Use AutoTURN® to design infrastructure adjustments to safely operate trucks transporting wind turbine components.
Engineer Alessio Gori - collaborator at POLITECNICA INGEGNERIA ED ARCHITETTURA SOC. COOP. (Infrastructure division - Head Office Firenze)
Narrow mountain roads, steep hills and challenging ‘S’ curves are just part of the landscape in the ‘toe’ of Southern Italy, where wind farms are becoming a common part of the countryside. With green technology like wind farms gaining popularity as generators of clean, efficient energy sources, technology and engineering are coming together to make these projects as safe and cost-effective as possible.
In Reggio Calabria, the ENEL Green Power project proposed 2 wind farms development to be constructed in two areas: Piani di Lopa with 14 wind turbines rated output 0.85 MW and Campi S.Antonio with 25 wind turbines rated output 0.85 MW, within the boundaries of the three southern Italian municipalities of Bagaladi, Montebello Jonico, and Motta San Giovanni.
The Aspromonte region infrastructure network has a limited number of paved roads. They are mostly classified as "mountain roads", both for the geometric road characteristics and for horizontal curves of low radii. The location of Piani di Lopa and Campi S.Antonio wind farm sites, which experts say are excellent for the wind and the rated power output, means engineers must study and plan the routes carefully prior to the transportation stage of the wind turbines components.
Special Software RequiredDue to the conditions, use of specialized software simulating oversize vehicle paths is important for evaluating how the transportation of wind turbine components along the provincial roads might be achieved. Two routes in particular: Strade Proviciale (SP) 3 and 107, from Reggio Calabria harbour to the project sites presented challenges to the engineers.
Figure 4: Definizione veicolo
The aspects listed below are potential issues in the traditional approach, which is suitable for short routes and/or simple studies:
- The route length (40km)
- The number of potentially critical points (about 150);
- The presence of bridges, with geometry shown to be unsuitable for oversize vehicle paths.
Figure 5: Tipologico veicolo Autoturn
The oversize vehicle geometry and the steering characteristics of each component have been reproduced in a plan and meets the guidelines regulating the automatic steering of rear axles of the semi-trailers in relation to the front truck axles (Fig.4). Through a range of speeds, from 5km/h to 20km/h, each iteration showed the swept path of the simulated vehicle matching the swept path of the field test vehicle accurately. (Fig.5)
Choosing the Vehicles, Simulating the Route with AutoTURNMelca Transporti worked with ENEL Green Power to conduct the path simulations. The inspection process designed by the two companies helped identify critical points along the route and the company made adjustments to ensure the equipment could be transported safely. After this process, the companies used an unloaded vehicle to successfully test the path and the convoys drove the route safely without delays or issues.
Figure 2: montaggio
- fibreglass blade: length 26m, height 2.50 m
- single section tower: width 3.60m, height 3.60m, length 25m
- nacelle (to be installed at the top of the generator): width 2.50m, height 3.00m, length 7.00m, weight 40 tons
Wind turbine components are transported to the project site with wheeled vehicles, classified as "oversize transport vehicle", pursuant to Nuovo Codice della Strada (the new Highway Code). In accordance with the indications of the wind turbine producers, two "vehicle types" have been defined:
- Semi-trailer truck transporting a metal structure containing 3 "blade" components;
- Semi-trailer truck transporting the tower sections (Fig.3): the evaluated section is the critical one for its geometry; it is where the nacelle sits on the trailer. The nacelle also houses the rotational movement of the 3 fibreglass blades.
The two "vehicle types" definition has been fundamental because type 1 has optimized the dimensions related to the length of the freight while type 2 has shown the issues related to the semi-trailer truck width. The vehicle manoeuvre was conducted on both types of vehicles concurrently. The analysis was based on the hypothesis of keeping general traffic on the Piani di Lopa roads separate from the lower speed semi-trailer traffic. In order to ensure the safety margin between the simulation and the real path, the semi-trailer truck with steering axles have been taken into account. However, they have not been provided with a remote control of the steering angle of each axle. The decision to not include this variable in the path simulation is related to a larger flexibility in the vehicle selection for the company responsible for the transport execution.
Figure 6: Confronto interventi
Simulations and other editing operations are managed within the CAD-based program and this kind of versatility is built into the software. Customization of design attributes is an integral part of the software allowing simultaneous visualization of multiple vehicle combinations including:
- The precise position of the truck and semi-trailers during the manoeuvre
- The convoy path with distinct single paths of rear and front wheels
- The vehicle clearance, including the trailer ground clearance
Figure 7: intervento tornante
The articulated vehicle simulation was performed with AutoTURN® and the path manoeuvres have been defined and designed, preventing errors in path modelling due to possible design inexperience with the semi-trailer truck. Without the aid of AutoTURN®, the path analysis would have been performed qualitatively, deducing the vehicle clearance from the turn radius values and then overlapping the oversize vehicle swept paths to the topographic measurements.
Figure 8: intervento con paratia di micropali
Figure 9: Intervento ponte
At a later stage of the two vehicle types path simulation, the required adjustments to the existing infrastructure were identified, including about 100 small scale "ad-hoc" projects, like bedrock excavation to widen the road, pile bulkhead structures (Fig.8) creating manoeuvring space, removal and replacement of direction signs and safety barriers and removing trees. From an economic standpoint, it is important to identify any conflicts along the route (Fig.9), including lighting and telephone wiring. AutoTURN allows the planning to take place ahead of time, speeding up the permit stage and allowing for repositioning or replacement of any obstacles along the way.
The oversize convoy path along the 40km route, with more than 100 adjustment points, has not found issues or conflicts with any obstacles along the path geometry (Fig.10, 11), showing the reliability of AutoTURN® for projects of this kind.
Figure 10: particolare manovre su ponte
Figure 11: transito mezzo