Determination lifting capacities at great heights requires new ...Eager.one – STERK New Approach...

Eager.one – STERK New Approach - All rights reserved 2018.03.20 Sheet 1

Determination lifting capacities at great

heights requires new approach.


Demands for capacity at height do increase.


Reasonable footprint and transportable boom dimensions do notincrease.


Ringer cranes, though better boom stability, are not an option.

• Operational costs too high• Very low mobility• Footprint too big


Conclusion :Cranes are getting higher with increased slenderness as a result.

What does this mean for the determination of capacities of cranes?


Since the 2nd order** effect increases for slender (high) cranes, calculations get more complex and more time consuming due to its non-linear (cyclic) character.

** Definition 2nd order effect:Additional loads on the crane induced by geometrical changes.


Additional sideward bending moment due to change of shape:

2nd order effect!!


Additional longitudinal bendingdue to change of shape.

2nd order effect


Large deformations are not “always” of 2nd order!! In some occations the deformations poorly induce “additional” 2nd order loads.

Mainly….. 1st order effect!!

(in this situation because boom notsteep)


• 2nd order effect increases • Calculations get more complex and

time consuming.• For every boom-, jib length and

lifting radius it requires a cyclic (non linear) calculation to predict the deformations

• These calculation are done by “non linear” FEM (finite element method).

• Satisfying customer needs, when it comes to crane capacity, becomes very slow.

Slender (high) cranes.


This gave reason for the development of a hand written code, applicable to run different configurations at the same time, without the need for re-modelling.

We called it…………


Formerly known as :


consists of 6 parts:

1. Source code STERK A 2. Validation STERK B 3. Manual STERK C

4. Crane STERK D (project based)5. Ratings STERK E (project based)6. Listings STERK F (project based)


Source code STERK A

600 pages of code, developed in the latest 5 years during approx. 2000 man-hour's.


Validation STERK (B)

500 pages document that describes the validation of the STERK code with STERK.

Validation


Validation STERK (B)


ValidationSTERK (B)


ManualSTERK (C)

150 pages of guiding for :

• Interpretation of STERK source code• Using STERK during the making of

ratings


Crane sheet (project based)STERK (D)

Spreadsheet for completely describing the crane (pre-processing).

Every cell has a graphical remark to guide the STERK user.


Ratings sheet (project based)

STERK (E)

Spreadsheet for completely describing the ratings (post-processing).

Every load chart value( SWL@Radius ) has a remark, describing the critical issue (strength, stability, etc.)


For every rating-position or configuration a graphical output of the crane can be generated.


Listings STERK (F) (project based)Complete summary of all results for a single load chart position (SWL@radius ).

Including :

• Deflections• Stresses• Bending moments • Shear forces • Etc,


Utilisation 2st order.

• short radius• Non-linear calculation• Safeties applied on loads

(limit state method, partialsafeties)


Utilisation 1st order.

• Large radius• Linear calculation• Safeties applied on final result

(not limit state method)


Applicable for which type of machines?

• Crawler cranes with lattice structure boom• Telescopic cranes• Excavators.


Applicable standards

• EN13000• EN13001• EN13852-1• EN13852-2• EN16228• ISO10567• DNV• Lioyd’s


Thanks for yourtime!

Determination lifting capacities at great heights requires new ...Eager.one – STERK New Approach...

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