Some towers are more iconic than canonic. One of them is the Signal Box that lies next to the new railway engine depot in Basel, Switzerland. Designed by Herzog and de Meuron, the six-floor erection is recognized for its beauty and unrivaled uniqueness. The other is the impressive Sears Tower (now Willis Tower). The 1,700 feet building designed by SOM dominates the Chicago skyline, luring tourists in a daze. While the two towers are magnificent marvels of construction, they harbor more differences than they do similarities.
The Signal Box is an imposing megalith fashioned out of concrete. It has an open indeterminate scale that allows it to take up a specific relation with the adjacent railway tracks. The exterior cladding is made of 20 cm strips of copper twisted at several places to let in daylight (Jarre 16). These copper strips act as a faraday cage for safeguarding the equipment within.The building incorporates a rare set of materials unseen in other buildings. It uses copper, plywood, timber, mud, iron, glass, polycarbonate, and stone among others.
In contrast, the scale of the Sears tower is more discernible. The 110-floor structure is made out of a revolutionary technology of tubular configuration (Ali and Moon 213). The structural steel frame is a series of nine bundled structural tubes that rest on caissons made of reinforced concrete that go down to the bedrock. These caissons are held together using a strengthened concrete mat. While the Signal Box copper protects the equipment within from destruction, the vertical steel tubes of the Sears tower provide rigidity that limits the vertical sway from wind forces. The basic structure is structural steel made in prefabricated modules. Each 7.6*4.6 m module consists of a steel column and a girder welded on each side in the middle. The floor slabs are made of reinforced steel and are supported by 1m deep rolling trusses bolted to the columns. The steel was prefabricated offsite and then bolted in place on the site.
While the Sears Tower is remarkable in its construction, the Signal Box is outstanding in its façade. Herzog and de Meuron designed a façade that is chiefly homogenous and unornamented. The face consists of vertical bands of rust-colored metal brackets that project the narrow horizontal metal siding at an angle, presenting a perceived parabolic shadow that blends seamlessly with the surrounding tracks. The subtle twist of the metal siding allows for some degree of visibility of the windows behind while also letting in natural light into the offices. The skin is otherwise unbroken except in the lounge area where there is a ribbon window.
Where the Signal Box employs one material for the skin, the Sears tower exploits two. The Tower has a black anodized aluminum peripheral and 16,000 single-pane windows that are bronze-tinted. These enormous windows maximize the view and natural light coming in proliferated by the slant of the modules (Kolarevic 96). From the outside, one can discern some black horizontal bands which are the trussed levels of the building. The bronze-tinted glass and black aluminum serve to reduce reflections as well as acting as insulation between the outer and inner structure (Tower 1). This assures a constant temperature that minimizes the expansion and contraction of the frame.
In conclusion, the two towers are dissimilar in many ways, from proportion, to use, to construction material. Each tower, however, is revolutionary in design and construction and provides a benchmark on which future architects can base their work and borrow from. Both towers have received numerous awards and will continue doing so for the foreseeable future.
Ali, Mir M and Kyoung Sun Moon. “Structural Developments in Tall Buildings: Current Trends and Future Prospects.” Architectural Science Review 50.3 (2007): 205-223. Document.
Jarre, Nils. “Mimoa- Herzog & de Meuron.” Mimoa Guide (2013): 1-52. Document.
Kolarevic, Branko. “Manufacturing Surface Effects.” Acadia (2006): 94-103. Document.
Tower, Sears. Sears Tower. 2015. Document. 23 October 2015.