Floating Islands Of Sky / Unarchitecte

Architects: unarchitecte
Area: 347 m²
Year: 2021
Construction Company: unarchitecte & Superstructure
Lead Architect: Hetian Zhang
Design Team: Hetian Zhang, Yonggang Fan, Jinxian Zhang, Xuan Xu, Qi Liu, Jing Liu
The Client: Wide Horizon Group, A8 Design Centerc
City: Chengdu
Country: China

Floating Islands of Sky, a pontoon-based structure by unarchitecte in Chengdu, connects C9 Food Street with the Chengdu Rainbow Hut via modular hexagonal islands. Commissioned by Chengdu Wide Horizon Real Estate Development Co., Ltd., the project adapts to seasonal water level changes and integrates floating walkways, artificial vegetation, and atmospheric devices. Initially conceived as a disappearing bridge, the final scheme evolved into a dynamic public space merging engineered buoyancy, reflective materials, and environmental interaction, forming a hybrid system between structure and landscape.

Pontoon bridges float on water and typically lack permanent underwater foundations. They are often constructed for temporary pedestrian use and rarely integrate design complexity or long-term durability. Referenced precedents such as Christo and Jeanne-Claude’s Floating Pier and Copenhagen Islands by Marshall Blecher and Studio Fokstrot demonstrate the intersection of form, mobility, and public interaction. Floating Islands of Sky approached similar ambitions under tighter constraints, offering a modular, semi-permanent solution that functions both as infrastructure and artificial terrain.

The project was commissioned by A8 Design Center on behalf of Chengdu Wide Horizon Real Estate Development Co., Ltd. to connect the C9 Food Street in LUXELAKES Water City to the Chengdu Rainbow Hut, an installation by Japanese artist Tsuneo Sekiguchi. The design spanned over 70 meters in straight-line distance. The brief required a low-cost, creative, and detachable solution with a lifespan of ten years. Beyond pure connectivity, the bridge was expected to introduce spatial richness, accommodate seasonal water fluctuations, and explore unconventional materials and geometries.

The first design proposal introduced the concept of a disappearing bridge. The intention was to dissolve the structure into its environment by using materials that mirrored the lake’s surface. Stainless steel panels with embossed and sandblasted textures were selected for reflectivity and skid resistance. Water-permeable zones on both sides and at the center were positioned slightly below the waterline to reinforce the bridge’s hydrophilic character and further reduce its visual impact. The absence of guardrails allowed continuity between water and sky to be emphasized across the user experience.

To ensure stability near the surface, the design included a pre-buoyancy strategy using dynamically retractable steel cables anchored to the lakebed. These cables fixed the bridge at the rated bearing water level, limiting vertical movement and allowing the platform to hover just centimeters above the water. This system stabilized the bridge under standard loads and accommodated seasonal fluctuations without undermining the design’s reflective and dissolving intent. Alongside structural requirements, the bridge had to resolve changes in shore connection due to varying water heights throughout the year.

Hexagonal modularity became the dominant geometry. The decision to work with four to five sizes of regular hexagons stemmed from the need to contrast with the curved edges of the Chengdu Rainbow Hut and natural shoreline while reflecting a pixelated sky image. The modules were staggered in small oscillations along a defined axis. The surface of the hexagons used skid-resistant, reflective stainless steel, while water-contact zones were perforated and designed to eliminate buoyancy. Structurally, the pontoon was divided into three zones—start, middle, and end—with varying buoyancy control measures to adapt to slope and elevation.

Three different systems for dock transfer were explored. The final approach allowed near-shore hexagonal blocks to shift via vertical slide rails while controlling buoyancy internally. Stored water inside the modules could be adjusted to modulate height, resolving differences during dry and wet periods. The final form of the bridge shifted between light superimposition of elements in low water and a flattened continuum in high water. This controlled morphology supported walkability while responding fluidly to changing hydrological conditions.

As the project progressed, the design transitioned toward a second concept: the integration of clustered artificial islands. Recognizing cost limitations and the impracticality of full visual disappearance, the design team explored landscape-based configurations. Seven vegetated islands of differing scale and use were scattered across the water. These artificial islands introduced spaces for fishing, resting, and picnicking, each accessible through both submerged pathways and rope-pulled rafts. These dual pathways offered visitors alternative routes to engage directly with the water.

This second iteration reoriented the project toward a floating archipelago that could blend into LUXELAKES’ broader water landscape. Though the development already included a concept of outlying natural islands, unarchitecte proposed replacing organic forms with refined hexagonal geometry to retain spatial clarity and contrast. The revised modules stretched along a true north alignment and were spaced rhythmically to reinforce visual coherence. Walkways parallel to the hexagon edges formed a molecular-like spatial system, while controllable air cushions were introduced to manage elevation shifts among pathways and platforms.

Further adjustments refined the system. The revised design merged both earlier strategies—disappearance and landscape clusters—into a unified floating system. The bridge and island modules were distributed to optimize structural rhythm and spatial variation. A small floating island, powered manually by a pair of propellers, replaced the rope raft system and allowed flexible movement across the water. Rope-based and underwater routes remained, creating three distinct circulation modes: above-water paths, submerged stepping access, and floating raft movement.

We built it ourselves with local workers, developing many practical yet poetic on-site construction details.
Interview with Zhang Hetian of unarchitecte

The swimming zone, which was added after water quality assessment, became the center of hydrophilic activity. The surrounding islands were scaled down to balance the water surface area while still preserving their distinct forms. Reflective surfaces, vegetation, and topographical modulation reinforced contrast between the artificial and natural context. Hidden fog devices, lighting, and gentle elevation shifts heightened the sense of environmental immersion. The integration of functionality and atmospheric detail ensured that the system remained spatially varied while being cost-effective and technically sound.

Construction was managed directly by the architects, with numerous on-site adjustments to optimize performance. Simplified connections and tested materials were selected to meet lifting requirements and buoyancy stability. Bob-weight systems were introduced to align islands to a consistent elevation despite inconsistencies in the density of treated timber and local steel components. Each module was also engineered for future detachment, with one branch already removed and tested for reconfiguration in a second phase of implementation.

Floating Islands of Sky continues to serve both as a crossing and a place for recreation and visual engagement. The architects described their intent as presenting “a place subtly with wonderful landscape, creating a special flavor of fun for people while walking.” Its layered geometry and engineered adaptability allow for seasonal transformation while remaining aligned with the aesthetic and functional aspirations of LUXELAKES. The structure remains open-ended, with future iterations planned for expansion and further experimentation in buoyant, inhabitable infrastructure.