3andwich Design / He Wei Studio

Location: Kang County, Longnan City, Gansu Province, China
Client: Kang County People's Government
Architectural Design: 3andwich Design/He Wei Studio
Lead architects: He Wei
Team: Cheng Long, Wang Ziyi, He Xingchen, Liu Hao
Special design for wooden structure：LLMMwoodtech
Lighting Design: Beijing AN-Design Architects Co.,Ltd.
Team of Lighting Design: Li Dawei, Hou Mingyu, Ma Longxiao, Zhou Zhe, Ma Pinxiao
General construction unit: Gansu Tianchen Construction Engineering Investment Group Co., Ltd
Construction unit for wooden structure: Jiangxi Guojin Green Construction Technology Co., Ltd.
Construction area: 800 sqm
Design time: 2022-2023
Completion time: Dec. 2023
Photography: Jin Weiqi (Faculty of Humanities and Arts, Macao University of Science and Technology), 3andwich Design/He Wei Studio

The project is renovating an old bridge. The bridge is located in the center of Kang County, Gansu Proince, at the confluence of two rivers, 200 meters away from the county government. To the north of the old bridge is a commercial street, to the west a kindergarten, and to the east a residential area. But the mixed traffic of people and vehicles poses a danger to pedestrians and slow traffic crowd, and also affects the operation of the commercial street. The new bridge reduces vehicular traffic and is planned as a pedestrian friendly area along with the commercial street. Meanwhile, the new bridge extends the commercial street, creating not only more diverse and comfortable public spaces, but also a new landmark for the county town.
The inspiration of design comes from a local Qing Dynasty corridor bridge: Dragon and Phoenix Bridge. Corridor bridges are ancient Chinese bridges combining bridge and architecture, with passage in the middle and rest areas on both sides, effectively integrating transportation and non-transportation functions into one space.
The project adheres to the principle of sustainability. The main structure of the original bridge has been retained, and the new building structure continues on the old bridge deck. The building is of timber structure, with the portal frames at the top of the slope as the main body, and slant support is applied to the columns on both sides. The main timbering is Douglas fir glued wood, which is prefabricated in the factory and installed on site, with a total carbon sequestration of about 144 tons. In addition, the white marble breast boards of the original bridge are retained for further use.

The layout of the corridor bridge follows the original bridge trend, with a width of 9m, the highest point of the roof of 7.2m, and a eaves height of 3.2m, which ensures the passage of fire trucks. The middle of the bridge is passable, also serving as a venue for temporary markets, outdoor performances, and other activities. The seats and independent box-shaped spaces are located on both sides of the bridge for leisure viewing.

The corridor bridge is divided into three wings, forming a large space at the convergence point in the middle. The portal frame here becomes a single side standing structure, which, together with the tree shaped steel column located in the middle, supports the inward curved triangular steel beam.

A skylight is set up on the ridge of the roof, inlaid with colored glass, which ranges from red to blue, representing time. Light shines through the skylight into the interior of the bridge, adding a romantic atmosphere to it.

As for the lighting design: the downward spotlight in the middle illuminates the road surface, the top of the bridge provides light slightly, guiding the visual upwards, and the sloping roof utilizes stronger light to enhance the rhythm of the structure. The exterior of the corridor bridge uses the overflow light on the outside of the channel to clean and brighten the columns, while the roof is not equipped with lighting. The colored roof windows use internal transparency and the lower part of the corridor bridge to form a brightness echo.