Using its Terex TC 2800-1 lattice boom truck crane, Swiss-based Welti-Furrer Pneukran & Spezialtransporte erected three E-92 wind turbines on behalf of German company Enercon at the Gries Pass in the Swiss Alps.
Welti-Furrer project manager Werner Häfliger said, “The TC 2800-1 is extremely maneuverable. On and features extraordinary gradeability. These are two indispensable prerequisites for working in high mountain areas, and they’re exactly the reason why this crane is our preferred machine when it comes to this type of high-altitude project.”
This is further complemented by the crane’s flexible outrigger system, which can have an area of either 10 x 10 metres or 14 x 14 m and makes it possible to adapt to difficult work site conditions.
Even the drive up to the work site on the evening of July 25 at 9pm was tough for the TC 2800-1, its assist crane, and 15 transportation trucks accompanying it: Uphill slopes of up to 18.5 percent, numerous narrow passageways, and the vehicles’ altitude-related power loss made things hard not only for the equipment, but also for the people involved in the project.
In fact, entire paths and setup areas had to be literally hewn out of solid rock and, in certain cases, cleared by means of explosives in advance. However, this time-consuming prep work was exactly what enabled the team to get the TC 2800-1 crane to the work site on schedule, at 2:30am.
The team had estimated a total of two days for setting up the crane with four assembly technicians, and was able to get things done according to plan once again. This was due in large part to the TC 2800-1 truck crane’s ease of assembly. For the upcoming lifts, the crane was set up with an outrigger area of 14 x 14 m and a counterweight of 200 tonnes on the superstructure.
For the boom, the Welti-Furrer specialists chose an SH/LH SGL_S7 configuration with a 90 m main boom. In addition, they mounted a lightweight, rigid LF-2 jib, which contributed an additional 12 m to the total height. This resulted in an available boom length of 102 m – enough to erect the wind turbines’ 84 m-tall tubular steel towers and easily lift all components – with a maximum weight of 64 tonnes – while working at radii between 22 and 25 m.