Construction of the first of 28 chalice-shaped concrete pillars that will be the eye-catching feature of the 400m long and 80m wide train station concourse in Stuttgart begins. The pillars will support the roof of the underground station and serve as “light eyes”, allowing daylight to enter the hall below.
What began with extensive testing in 2015 can now finally continue: The construction of the spectacular and complicated pillars for the underground through station in Stuttgart. The finished pillars will weigh over 1,000 tons and be of up to 13m in height. Building one pillar takes approximately five months; two pillars can be built simultaneously in each construction stage.
The requirements for the concrete used for the design are equally demanding. Christoph Ingenhoven, architect of the Global LafargeHolcim Awards Gold 2006 prize-winning project, requested that the surface of the concrete has to be white and smooth; the imprint of the wooden molds not visible on the finished pillar. To achieve this non-porous surface, a special resin has to be used to coat the molds.
When the first molds were taken off, a perfectly even surface appeared that was slightly turquoise. This effect called “greening” was expected and happens because of metal sulfides contained in the special concrete mix that makes the pillars extra durable. Once the molds are taken off and the concrete gets in touch with oxygen, it gradually turns a perfect white. To protect the foot of the chalice of the pillar from rain and wind, it is covered in plastic until construction of the upper part continues.
A mammoth project
The pillars are only a small part of the extensive project Stuttgart 21. The project includes the rearrangement of the Stuttgart rail hub with four new stations and 57km of new track, of which roughly 30km are in tunnels. The aims of the project are to transform the station quarter in Stuttgart, improve the rail network for high-speed trains around the city and thus reducing journey times. Due to many delays, protests, and debates about funding, the project is expected to finish in 2024, three years later than planned.
Extensive construction work for this urban redevelopment and railway realignment project starts in October 2015, just to the south of where the new Stuttgart Main Station will be built. To keep noise levels for residents as low as possible, acoustic barriers up to ten meters high will be erected before construction work commences. One of the main project tasks is to construct a new underground hall of railway platforms that will form the hub of the rail network.
The design features distinctive chalice-shaped concrete pillars: a test pillar one-eighth of the final size is being tested adjacent to where excavators are preparing the first pit for the underground platforms. Eventually, 27 of the “chalice pillars” which form large “light eyes” to allow daylight to enter the railway platform hall while supporting the roof.
After testing, the model pillar will be dismantled. The aim of the exercise is to become familiar with the complex structure of the chalice and to gain experience in forming the material. Particular attention has been given to the concrete which is produced in a purpose-built factory on site. In addition to color, the finished surface must meet high demands.
The construction of the pillar took eight weeks, excluding preparatory work for the molds and structural reinforcement (rebar). Both are complex and unique in form which would not have been possible without computer aided design: “We are constantly working on the 3D model,” says Michael Pradel, director of the section around the main railway station in the Deutsche Bahn Projekt Stuttgart - Ulm (PSU). “All of them will be similar, but there are no two pillars that will be 100 percent identical,” he says, describing the challenges of construction.
In the coming weeks, the concrete will also be tested for its durability. A cast of the concrete slab will be exposed to 1200 degree flames over several hours in a test facility in Leipzig, to ensure the structure’s resilience in the event of an accident. If the testing proves successful, construction will commence on the first support pillars next year.
Tunnel work using specialized excavators to accommodate the railway lines approaching the station will start in January 2016.
A new station for the city railway
The construction work for an underground city railway (S-Bahn) stop that will be directly linked to the Main Station is currently progressing as well, starting with the excavation of the construction area to link the tunnels to the new “Staatsgalerie” stop. To make room for the construction site, all traffic around the station will be diverted for approximately 18 months.
General facts about the project
The Main Station Stuttgart is a core part of the comprehensive large-scale railway and urban development project Stuttgart 21 integrating the city into the Trans-European highspeed railway network between Paris and Vienna. It will create some 57km of new railways, including 30km of tunnels and 25km of high-speed lines.
The new concept will change the current terminus Main Station into an undergroud “through station” with eight tracks. Due to the improved efficiency of the configuration, the new station will have greater capacity for trains, thus coping with the increasing passenger demand and ensuring fast, convenient connections in the regional and national train traffic. The relocation of the rail into the ground will open up around 100 hectares of land in the inner city to use for other purposes. Completion is scheduled for 2021.See more
The project is highly commended for its innovative approach to integrating material, structural, and product research in a straightforward, sustainable response to reclaiming lost territory of the city. An efficient and refined deployment of technology is combined with intelligent resource management that offers valuable knowledge transfer across the disciplines of architecture, planning, landscape design, as well as civil, urban, and environmental engineering.
Priority is placed on inspiring a new sense of collective values regarding the potential of place without indulging in extravagant or nostalgic gestures. With spatial continuity of the urban fabric given utmost significance, the initiative promises long-term beneficial impact on the social, economic, and cultural livelihood of the community by giving viable expression to the potential of returns on shared assets.
Due to its attractiveness, the new station will link two parts of the urban fabric that have previously been divided, amplifying the conditions for social coherence while providing novel possibilities for leisure and communication across generations. Furthermore, such a broad ranging improvement to an otherwise neglected part of the city will encourage more concerted use of public transport due to the emblematic presence of the facility.
Moreover, the resulting reduction in energy consumption will certainly yield long-term environmental benefits and hopefully spawn more widespread awareness of the need for joint action in resource conservation. Serving to catalyze a dialogue on the future of municipal sustainability between diverse stakeholders, the project expresses as much consideration for the productive flow of competences as it does for the cost-effective flow of energy and material. The virtuosity of tectonic articulation achieved at such a large-scale infrastructural undertaking not only conveys an ambience of aesthetic intelligence, but also delivers a culturally refined celebration of collective space.See more
The design for a new main railway station in Stuttgart, Germany by Christoph Ingenhoven of Ingenhoven und Partner Architeckten, Düsseldorf was one of two winners of the Global Holcim Awards Gold 2006.
TEN Arquitectos Principal, member of the Advisory Board of the Holcim Foundation and of the jury, Enrique Norten (Mexico), praised the project for stimulating social pride through a new urban center: “This project innovatively incorporates material, structural, and product research into a straightforward and sustainable design for reclaiming urban space,” he said. The new station will link two urban quarters that were divided, promoting social cohesion, and providing new opportunities for leisure activities and interaction among all age groups.Holcim Awards honor sustainable construction » pour en savoir plus (French) » más información (Spanish) » leia mais (Portuguese) » lesen Sie mehr (German) » per saperne di piú (Italian) » อ่านเพิ่มเติม (Thai) »
Following five regional competitions, 15 Award-winning projects including Main Station Stuttgart will now compete in the first global Holcim Awards competition for sustainable construction projects. The global phase of the competition showcases the best entries from more than 1500 submissions from 118 countries, and encourages innovative, future-oriented and tangible approaches within the building and construction industry.Holcim Awards competition goes global » pour en savoir plus (French) » más información (Spanish) » leia mais (Portuguese) » lesen Sie mehr (German) » per saperne di piú (Italian) » 更多详情 (Chinese) »
The second prize of USD 50,000 went to Christoph Ingenhoven from Düsseldorf. The German architect’s design for a new ICE terminal in Stuttgart convincingly integrates architecture, landscape design, engineering, and other building disciplines. The rail terminal is underground, freeing the surface above for a new urban center. Refined environmental systems permit daylight into the station, the construction of which consumes relatively little material. Says jury president Mohsen Mostafavi: “This project establishes in an aesthetic way a dialog between the natural and the man-made environment.”Media release – Prizes for sustainable construction projects in Europe » lesen Sie mehr (German) » pour en savoir plus (French) » más información (Spanish) » per saperne di piú (Italian) »
The project presents an innovative scheme for recovering forfeited urban territory and at the same time creating a new spatial presence in the city. The work is significant because it contributes in an integrative manner to the disciplines of architecture, urban and landscape design, civil, urban and environmental engineering, and other related fields pertaining to construction.
Equally important is the ethically oriented stance toward socially viable environments and cultural values. Of particular interest are the proposed “light eyes” that serve simultaneously as a tectonic attractor and a creative means for distributing light to the station below.
The project successfully demonstrates an efficient use of natural energy resources that are coordinated in such a way as to improve the experiential quality of the site and to increase material performance of the infrastructure. Serving to promote public transportation, the project is economically viable in that it implements a model for recycling existing structures while offering a functionally flexible platform that can accommodate future programmatic changes. The work responds in an aesthetically convincing way to establishing a dialogue between natural and man-made environments and manifests a sensitive approach to contextual restoration.See more
The heyday of railway stations in the 19th century saw bold engineering feats for the new halls for train terminals in all major European cities. The stations were erected in the expansion areas of the historic cities, which continued to grow around them. Many years later, of course, the rail tracks would become a hindrance to further urban development. Stuttgart is a particular case in point.Download project entry poster (PDF, 6.71 MB) »
The 5-minute film visualizes Stuttgart 21 (S21) and the new high-speed line between Wendlingen and Ulm. Created by …
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