June 2008
One of the usual actions in the energy and industrial area for EUROGRUAS, through its Heavy-Lift Division, ALTON Lifting and Sliding Systems, is the positioning of equipment belonging to thermal power stations, from its transport to the base. In this article, we will focus on the positioning of 2 gas turbines (of 320 tons each) and 2 alternators (of 400 tons each), belonging to 2 single-shaft groups, for Lares Combined-Cycle Power Station located in Figueira da Foz (Portugal), carried out throughout June and July 2008.
The equipment was assembled using alternative systems due to the structure of the building containing the power unit, which made the positioning with cranes economically unfeasible. Thus, ALTON proposed Cobra-CME, main contractor of the works, the use of ALTON sliding gantry frame, with a capacity for 400 tons.
The positioning system is based on a fixed framed structure, consisting of 2 lines of tubular girders supported by a series of lattice gantry frames and booms. This structure supports the sliding lines composed of a series of lanes all linked and made of neoprene-base pieces of Teflon.
Using those lines as support, another framed structure is built, composed of 4 sliding blocks made of a stainless steel plate-based profile, supported by the lanes. The sliding system of this structure is driven by two hydraulic jacks of 25 tons each, successively anchored to the lanes while the rod is being extended.
On the other hand, the equipment’s lifting system is based on the use of 4 strand jacks with a capacity of 2000 KN each, placed over the sliding gantry frame.
The positioning procedure is the same for all the equipment: the transport is placed under the sliding gantry frame and introduced between the booms of the fixed gantry frame. Once the equipment is hooked, the strand jacks lift the piece up to the necessary height (8 m), to overcome the base interference. The next step is the sliding of the sliding gantry frame through the fixed one (around 60 m), until it reaches the vertical of its final position. Finally, the equipment is dropped until it is supported by the base.