18.06.2021

We have a winner!

We have now concluded the rigging and load handling quiz that was put together by Industrial Training International (ITI).

Originally scheduled to run for a week, it was extended by a couple more weeks in order to give more people the chance of getting all of the questions correct. In the end, more than 50 people tried their luck with only Dale Thornton managing to give the correct answers to all of the answers! Get in touch with us at editors@vertikal.net to claim your prize.

Although Dale was the only winner, a good number of participants came very close, or answered three of the four questions correctly. In recognition of their efforts we have decided to provide them with a year’s subscription to our publication Cranes & Access.

For everyone else, we are providing the questions along with the answers and relevant workings for you to review. And perhaps, it might not hurt to take a second look over the training courses ITI has on offer?

Question 1
Web Sling Removal Criteria
The correct removal criteria that best identifies the descriptions below are as follows:

Question 2
Corner Loading
Q: Estimate the corner loading for NW, NE, SW and SE.

Answers:
NW = 3,078 lbs/ 1,396kg
NE = 3,762 lbs/ 1,706kg
SW = 2,052 lbs/ 930kg
SE = 2,508 lbs/ 1137kg

Workings out (lbs):
NW = .45 x .60 x 11,400 = 3,078 lbs
NE = .55 x .60 x 11,400 = 3,762 lbs
SW = .45 x .40 x 11,400 = 2,052 lbs
SE = .55 x .40 x 11,400 = 2,508 lbs

Question 3
Jack to Load PSI
Q: Estimate the loading to each jack (1,2,3) then identify the PSI (pounds per square inch) to the load’s understructure.

Answers:
Net load to:
Jack 1 = 6000 lbs/ 2720kgs
Jack 2 = 9000 lbs/ 4080kgs
Jack 3 = 9000 lbs/ 4080kgs
PSI @ Jack 1 load contact pt = 667 psi / 47 kg/m²
PSI @ Jack 2 load contact pt = 1,000 psi / 70 kg/m²
PSI @ Jack 3 load contact pt = 1,000 psi / 70 kg/m²

Workings out (lbs):
Jack 1 net load =
3.5 + 10.5 = 14, 3.5/14 = .25
.25 x 24,000 = 6,000 lbs.
Jack 2 net load =
3.5 + 10.5 = 14, 10.5/14 = .75
.75 x 24,000 = 18,000,
18,000/2 = 9,000 lbs.
Jack 3 net load =
3.5 + 10.5 = 14, 10.5/14 = .75
.75 x 24,000 = 18,000,
18,000/2 = 9,000 lbs.

PSI @ Jack 1 head to load = 6,000/9 sq. in. = 667 p.s.i.
PSI @ Jack 2 head to load = 9,000/9 sq. in. = 1,000 p.s.i.
PSI @ Jack 3 head to load = 9,000/9 sq. in. = 1,000 p.s.i.

Question 4
Floor loading

Q: An offshore marine construction company is preparing to jack up a preassembled pump package. It is currently resting on 4 wide-flange beams. If two jacks with 1’ square bases are placed 10’ south of the CG, where would the third identical jack have to be placed to receive about the same loading?

No jack should impose more than 15,000 PSF (pounds per square foot) to the floor.

Answer
The third jack should be approx. 20ft north of the load’s CG.

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