Crane Hardstands for Installation of Wind Turbines

This publication about hardstands for the installation of wind turbines is intended for experts designers, geotechnical engineers/designers, insurers, inspectors, equipment suppliers and other contractors and subcontractors. It will also be useful for permit- and license-issuing authorities, such as water authorities and municipalities, for support in assessing applications.

The size and height of wind turbines on land have grown considerably during the past decades. The cranes needed to install (and to maintain) these turbines have therefore also undergone huge increases in size and weight, resulting in increased crane loads.

Hardstands for these increasingly heavy cranes demand careful, safe and economical design. At the same time, many location-specific factors play a role in hardstand design, such as crane type, the loads to be lifted, the environment and characteristics of the supporting soil, which in the western regions of the Netherlands is often weak. The correct handling of potential risks involved in the lifting operation is another area that demands particular concern.

Against this backdrop, the industry initiated an effort to develop a design guideline for crane hardstands used for installing wind turbines. Back in the days of SBRCURnet, a plan of action was developed and funding obtained. Then development of the guideline began. When in late 2017, SBRCURnet closed its doors, Stowa stepped in to support continuation of the process.

While initially the intention was to develop a design guideline, it gradually became apparent that development of a specific guideline would be an exceedingly complex task. This is because there are many location-specific factors that make customized design necessary for each indi- vidual site. Moreover, designers often don’t know until a very late stage which crane or crane type will be utilized and what loads will in fact need to be designed for. Preparation of a concrete customized design before knowing what crane will actually be used – including the corresponding ground pressures and wind loads – will often lead to the need for a re-design at a later stage. The present publication therefore should be read more as ‘a handbook for design’, than as a specific design guideline. The hope is that experience gained using this handbook in the coming years will feed into development of an actual design guideline in the future.

This publication is intended for experts involved on the client side, designers, geotechnical engineers/designers, insurers, inspectors, equipment suppliers and other contractors and subcontractors. It will also be useful for permit- and license-issuing authorities, such as water authorities and municipalities, for support in assessing applications. In developing this handbook, somewhat of a balance was sought between the responsibility of the entities involved, on one hand, and demands from the market on the other.

Aspects specific to the crane hardstand itself are central, given that this is the location that receives the heaviest loads, and therefore also has the most stringent design and execution requirements. Site access and construction roads to crane hardstands are not considered here.