Have anybody done load test for trolley hoist monorails? I was told to do it by pulling the weight of 1.5 of SWL along the monorail or hand it at the midspan? Fyi, we recertify the trolley hoist onshore every 6 months.

This message has been edited. Last edited by: Josh,

Josh,

In your procedure, what measurements do you take?

Deflection ?

There is no procedure or PM yet for load testing the monorails which are not straight lines. Is it a common thing to do? No response from OEM (J Barnsley Cranes UK) either. We have had inspection program including dye penetrant & magnetic particle tests of the monorails as one of topside structures.

I'm familiar with load testing overhead cranes having a straight line lifiting beams using concrete blocks permanently kept in the plant's yard.

For pedestal cranes offshore, I was informed that they use bags to scope seawater as weights for the load testing.

The monorails are used for lifting equipment on offshore oil & gas platforms for overhauls etc. So the equipment may be running while testing & any failure affects the equipment underneath the monorail.

Somebody suggested to measure deflection but is it necessary because we didn't do this for overhead cranes ie just load test at 1.5 design weight & hold for 30 minutes? Any better ideas?

This message has been edited. Last edited by: Josh,

Josh,

Yes, measuring delection gives you a good idea of the residual strength. Recall that deflection is inversely related to the Moment of Inertia(proportional to the fourth power of beam height) while stress is inversely related to Moment of Resistance (propoortional to the third power of beam height).

While testing, the area below must be corddoned off, whether you work on land or offshore. If the monorails midpoints are directly above the equipment and there is no free space available on the monorail at any other span, you have three choices.
1. Do the test when the equipment is physically removed for overhaul/replacement, OR
2. Do the load test at a point or points just clear of the equipment, measure the midpoint deflection and compare with the calculated deflection for the off-center load. If there is a convenient cantilevered point, load test it there, OR
3. Dismantle and re-erect the monorail at a safe location just above floor level, using fixing points and methods identical to the one at site. Load the beam from above the beam and measure deflection.

If none of these are feasible, it is still possible to find an acceptable solution, but this will have to be designed to suit.

The hoist must be tested in any case.

Is the hoist vendor the supplier of the monorail as well or was it fabricated locally?

This message has been edited. Last edited by: Vee,

Thanks Vee. How to measure the deflection, using strain gauges? Is this done in the North Sea?

Have to check the supplier of the monorail. Do you know how to contact J Barnsley?

The trolley hoist monorail manufacturer must specify the maximum deflection allowed when the 1.5 design load is applied.

Check:
http://www.korins.com/m/jb/
http://www.threev.com/J/1564.htm
http://www.applegate.co.uk/company/coc/28323.htm

Josh,

A good old dial guage will do, but a strain guage is fine too. You may also be able to use a laser alignment instrument. I dont know what method is used in the N.Sea, since I did not design these tests or witness them myself.

Darth, you are quite right, the monorail vendor has a duty to supply a test procedure and the measurements required.

Josh,

A Google search produced the following website, which Darth has also quoted. In it there is a tab to contact them by e-mail and another to visit their website. Have you already tried these?

http://www.applegate.co.uk/engineering/company/co_28323.htm

I got the same & sent email but no reply until yesterday I called them. They gave BS2853 for load testing the monorail during commissioning & did not specify any load test during the monorail's lifetime except inspection & NDT. J Barnsley supplied the trolley hoists but not the monorail.