Introduction

The Chicago Spire, originally designed to be an icon for the city by Santiago Calatrava, has been nothing but a mere hole adjacent to Lake Shore Drive since the 2008 recession. Since its first proposal’s cancellation, numerous concepts have been envisioned and shot down due to a variety of factors. Set in the year 2029, this proposal aims to conceptualize how the building can serve as an icon different from all other previous designs: one that expresses a more sustainable future for the city, and more specifically, for the office building skyscraper typology. Through unique spatial organizations responding to local data and passive and active sustainable strategies, this proposal rewrites the definition of the modern day skyscraper.

 

The driving concept for the building comes directly from data regarding the urban landscape of Chicago and the office skyscraper typology itself. 13.3% of all office buildings in the Chicagoland area are left vacant, and many of them being skyscrapers, produce two times the carbon emissions as low rise office buildings. Thus, the building applies this vacancy to its mass, providing vertical farming, light shafts, and promote programmatic overlap to fill its gaps. Given that Chicago has been ranked within the top ten food deserts in the United States, the contrasting vertical farming was chosen to provide the area with fresh produce. 

 

Community Engagement

By using the previously poured building foundation for the original spire, the project’s building footprint only occupies 13% of the overall 80 by 130 meter site. By only taking this small amount of the overall development, the building lends the rest of its site as an extension of the adjacent DuSable park. As a result, the leftover area is given a public program for community engagement. Also, the first eight floors of the building features a vertical farming market where crops grown within the building can be sold to the public. With a mass distinguished from the rest of the building and a continuous spiral ramp connecting the entirety of the market, both the site and the first eight floors are a publicly engaging spectacle.

​

Optimized Massing

To ensure the building mass was optimized to its full potential, the building underwent a rigorous massing process. Given the site possesses high wind loads coming off of the adjacent Lake Michigan, the original twisting building form was chosen to break up such stresses. After the overall twist motif was decided, different floor plate profiles and degree rotations were tested using Ladybug to choose which form offered the most daylight exposure for vertical farming purposes, while balancing Winter and Summer heat gain. Finally, the ninety degree twisting triangular tower mass was subtracted to create a double envelope, a differentiated ground mass for community engagement, air intake gaps, and interior light shafts.

​

Environmental Consciousness

Regarding the site’s environmental sustainability, the site features only 46% impervious surfaces. By filling the site with penetrable greenscape, the proposal sets an example for the city of Chicago as a project that combats the issues of water management and flooding that are currently present in the city’s urban landscape. Also a contributing factor to the design of the site, the proposed area is one of the last major vacant lots east of Michigan Avenue. By providing a large amount of green landscape, this project creates a public stopping point between Millennium Park and Navy Pier. As a result, the development completes one of the last pieces of the puzzle that is Chicago’s green strip of parks that line the shore of Lake Michigan.

​

Programmatic Overlap 

As a main driving concept for the interior design of the building, the project focuses on the idea of programmatic overlap.With light shafts, communal sky lobbies, research areas, mechanical intake floors, and a central ancillary activity mass, the interior’s monumentality is divided to create a dynamic working environment for its users. Featured in the axonometric drawings are examples of a few primary typologies and layouts in which lease holders could potentially organize their space. Given the statistic featured previously, the 13% vacant area found in the Chicagoland office building is applied directly to the building mass to feature and array of possible programs that could occupy its interior spaces.  

​

Light as Subtraction

Another main concept found at the building scale revolves around the method of using light as subtraction. Using Ladybug light tracing and sun diagram techniques to trim out volumes within the building mass, the project has four main light shafts to penetrate light deep into its interior. Where gaps between same level floors are found, circulation bridges connect the gaps. Each light shaft is calibrated to a given equinox or solstice of the year to ensure direct sunlight in some portion of the building, regardless of the season. With vertical farming enveloping most of the building’s south, west and east facades to diffuse this solar exposure, the lighting quality is natural, yet intended to minimize issues of glare from direct exposure.

 

Interaction between Floors

As an inherent quality in the design of the light shafts featured previously, these negative spaces provide visual connection between programs and promote interaction and invitation. To challenge the common horizontal disconnection between floors found in the contemporary skyscraper, the light shafts also feature communicating staircases to connect each floor to the one below and above. In doing so, the communicating stairs re-emphasize the main interior concept of programmatic overlap mentioned earlier. Finally, the reduction of such floor plates through the resulting light shafts also help to communicate the overall twisting motif to the building’s interior, giving its occupants the opportunity to recognize its dynamism.

​

Systems Integration

Extending the environmental consciousness and technological innovation of the proposal to the smallest detail, the building also features an array of measures to promote system efficiency and passive solar and wind design. Composed of a diagrid system, the building uses much less steel than that of the standard beam, column, and purlin assembly. Also, the floor plate on each floor is offset half a meter from the outermost envelope, allowing for hot air to rise through the double envelope. Using this stack effect to its advantage, updraft turbines are used to both accelerate this process and produce a clean form of electricity for the building. Growing lights are also used in vertical farming program areas to maximize yield size and output.

​

Breathable Envelope 

In order to make vertical farming viable in a double skin system, multiple aspects of the envelope design ensure that the skin can ventilate and insulate properly in the fluctuating Chicago climate. In the winter months, heat gain in the outer skin can provide warm air to the mixed program interiors through inlet awning panels integrated into the inner envelope. In the summer months, cool air from the interior spaces can be exhausted through the same awning panels. To also assist in ventilating vertical farming zones of the building in the summer, the top of each enclosure has an operable roofing system to allow naturally rising hot air to escape the building, further helping to regulate the interior temperatures of all areas. 

​

Iconic Expression

Being that this project is located in close proximity to Navy pier, along Lake Shore Drive where much of the public walks between tourist attractions, at what many Chicagoans call ‘the Gateway into Chicago’ as well and in the front line of the Chicago skyline, it is only essential that the building must serve as an sustainably iconic expression for the future of Chicago. To serve as such, the building uses an array of methods to express its qualities to its surroundings. Ultimately through its twisting triangular profile, expression of vertical farming and office building programs, diagrid system and double skin assembly, the proposal is a symbol for the future of a more sustainable vision of Chicago. This is the Chicago Spire 2029.