Metropolitana Linea 1 Santa Maria Del Pianto
As well as creating a marker for the metro station, the key design criteria for the roof canopy were to: maximise sunlight penetration and views of the sky from the bottom of the 40m deep station shaft; provide some degree of shading on the lift platform at ground level to prevent overheating in summer; prevent rainfall from entering the station; and, be structurally efficient with minimum use of materials. RSHP worked closely with Expedition Engineering to develop a form that would respond to these criteria.
The 2,300m² double curved shell is structurally strong, and is tilted back in order to open up the entrance to the cemetery. Mapped onto this form is a lattice of thin steel plates, which resemble a honeycomb in plan.
FiIn order to optimise the arrangement of the honeycomb structure, and maximise environmental and structural performances, an evolutionary algorithm was applied. more than 70 ‘generations’ of the arrangement of the honeycomb was adapted gradually, loosening the mesh above the well to let sunlight into the station, and increasing the density of the mesh above the lift platform to provide shading. Near the ground supports the density is also increased to add structural integrity. Interestingly, the algorithm was run twice, once with an orthogrid as initial arrangement and once with a random initial arrangement. In both cases the layout converged through this artificial evolutionary process to a similar final arrangement.
For the construction, steel plates are aligned vertically in order to form as transparent a structure as possible, and joined together to form a web. a series of ETFE cushions map onto the toroidal surface, to form a lightweight cladding system.
Safety and efficient passenger flow were the two key considerations in the design of the station below grade. Four spiral staircases around the outside of the well, inspired by the Pozzo di San Patrizio (St. Patrick’s well) provide fire access for the platforms, whilst four banks of transparent lifts dramatically take passengers to the metro 40 metres below. Because of potential high volume of traffic through the station on Sundays and festivals, a high degree of redundancy was built into the circulation systems for day to day use, also allowing for expansion of the station as a key transport interchange for Naples.
A triangular mesh for the roof - in conjunction with the toroidal surface - has been adopted as the most structurally efficient shape, minimising the resources required to build the canopy.
Situated on the edge of the city, close to the airport and key road infrastructure, the station will become a key interchange for local buses and intercity coach services, as well as for people visiting Naples from the surrounding area.
A new piazza in front of the station will provide a meeting place for visitors to the cemetery.
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