes might affect their warrantee of their crane, if anything does come up. What do your nuclear regulatory, and OSHA type agencies have to say about crane changes like this? And then, the 125% load test should be the icing on the cake.

 

[thaidavid40]

Hang the test load with the trolley at the midspan of the crane bridge. That way, the end reactions are only 62.5% of the live load (plus the calculated bridge dead weight). That is certainly less than the design load for the crane runways with the trolley near the end, which would include practically 100% of the live load, plus the trolley equipment. No calculations are needed, by simple inspection. The bridge girders are already designed to withstand this test load, so again, no calculations are necessary.
Dave

Thaidavid

 

[MikeHalloran]

Our group has changed some components

Which components?


Mike Halloran
Pembroke Pines, FL, USA