Hoffmann Ladewig 3501 Fall 2008 Web

MATERIAL STUDY: STEEL RESEACH PRECEDENTS MODEL DEVELOPMENT SPECIAL THANKS

STRUCTURAL MATERIALS RESEARCH CATALOGUE CONTRIBUTORS

Phil Hoffmann and David Ladewig

STUDIO 703

ARCHITECTURAL DESIGN STUDIO 4 ARCH 3501

COLLEGE OF ARCHITECTURE TEXAS TECH UNIVERSITY - FALL 2008

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STEEL USES TODAY Steel was first used in the creation of long spanning bridges and railroad tracks across the world. It has quickly become one of the most popular structural elements in the construction of tall buildings and skyscapers due to its incredible compressive and tensile strength. Steel consists almost entirely of iron, with just a hint of carbon in its composition. Because of this, steel weighs less than iron, even though they have many of the same components. Steel has quickly broken away from its common use of purely structural strength as its beauty has been discovered. Today steel is used throughout the world to not only strengthen structures, but to also give them distinct visual forms and characteristics. Steel can be bent, curved, and twisted to create amazing architectural components. Steel can be used to span long areas to open up large interior spaces. Steel can be used to create window walls as it can carry much larger loads than most other materials. It seems as we continue to try new things with materials, we will continue to see new ideas used in different ways.

Right: an aerial perspective of Incheon International Airport located 30 minutes away from Seoul, the capital of South Korea.

Below: Munich Airport Terminal

Right: an interior perspective of Beijing International Airport located in Beijing, China.

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STEEL JOINTS AND CONNECTIONS As with any material, the integrity of the entire structure relies on the connections. If the connections of a structure fail, the building will fall. Therefore, the connections are perhaps the most important part of construction. There are many ways to connect steel beams to one another, and they are some of the most sound ways to build a structural skeleton. The most typical method is welding, which uses direct heat to melt metal pieces into one another. This is a very common connection method used in steel construction everywhere. Another way for steel to be connected is by the use of plates and bolts. Plates must be welded in place to use, but when used in conjunction with bolts, they only add more strength to the connections. With a welded corner supported even more by thick bolts holding it in place, it would take a great amount of stress to bust it apart. This is why most failures in steel buildings come from bending and buckling in the columns and beams themselves. Right: David is looking through a book we checked out for the best picture to convey our idea about the airport.

Last is soldering, a common method used to connect smaller pieces together. Though it may not be as strong as welding, it is a very simple, accurate, and clean way to combine many types of metal pieces.

Right: David is looking through a book we checked out for the best picture to convey our idea about the airport.

Right: A display of all the study models we have worked on thusfar. We started by working with simple triangular truss systems and worked up to a portion of Stansted Airport.

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STEEL SPANNING AND LOAD BEARING Every type of material has its limits, and the structural integrity of all buildings rely on a material’s bearing capacity and spanning ability. The chart to the left shows the effective spans in meters of steel for multiple different sizes. Today, steel is perhaps the strongest steel that can span the longest distances without failure. This is the reason why structures like airports and buildings that need to be unsupported over long distances are constructed using steel. Though it may be relatively expensive, steel spanning requires much less material than most others, including wood, concrete, and masonry. The incredible compressive and tensile stability that steel has makes structures much safer for human use.

Below: New River Gorge Bridge

Right: A chart that describes the specific lengths that specific steel types can span and the maximum loads that those steel types can bear.

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PRECEDENTS: STEEL INCHEON BEIJING MUNICH SHENZHEN STANSTED

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INCHEON INTERNATIONAL AIRPORT Incheon International Airport was one of our top building choices when we were looking into the material study of steel. Incheon is located just outside of Seoul, South Korea and remains the largest and most interactive airport in the country today. The steel lattices that make up the roof system in the picture below is perhaps the most beautiful part of the building. The strength of the steel allows for windows to flood the entire interior corridor with light. With the great spanning abilities of steel, the interior space has little problem accepting this light. Exposed steel has only recently become a commonly used idea. Modern airport architecture has been a leading building type in popularizing this technique. Incheon Airport uses exposed steel throughout its structure to show how the elements of strength and beauty can work together to create attractive architecture.

Right: An interior perspective of the ceiling. The scale of the people in the photograph show how large the huge steel trusses are that keep the building standing.

Below: Incheon Airport Terminal

Right: The complex steel lattice that creates the long arched corridor remains structurally strong but capable of allowing the sun to infiltrate just about every section of the room.

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BEIJING INTERNATIONAL AIRPORT Beijing International Airport is a fairly new building that is made almost entirely of steel. It is very unique in its design that utilizes gigantic spans that open up spaces throughout the terminal. The high ceilings and natually entering light at Beijing Airport give onlookers a feeling of freedom, no matter where they go. The composition of steel throughout the building clearly proves that steel can be used not only for strength, but for beauty as well. Beijing Airport is a perfect example of how steel is used for light. Because of its strength, it takes little steel to create the structural skeleton, allowing for glass windows, which have a very low bearing capacity, to fill in the open spaces.

Right: The large circular spans that cover the airport terminal show the incredible strength of steel while maintaining the natural light than is allowed to enter.

Below: Beijing Airport Terminal

Right: A perspective from the interior of Terminal 3 at Beijing Airport.

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MUNICH INTERNATIONAL AIRPORT Munich International Airport utilizes the same steel structural system as Incheon. The large central membrane consists of a steel lattice that allows natural light to flow in freely without sacrificing structural support. The terminal shown below acts as a tent, since the covering is still exposed to the exterior. Although the area is enclosed, onlookers don’t have the feeling because of the long spans and high columns that make up the roof. Steel is perhaps the only material that could make a structure like this stand without failure.

Right: A great example showing the long distance that the steel spans to create the wide open interior space.

Below: Munich Airport Roof

Right: An overall perspective of Munich Airport from afar. Very easy to see how massive the scale of the lattice and spans are.

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SHENZHEN INTERNATIONAL AIRPORT Shenzhen International Airport is located in Shenzhen, China and is a minor airport compared to the others throughout China. The most interesting thing about Shenzhen Airport is its repeated use of the popular triangulated truss system. The shape helps to balance the loads that bear down on it to eventually carry the loads down to the ground. Just about all of the skeleton is exposed so onlookers can see first hand what parts make the building stand up. Not many buildings of this span distance are possible without steel. The gigantic room that houses all people who interact in the airport is spread wide open due to the strength of the steel that houses it.

Right: The repetetive column system of the terminal is a great example of the way steel is used in exposed construction.

Below: Shenzhen Airport Terminal

Right: The curved truss system on the interior of the building uses the typical triangulated truss system because of its attractive look and structural strength.

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STANSTED INTERNATIONAL AIRPORT We chose Stansted International Airport because of the unique canopy design Norman Foster utilized to create a roofing system. The four columns that protrude from the ground carry the load from the dome lattice above it. Attached to the pyramid above this section are cables that span outward toward the corners of the canopy itself. This system gives onlookers the idea that the diagonal beams are supported solely by these cables, which actually act to pull the dome in to prevent failure and keep the roofing structure stable. The Jesus Bolt is the name for the connection atop the pyramid where all four cables are attached. A large single bolt straight down the middle holds the welded cable rods in place. It is nicknamed the “Jesus Bolt” because if this bolt is removed from its position, the entire lattice would fail.

Right: Shown is a good example of the scale of the structure, particularly the size of the “Jesus Bolt” that holds the canopy and its pieces together.

Below: Stansted Airport Terminal

Right: A detail of the “Jesus Bolt” from below. As seen, the bolt slices through the peak of the pyramid and holds all four cables in their positions.

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MODELING: STEEL SPORTS COMPLEX SHENZHEN EXTERIOR TRUSS SHENZHEN INTERIOR TRUSS WELDING/SOLDERING STANSTED TREE STUDY STANSTED LATTICE STANSTED JESUS BOLT DETAIL STANSTED TREE DETAIL

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STEEL SPAN STUDY MODEL This is our very first preliminary study model of a simple sports complex. The goal was to learn a bit more about how steel spans and how it is possible. On the actual building, the thick steel beams curve from anchor point to anchor point and create a giant semi-ellipse. The steel that spans perpendicular to these columns gives the structure of the roof the added stability it needs to stay where it is. To build this model, we curved some thin aluminum pipes to take the shape of the complex. Next we used wire to line the inside of the roof, just as in the building itself. These thin strips of steel are used to keep the roof sturdy and maintain its structure. Right: A representation of the 3d sports complex. The goal was to experiment with a steel span and solve how it is able to be structuraly sound.

Right: An image showing how the arch spans over a structure. (In this case the wood block represents the interior space).

Because this was just a shape study, we used hot glue to put the model together. At this point, the way steel connects was not yet important.

Below: 3D Rendered Sports Complex

Right: A close up of the underside of the span. The lattice consists of smaller rods that frame the canopy.

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TRIANGULAR TRUSS SHAPE STUDY MODEL Shenzhen International Airport was one of the first buildings where we found a very interesting system. The triangulated truss is perhaps one of the most popular ways steel buildings are stabilized. Therefore we had a good reason to model some. One of the most interesting parts of the Shenzhen Airport is the huge cantilever that hangs over the road. We felt that this would be the best part to model since we had some great photographs of how it works and it is also a beautiful structure. We put this model together with piano wire, thin aluminum pipes, and hot glue. These are probably the best materials we can use for a simple study model of a steel system. Through this model, we learned why triangulated truss systems are so popular. Right: A front view of a representation of the exterior facade at Shenzhen Airport.

Right: A close up of the underside of the roof truss system.

The two top beams that rest just below the roof carry the load of the roof down to the multiple thin strips just below it. These then carry the load down to the thicker beam, which holds all of the weight at that point. Next, this beam carries the load down to the ground through the diagonal columns located halfway down the beam.

Below: Shenzhen Airport Facade

Right: A close up of hoiw the steel support rods connect to the roof truss.

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TRIANGULAR TRUSS SOLDER STUDY MODEL The goal of this model was to create a truss using solder for the connections and to make it strong enough to span a long distance. This was our first experience with soldering, and it was quite a task at first. The roof is framed by a steel arched truss connected on either side to a load-bearing wall which allows the truss to reach a great span. There are three main steel rods that frame the truss and are connected by smaller rods whos purpose is to transfer loads.

Right: A represenation of a steel truss spanning a distance.

Right: A ground level view of the steel truss span.

While we were making this model, it was very difficult to heat the wire enough to get the solder to melt into the joints we wanted it to. We left the soldering gun plugged in for almost four hours, keeping the trigger pulled just about the entire time hoping it would heat the wire. To our dismay, the soldering iron basically blew up in our hands as we were heating the wire, effectively ending our attempts to get this truss finished using only solder.

Below: Shenzhen Airport Roof Structure

Right: A close up of the soldered connections in the steel truss.

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WELD AND SOLDER STUDIES Because welding is the main connection method in steel construction we decided to learn the process of welding. A stick welder was used to weld lines on a steel plate. The goal was to accomplish a uniform weld across a 3” width. The technique is to move at a slow pace but quick enough that the weld doesn’t burn through the material. We also learned how to weld steel corners. A stick welder with copper wire was used to connect the two plates. The technique is to hold the weld stick on the base for two parts and one part on the top. This leaves a clean transition between the two plates.

Right: A study of the process of welding. A stick weld was used in this example.

Right: A study of connecting two plates by the process of welding. A stick weld was used in this example.

We learned how to solder after buying a soldering iron from Home Depot. We heated the two rods we were hoping to combine, and once they were hot enough, we applied the solder, which melted into the joint. We tried to quickly cool the connection by blowing on it, and once it had a few seconds to sit, the connection was solid.

Below: Stuttgart Airport Terminal

Right: A study of the process of soldering. A soldering iron was used to connect the rods in the truss together.

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STANSTED AIRPORT TREE STUDY MODEL The exterior facade of Stansted Airport in the United Kingdom by architect Norman Foster. The 18m x 18m roof is supported by a steel “tree”. The tree consists of four pillars that are connected horizontally by smaller diameter steel. Four steel rods from all corners extend out and hold the base frame for the roof. The roof is held in tension by four steel cables at all corners which is connected to what is known as the “Jesus Bolt”. This connection holds the roof in compression. If it were to fail, the roof would collapse; thus you would be praying for its survival.

Right: A representation of the “tree” structure.

Right: A compositional image of the “tree” structure next to its origin.

The goal was to experience how the tree is constructed and why each connection is important. Our main focus was to identify how the architect was able to accomplish each connection accurately while maintaining the structural integrity of the building.

Below: Stansted Airport Facade

Right: A close up of the main connections in the “heart” of the tree.

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STANSTED AIRPORT LATTICE SHAPE MODEL The lattice system of the roof at Stansted airport is not as significant structurally as the tree itself. However, Norman Foster clearly found a way to use steel to improve the overall look of the interior areas. The lattice acts as a dome that sits on top of each tree system at the airport. Because of the great strength of steel, Foster only had to use a few very thin strips to keep it structurally sound. The small oculus at the peak of each dome allows natural light to enter the airport freely. This is just another example of how steel can open up possibilities in a building. The pieces on this model were laser cut to ensure accuracy of measurments and scale. The model is a great representation of the way the steel works on the lattice at Stansted.

Right: A represenation of the structure of the roof lattice.

Below: Stansted Airport Interior

Right: A side view of the roof lattice. Notice how the minimal amount of framing allows for a large open interior.

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STANSTED AIRPORT JESUS BOLT DETAIL Stansted Airport is a unique airport in the way it was designed and constructed. Instead of using typical load bearing vertical walls, the tree holds up the roof system. The “Jesus Bolt” is located at the very top of the triangular prism that comes to a point just above the base columns of each tree. It is bolted straight down into this point, and has four cables systems that come out from in that hold up the diagonal columns and the roof. The term “Jesus Bolt” is used in this building because it “saves” the structure. If the bolt is removed from the top of ANY of the tree systems used in the airport, the entire structure will fail. It is the main component that holds the cables in place and preventing the large diagonal columns from plummeting to the ground. The “Jesus Bolt” may be very small, but it is clearly the most important component in the structural stability of Stansted Airport.

Right: A perspective of the “Jesus Bolt.”

Below: “Jesus Bolt” detail

Right: A detail of the top of the “Jesus Bolt” and connections.

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STANSTED: TREE CORNER DETAIL The tree system at Stansted Airport is only successful when all parts of the structure work together to keep the building standing. Behind the Jesus Bolt, the hinged corner is the most important structural element to the building. The cables that come out of the center bolt are meant to pull the long diagonal columns inward. These columns then hold up the lattice of the roof and keep the dome in compression. This model was made operational with a removable bolt and hinged joint to show how important the connections of the trees at Stansted Airport are. The diagonal columns are similar to cantilevers and would not stand the way they do without the cables to pull them in. This is why the operation of each of these gigantic columns is so important to the integrity of the building. The copper pipes were soldered together using a torch, providing a very sound connection. The wood pieces that were laser cut to create accurate hinges were glued to the copper corner using epoxy, which is probably the only way they could be connected. Just as in the actual building, the connection of this hinge to the corner is very important, as the entire structure would collapse due to dependency on all the parts working together.

Right: A top perspective of the corner detail Stansted model. Scale 1/2”:1’

Below: Stansted Tree Perspective

Right: A detail of the corner showing how the model was put together. The solder bonded the copper together and epoxy was used to bond the wood hinge to the copper. Scale 1/2”:1’

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SPECIALTHANKS RESEARCH New Transport Architecture by Will Jones Stansted: Norman Foster and the Architecture of Flight by Kenneth Powell Global Architecture: Transportation by Yukio Futagawa The Modern Terminal by Brian Edwards

IMAGES www.flickr.com www.greatbuildings.com Zach Pauls

PRESENTATION LAYOUTS

“...but architecture is a public art and the quality of our urban design also affects our well-being...”

Justin Kyle Zach Pauls

PROJECT Foster + Partners Zach Pauls

-Architect Norman Foster

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