MANAGING FOUNDATIONS IN WIND FARMS
In the last 20 years, wind turbines changed in power, rotor diameter and tower height reaching nowadays 120m. On-shore wind turbines are typically founded on circular or octagonal shallow footing in huge massive cast-in-situ reinforced concrete subjected to extremely eccentric loads. Some wind farms are in remote location even in extreme weather. Wind turbine foundations have dimensions large enough, normally from 300 to 900m3, to require measures to cope with generation of heat from hydration of the cement, weather conditions, concrete placing temperatures and attendant volume change to minimize thermal cracking to deal functionality, durability and appearance. The Construction Project Manager and structural design engineer must work closely on specifications which impact strongly on risks of the project. Based on location and weather, the CPM must make important decisions such as concrete mix design, type and quantity of cement, type of aggregates, concrete batching plant and mixer, water availability and road accesses. Decisions on specifications, scope, cost and types of subcontractor contracts are the starting point to manage the risks. Those risks will be clearly tested on the procurement phase. Schedule and quality are consequences of good decisions. Wind turbine foundations demand professional PM approach.