During the last 15 years the wind power industry has experienced a vast growth increasing its installed capacity globally by more than 10 times. Reducing the cost of energy is a notable driver for technological development, and it supports the wind power industry becoming a fully commercialized and unsubsidized power-generating industry, while fossil and nuclear energy industries are becoming heavily subsidized. To reach this milestone, development is required in all possible areas – including the construction industry.
Technological leaps should not sacrifice productiveness
Speaking of development in the wind power construction industry, we have already experienced the introduction of anchor cages instead or casted steel cans, the development of ground condition specific foundation solutions (gravity, piled, ribbed and rock anchor foundations etc.), the introduction of more pre-fabricated and specific reinforcement systems to speed up the construction works on site, the use of more and more advanced design methods, and so on. All these improvements have provided cost savings in materials and transport. But what about time? Time is an important factor in total investment costs. Each day at a construction site costs a remarkable amount of money, and expediting the launch date of a wind farm would increase project return. Thus, reducing total construction time is now as important as material savings. Imagine you had a 100-turbine wind farm and you could cut down construction works with one day for every built foundation – you might be able to launch your farm few months earlier.
How to keep the development ongoing? How much money should be spent in R&D? Where to find new ideas? One viable alternative is the utilization of cross-industry innovations. This is the first, fastest and cheapest way of introducing something new, as a commodity in one place might be a complete innovation elsewhere, even in today’s world.
Innovative use of a simple solution brings results
One good example of cross-industry innovation supporting to reduce the cost of energy is the introduction of headed reinforcement into wind turbine foundation design. Headed bars are commonly used as a punching and shear reinforcement. The main reason for shear rails to become a commodity in European and North American construction sites was better performance compared to conventional stirrups, and the speed of installation. Even though shear rails have been provided by multiple companies around the world for about two decades, just five years ago Peikko introduced a modification of its solution called PSB® Punching and Shear Reinforcement as an innovation to the wind power construction industry.
The main benefit of the PSB® solution used in wind turbine foundations is, just like with conventional buildings, the speed of installation. Shear reinforcement can be placed as the final touch when the rest of the reinforcement is already installed. You just hang it like an umbrella. And since the reinforcement bar has a forged head on the other end, anchorage in concrete is ensured. Or in case you have a highly reinforced structure where a proper installation of stirrups simply isn’t possible, PSB® studs with heads on both ends can be used instead. Despite a remarkable track record and attractive benefits, this system was not immediately accepted by the engineers of the industry; the problem was missing fatigue design parameters. But this was not an obstacle for a true forerunner. Peikko performed an extensive fatigue testing program and delivered the first head bar system with a complete S-N curve for a whole reinforcement range. The test proved that headed bars have even better fatigue performance than conventional stirrups and hooks.
Peikko conducted an extensive research program to find the best solution, and adopted it for the specifics of the wind turbine foundation structures by performing additional tests. So here you go – better performance in combination with time-saving installation. This is a true innovation supporting the reduction of the cost of energy. To date, close to 600 foundations have been built using Peikko’s headed bar system – and this number is continuously growing.