There are more and more large scale high rise buildings in the city. What are they doing for us? As an important building type in city entity, they carry not only functional responsibility but also social public responsibility. Today, construction speed and height of the building seems to be a competition. But like other types of building, it can't be divorced from the specific building features and the surrounding environment. It can't ignore the need of social development. The most important point is the ground floor of tall building and the way of tall building melt into the urban realm. As designer, we should find the way to build up right relationship between tall building and people on the ground. From specific people's lives, from the psychological characteristics and from the practical need of space, we should create better urban and architectural space. Ground floor of tall building is not only focusing on the scale, dimension, material, colour and detail. It can't help to create a humanized environment. This paper attempts to start with some failure and successful cases to study human behavior and psychological needs, then try to build a key points of ground floor of tall building and urban space. It will use environmental behavior, environmental psychology, visual perception, architecture and urban design principles to summaries the design element of the ground floor of tall building.
Self-consciousness of tall building made the urban space fragmented, lack of comminuting and integrating with surrounding buildings. From the overall perspective of the urban environment, tall building shouldn't be self-exaggerated and totally against the context. It should coordinate as a whole. Philip Oldfield and Antony Wood talked about challenges for future tall building; they indicated that "A second challenge for the tall building is to develop in design terms, and especially in the relationship between a tall building and its urban location. Many tall buildings historically seem to have been designed as either vertical extrusions of an efficient floor plan, or stand-alone pieces of high-rise urban 'sculpture'. â€¦â€¦ Future tall buildings need to relate to their specific location beyond just becoming synonymous with that location - the way forward is for the design to be inspired by both the physical and environmental aspects of place." (WOOD, A. & OLDFIELD, P., 2009)
FAILURE CASE STUDY
JIN MAO TOWER
The Jin Mao Tower is a landmark supertall skyscraper in the center of Lujiazui Finance and Trade Districts in Pudong district of Shanghai. Along with the Oriental Pearl Tower, it is a centerpiece of the Pudong skyline. At the ground level, the building has 3 main entrances to the lobby, two for the office portion and one for the hotel. Each entry is designed as a moongate. Each moongate consist of two glass layers that enhanced the entry sequence and give it a timeframe, a zone of through movement, not an instant threshold of crossing, from outside to inside. However, for the 420.5 meter height super-tall skyscraper, the 2 story tall entrances seem look like out of scale. In addition, the style of the entrances is not in the same design language with the body of the Jin Mao Tower, they are rather looking like a component which attached to the building after it finished. The base of the tower is surrounded by a landscape courtyard with a reflecting pool and seating, offering visitors a peaceful retreat from Shanghai's busy street activity. But actually the connection between the tower and the street is not significant. Outside of this building, there is a public square right at a traffic junction. This cannot make the transition better and in fact it is not really comfortable for people using and create a strong barrier.
30 ST MARY AXE
The 30 St Mary Axe is a famous landmark tall building in the financial district of London. It designed by Norman Foster and completed in 2003. It has 180 meters tall with 40 floors, mainly occupied by a head office of global reinsurance company - Swiss Re. As the node of that district, it is a remarkable building with excellent concept of design by Norman Foster. But from the bottom, the building is basically closed to the walkway around. To ensure the integrality architectural form, the only opening point is the several peeled off triangle façade. The public area outside the building is restricted by tedious side walk and unpleasant lineal seats along the street edge. The bottom public space is quite empty and has no public facility and activity. So if you spend some time there, you will find there are not many people actually want to stay on the seat and relax. More than this, the strong wind created by the building makes the place uncomfortable. For an important building of London, the building did not play a friendly role to the public and there is rarely nothing green around the building at all.
Broadgate Tower which just completed in 2009 is another skyscraper in the district, designed by SOM. It is standing in the northeast corner of the city, north of Liverpool street station. The tower was designed by SOM and actually those two commercial buildings formed vibrant public space in between which also a walkway connected to the station.
Frankly speaking, the bottom area works very well inside the building, the large floor height of lobby was designed to allow transparent and reveal the context of the site. Outside the building, the most conspicuous space for public is the walkway between the two towers. The huge component create a shelter along the walkway, by the issue is the scale of those structure in the way of integrated with human scale. The out of scale and cause less using frequency and create uncomfortable public circumstance.
SUCCESS CASE STUDY
122 LEADENHALL STREET
122 Leadenhall Street was a new office building on Leadenhall Street in the City of London, designed by Richard Rogers. It stands next to the public plaza. The challenge has been to continue the feeling of this plaza and the openness it brings whilst at the same time sticking a skyscraper on it. Rogers has taken things a step further and built a large amount of the base on stilts and surrounded on three sides of transparent cladding. They always consider the way in which the structure meets the ground and the way in which the lower level of the building relates to during the whole design process. Inside this lobby is an indoor garden creating the illusion of an open public space that is in fact internal. The clever move of providing clear views all the way through the base of the building to Leadenhall St on the other side helps remove the feeling on ground level of the building acting as a barrier. Architects really believe and insist what they are trying to achieve in this project, 'We are confident that this can be successfully resolved, and we think there is the potential for something special to be created. Interesting and high quality detailing at the street level is likely to be valuable in creating a successful environment.'(CABE 2003)
The Chongqing Tower is designed by Ken Yeang to accommodate the headquarters of the Jian She Industry Corporation Ltd in Chong Qing, China. The tower is conceived as a vertical extension of the roof garden of the exhibition hall. A spiral planter system encircles the tower bringing vegetation to the summit. The site edge is planted with hardy trees and plant species indigenous to Chongqing with the landscaping continuous from street level to the office tower. The rainwater at the podium section is collected through eco-cells. A number of Eco-Cell as vertical cellular slots are integrated into the exhibition hall podium with a spiraling vegetated ramp that starts from the basement up to the roof garden of the podium to bring biomass, vegetation, daylight, rainwater and natural ventilation into the inner depths of the floors. The eco-cells can harvest and recycle rainwater for watering the landscape areas on the green belt and to clean the cultural plaza.
The Hearst Tower in Manhattan, which is designed by Norman Forster and Partners, is a 46-storey tall office building. It is not super tall, but the unique appearance of the Hearst Tower building enriches the skyline of the New York City. The Hearst Tower is erupting from a 40,000-square-foot six-story old building which is built 82 years ago. The existing cast-limestone building is become the base of the Hearst Tower. It is a light yellow limestone building, adorned with grandiose allegorical sculptures and monumental urn-crowned columns. The combination of the modern glass and steel body of the Hearst Tower with the traditional heavy stone material make a great contrast between the aesthetic and culture of time impact on architecture. The existing building was used for the Hearst Corporation's magazine headquarters for more than 70 years. In the design of the Hearst Tower, Foster and partners ultimately decided to let the glass modern office building body radical "way in" involved gutting the original base building and preserve its exterior, the traditional look. But the original building is been opened up the interior by removing the existing floor plates, because the original floor-to-ceiling height of 11.5 feet cannot fully satisfy the state-of-the-art standard for the modern offices. Furthermore, this rehab would change the base structure becomes the communal spaces for the users in the tower, a lot better than the tower hit the ground and connect with the street directly. The team envisioned turning the hollowed-out volume into an interior "town square," with the tower "hovering" above it. In the other words, the modern tower makes the original tradition building better Integration to the surrounding context, and the traditional building provide a gracious historical public ground floor space for the occupants, and also the intact old building exterior enriches the city with a historical element and maximized the building impact on the city.
Those case studies reveal the present situation of some tall buildings built so far and the ground level of tall building design. Generally speaking, the ground floor of tall building is the transition space. 'The experience of entering a building influence the way you feel inside the building. If the transition is too abrupt there is no feeling of arrival, and the inside of the building fails to be an inner sanctum.'(Alexander, C. 1977, p. 549) It is blurry sometimes, but the fact is this role has huge impacts on spatial, virtual and cultural aspect.
First of all, it has to be enough space for access. It carries a lot duty but also allows public to participate. If it lack of this participation, then the bottom space will lose the social benefit. That's simply not a good public place. If we want people to have good use of the space then essentially the space of ground floor should be simple and clear for people understanding the structure of the space. That means, not by using artificial sign and even architecture plan, the ground floor itself should be able to tell users the way of using it, where are the escalator and lift lobby, reception and relaxing place etc? Another point is the space should also be dynamic. The ground floor is the place to show the power of the entire building. As fuzziness of ground floor, people will be easy to find the dynamical mind balance. Different enclosure surfaces are sending different massages to the user of the space; people use the actions and elements to get the spatial perception. It becomes more about an information exchanging process and the ground floor becomes a comfort zone where people can communicate both physically and emotionally. Moreover, the dimension of the space can control the range of activity and the level of participation of people. The truth is people feel and behavior extremely differently in different scales. People can't get the sense of being the huge scale of modern urban surroundings. But for the ground floor space, it has to be comprehensive with enough activated volume. Ground floor space with lower floor height will constrain people both physically and emotionally. It is the most significant gathering place in any tall building, so the space has to be big for varied activities.
There is a consensus of modern visual aesthetic theory and art creation. In any cases, if it can't be in control of the balance of entirety, it will never be a successful piece virtual artwork. The appreciation is primarily visual and kinesthetic. Buchanan indicated 'they should have character and coherence that acknowledge conventions and enter into a dialogue with adjacent buildings and have compositions that crate rhythm and repose and hold the eye.' (Buchanan, P., 1988b, pp.25-7) Therefore, an inconsistent tall building introduced into the urban space could break the virtual balance. The bottom area, as the part of the space, should virtually coordinate with the surrounding. Recently, the façadism in Hong Kong and Canada raised questions about the value of retaining the façade of an older building. It is dubitable, but from inside, maybe the bottom of new building could somehow be an extension of older one, the ground floor space could be well integrated but also showing the aesthetical impression, like Hearst Tower in New York. On the other hand, as we know, tall building can give an excellent perspective from distance; however, for people on the street, the virtual coherence is really the most important to adjacent streets. For this reason, on the street, the bottom part has to create an interface to connect with the outside. When there is appropriate virtual response from the interface to the urban space, people will easily get a livable expression and clear continuity.
LACK OF CONSIDERATIONS IN DESIGN
THE LACK OF PUBLIC SPACE
Many tall buildings are lack of open public space for comminuting on ground level. They usually have expanded podium building, but those kinds of space are normally unpleasant for people to rest or stop by when they walking through. The sense of communicating is crucial to the ground level. The lack of public space could also cause badly in finical return, Antony Wood summarized eight design principles for more appropriate tall buildings of the future. He pointed out 'such spaces have been proven to improve the quality of the internal environment which has an impact on the productivity of workers, satisfaction of residents etc. This will have a direct financial returnâ€¦â€¦' From large scale of perspective, he also said that 'Social sustainability on an urban scale is a major challenge for our future cities.' (WOOD, A., 2008)
THE LACK OF OVERALL PLANNING OF PUBLIC FACILITIES
Tall buildings next to each other need the spatial continuity. The entrances for pedestrian and vehicle, the ground lobby and the podium, the facing and height of the entrances, they should be precisely planed by the designer. Without this planning, the street becomes a barrier of buildings which cut the city into pieces. It brings user inconvenience and increases the city traffic load. From inside, this situation has led to a lack of interior planning for functional facilities. In many lobbies of tall building, the arrangement of facilities is not in the appropriate way. The position of the escalator and the lift is not comfortable and efficient for people using. Transportation is also a crucial point. It affects the type and efficiency of the space. Common issues are crowded and poorly managed crossing, narrow and boring pavements, unpleasant subways etc. Effective reasonable design of the spatial environment can help to expand outdoor space, connect street, gourd floor and first floor so that it could became a three dimensional space with good permeability between inside and outside, creates more active street in the meantime. By all means, a more humanistic integration of sharing facilities should be pushed.
THE LACK OF CONSIDERATION OF ECOLOGICAL DESIGN
The greening rates are generally low in most tall buildings ground level. In many ground lobby, the space is restrained and functionally organised. As the increasing number of tall building, the level of green covering will draw more impact on greenery of the city. It will accelerate the deterioration of the urban environment. Ken Yeang wrote about ecological design in tall building, he thought tall building is not an ecological building type but to design ecologically is crucial today. Especially at ground level, it doesn't only means to import greenery at ground level or introduce natural light into the lobby. The space between entrance and lobby could be a continuity of ecological environment, inside the lobby there is an opportunity to integrate with more sustainable functions, such as garden, rainwater collection, natural air-condition etc. Or even from a larger scale, the designer should consider the surrounding circumstance like what Leadenhall did; the site has tied together by the sequences of greenery and public space.
KEY ASPECTS IN DESIGN GROUND LEVEL OF TALL BUILDING
Integrity refers to the combination of urban relationships, construction, transportation, open space, ecosystem and cultural heritage. The ground floor of tall building integrated with complex architectural form. It is not only an extension of indoor space, but also the external units of urban environment. The bottom of tall building is the agency to make architectural space break their close form and be involved into multi-level, multi-factor dynamic open surroundings.
There is an open trend of modern city. The bottom of the building should be open to the street, community or park. The indoor space and semi-interior space are combined with the urban space. They form sharing space with a variation in size, shape and function which not only belongs to building but also to the city. There is no obvious boundary between the bottoms of each building; street, sidewalk, pedestrian bridge and park are smoothly blended together. It reduces the congestion sense of space and expands the activities space, together makes our city a more livable place.
Complexity means the overlapping of varied functional levels, the linkage and permeability of different units. It is based on the compatibility of people behaviors in the city, such as shopping, walking, resting and other social leisure activities. The ground floor of tall building should accommodate a wide range of urban activates. The ground space should integrate with road and square and provide more contents with hybrid configuration, such as retails, leisure and entertainment, like what Hybrid Link did in Beijing. It should aim to meet the public diverse requirements and to make the hierarchy of urban space composited.
Walkability in public space is the fundamental point of urban humanness. As traffic into the city, it breaks the traditional feature of urban pleasant. The design of ground floor should take people out of the tension of traffic, create a relief comfort zone. On the ground floor, the principle is to let pedestrian have the priority and traffic go around, by organising of traffic, so that to provide a safe, comfortable pleasant, continuous walking space. People are willing to walk to their destination in 7-10 minutes. The parking area could be underground, so people could get rid of cars on the ground. The entire ground level should allow and encourage people to walk free like the podium of Chongqing Tower. This kind of area should make people walk intimately and create a feeling of belonging and emotional identification.
The design of ground floor should respect the cultural context, so that residents could get the sense of identity. The public space of ground floor can reveal the cultural content, not only in architectural style but also maintain or respect the scale of street, the way of people moving around and the living habit.
In conclusion, as the age of high rise, what citizens really get from the building? How should the tall building hit the ground? Ground floor of tall building should effectively link the outdoor space with the building, relieve urban pressure, increase the coverage of greenery, improve the urban ecological environment and provide a platform for comminuting. It is a long term process, but with the better consciousness and technology it will enhance the flexibility and compatibility. As all the study of failure cases and successful cases, the importance and advantage of good design of ground level is conspicuous but we still could see so many unfriendly building sitting in the city by the sidewalk. The tough part for designers in the future is to really integrate those crucial points or principles in every project. People are looking forward a spectacular and innovative way of connection between skyscrapers and urban realm.