Sunday, September 28, 2008

Vault & Construction | Munich Subway Stations

Munich Subway's construction begun in 1965, and the first trains ran in 1971, five years ahead of Washington DC. Given the geological and groundwater conditions, as well as cost consideration, there are five principal construction processes used in Munich subway stations.

1) Open-Cast Construction
- just below grade
- building pit is beveled or secured by walls
- requires large construction areas
- more flexibility in design


Open construction, Subway Architecture in Munich, p.33

2) Bored-Pile and Cover-Slab Construction
- bored-pile wall
- generates column-free space
- reduce surface interruption


Bored-Pile and Cover-Slab construction, Subway Architecture in Munich, p.33

3) Bored-Pile and Cover-Slab Construction with Inner Shell
- when the station is under groundwater level
- additional impermeable inner concrete shell is built

4) Diaphragm Wall and Cover-Slab Construction
- when the station is fully under groundwater level
- excavation after diaphragm wall and cover-slab are constructed
- multi-story basement structure
- structure grows form top downwards


Diaphragm Wall and Cover-Slab construction, Subway Architecture in Munich, p.37

5) Mine Tunneling Construction
- extremely deep situation
- use of shotcrete, but cracks and leakages are not avoidable


Mine Tunneling construction, Subway Architecture in Munich, p.39

Friday, September 26, 2008

Vault & Construction | Introduction

"The design of a subway station starts with the structural design of the shell and ends with the artificial light reflecting from ceilings, walls and platforms." [Christoph, p.11]
Rolf Schirmer wrote in Christoph Hackelsberger's book "Subway Architecture in Munich", concerning the design of the subway stations that lie underneath a street or building. It prompts me to start my research on the structural system and construction of underground stations.

The Metro stations in Washington DC employed vault design for the underground stations. The concrete vault provided a vast column-less space for the platform and have become a signature of the Metro system.

In this series of post "Vault and Construction", I will document different construction methods of the subway stations, and explore the design of the vault.



Cast-in-place concrete vault of Metro station

Sunday, September 21, 2008

Canning Town Station, London










http://www.chiark.greenend.org.uk/~owend/I/R/stnpages/canningtown.html

Metro Light Show

A very interesting idea came out from last Thursday class - Light Show of Metro Arrival. It is to react to the lack of locality and distinctive features in the existing underground stations.

The idea is to install LEDs on the concrete vault, and they will be powered by wind turbines which capture the air flow in the tunnel when the train is approaching. Therefore, dynamic patterns, that react to the speed of the train, will be generated as the train arrive and leave the station. In addition, platform paving, seating and lighting can also be modified to incoporate with the local theme.




By the way, there are too many words than graphics in this blog right now. It's time to start producing pretty graphics to convey my thesis.

The Jubilee Line Extension

The Jubilee Line Extension (JLE) in London is the greatest example to learn from. Each stations of the line are custom designed by architects. It would be interesting to understand the arguments behind that decision and to see in what extend DC Metro can learn from it.

Following are quotes from the Roland Paoletti's Foreword to the book "The Jubilee Line Extension". Roland is the Architect-in-Charge of the overall JLE project, who was also a transport architect in Hong Kong.

The Jubilee Line has a maintenance depot, a control center and eleven stations.... Nine of the eleven are interchanges, making this the only line on the Underground to connect to all existing lines. Four of the stations have large new bus stations attached.

The route and stations of the extension effectively link Victorian construction with the modern world....new stations have been built to advanced architectural concepts...based on the latest technology.

In short, the proposal was that each of the eleven stations of the extension should be designed as an individual entity, but linked to the others by an underlying philosophy and essential elements. Each should be unique and should contribute strongly to its neighborhood while at the same time representing recognizably the best of London Underground.

They are a great expression of confidence in the future. Our stations are big enough to accommodate the needs of Londoners for the next 100 years. In all this innovation, there is also a profound continuity. The Extension shows that the Underground can power the re-shaping and revitalization of our great city like no other force.

The most popular millennium sight of all has turned out to be ... Canary Wharf tube station (not the Ferris Wheel). It has really caught the public imagination. And everybody can afford the tickets. This is the true people's building.



The Canary Wharf Station, London, by Norman Foster

Tuesday, September 16, 2008

Potential Sites

After considering different criteria for site selection, I am now in favor of the following 4 stations. These sites include different conditions of the station, and each of them has very unique context. They will be used as case study sites for the thesis. Existing stations and their context will be analyzed and documented. The intention is to suggest alternate ways to perceive Metro stations in a broader context.

Farragut North Station
- Need capacity improvement
- Pedestrian pathway to Farragut West station
- Potential intersection station with the separated Blue Line
- Downtown underground station

New Carrollton Station
- Terminal station
- Interchange of Metro, Amtrak, and Purple Line
- Transit-Oriented Development
- Above grade station

Reston Parkway Station (Silver Line)
- Silver Line connects Dulles airport with Washington DC
- Mixed-use development
- Existing active neighborhood center
- Above grade station

Oklahoma Ave Station (North of RFK Stadium)
- Major Redevelopment envisioned by NCPC
- New station on Orange Line
- Potential intersection station with the separated Blue Line
- Strategic location: East gateway to the city
- With both above grade and underground conditions
- Proximity to Anacostia River

Thursday, September 11, 2008

Site Issues

As I am still struggling with the site for my design proposal, I want to sort out some thoughts by this post.

1) Not a prototype
My thesis will debate for a localized station design versus a unify architectural theme. The intention is to tie the design of the station with the urban, socio-cultural and economic context of the neighborhood. Since each neighborhood has its own character, the design on different site will be different to reflect local needs and characters. I believe Metro station is a neighborhood center, which plays important role in shaping the image of the neighborhood.

2) Limitations in renovating existing underground stations
As I said in previous post, the concrete vaults of the existing underground stations create a strong image for the Metro system as well as the city, which I think it should be preserved unless with strong reasons. And technically, it is also challenging to renovate the underground station without disturbing the train operation and to justify the cost.

Yet I think it is still possible for me to have a site as existing underground station. I imagine it may be an existing station that intersects with a new line in the future. It would be interesting to see how the two come together if the two lines do not share track.

3) Strategic and important location
My thesis argues that strategic and important location of the stations will help justifying the need to consider metro stations to be more than infrastructure. For instance, a gateway to the city, stations along major axises of the city or memorial sites, terminal stations, key intersections of metro lines or intermodal stations are all potential sites for the thesis proposal.

Tuesday, September 9, 2008

Existing DC Metro Stations


Entrance of Existing Metro stations.


Platform of Existing Metro Stations.

The image above shows the platform conditions some existing stations. Despite of their gloomy interior, the concrete vaults, coffers or arches provide a unifying theme for the 46 underground stations. These vaults are impressive and have created an unique atmosphere to welcome the train. They are signatures of DC Metro that really capture DC newcomers' eyes.

Although my thesis wants to argue that the architecture of the stations are currently lacking a relationship with the neighborhood context, I still think that unless I have really strong reasons, ie. not just from architectural point of view, the existing character of vault should be kept.

Sunday, September 7, 2008

Thesis Abstract #2

With soaring gas prices, and rapid urbanization, many transit-oriented developments are planned and being built in the Washington Metropolitan Area. The Metro system has become more popular and many stations are reaching their capacity after 32 years of service. Studies have been done to identify the various needs in capital improvement. However, the architectural opportunities for station improvement remain underexplored.

This thesis intends to rethink the role of Metro stations. It considers Metro stations as more than infrastructure, but also as neighborhood centers and vital physical elements in the city. It anticipates an organic relationship between the station and the neighborhood and explores the opportunity to animate the program of the stations by reexamining the relationship between Metro stations and their urban / suburban, socio-cultural and economic context.

Existing stations with capacity-improvement needs or potential future stations will be investigated as test sites for the proposition. Precedents of railway station designs will be analyzed to compare and contrast with the existing Metro stations as part of the research.
They will lead to the exploration of the programming and design of the stations.

The goal of this thesis is to seek opportunities to create more dynamic and culturally integrated architecture of Metro stations for the national capital and thus to strengthen the urban centers as well as enhance the image of the neighborhoods in the Washington DC Metropolitan Area.

Retrospect of the Thesis Match Event

I agree with what Brian said that it is a "reiterative" process for us to introduce our thesis propositions over and over again. I really enjoyed talking with the professors and the students passing by. Even though I didn't talk to all the professors, I gained far more that I expected through this process.

From the conversations I had in the two evenings, I discovered that the key issue for me right now is to decide how I want to look at site in my thesis. Should I marry with one particular site? Should I consider a sequence of stations? How about several case study sites? Or make up a station? At some point I agree with Ambrose that my thesis proposition is more program-driven. So I will give myself one week to figure it out.

Another question I need to address is that not many people have problem with the existing stations. So how should I position my statement such that my thesis make more sense to them? How can I present the issue such that they will find it relevant? I guess right now I am still not quite clear about what my thesis statement is about.

Saturday, September 6, 2008

Metro Map (To Scale)



This map is created to understand how the Metro stations spread in DC Metropolitan area.

Thursday, September 4, 2008

Thesis Flyer



I created this flyer to give out in the committee match event. The diagram represents the current outline of my thesis.