A vaulted concrete base supports an elevated football pitch and running track at the Hexi Sports Field, which The Architectural Design and Research Institute of Zhejiang University has completed in Shaoxing, China.

Hexi Sports Field is located on a site to the northwest of Shaoxing University's campus, which borders the old town and overlooks the Fengze River.

According to The Architectural Design and Research Institute of Zhejiang University (UAD), it is intended as a public space shared by the students and the city.

UAD was commissioned to create new and extensive sports facilities for Shaoxing University, but as it already had a sports field, the studio decided to "overlap" them.

The existing track field has been replaced with an elevated version, which now also incorporates a football pitch.

It shelters a partially sunken ground floor with basketball, badminton, volleyball and tennis courts, alongside a gym, climbing wall and skateboard area, all framed by large concrete vaults and columns.

"Faced with the huge challenge of insufficient space, the core contradiction of this project is to retain the existing track field and add more functional venues to meet the needs of teachers, students and residents for exercise activities," UAD told Dezeen.

"By lifting the existing track field into the air, a super large overhead roofed space is naturally formed below," it added.

Looking to create a feeling of openness, three sides of the vaulted concrete structure have been left open to the surrounding city, intended to encourage "shared experiences and mutual support", UAD said.

Areas that require greater climate control have been placed inside the centre or to the rear of the site and are enclosed by walls.

"The arch forms a continuous combination of spatial rhythm and a sense of enclosure within the venue, blurring the boundaries of beams, slabs, and columns," the studio told Dezeen.

"Meanwhile, the grey space under the eaves blurs the interior and exterior boundaries of the building, achieving integration with the campus."

Two long ramps at the east and west ends of Hexi Sports Field lead to spiral staircases that wind up to the pitch, finished with perforated white-metal balustrades. Additional ramps and stairs provide access to spaces that are partially sunken due to the sloping site.

The concrete structure has been left exposed throughout the interior, complemented by glossy green and black tiles informed by the more impromptu public gathering spaces found in the city.

"These public spaces do not require fancy decorations or high costs, and they are simple and rustic in nature," explained UAD.

"Every time the scorching sun shines or showers pour, people would quickly burrow into these sheltered open areas."

UAD is an architecture firm established as part of Zhejiang University in 1953.

Its other projects include Shunchang Museum, which is organised around an "urban living room", and a hall for the Shaoxing Hotel.

The photography is by Zhao Qiang.