Skidmore, Owings & Merrill (SOM), which has been active in China for more than 20 years, continues to shape the skylines of rapidly growing cities around the country. In the north-central city of Zhengzhou, in Henan Province, the firm recently completed a partially hollow, 60-story, mixed-use tower with a glass-enclosed roof. The 280-meter-tall structure, which opened to office tenants in fall 2012, is the tallest building in the city.

Named Zhengzhou Greenland Plaza, the office and hotel tower is located on a small peninsula at the edge of a man-made lake and is next to a performing arts center, a large convention center, and a park. Its cylindrical form is a nod to the city’s master plan, which calls for a series of arcs radiating out from the tower in the middle. “This tower is the centerpiece for a whole new city,” says Ross Wimer, the design director in SOM’s Chicago office who was in charge of the project.

The steel-and-concrete structure contains 40 stories of office space topped by a 20-story Marriott-operated business hotel, which is scheduled to open this spring. The hotel has an open atrium, and its generous skylight is equipped with a 12-meter-tall solar reflector that helps direct sunlight 20 stories deep. A structure at the front of the tower provides four stories of retail space for the complex.

The column-shaped tower has a glass exterior that is screened by aluminum louvers. Oriented to cut glare coming inside, the louvers are set three to seven feet from the glass skin to leave a gap for window cleaning. Painted white, the sun screens were fabricated off-site in three- to five-story sections and then lifted into place. Close up, the building seems to be coated in aluminum, but the glass behind the louvers becomes evident further away.

SOM won a competition to design the building in 2007. The tower was commissioned by the Greenland Group, a major Chinese commercial developer that has worked with SOM on several projects, including the Zifeng Tower, a 450-meter-tall, 89-story office, hotel, and retail complex in Nanjing.