With escalating land values in urban centers, there has been a growing trend to float public spaces from ground level to elevated locations, such as rooftops or podiums between buildings. From a development perspective, maximizing floor area has become crucial as urban environments expand. Ground-level spaces are highly sought after for retail use due to their strategic location, which attracts foot traffic and potential customers and drives city development and economics.
This financial consideration, which often guides building activities and directions in urban centers, contradicts design principles advocated during the modernist era for the benefits of better outdoor space for the public, such as the concept of ‘Freeing the Ground’. Architects like Le Corbusier championed this concept through projects like Villa Savoye and Unite d’ Habitation. These modernist designs envisioned a future where buildings were elevated to restore open, accessible outdoor ground-level spaces for its users. However, for the reasons above, many contemporary projects instead seek to replicate the function of public grounds within the building’s structure.
This raises important questions about the implications of relocating public spaces to elevated positions: What are the consequences for urban environments when public areas are no longer situated at ground level, but dispersed throughout the vertical dimensions of cities?
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The Social Effects of Elevated Public Spaces
As humans, our primary mode of movement is walking. Our bodily-scale biases—our feet—shape our perception of the physical world, making us more attuned to spaces grounded at street level for various activities. When the ‘perception’ of the ground is displaced, sometimes elevated up to 100 feet, it significantly alters social interaction dynamics and community engagement dynamics. Elevating public spaces can diminish the connection between users and the surrounding neighborhood, reducing incidental interactions and community engagement as it is vertically disconnected from its surroundings. This can fragment and disconnect the neighborhood as the vibrant street-level horizontal engagement diminishes, reducing the strong sense of community.
Many of the world’s most vibrant cities thrive on this rich street-level engagement, where a blend of retail, service, and public spaces creates a dynamic, balanced, and walkable neighborhood. However, as large-scale developments continue to become more prevalent, they combine plots of land and tend to elevate public spaces as described. The notion of ‘common ground’ is relocated, erasing the essence of ‘common’ from the ground. This shift not only segregates the community but also decreases natural surveillance. Residents become less able to respond to unusual activities, reducing the collective ability to maintain safety and cohesion.
Nevertheless, elevating public spaces has its benefits. Elevated areas often provide increased privacy, allowing individuals to enjoy their surroundings in solitude and tranquility. This separation can create small, self-contained communities with distinct characteristics. Elevated spaces offer improved hygiene, as there is less foot traffic from passersby who might litter. Those who frequent these elevated areas often take on the responsibility of maintaining cleanliness, supported by building management, which typically ensures better upkeep. Furthermore, vertical distance away from the street level can reduce exposure to pollution from vehicles and HVAC systems, creating a healthier environment for prolonged habitation.
A Closer Look at Miyashita Park, Shibuya
At Miyashita Park designed by Takenaka Corporation + Nikken Sekkei, a significant transformation has been achieved through a public-private partnership, converting a deteriorating, earthquake-prone parking structure and park into an elevated network of public spaces. Due to its unique location adjacent to a railway, the public space was designed atop a new multi-story structure with integrated commercial and retail activity, thereby reimagining the integration of commerce and public development. The elevated public space offers several advantages: it receives ample daylight that would be obstructed at ground level by surrounding structures and the elevated railway. Additionally, locating sports facilities on the rooftop provides a controlled environment, enhancing safety by minimizing concerns related to traffic, pedestrian flow, and train interruptions.
The rooftop, now branded as a community park, functions as a recreational area and an event venue for community engagement, featuring amenities such as sand volleyball courts and a skatepark. While the project successfully integrates retail and an ‘elevated community’ through the extensive provision of circulation space, it inadvertently places less design emphasis on the street-level community. The ground-level area, which had the potential to become a vibrant and diverse public space, has instead been replaced by continuous glass storefronts. This design approach prioritizes foot traffic geared toward spending and pedestrians through traffic, unfortunately diminishing opportunities for meaningful street-level neighborhood engagement.
“Weighing” the Costs: The Trade-Offs of Elevating Public Spaces
Beyond the social implications of relocating public space to rooftops, there are significant concerns related to cost and sustainability. Elevating a public ground requires substantial structural enhancements to support the added weight typically associated, such as the support of soil for greenery, including lawns, bushes, and trees. This process necessitates increased materials, engineering, and expense, particularly in regions with high wind loads or seismic activity. Despite these considerable financial and sustainability trade-offs, large-scale development projects remain interested in floating public grounds to reclaim ground-floor retail space, underscoring street-level rents’ allure and economic value. This trade-off may be justified for specific projects, especially when the design thoughtfully incorporates an overprovision of circulation space and plenty of access points to the elevated ground.
However, it is undeniable that this approach effectively absorbs the ‘public ground’ into the structure, creating a physical and conceptual barrier between the street and the public – a layer of invisible film. On the one hand, it adds protection or privacy. On the other, it may marginalize specific groups within the urban community. Moreover, while integrating public spaces with private incentives like retail might initially seem like a mutually beneficial arrangement, one must critically examine how the notion of ‘public’ is compromised. By forcibly merging public spaces with retail, the ‘public’ ceases to be a neutral environment, instead becoming a space perpetually influenced by advertisements from large corporations and subtle marketing by sponsors. This represents the ‘opportunity cost’ developers are willing to accept, sacrificing the short-term trade-offs associated with the construction and cost of creating an elevated ground.
Additionally, the concept of ‘filtering’ is further complicated by the question of 24/7 access. Can these spaces truly function as public spaces at all times? Integrating public areas within a building may not provide convenient, round-the-clock access, further undermining the definition of ‘public.’ Besides, while designers often present an idealized vision of how these outdoor public spaces will function during active commercial hours, what happens to these spaces after hours? When commercial activities cease, the public space may transform into a ghost town, adjoining empty stores, and blacked-out areas, raising concerns about safety and accessibility, specifically during off-hours. These are critical considerations that designers and developers must continue to address as more outdoor public spaces are intertwined and floated with building structures and commercial activities in the near future.
Are Hybrids Our Future?: Half-Floating, Fully Functional
Specific projects transcend merely placing public spaces above structures by rethinking the hybrid approach to offer the best of both worlds. They strive to maintain uninterrupted connectivity with the ground for constant public access while providing the serene atmosphere of elevated spaces. Additionally, they can repurpose parts of the ground-level areas for alternative uses. Mecanoo’s National Kaohsiung Center for the Arts exemplifies this approach. The public ground at this site gently lifts and dips, reaching for the sky while reconnecting with the ground at several points throughout the building. These gentle slopes may not provide a highly usable surface for retail or office functions. Still, they are well-suited for public space, encouraging visitors to linger, wander, and explore while enabling children to engage and play. The design also allows the creation of an outdoor amphitheater, further promoting diverse public programming and use of the space.
The hybrid concept does not entirely disconnect from the ground but instead introduces a mix of spatial experiences—sometimes elevated, sometimes sunken. While the National Kaohsiung Center for the Arts is situated in a tranquil location adjacent to the Weiwuying Metropolitan Park, this project raises intriguing questions about the potential for similarly designed urban spaces. Could future floating public spaces successfully integrate the notion of the public ground while offering the benefits of elevated parks? This approach may represent our contemporary evolution of “freeing the ground”—a new hybrid public outdoor space that benefits both the building environment and our city’s community.
This article is part of the ArchDaily Topics: Outdoors and the Built Environment. Every month we explore a topic in-depth through articles, interviews, news, and architecture projects. We invite you to learn more about our ArchDaily Topics. And, as always, at ArchDaily we welcome the contributions of our readers; if you want to submit an article or project, contact us.