Architects from Rogers Stirk Harbour & Partners London office and engineers from Expedition Engineering designing roof of metro station "Maria Del Pianto" in Naples used innovative way of covering optimization in terms of sunlight. Basing on the application of software automating insolation, they have used a genetic algorithm to search for covering with demanded parameters. According to that, optimization process could be done almost entirely by computer.
Application of such solution won't be possible without use Rhino software plugin, created especially for this purpose by Fredd Labbe, an engineer from Expedition Engineering. How Labbe explains, evolutionary algorithms made operations on possible solution populations and following evolution process - through the use the principle of survival of the fittest rule - in the purpose of creating still better solution approximations with every next generation.
Before accession to optimization of overlap architects needed to define its form. They have decided to double curved hyperbolic paraboloid. It has been proposed construction structure of thin steel elements, which the system resembled a honeycomb, covered with ETFE membrane. The roof had to provide maximum access to light and sky view for platform placed duct at the base station at depth of 40 meters. Moreover, designers goal was shading ground floor level and avoid of overheating station premises. The Huge meaning has also economic materials use.
Achieve of those all goals at the same time require an innovative approach to the optimization of covering. For this purpose was used a genetic algorithm because it is especially effective in searching of balance between opposite demands. With it help effect the conversion of the structural members in such a way, that optimized form ensures fulfilling all from above-mentioned conditions.
Roof optimization was made based on the group of 400 potential solutions. As a result of crossing and mutation of those proposals (potential solutions) over 70 generations, achieved a satisfactory solution. The disposable calculation takes about a week because it demands to generate and analyzing of 28 000 different versions of the design. All those actions were made only by computer, without any human's interference in this process.
Whole roof optimization process takes four months. In comparison to primary, regular grid layout of "honeycomb" it was possible to improve about 30% of lower station part insolation. For rooms on the ground floor, which demands shading, it has been improved by 15%. All those things were achieved with a reduction of the steel structure weight by 2,5% (12 tons).