Cheongna City Tower
Design Concept
The design of this tower is inspired by hyperbolic geometry, elegant mathematical forms, and the dynamic yet infinitely balanced taegeuk. The result is an iconic sculptural form that is reminiscent of natural phenomenon. The lattice tower design removes the central core which is archetypical of tall observation towers and replaces it with a lightweight and transparent structure. Within the vast vertical interior space two spheroid volumes that contain the observation platform and educational / entertainment program are suspended in the void creating a tower that is both introvert and extrovert.
The Cheongna City Tower is to be a dramatic statement of design quality and technological innovation whilst also being of a form which is economic and practicable to build. We have attempted to create a dynamic tower proposal that will add an unique iconic element to the IFEZ Cheongna Central Lake Park development. This tower will surely become a symbol of economic growth in South Korea, a national landmark, and an international tourism destination.
We believe that our solution is unique to observation towers in that the tower functions are contained in volumes suspended on the inside of the structure, creating an opportunity for dramatic views both outside of, and inside the tower itself. In addition to high-speed inclined elevators on the tower interior we have also proposed a one-of-a-kind external panorama ride that would lift visitors to the top of the observation tower while slowly spiralling through 450 degrees of views.
This project has been designed by a creative team of architects and engineers to give an end result that is both sculptural, exciting, practical, and with economical use of material. Sculptural design sketches have been translated into circular and elliptical hyperboloids of revolution. These forms extend upwards to create a tower where the plan of the building is dynamic and changing in perfect balance about an invisible central point.
Inspiration and reference
Shabolovka Tower, Moscow The mathematics of hyperbolic geometry and the application to building design was first established in the late nineteenth century with the work of Vladimir Grigorievich Shukhov. Shukhovs exploration of doubly curved structural forms led to the steel lattice tower at the 1896, 16th All Russian trade and industry exposition and twenty years later the Shabolovka Tower in Moscow (1919), see below. The latter is particularly relevant to our Cheongna Tower submission as it used the principle of stacked hyperboloids. This meant that the ‘neck’ or ‘waist’ between the tension rings of each individual hyperboloid is not read within the context of a large tapering tower. The tower was originally designed as 350m tall in 1918 and would have been 50m taller than the Eiffel Tower. The tower was built with each stack assembled on the ground and successively lifted in position like extending a telescope. It is claimed that if the original scheme had been built it would have used a quarter of the material of the Eiffel Tower.
Other reference points Later elements of the Sagrada Familia in Barcelona and the recent Killesberg Lookout Tower in Stuttgart are further reference points, which show that although our proposal is unique in appearance it has been based on the logic of previous innovations in engineering. The Spanish Engineer Eduardo Torroja designed several concrete water towers that exploited the principle of the hyperboloid.
Spirals in nature Spirals are fascinating mathematical curves that also appear in natural phenomena. The red and blue taegeuk symbol was originally derived by graphing the length of the sun’s shadow as a series of lines drawn radiating from the middle of a rotating piece of parchment. Plants like the Giant Lobelia and sunflowers arrange their leaves and seeds in spirals. The twisting form of the tower and the distribution of elements recalls these natural shapes.
Site
The City Tower is the key element for activating Central Park, a large open area for recreation in the center of the city plan. The green space available is important with the dense urban structure which is proposed elsewhere. The tower and it’s supporting facilities will act as a cultural magnet for attracting visitors to the park. The wide base of the tower apparently rises up from the Central Lake with all of the lower tower functions at lower levels inside the sunken central garden provides a spectacular and suprising view up the inside of the tower. Outdoor garden functions and a circular dock also give access to water-taxis and tourist boats.
Access to the tower by car is from the motorway to the west. Underground parking is available to the north-west and south-west of the tower. The two parking lots are connected to the tower via an underground passageway. This passageway is creatively lit with lightwells that frame the tower from strategic views. This approach creates suspense as the first close-up view of the tower is from the interior courtyard. Pedestrian access from town or from the Central Park is also connected to the same passage via openings on the walking path. This could be supplemented by bridges to make access for pedestrians easier. The proposed cable-car or gondola system travels through the park and the gondolas pass through the lattice of the tower to a station on the inside. From here visitors can enter the tower, or follow the passageway out to the road and other public transportation into the city.
Tower program
While we believe that the design of the tower is robust enough to suit many kinds of program, for the purpose of the competition brief we have proposed the following educational and entertainment elements within the tower and tower base. These can easily be changed or adapted to suit the needs of the client.
Observation sphere At the top of the tower an ovular volume surrounds 4 floors of functions related to the observation tower. In addition to a floor dedicated to observation this volume contains a skybar, souvenir shops, and entrance/exit from the panorama ride. With a top floor height of +425 meters the observation floor provides stunning views of the city and landscape around the tower, as well as breathtaking views back down the tower structure. The bar at the bottom level would be placed in the middle of a large circular patch of glass floor, testing visitors resolve when the que up to order a drink. Hanging in the middle of all floors is a massive concrete “tuned mass damper” which helps prevent tower sway.
Education and entertainment sphere Two-thirds of the way up the tower a large volume with 6 suspended floors houses the main educational and entertainment space within the tower itself. This is divided between a Technology Museum and a series of restaurant / bar spaces. To celebrate the technological achievements of South Korea and the Cheongna area we propose the inclusion of a science and technology museum in the tower. This features three floors of hands on exhibits for both children and adults. A sphere containing a planetarium and/or Imax theatre is placed at the lowest level such that it’s exterior is a visible element of the tower. The top two levels contain restaurants and cafe’s with an open terraced space on the upper floor. From here you can enjoy the view from +295 meters up or watch the light show from the inside of the tower at night. With the panorama ride, planetarium visit, lunch and the science museum the tower can easily become a whole-day destination for tourists or the local population.
Lower level program For the purpose of the competiton we have made a basic proposal for the lower level mixed-use functions of the tower. Lower level tower activities include an aquarium, entertainment, shopping, and childrens world. Entrance and exits to the Panorama Ride are included in the visitors information area. The lower level of the tower has been divided into four functional quadrants that relate to the four trigrams of the South Korean flag and center around the sunken taegeuk formed plaza. The spiraling plaza shape has a clear relationship to the spiraling form of the tower thus making a strong visual connection between the two. We have provided for 3 levels of mixed-use activity in the base of the tower, connected to underground parking levels to the west. To maintain the appearance of the tower rising out of the Central Lake we have placed the lower level mixed-use program “underwater”. A thin reflecting pool is all that would be needed on top of the central program to maintain this appearance. The sunken plaza has a diameter of 60 meters and will feel open and airy under the volume of the tower. Additional skylight for the four program quadrants can be achieved through openings in the form of the trigrams of the South Korean flag. These can also be used at night to light up the tower from below.
Vertical transportation and emergency escape
There are four forms of vertical transportation utilized in this tower design proposal.
Spiral Panorama Ride (shown in blue) The external spiral panorama ride is a unique proposal that relates to the spiral design of the tower. This would be a tourist attraction in it’s own right, much the same as the London Eye. The spherical cars carry visitors to the top for a 30 minute ride through more than 360 degrees of rotation to ensure that they can enjoy the view in all directions. The ride includes a programmed guide and multimedia presentation inside each cabin with information about Cheongna and Korea. Each cabin would hold from 20-30 people comfortably with seating provided in the middle, and unobstructed views at the edges. Visitors can begin or end their visit with the panorama experience. Half of them would purchase a ticket to take the ride up to the top, where they can disembark at the observation level before taking the inclined elevators down to the entertainment and educational offerings of the technology museum. The other half could work their way up the tower to the observation level, and then take a relaxing ride down before enjoying the facilities at the tower base. The panorama ride would require more research and development to be feasible. It could likely be constructed as a spiral funicular lift, using ski-lift/gondola technologies, or with techniques from amusement park rides. While we consider this ride to be a unique and exciting feature of our tower proposal, it is not a necessity for the project’s function due to the inclusion of the other types of lifts for direct access.
Duo-lift inclined elevators (shown in green) For rapid transport from the lower tower level to the technology museum or observation levels visitors would use the duo-lift inclined elevators. The hinged cabins of these lifts follow a vertical plane up the inside of the tower structure. Inclined lifts use exiting technology and can be found in The Luxor Pyramid in Las Vegas, The Pinnacle Tower in Portsmouth, and in the Eiffel Tower in Paris. Of these the Eiffel tower also uses the duo-lift principle where two cars are attached to the same pull-cable. The balance in weight between the lifts is an energy efficient way to power the lifts. Lift size and capacity can be adjusted to suit visitor numbers. There are 6 lifts in the current scheme - two pairs that stop at observation and technology museum levels, and one which only services the museum and it’s restaurants. Service elevators can be provided using dual level cars. This is also an alternative way to increase capacity without increasing the number of lifts. These lifts stop only once per volume, separate lifts are provided for internal communication.
Escape Stairs (shown in red) Two means of escape are provided from all levels of the tower. Next to the inclined elevators on each side of the tower there would be an enclosed fire stair which follows the interior curve of the tower. Larger enclosed waiting areas can be placed along the exit route if necessary. The panorama ride may require an alternative exit in case of failure, this could be incorporated to the inside of the structure or as part of the rail system for the cars. It is possible that this could be an alternative to the vertical escape stairs shown in the communication diagram. This design provides for multiple possible escapes, the physical separation of the two exit routes due to the width of the tower could offer a more robust escape strategy than a traditional concrete core tower. A more detailed study would be required in the next design phase.
Internal elevators Additional internal lifts would be provided within each of the observation sphere and the technology sphere. These are traditional mechanical or hydraulic short run lifts that span 4 and 6 floors respectively. Mechanical rooms provided locally.
