The structure is one of two new stations linking the existing metro network with Changi Airport. Designed to accommodate 17,000 travelers per hour, its large ticket hall leads up to the elevated platforms, which are supported by fair-faced in-situ concrete. A metal-clad roof, with a curved-like shape, rises up in the middle of the platform, where passengers congregate, allowing heat to dissipate and improving overall ventilation. Mirrored steel and thin gauge titanium were used for the ceilings, and gray flamed granite for the floors, making the latter water-resistant and easier to maintain.
Source: Aga Khan Trust for Culture
See also:
"EXPO Station, Singapore, 1997-2000." Foster + Partners Official Website.
http://www.fosterandpartners.com/. [Accessed January 17, 2007]