FREE ENGINEERING B.V.
For an assembly yard for the fabrication of jackets for offshore wind farms, we have developed a gantry crane with a hoisting capacity of 4x350 t and a hoisting height of 100 m. The design meets the applicable regulations and rules and specific environmental requirements on site.
To minimize the load on the foundations and especially the supports above water a rather open tubular construction is chosen. This results in a more complex build but decreases the effects of wind loading during storm conditions, which form a governing load case.
The crane sits on wheel sets with in total 64 wheels with a four tier hinged system, and is fitted with hydraulic rail clamps.
Using our primary calculations the design of the foundation and over water support structure has been performed by the client and the construction of the rails is commenced immediately whilst the overall design of the crane was still in progress, in order to reduce the overall lead time.
To further minimize the lead time, at an early stage in the design process, reviews and meetings have been held with workshops, subcontractors and suppliers to start work on the long lead items.
Directly after the main structures have been designed they are taken into production, in good compliance with the workshops, where specific details, such as walkways and such are in principle designed by us, but worked out in detail by the workshops.
Beside the primary structures we have designed secondary constructions which support the operation, instalment and maintenance of the crane.
Such auxiliary constructions are for instance hydraulic pen mounting equipment, jacking systems for maintenance on the wheel sets, temporary access ways and platforms, auxiliary hoist equipment for exchanging the wheels and drive of the hoist trolleys, sea fastening and erection tools, etc.
The design of the girders and legs are for instance optimized for transport and the means of erecting on site in Poland.