Overhead Crane - OSHA 125% Loading
Overhead Crane - OSHA 125% Loading
(OP)
Do you design crane runway beams to accommodate the 125% OSHA test loading for overhead cranes or do you allow the test load to rely on the safety factor?
I am having a difficult time understanding why a 20 ton crane would need to be designed for 25 tons.
I have not seen any crane design references (including AISC Steel Design Guide Series 7) that address the 125% test loading requirement.
Any documented information that indicates the crane support structure shall be designed for 125% of the rated crane load would be appreciated. Thanks!
I am having a difficult time understanding why a 20 ton crane would need to be designed for 25 tons.
I have not seen any crane design references (including AISC Steel Design Guide Series 7) that address the 125% test loading requirement.
Any documented information that indicates the crane support structure shall be designed for 125% of the rated crane load would be appreciated. Thanks!






RE: Overhead Crane - OSHA 125% Loading
I guess you are talking about following:
ASCE7-10 Crane load 4.9.3: vertical impact load, maximum wheel load for 2 type cranes need increase 25%. (page 16)
RE: Overhead Crane - OSHA 125% Loading
To answer your question I do not design for this. My reasoning is the intent is to test the crane by purposefully going into the safety factor a little bit during a safe/controlled test load. By increasing the design strength you aren't going into that safety factor and there may be a fault that goes undetected during the test.
Short answer, don't design for the 125% test load. But, as chrislaope said, design it for the impact factors as appropriate.
You'll also want to look at the gantry crane design specification; CMAA Specification 70. There are additional rules for deflection, straightness, and so on for runway beams of gantry cranes.
Maine Professional and Structural Engineer
American Concrete Industries
www.americanconcrete.com
RE: Overhead Crane - OSHA 125% Loading
The location of the 125% test load is not specified. Apply the 125% test load at midspan and the reactions at both ends are still very reasonable when compared to normal operating requirements. See this sketch:
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Overhead Crane - OSHA 125% Loading
Maine Professional and Structural Engineer
American Concrete Industries
www.americanconcrete.com
RE: Overhead Crane - OSHA 125% Loading
This load test is for the hoisting equipment and can be conducted anywhere along the support system, so you could specify where along the rail/runway the test should be conducted.