Case Study - The WTC Transportation Hub - Jan Baxewanos

Page 1

World Trade Center



Author and Photographer

Baxewanos Jan 1128327

Technical University Vienna Institut fĂźr Architekturwissenschaften E259.1 Abteilung Digitale Architektur und Raumplanung Summer Semester 2016 CAAD & Geometry

Case Study World Trade Center Transportation HUB by Santiago Calatrava

Content 1







Construction Company


September 11


New Master Plan


Delay and Costs




Lower Manhattan


Rail System


Urban Situation


Retail Space


The HUB and Grand Central




Architectural Evaluation


Geometrical Analysis






Renderings Endresult



Introduction World Trade Center

Transportation HUB By Santiago Calatrava


Since the destruction of the World Trade Center plaza in 2001, the Federal Transit Administration (FTA) has been heavily involved in the recovery process. In coordination with federal, state and local agencies, the FTA has been providing financial and technical support to rebuild and improve the public transit system of Lower Manhattan. The new World Trade Center Transportation HUB, it`s large undergwround pedestrian connection network, and its new retail space is designed to play a vital role in the rehabilitation of Ground Zero. [1]

� A railway station is something that can generate a city � Santiago Calatrava



Research Architect Construction Company September 11 New Master Plan Delay and Cost



Santiago Calatrava Santiago Calatrava, born 1951 in Valencia, Spain, is one of the most famous architects and structural engineers of our time. He graduated in architectural studies from the Escuela Técnica Superior de Arquitectura de Valencia in 1974 and in civil engineering from the ETH Zürich in 1979. Three years later, in 1981, he obtained his doctoral degree in technical science, also from the ETH Zürich. Although his projects often exceed the time and budget initially provided for, he was selected to design the new World Trade Center Transportation HUB around 2004. [2] [3] In Calatrava´s vision, the HUB’s structure should resemble a bird being released from a child´s hand. However, due to various structural challenges, the design had to be changed several times during the planning phase.

“In the name of security, Santiago Calatrava’s bird has grown a beak. Its ribs have doubled in number and its wings have lost their interstices of glass ...... The main transit hall, between Church and Greenwich Streets, will almost certainly lose some of its delicate quality, while gaining structural expressiveness. It may now

evoke a slender stegosaurus more than it does a bird. David W. Dunlap, NY Times




Construction Company SKANSKA

The Swedish company SKANSKA, one of the largest multinational construction and development companies in the world, was responsible for the fabrication and erection of the steel structure for the Transportation HUB. They used approximately 11,500 tons of steel for the structure, which consists of various prefabricated elements. [5] Fabricating this structure presented SKANSKA with a massive engineering challenge, as almost every element has its unique size, shape and weight. In addition, there was also a huge logistical challenge. Maneuvering the structure’s elements, some of them over 30 meters long, proved very difficult in a dense urban area like Lower Manhattan. Transporting the elements from their warehouse in Brooklyn to the construction site alone kept a whole team of people busy for years. Most of the HUB’s components were fabricated In Italy and then shipped to a Brooklyn port via cargo ship. Then, by merely one or two pieces a night, all 588 pieces were transported via truck on the 7 miles long route to Lower Manhattan. On their way, they often had to tow cars or temporarily relocate phone booths and street lights . [6] [7] As Executive Pat Tamburri puts it,

”Getting the steel to the site was almost as complicated as putting it up”





9/11 Attacks &

Original WTC Plaza On September 11, 2001, an act of terror left a huge hole in the heart of Lower Manhattan. Two planes crashed into the two highest buildings of the Word Trade Center Complex. Both skyscrapers - WTC1 and WTC2 - collapsed after several hours, due to the severe damage to their structural system. WTC7, which was much smaller, was hit by falling debris and also collapsed as a consequence. WTC 3, 4, 5 and 6 were demolished during the cleanup process, because they were too unstable to be rebuilt. [8] In addition, the World Trade Center underground train station, which had been crucial for Lower Manhattan’s accessibility, was destroyed. Thousands of commuters had traveled from New Jersey and other parts of New York to work everyday. As a transitional measure, the New York/New Jersey Port Authority therefore established a temporary train station, which will be demolished upon completion of the Transportation HUB. The original World Trade Center Complex had also housed a highly popular shopping mall, which will now find a new home in the underground pedestrian network of the new World Trade Center station. [9]


New Master Plan & Delay and Cost Daniel Libeskind The new master plan, designed by Daniel Libeskind for the World Trade Center project site envisions five new skyscrapers, a Performing Arts Center, the 9/11 Museum & Memorial and a new underground train station with an above ground level access building. The empty space left by the destroyed towers was redesigned into two rectangular fountains. Most of the 9/11 Museum is located directly beneath them. The original concrete base and some of the towers’ remaining steel structure was used in the interior design of the museum. Shortly after the cleanup was finished in May 2002, construction began on WTC7. In 2003, Daniel Libeskind won the competition to redesign the World Trade Center site. WTC 1, WTC 7, WTC 4 and the 9/11 Memorial & Museum were completed until May 2016. Most of the other buildings are currently under construction or on hold .


Construction of the Transportation HUB as the permanent train station was supposed to begin in 2004. However, due to the various security issues that Calatrava’s original design had raised, and the US government’s eagerness to finish the 9/11 Memorial before the attacks’ 10th commemoration day, the start date was pushed back a few times. The Memorial was ultimately completed in 2010/2011, and the construction of the Transportation HUB could begin. In early 2016, seven years after it was originally scheduled to be completed, the HUB was partially opened to the public. [10] Because of this delay, among other reasons, the HUB´s original budget of two billion dollar increased to almost 4 billion.

”What did nearly $4 billion buy? Certainly an arresting structure, but one whose details do not match the shimmering images that Mr. Calatrava used to seduce officials a decade ago. For instance, the ribs of the mezzanine looked sleek as silk in the renderings but in reality have the texture of stucco because of a fire-protective coating. Asked in March why no one had smoothed the surfaces, Mr. Calatrava’s office an-

swered, “The client was not prepared to spend the additional money. David W. Dunlap, NY Times






Analysis Lower Manhattan Rail System Urban Situation Retail Space The HUB / Grand Central Construction


New York City

Lower Manhattan New York City is one of the most economically powerful cities in the World. Lower Manhattan is the third largest business district in the US. Besides being one of the world’s biggest places for business, it is also home to many government facilities. Countless companies from all around the world and of all possible different sectors are based in this dense urban area. The Skyline is iconic and globally known from the back of billions of postcards. The World Trade Center lies in the very heart of Lower Manhattan. Its´s skyscrapers are mainly used for office space. From an economical perspective, these are some of the reasons, why the recovery and rebuilding process after the September 11 attacks was crucial. However, far more important was the rebuilding process’s psychological effect. On the day of the attacks, the US’ presumed invulnerability took an enormous hit. Many New Yorkers were left with a traumatic experience, and the attacks gave rise to a number of grave changes in US policy over the past decade which still affect the world today. Considering the World Trade Center’s economical, historical, and psychological significance, it is fair to say, that its reconstruction has been and still is an enormous task, which should be planned and executed with utmost care.



New York Rail system

& PATH Rail system With over 500 stations, the New York City rail system is one of the oldest and largest in the world. It opened in 1904 and most of its structure was build before 1940. The Transportation HUB is designed to play a similar role as Grand Central Terminal in Midtown New York, which connects several different public transit systems. The Transportation HUB replaces the original PATH rail system that was destroyed on September 11, 2001. The Port Authority Trans-Hudson Corporation (PATH) was founded as a subsidiary of the Port Authority of New York and New Jersey. Its rail transit system is the primary link between Manhattan and neighboring New Jersey as well as suburban commuter railroads, serving over 250,000 passengers every day. In 2003, a temporary station was established, serving as a transitional solution until the Transportation HUB is finished. [12]



Urban Situation &

Underground Pedestrian Network Calatrava´s above ground level sculpture serves as the roof of the main transit hall. It is situated between World Trade Center Towers 2 and 3, as part of the master plan designed by Daniel Libeskind. The Transportation HUB will service PATH riders, connect to New York City 1, E and R subway lines, and provide underground pedestrian with access to Brookfield Place, One World Trade Center, One World Observatory, World Trade Center Office Lobbies at Towers 2,3 & 4 and the Fulton Transit Center.





Retail & Gastronomy Space The Westfield Group, a real estate investment company, will develop, lease and operate most of the new retail space at the WTC site, including in the Transit Hall. The Transportation HUB will incorporate 7,300 square meters of multilevel retail and dining space. The various hallways linking the entirety of the site will provide an additional 27,000 square meters of commercial space. The World Trade Center is designed to become the new commercial centre of the entire Lower Manhattan District. [13]

”This place cost billions of dollars of public money, and it’s still a shrine to the commercial marketplace. I wish it were otherwise. But that doesn’t destroy the impact of the architecture, or negate the fact that this is the first time in a half a century that New York City has built a truly sumptuous interior space for the benefit of the public.



Paul Goldberger , Vanity Fair


The Transportation HUB The Transportation HUB is defined by a series of steel ribs arranged in a large elliptical shape. The space between every rib is transparent and allows natural light to flood the transit hall. In addition, the HUB looks like a glowing lantern at night, its light illuminating the adjacent streets. The column-free space underneath is approximately 111 meter long and 43 meter wide. Above ground level, the ribs extend vertically, connected to two 107 meter long arches. Between the arches, a 100 meter long skylight allows you to see the sky and One World Trade Center, which with its 541 meters is the tallest building in New York. The ribs continue, forming the distinctive outside shape of the Transportation HUB. The main level sits at 10 meter below street level and about 50 meter below the maximum height of the skylight. Street access is provided from the east and west arch abutments , with overhanging staircases leading down to the main transit hall.



The Transportation HUB

& Grand Central Terminal Apart from the general shape, Grand Central Terminal and the new Transportation HUB have a lot in common. In fact, they carry out exactly the same function, albeit on a different scale. The HUB’s main transit hall is 27 meters longer than Grand Central Terminal’s main hall. Both have balconies with staircases at their ends, leading down to the main halls. In addition, they both channel commuters through hallways in every direction to different transit platforms. However, in terms of passenger count and connectivity, Grand Central cannot be outperformed. 750,000 persons pass through Grand Central on an average day, with the number climbing to 1,000,000 on holidays. It connects 44 different train platforms with 67 tracks, which makes it the busiest stop in the New York City subway system. It´s design was an innovation in transit-hub design and continues to influences the planning process of modern transportation hubs.[15] [16] The Transportation HUB, by comparison, will serve an estimated 250,000 commuters daily.



Construction of the Steel Structure ”The steel for the Transportation HUB is so specialized, only four firms in the world were able to make it. The steel (fabricated in Italy and shipped by boat to Red Hook, Brooklyn) was trucked over the Manhattan Bridge at night directly to the

World Trade Center.


Transportation HUB’s construction company




Architectural Evaluation Despite its enormous cost and questionable urban situation, the Transportation HUB offers widespread connectivity and an extraordinary architectural experience, made possible by an engineering effort unlike any I have ever seen before. In May 2016, during a trip to New York City, I had a chance

Its crowded urban surroundings are the only regrettable

to visit the World Trade Center and the new Transporta-

element in the HUB’s design. The street level plaza around

tion HUB. Stepping into the main transit hall surely is an

the structure of the main transit hall is still under con-

experience I will not forget in a long time. Although there

struction and shielded by banner ads, so I can just imag-

is over 11,000 tons of steel hovering above your head in

ine how it will feel being a pedestrian under its rafters. My

a column-free hall, it felt in no way intimidating or over-

guess is, however, that the two over 200 meter tall towers

whelming. Because of the skylight and the structure’s gen-

closely guarding both sides of the Transportation HUB will

eral transparency, the hall is flooded with natural light. Ev-

feel somewhat restraining/claustrophobic. The distance

erything is glowing inside because almost every surface is

between the longest rafters and the glass front seems to

white and partially reflective, which gives the space a light

be around two meters. Of course, building space in Lower

and calm feeling. You would expect it to feel somewhat

Manhattan is scarce and valuable, but such a complicated

sterile, but instead the HUB feels very warm and welcom-

and expressive structure needs space around it to fully con-

ing. Most of the light inside is natural sunlight and there-

vey its intention and sensation.

fore very warm light. Even the position and the color temperature of the artificial light is contributing to the hall’s welcoming effect. Because of fire protective coating, the

”It’s the most architecturally complex structure ever built by humankind,” Steven Plate, Director of construction [17]

steel structure’s surface is not smooth, but instead pretty bumpy, which reflects light very differently than a glossy

Although I don`t think Steven Plate’s statement is indeed

surface. Although the original plan was to sand all surfaces,

accurate, regarding the HUB’s general geometry, it surely

I personally think that for this particular space this bumpy

was one of the most complex structures to engineer, fab-

texture is actually preferable to a sanded one. The smooth

ricate and erect. Whether 4 billion dollar was a waste of re-

white marble floor stands in contrast to the rest of the sur-

sources or money well spent, I can`t help but admire the

face materials.

amount of structural engineering and precision that went

The underground pedestrian network, which was already

into the design and construction of this building. Without

partially open, was straightforward and very easy to navi-

such dedicated work, generating such an amazing archi-

gate. I had no problem to find my way.

tectural experience would have never been possible.





Analysis 3D Modeling above Ground Underground Statistic


Blueprints I started out by digitalizing the two useful blueprints I found (ground-floor and a section). I realized that the general shape is not a perfect ellipsis, but one circle on each side connected by two arches.

3D Then, I combined both drawings and created the third dimension. Every line I drew was helping me later to generate the surfaces of the different parts.


Skylight I used multiple photo references to figure out how the skylight was constructed. The surfaces are all evenly separated in different shaped pieces and slightly inclined. I adjusted the curves I had drawn earlier and used Grasshopper to generate the shape.

These functions interpolate the curves I drew and generate a surface. In addition, the one on the left generates a gap between every piece using the trim command, to be as accurate as possible.


Guidelines for the Steel Structure Next, I generated guidelines, which helped me to create the steel structure. It was a long and tedious process to adjust the curves I had drawn earlier, but it ensured that they would ultimately come out right.

These functions are connecting multiple division points on multiple curves with a curve. The contour command makes it possible, that every generated curve is parallel to each other, because it uses a vector and a predefined length to divide objects. The curves on the outside are rounded.


Over 50 unique Elements To generate every element with its unique shape without drawing them one by one, I had to find / modify a Grasshopper function. The original sweep2 command wasn´t adequate for the task, so I had to create a new one.

This function makes it possible to sweep one section curve multiple times on multiple rail curves at once. It defines frames along the rail curves and re-orientates the section curve based on them. The more frames (green in the picture above) you instruct the function to use, the more accurate the model becomes.


Steel Structure This is the resulting structure with it´s unique elements. After hours and hours of failed attempts and various different approaches, I managed to achieve an accurate result. This was the most crucial step, because the structure defines the Transportation HUB from the outside and inside.

Arch Two arches are connecting the skylight and the steel structure on both sides. There was no available cross section of the arch, so I used multiple photo references to figure out the shape


Preliminary result Preliminary result of the structure above ground. The last element left above ground level was the external shell of the abutment. Again, I had no blueprints. I had noticed that in the original design, they also had problems to create the shape of the shell out of one surface.

External Abutment Shell Some of the photographs I took at the site clearly show lines created by shadows on some seemingly smooth surfaces. I split the curves I used to create these surfaces, too, and again used Grasshopper to interpolate them in order to generate a smooth surface.


Steel Structure Underground Again, I used my photographs as reference in order to create the two different structural elements. I arranged them on an arch and linked them with two beams. It was important that they have a smooth surface and accurately connect with the structure above ground in one line.

Underground Floors Next I created the different floors and hallways of the pedestrian network.


Staircases, Railings and Glass Elevators The last complex elements were the balconies on both sides.

Artificial Light Sources Next, I positioned over 600 light sources inside of the Transportation HUB in order to make the interior renderings look accurate. This dramatically increased the time I spent on rendering, but made the renderings much more realistic as the sun was no longer the only source of light.


Finished Underground Underground elements put together with a transparent ground level floor.

Glass Front The Glass front of the Transportation HUB and it´s frames for the glass panels.


3D-Model of Ground Zero

3D-Model of Lower Manhattan


Materials I created a glass, metal and marble floor material in Vray. The marble floor tiles’ measurements are accurate, in the sense that they are proportional to the original ones. The floor central, because it is the only material that has a noticeable texture and reflection. For the rest, I used simple materials to keep the time spent on rendering at a reasonable length.

Distributed Rendering I used 3 quad-core i7 processors to render the scenes, using distributed rendering over my home wireless LAN network. Because of the 600 additional lights that I positioned inside the Transportation HUB, an enormous amount of computation was necessary, resulting in a render time of approximately. 5 hours for each interior scene at a quality of 1920x1080 pixel.


45h 23min

of pure 3D-modeling (video recorded)


Render Time each Interior Scene at 1080p


Render Time each Exterior Scene at 1080p

13.381 Mouse Clicks

2.557 km

Traveled with the Mouse




Endresult Photomonatge Interior Exterior
















Bibliography [1] : Photograph of construction banner ad, Port Authority of New York [2] : [3] : [4] : [5] : [6] : [7] : [8] : [9] : [10] : [11] : [12] : [13] : [14] : [15] : [16] : [17] :

Photo Credits [Cover] : © Baxewanos Jan, May 2016 [Page 1] : © Baxewanos Jan, May 2016 [Page 3,4] : © Baxewanos Jan, May 2016 [Page 5,6] : © Baxewanos Jan, May 2016 [Page 7,8] : © Baxewanos Jan, May 2016 [Page 9,10] : © Baxewanos Jan, May 2016 [Page 14] : ter_Transportation_Hub_%E2%80%93_Courtesy_of_Santiago_Calatrava__LLC.jpg?1418140016 [Page 14] : [Page 16] : [Page 16] : jpg?width=540&mode=crop&scale=both [Page 16] :


[Page 17] : [Page 17] : svg/800px-WTC_Building_Arrangement_and_Site_Plan.svg.png [Page 17] : [Page 17] : [Page 19] : site_plan.svg/2000px-WTC_Building_Arrangement_in_preliminary_site_plan.svg.png [Page 20] : [Page 21] : © dbox by_DBOX_original.jpg?1433864260 [Page 22] : © Baxewanos Jan, May 2016 [Page 25,26] : © Baxewanos Jan, May 2016 [Page 27] : [Page 28] : [Page 30] : [Page 30] : [Page 31,32] : [Page 34] : [Page 35] : [Page 36] : © Baxewanos Jan, May 2016 [Page 38] : © Baxewanos Jan, May 2016 [Page 39] : [Page 40] : [Page 40] : [Page 40] : [Page 40] : [Page 41] : [Page 41] : [Page 41] : © dbox [Page 42] : © Baxewanos Jan, May 2016 [Page 44] : © Baxewanos Jan, May 2016 [Page 47-72] : © Baxewanos Jan, May 2016




Author and Photographer

Baxewanos Jan 1128327

Technical University Vienna Institut fĂźr Architekturwissenschaften E259.1 Abteilung Digitale Architektur und Raumplanung Summer Semester 2016 CAAD & Geometry

Case Study World Trade Center Transportation HUB by Santiago Calatrava