Wallace Liu: London based design studio WallaceLiu have re-imagined a 20 m wide, 1 km long highway in the South Western Chinese city of Chongqing as a shared surface ‘livable street’ by replacing the delineation and monolithic character of the highway with the language and scale of a public space. The site represents the typical periphery of a modern Chinese city that has changed its land use as the city expands. The highway, Yannan Avenue, along which 7 large plots of land were purchased by the state-owned developer PKU Resource (北大资源), will become the route through nearly 20,000 sqm of street retail and high-density residential compounds and adjacent to existing low-income social housing. For the city, the client and ourselves the project provided an opportunity to explore how China’s infrastructure, built to facilitate rapid growth, can be transformed to nurture an emerging urban culture.

WallaceLiu won the project in 2014 through a competition with an initial idea that certain safety issues created by pinch points in the street could be used to argue that the highway width in its entirety could be reduced to two lanes. This however raised concern in the local planning and transport department and eventually, with the support of the client, we managed to secure support for a shared surface design where we paved over the highway instead. We imagined the entire highway to be transformed into a walkable and playful place where the elements of a highway dominated urban landscape – kerbstone, road markings, traffic signage, pedestrian fences, hedge boundaries and limited pedestrian crossings – would be replaced by a characterful and vibrant open promenade.

The technical resolution of the idea was made through the paving of the highway with a new granite surface, the repaving of pedestrian areas with a similar material and the introduction of a new type of kerbstone that was flush with both sides therefore blurring the boundary between highway and pavement. Through careful design of the new street levels we were able to retain the existing sub-base and drainage therefore significantly reducing the cost of the new work. Because we could not reduce the width of the carriageway we had to engage with its scale through design to remove its visual dominance. We did this by enlarging the new landscape elements such as public benches and planters, the main path through the park and the width of pocket squares to radically alter the visual proportion and impression of the overall place as one walks down the street.

The middle section of the street is the most significant part of the change where the existing street park on one side adopted an entire new geometry of paths whilst keeping existing mature trees. An informal and unfenced public playground was created at the southern end of the park by digging into the landscape to create walls and slopes for climbing, sliding and imaginative games. Timber log type seats are located near to the play, encouraging and expressing a possibility that this play can also extend into the street. A set of large planters and seating was placed opposite the park creating a mirrored green space in a consistent language, therefore locating the highway at the centre of a green promenade. To emphasise the idea that this is a single place we used three types of commonly available granite to create four different mixes by altering the coursing dimension, the finish, the joint width and the proportion of each type to introduce subtle differences in the paving texture. To soften the edges of the hard paving where it meets planting in the park or planters along the street, we used both bonded gravels and loose gravels to achieve a relaxed ground cover for sitting and gathering. The existing gingko trees were to be become part of the open park and offer shade alongside newly added mature trees to encourage people to use the street in the extreme hot summer of Chongqing. We also designed a series of coloured canopies to help lift the generally grey tone of surrounding towers, framing and filtering views at significant stopping places in the street. They are made with hanging perspex panels mimicking coloured clouds over a pebble-grey coated steel structure to cast complex and vivid shadows on the ground. Other key design elements include a set of off-site manufactured steel-timber furniture. This seating is designed to form a ‘wave’ of sit-able and climbable decks that can be used for large or small gatherings and that encourage children to play on them. They also act as new psychological signals for traffic to slow down as they pass by. The smallest seats are mostly clustered around the park for calmer individual use.

The project started on site summer 2015 and the whole middle section and part of the northern and southern sections were completed in summer 2017 with the remaining work due for completion at the end of 2018.

Design: WallaceLiu
Project location: Yannan Avenue, Chongqing, China
Design year: 2014-2018
Year Built: 2015-2018