Archive for the 'Metals' Category

23
Jun
08

Frank Lloyd Wright’s Price Tower

three views Price Tower

In The Atlantic, Wayne Curtis explores an Oklahoma landmark, the Price Tower. Way back in 1952, a pipeline entrepreneur named Harold Price asked for a three-story, three-quarter-million dollar building and ended up with a 19-story building that came in at over two million. Finished in 1956, it was, says Curtis,

…easily one of the more bizarre towers ever built. Wright, who is best known for his low Prairie-style buildings, had a complicated relationship with tall buildings, calling one an “incongruous mantrap of monstrous dimensions.” Yet late in life he created drawings for a 528-story skyscraper featuring atomic-powered elevators with five cabs strung vertically in each shaft. (It was never built.)

Despite his aversion to height, it was Wright who talked the businessman into the 19 floors, although it doesn’t seem to have been a difficult selling job. Price’s son later joked that the Price Tower was basically 18 floors that existed to hold up his father’s office on the penthouse level. It stands today as the tallest example of Wright’s architectural accomplishments. Apparently there had been plans for a number of New York City high-rises on Wright’s drawing board, back in the 1920s, but none were ever built.

After passing through other hands, the Price Tower eventually became the property of an arts center, which remodeled part of it into a hotel in order to support the more culturally relevant sections. More recently, the owners had a new arts center designed by world-class architect Zaha Hadid, but funding problems have kept the actual construction of it on hold.

Upon personal inspection, the author found the tower to be interesting from the outside, not quite looking like the same building when seen from different viewpoints. The interior is replete with many triangular features, and being inside it definitely gives the observer a different feel than any experienced in more conventional, rectangle-based structures. The author calls it a space “almost perfectly scaled for human occupation,” thought it did start out with a couple of problems, like leaky windows, which had to be dealt with. Curtis quotes Wright on the virtues of the triangle, then remarks, “This statement, like much of the architect’s writing, recedes further from comprehension the longer one considers it.”

This building is characterized by a lavish use of copper inside and out.
In Architectural Graphic Standards, 11th Edition, the chapter on metals discusses copper, along with its alloys bronze and brass, as having such properties as conductivity, resistance to corrosion, and malleability, so it’s available pre-formed into all kinds of shapes. The advantages are offset by a not very good strength-to-weight ratio.

The inspiration for the basic structure of the Price Tower was arboreal. Wright was neither the first nor the last architect to take the tree as an exemplar. He designed the “trunk” as the sturdy service core and cantilevered the reinforced concrete floors off it. Without the need for weight-bearing columns around the periphery, the architect was free to treat the shell as an almost purely decorative element. Like a tree’s leaves, the copper fins protect the interior from direct sunlight, and the myriad textures that result from the various external ornaments make a very eye-pleasing arrangement.

While visiting the building in order to write about it, Curtis waited out a rainstorm inside and fancied that it felt like being in a safe, snug treehouse. Unlikely as it might seem, Bartlesville, near Tulsa, is also the home of structures designed by other noted architectural firms, such as John Duncan Forsyth, Bruce Goff, Welton Becket, Edward Buehler Delk, Clifford May, and HOK. So, whether it’s regarded as radically innovative or simply bizarre, the Price Tower is in good company.

SOURCE: ” Little Skyscraper on the Prarie ” July 2008
photo courtesy of ercwttmn , used under this Creative Commons license

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11
Jun
08

Bird’s Nest, Water Cube, and More in Beijing

Olympic Stadium, Beijing

In only two short months, the Beijing Olympics will take place, and a very interesting article by Paul Goldberger in The New Yorker gives us a tour of some of the major structures created for the event. He begins by reflecting on the architectural layout of the whole city in relation to the 2,800-acre Olympic Green. Back in 2002, 96 architects competed for the honor of mapping out the master plan. Sasaki Associates of Boston became the decider, and Goldberger explains the significance of the placement of the National Stadium and the National Aquatic Center. Here’s how the author describes the National Stadium (pictured):

The concrete wall of the arena is wrapped with a latticework exterior of crisscrossing columns and beams, a tangle of twisting steel twigs. The lattice arcs upward and inward over the stadium’s seats, supporting a translucent roof and forming an oculus around the track. The building may look like a huge steel sculpture, but most of the beams are structural, not decorative…. The outer wall of the concrete structure is painted bright red…and when lit up at night it shines through the latticework, an enormous red egg glowing inside its nest.

It’s not difficult to see why the enormous building is informally called the Bird’s Nest. It was designed by two Swiss architects, Jacques Herzog and Pierre de Meuron, and built by a crew that totaled as many as 9,000 workers at a time. For the Olympics, the stadium will seat 91,000 guests. Afterward, many tiers of seats will be removed and the capacity brought down to 80,000 for the remainder of the building’s life as China’s national stadium.

Just as startlingly original, in a different way, is the appearance of the National Aquatics Center, or Water Cube, designed by PTW Architects, an Australian firm. The bubbly exterior is a cladding formed from cells of a plastic called ethylene tetrafluoroethylene. Goldberger explains the wonders of ETFE, as the substance is familiarly known. It transmits light better than glass and only weighs 1/100th as much as glass, plus it has better insulating properties than glass. This remarkable exterior treatment was developed with the help of Arup, an engineering firm. For the Olympics, the Water Cube will seat 17,000, but when the games are over, nearly 2/3rds of the upper tiers will be removed and multipurpose rooms will take their place.

Goldberger lyrically describes the surreal experience of being inside the Water Cube, and speculates on the motives behind the Chinese bringing in international architects for the most prominent structures. There are 31 structures in all, and most of the ones designed by native architects are not particularly noteworthy, except for Digital Beijing, the control center, whose four slicey sections remind some observers of the internal parts of a computer. Its designer, Pei Zhu, received his education at the University of California.

Goldberger also takes a retrospective look at previous Olympic venues in cities around the world, explaining why they were the way they were. In recent decades there has been a strong tendency for the host cities to use the Olympics as a catalyst for extensive urban renewal, going far beyond the requirements of the games themselves. Barcelona redeveloped its entire waterfront. London is gearing up in a big way for 2012, with a $19 billion plan for the East End, which has traditionally been the low-rent part of town.

Many people are not sure what to make of Beijing’s Olympic preparations. The subway system has been upgraded and extended, and there’s plenty of cosmetic touching-up, with trees planted and roadways tidied, but there is a feeling in some quarters that it’s largely an optical illusion, composed of more façade than substance – as Goldberger puts it, “driven by image, not by sensitive urban planning.” His question, and one worth asking, is, “Beijing’s Olympic architecture is spectacular, but what message does it send?”

SOURCE: ” Out of the Blocks ” 06/02/08
photo courtesy of borkur.net , used under this Creative Commons license

16
May
08

The Cladding of Porter House, New York City

Porter House

In Manhattan’s meatpacking district, an existing warehouse needed an extra 15,000 square feet for a housing addition. The job was done by Sharples Holden Pasquarelli (SHoP) who, as described in the Computing Technologies section of Architectural Graphic Standards, 11th Edition came up with a “custom-designed, laser-etched zinc metal wall panel cladding system…The condominium’s zinc rainscreen emerges from a family of 15 profile types, from which there are 150 versions of profiles, yielding 4000 total panels.”

The variations were achieved by cutting and bending each profile type of panel differently. After four initial drawings, the rest of the communication between SHoP and the fabricators was carried out electronically.

This case study is presented in order to explore the use of software by SHoP in design, construction, and fabrication. It entailed a lot of originality, all of it concentrated in the few-inches-deep cladding system, with the other parts of the project achieved more conventionally. Part of the reason for this concentration on the outer layer was to astonish the eye, because making a visual impact was a priority. The creators were going for an ambiance of complexity and randomness, to fit in with the existing environment. This aim was also achieved by offset from the underlying warehouse. The addition looks like it grew there.

The use of building information modeling achieved huge gains in fabrication and installation time, accuracy in the production of the varying panel elements, and efficiency of material use. The builders were able to get the most bang for the buck out of standard zinc sheets of 39″ by 118″, by careful planning of how the various sized pieces would be obtained, cutting waste to the bone. They started with several basic shapes: flat panel, bent sill panel, window panel, light box panel, and more.

To deal with the numerous idiosyncratic factors that needed to be taken into consideration, ShoP used the 3D NURBS program Rhinoceros, which told them what shape to make each piece in order to meet the technical requirements of a rainscreen. Enthusiasts describe Rhino as very simple and powerful, able to do all levels of design for any discipline, and blessed with a high degree of interoperability. The program is said to be especially popular in Europe.

Rhino describes itself as having the capability to do uninhibited free-form 3-D modeling with extreme precision. It can create, edit, analyze, document, render, animate and translate NURBS curves, surfaces and solids, handle polygon meshes and point clouds, and support a wide variety of 3-D digitizing arms, 3-D scanners, and 3-D printers. It can handle large projects, and has the additional advantages of relative ease in learning and relative affordability. It can, in short, do everything but sing lullabies to the kids in a finished building’s daycare center.

After Rhino had done its bit for ShoP and the Porter House, everything was transferred to a program called Solidworks to fine-tune the 150 different panel shapes. For a short description of Solidworks, we turn to Architectural Graphic Standards, 11th Edition, which says on page 937:

Solidworks is most commonly used by mechanical engineers, industrial engineers, and product designers. By building “solid models” of objects (as opposed to surface models), engineers can perform finite material and structural analyses on objects, as well as communicate more seamlessly with CAM equipment, which often operates on proprietary software that more easily reads solid models.

Please feel free to share experiences other projects have had with Rhinoceros and Solidworks.

SOURCE: ” Computing Technologies ” 2007
photo courtesy of b.frahm , used under this Creative Commons license

07
Apr
08

AGS Case Study: Restoring 215 Fremont Street, San Francisco, California

215 Fremont San Francisco

The venerable L-shaped industrial building had been around since 1927, and had suffered badly in the 1989 Loma Prieta earthquake, and then stood empty for a decade. Its rebirth is described in “Renovated Office Building at 215 Fremont Street, San Francisco California,” one of the case studies detailed in Architectural Graphic Standards, 11th Edition, from the American Institute of Architects, published by WILEY. The piece was written by four of the participants: James Kellogg, AIA, HOK; Lynn Filar, HOK; and Navinchandra R. Amin, SE and Vivian L. K. Wan, PE, both of Middlebrook + Louie.

The team that took on the revival of 215 Fremont faced real challenges. A large part of the project consisted of figuring out just what they were dealing with, hindered by the fact that many of the original drawings were either missing or indecipherable. When the nitty-gritty evaluation phase started, some unpleasant facts turned up. For example:

Since the original construction, the building had experienced differential settlements of up to 5 inches. Core samples and dynamic load tests of the existing floor slabs provided data necessary to evaluate the viability of components of the existing structure…

A large part of the evaluation process consisted of cranking up ETABS and SAP 2000, respected CAD programs that together gave a picture of how nicely the building would work and play with gravity and seismic loading. The prognosis wasn’t good. For starters, an earthquake would turn the ground beneath 215 Fremont into soup. How would they get this thing to stay up? Equally important was the need to satisfy ever-evolving building codes. We’ll let them tell it:

A new structural system needed to be developed for the project that would be sufficiently stiff to alleviate the induced internal forces in the existing floor slabs and punched exterior walls. Additionally, the structural system needed to use the full length and width of the structure to minimize the seismic overturning forces applied to the foundation…

As often happens, necessity gave birth to invention, and an elegant, innovative solution was arrived at.

This retrofit of an early twentieth century building led to the creation of a unique connection between steel braces and concrete columns, as a combination structural system comprised of steel-brace, frame-and-concrete shear walls was developed to meet all critical requirements.

The article explains exactly, and in great detail, how the team did it. And that’s not all. Every bit of 215 Fremont was remade into a paragon of sustainability and a fully compliant respecter of seismic requirements. What had once been basement storage space was now a much-needed parking facility. From bottom to top, from the new pedestrian-friendly retail arcade to the attractive rooftop terraces, the whole edifice was transformed. Impressed, the Structural Engineers Association of California gave the building its coveted Excellence in Structural Engineering Award.

215 Fremont, later also known as the Charles Schwab building and the Emporis building, was a showpiece as its neighborhood morphed into the happening “multimedia gulch.” When the project was finished in early 2001, a major corporation immediately occupied the entire building. The renovators had successfully made a statement: the cultural tone of the whole area had been elevated.

But any project of this kind also raises disturbing questions about the ultimate futility, in the event of catastrophic emergency, of even the strictest building codes.

SOURCE: “Renovated Office Building at 215 Fremont Street, San Francisco California” 2007
Photo courtesy of WILEY by Michael O’Callahan