SKYSCRAPER Driven from Inside out Towards Nature

ctbuh.org/papers

Title: SKYSCRAPER Driven From Inside Out Towards Nature

Authors: Chang-Soon Choi, Associate Principal, Samoo Architects & Engineers Sooin Oh, Associate Principal, Samoo Architects & Engineers

Subjects: Architectural/Design Building Case Study

Keywords: Design Process Master Planning

Publication Date: 2015

Original Publication: Asia & Australasia: A Selection of Written Works on the World's Tall Building Forefront

Paper Type: 1. Book chapter/Part chapter 2. Journal paper 3. Conference proceeding 4. Unpublished conference paper 5. Magazine article 6. Unpublished

Chang-Soon Choi, Associate Principal & Sooin Oh, Associate Principal, Samoo Architects & Engineers

An essential element of skyscraper architecture city, and hosts numerous local and global at 414 meters tall, and includes luxury hotel lies in its adaptability to an existing environment. cultural events each year that include rooms, condominium units, topped by an For its massiveness in height and size, a worldwide conventions and film festivals. observation deck. skyscraper, while becoming a new landmark, In contrast to the rapid, unanticipated brings inevitable influences – both positive population growth during the Korean War, The project has been developed with one the current population is growing within overarching goal: how the supertall building and negative – to its surroundings. It is in that a carefully developed urban environment, will regenerate and harmonize with existing notion that Haeundae Resort Project (HRP) creating a desirable lifestyle. surroundings. Moreover, how the project will seeks for inspiration in nature as a key design enhance the City of Busan socially, culturally, principle, believing it is what will effectively Haeundae Resort Project regionally, and environmentally has been bridge a high-rise and society together. Haeundae Beach is best known for examined carefully. Hence, its primary design its beautiful beach, but has also been guideline focuses on integrating natural developed with several supertall buildings assets into the proposed high-rises. As the second busiest metropolis of South since the early 1990s. The high-rise Korea, Busan has a history that is more than residential tower is a necessary response Such an approach begins from the inside 1000 years long, which includes 140 years as to the city’s growing population. As a out, evolving from a unit plan that considers a port city. One month after the outbreak of component that houses mixed-use facilities, the natural lines and boundaries of the the Korean War in 1950, Busan was the only the podium provides many conveniences nearby sea and mountains, to a building city left that had not been captured during found in a dense urban area. mass, and then finally to a master plan. the North Korean attack; during this time, the This method of developing a unique city became a refugee camp site, and broke HRP is a mixed-use complex consisting of configuration of an interior space affects records for sudden overgrowth in population. residential, hotel, retail, and entertainment the form of the exterior, which requires Later, the South Korean and UN forces were components. Its development began in a delicate and morphological identity as able to rearrange the troops for retaliation. 2008 by Triple Square (AMC). The program is a new skyscraper. Haeundae has optimal distributed across three towers with a shared environmental conditions, with several Since 2000, Busan has been transforming podium at their base. To the north, there are extraordinary natural elements. Architecture into an international city through swift two 85-story residential towers, both 332 in Haeundae searches for design inspiration growth in urban structure. The city has meters tall. To the east and closest to the from its rich natural setting, in its aspiration begun to play an important role as a resort beach, the 101-story Landmark Tower stands to make the area a more wholesome place.

Left: Map showing phases of the Korean War. Source: Vox.com Opposite Left: View of the Haeundae beach view, showing the future site of the building. Source: Samoo Architects & Engineers Opposite Right: Aerial diagram showing the view boundaries of the Haeundae Resort. Source: Samoo Architects & Engineers

144 View Boundary

The beach forms a gentle U-shape, with develop an ideal form of architecture? While In the HRP Design Competition in 2007, Dongbaek Island visible in the distance. the ideal option lies in maintaining nature Samoo was selected as lead architect and People looking out to the sea enjoy a as is, it is inevitable to take a method of – in addition to collaborating with Kohn peaceful, calming landscape. “Dongbaek” vertical expansion as compact as possible Pedersen Fox Associates and Skidmore, is a Korean term for camellia flowers. - into account to accommodate the fast Owings & Merrill LLP as a team developing Blooming in the beginning of spring, the growing city. Busan, with its contextual and preparing design packages for multiple camellias alert people to the end of a long advantages from nature and infrastructure, proposals through from 2010 to 2012 – winter, and serve as a unifying symbol for seeks for a kind of skyscraper that would call has continued to work independently on the community. A neighboring bridge to attention to nature while functioning as an delivering the design development package Gwangan that was erected in 2003 is a great anchoring landmark. for three following years. addition to the touristic area because of its structural beauty that attracts more visitors In HRP, considering the residential density, The floor plan is developed to ensure to Haeundae Beach, as well as serving its providing every unit with an unobstructed that every unit gets an open view while basic function as a connector. view is a challenging task. The distance remaining a comfortable distance from between the three towers is determined each other, without losing the exclusive When overlooking the Pacific Ocean, by gross floor area (GFA). In order to offer quality of a luxury resort apartment. besides Dongbaek Island and Gwangan every unit a private terrace, the tower Accentuating the spatial quality of the Bridge, viewers can also see Tsushima mass becomes a tapered Y-shape. Such Master Zone that includes a master Island. Haeundae is a place of beautiful a shape has the advantage of having a bathroom with an ocean view, distancing scenery, holding the promise of a great longer perimeter to retain more visual between rooms within units for privacy, and resort destination, where Busan city officials openness. The tower placement has efficient kitchen layouts were all considered are trying to re-invigorate the tourism, undergone various forms of simulation as formative factors. To achieve the encouraging the city towards being a new analysis and confirmation to achieve the maximum number of rooms with southern- future international travel destination. wider perspective with optimal efficiency. facing ocean views, the core is shifted The 101-story landmark tower follows the from the center to the north, though the SKYSCRAPER Driven From Inside Out two residential tower shapes to create center is typically thought of as the most similarity in forms. After resolving the basic Relishing the attractive natural and artificial efficient. Fin walls between units support placement, the next step was to decide beauty of Haeundae, how would one the Y-directional loads. orientation angles for each tower.

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Determining the best orientation of the The first three conditions have the best Parameters for height have been set tower involved various simulations to views, and are thus are dedicated to through view simulations to avoid possible provide sufficient openness. To accomplish residential functions. A notion that the visual disturbances. For instance, the this, simulations were done for every single graded quality of a view could be converted podium program is set above the 7th unit, despite some of them sharing the into price for housing and/or hotel is not floor, which is the height that surrounding same layout. These were then presented to without precedent, but HRP’s architectural buildings are limited to. The design the public to communicate a better sense configuration featuring a detailed intention focuses on how the space would of the spatial experience. The view varies classification of views is a new approach in be perceived looking outwards, rather than from each floor level of the same tower, and a high-rise tower. how it would be seen from outside, leading from each direction in the tower, as well as its users to appreciate the value of the the distance between towers. Preferences Since the introduction of 20–30 story landscape by inhabiting it. of future inhabitants were thoroughly apartments in Korea in the 1980s, large- analyzed and were reflected in later designs. scale residential architecture has been Through these arrangements, unfortunately, Unit conditions are then sorted by field developed almost solely around efficiency the thickness of the north core wall reaches of vision in the following categories, in in unit plan, circulation, and function. 3.5 meters. These structural solutions aren’t hierarchical order: “ocean + bridge + island,” Regretfully, this has resulted in a culture made based on objective parameters, but “ocean + urban,” “ocean” and “mountain.” where large-scale housing developments as an immediate response to the design without such elements are seen as needs and conditions. By comparing unprofitable, and so are not typically built. various structural alternatives, the structural

146 Opposite Top: Tower and plan options in the concept phase. Source: Samoo Architects & Engineers Opposite Bottom: Plan showing the orientation of the towers with respect to each other. Source: Samoo Architects & Engineers Bottom: To achieve the maximum southern-facing ocean view, the core wall has shifted to the north from the center. The structural team suggested fin wall between units to support Y–direction lateral forces. Source: Samoo Architects & Engineers

“The project has been developed with one overarching goal: how the supertall building will regenerate and harmonize with existing surroundings… Such an approach begins from the inside out, evolving from a unit plan that considers the natural lines and boundaries of the nearby sea and mountains, to a building mass, and then finally to a master plan.“

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Bottom: The four categories, ocean + bridge/ island view, ocean + urban view, ocean view, mountain view. Source: Samoo Architects & Engineers Opposite Top: View simulation for each residential unit. Source: Samoo Architects & Engineers Opposite Bottom: On the process of mass variation, non- symmetrical methodology was used to reduce for each wing over outrigger floor. Floor plan shape is reduced from 50th and 78th floor level. Source: Samoo Architects & Engineers

engineers determined the most efficient residential unit are even more problematic; and further optimization of spatial use, the system for the project. thus, establishing a column grid that satisfies floor area on the 50th and 78th levels has the residential, commercial, and hotel floors have been reduced. To allow more panoramic The combination of units on a typical floor called for very careful planning. In order to views to the south volume, the north volume has since changed, but equally intentional accomplish optimal living conditions for the has been diminished as well. During the study architectural and structural evaluations and housing units, the project team confronted of massing, non-symmetrical methodology analysis are still in progress. Tight requirements several technical issues, such as column has been continuously used to deduct set by the client – to give every unit an open spacing for best views, building operable floor areas from each wing to highlight the view, and to create a gross leasable area that windows and outdoor balconies within high outrigger floors. is 70% of gross floor area, and six separate windy conditions. unit types – didn’t allow much morphological Adaptation to Allow for Natural Air-flow freedom in the tower design. To solve one of these issues, columns are in Residential Units located irregularly to avoid being exposed Other than through floor plans that brings Tower’s Column Spacing & Massing in living or dining rooms. These irregular the landscape inside and variance in elevation Principle – Regular vs. Irregular columns have various profiles for different that maximizes openness and closure on In residential building types, columns are programs, and are sometimes substituted required levels, what other ways could undesirable. Concrete is the preferred with appropriate fin walls; these are then architecture communicate through nature? material for residential buildings, due to further supported by edge beams added Despite the major structural implications of its high resistance to noise and vibration. to the end of floor slabs, which are used typhoons on the building, and the necessary However, when compared with steel, it to transfer loads properly and equally. strength and rigidity they have to provide to allows for smaller span lengths. Outrigger floors between independent account for those conditions, it was still very programs have been introduced as another important for the design process to consider In many high-rises, although various programs structural solution. the sensory experience of the building’s are stacked together physically, they stay inhabitants and neighbors. independent from one another functionally. Another structural irregularity is in transforming its vertical volume. The The lack of elevated connection between RWDI, BMT, and Chonbuk University have programs on different levels makes it difficult 101-story landmark tower is composed of four outrigger floors. For better efficiency in been brought on to the project to identify a to find a column spacing with the least way to optimize a design for this harsh wind spatial interruption. Exposed columns in a resisting the lateral force and wind pressure,

148 environment along with structural engineers Mock-ups were made and tested prior to the to block rapid air movement, and doors on and curtain wall consultants. The range of construction phase. other levels are remotely controlled to secure research covered tower shape, orientation, airlock. These systems all add to bigger and material selection and thickness. Evolution Tower of Moscow (2014) has a construction costs and a heightened need restaurant at the observation level. Its windows, for safety; however, they are still pursued Wind tunnel simulations were used to which are operated by remote sensors, open to provide sufficient exposure to nature on determine the ideal shape of the building up to delight visitors on the 61st floor. This higher levels, as such desire is considered and its orientation for the site. Cladding has greatly inspired the architectural team to primary to the residents’ wellbeing. pressure (net design and differential design create such an experience taking advantage cladding pressure) and wind environment of the natural beauty of HRP’s surroundings. Cascaded Shaping of Podium for Natural studies are executed to further optimize Some challenges of these operable openings Landscaping the cladding design. The average maximum included issues of drafts, air-tightness, air- The lower-level podium design has to be (positive) and minimum (negative) pressure pollution, noise, and safety. treated differently from the tower design. In on the cladding for each tower are tested contrast to how the tower needs to be quiet between 4 to 6 Kpa. However, from a Balconies on Tall Buildings for Communion and private for residents, the podium needs rationalized block diagram, pressure levels with Nature to be vibrant and public, as it is open to both at the most affected point is measured While operable windows are planned as residents and visitors. The podium includes from -8 to -9 Kpa. To keep balance between a passive ventilation system, a balcony for a water park, hotels, retail areas, restaurants, design intent and cost, the material division each unit is proposed as an active one. and other amenities. Such a contrast in tone of horizontal and vertical was tested which These balconies provide high-rise tenants led to a decision for a clear spatial separation would affect the façade design. with access to fresh air. Similar to operable between the two. windows, these balconies are followed by To maintain living conditions ideal from the concerns of maintenance as mentioned Creating a large-scale podium implicitly stack effect, the location of the core and above - which is why related consultants have causes visual interruptions for its neighbors. the entrances are arranged accordingly. been against them, regardless of the possible Local civic organizations resisted the Additional doors are added in the hall at cost savings from natural air-conditioning. construction of the high-rise building. One each floor to control air flow from elevator of the main reasons was the potential visual shafts. Additionally, operable windows in To cope with the stack effect, the entrances disruption of the surroundings. residential units boost natural ventilation. and elevators are situated in such a way as

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Left: The cladding maximum (positive) pressure and minimum (negative) pressure in elevation for each tower is general 4-6 KPa. But worst point from graphical presentations of rationalized block diagram is closed to -8~-9 Kpa. Source: Samoo Architects & Engineers Bottom: Each program has separate points of access. The podium mass is stacked in a cascade to allow the independent entrances and lobbies to be closer to the landscape. These setback spaces allow circulation in and out freely. Source: Samoo Architects & Engineers Opposite: The cascading terrace provides a connection from Haeundae beach. Source: Samoo Architects & Engineers

The upper middle section of the podium ocean view from the water park, they will Beyond New Technologies for Skyscrapers volume is removed to allow a big open surely have a strong desire to return. Each high-rise project requires that space facing the mountain, accessible from appropriate design technology is selected, the tower while in dialogue with the context Each program has separate points of access. based on budget, trend, and programmatic visually and physically. The visually open The podium mass is stacked in a cascade to relationships. Fortunately with current circulation paths on the north and south allow the independent entrances and lobbies advancements in technology, limitation for façades on lower levels allow panoramic to be closer to the landscape. These setback design and construction is becoming infinite views of the beach to the mountains. spaces allow circulation in and out freely. and calls for newer ideas and challenges.

The pedestrian retail entry at the south of Visitors exploring the shopping mall and Many of the earlier mentioned strategies are the Haeundae Beach has been developed complex may want to take a break to enjoy rather radical to the related consultants and as a gateway to the retail and entertainment the outdoors. A cascading terrace provides thus seem structurally risky and problematic program within the podium complex, as well a connection from the beach to the above from conservative perspectives. HRP has as a destination in and of itself. Designed podium levels, and offer seating with great been developed over the past seven years, as a gathering point for the public along views where visitors can rest. and its underground civil engineering Haeundae Beach, the interior and exterior work began in 2014. During this time, space has been designed as a space to The designers of the HRP Resort were several circumstantial changes were made gather and socialize. inspired by houses in Santorini, Greece, - including government reinforcement which are laid out naturally on the in tall building code (requiring extra A water park is located at the top level of the undulating contours of the hills, rather than permit processes); and program revisions podium, which opens up to the ocean. Much in an orderly arrangement, making each requested by the client. like in the infinity pool of the Marina Bay house unique and personal. Sands Hotel of Singapore, the HRP podium As an aftermath of 9/11, the preventive is designed to be a place memorable for its Getting away from the rigidness of a mega- measures in Korea against terrorism, fire unexpected openness, set in the middle of a structure, and incorporating the natural hazard, and other natural disasters have bustling metropolis. Through such openness flow seems extremely relevant considering intensified. Social demands for architectural to nature and the city, the skyscraper Korea’s mountainous topography. HRP aims solutions require newer systems, materials, approaches to people as more friendly and to become an urban paradise within a busy and methodologies. In delivering such an welcoming. Once people experience the commercial district. architectural response, a representation

150 “Columns are located irregularly to avoid having them exposed in living or dining areas. These irregular columns have various profiles for different programs, and are sometimes substituted with appropriate fin walls; these are then further supported by edge beams added to the end of floor slabs, which are used to transfer loads properly and equally.”

of tall buildings needs also be more harmonize with nature and bring its beauty Moreover, it has been carefully examined in sympathetic. A skyscraper is an ideal and experience into the city. many aspects above all how the project will architectural solution for a compact city that enhance the City of Busan. resolves extreme population density issues, Final Thoughts while its construction—aided by advancing The HRP design team was able to resolve HRP will indeed be one of tallest buildings technology—is cheaper, faster, and more all of the unique challenges of this project: in Busan by 2019, when the building is efficient. It is a solution that needs to be providing open views to the ocean, an projected to be completed; moreover, it will continuously developed and challenged. efficient structural system, and a vital dialogue truly be an icon of the city. with nature. In addition, the building design A skyscraper should not be an grandiose has been developed by unique and strong building that overpowers its community requests by the clients. For this, it has been and environment. Moreover, as it will confronted by several technical issues as significantly influence the urban and described above. In spite of all difficulties regional environment, the designer and the design team has been achieved the client should focus not on their profits, but most efficient solutions for the project. From should instead sufficiently consideration the beginning, the design team has been of how to contribute to the regional developed with one strong goal, which is how development and environment. HRP is the supertall building will harmonize with developed with a conscious effort to its surroundings and blend well with nature.

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