It follows the "Manifesto" for this competition:

Architecture cannot longer wait for an unlikely political will to respond to the planetary emergencies of overpopulation, pollution, and global warming.  Buildings cannot longer ignore their orientation to the sun path, or their local weathering patterns, and they cannot longer be passive consumers of energy and water, and be waste factories.  Acknowledging the failure of globalization (which creates more pollution, social inequality, and unsustainable supply chains) architects and building designers must now help implement localization, while creating self sustainable structures.
This does not describe a building-island concept (able to subsist within wastly different contexts while ignoring them); rather the idea is of a living cell, able to interact with its context along much of its envelope (membrane) rather than just the point of contact with the topography.  Drone techology will allow the CityScraper to interact with its immediate urban context at unprecedented levels.

However, buildings of the 21st. Century also must:

• Use recycled construction materials (steel, concrete, plastics, glass, etc.).
• Leverage all energy producing technologies, including solar, wind, and hydro-power from water pressure reducing valves and gravity black and gray water drain systems.
• Reduce their HVAC systems as much as possible, using strategies such as natural ventilation, solar exposure, efficient elevators, heat pumps, thermal masses, etc.
• Maximize rain and storm water collection, recycle and reuse in site, and include a black water treatment plant.
• Maximize waste recycling in site, using wood and metal shops in order to re-process and re-purpose the recycled materials.
• Maximize plastic recycling, no matter the cost.
• Reach a sustainable urban density (much lower than downtown distrcits, but much higher than urban sprawl).
• Provide for a low cost mixed use of residential, commercial, industrial, and agricultural programs.
• Maximize food production in site (mostly agricultural produces, but it is also feasible a small component of animal farming).
• Leverage 3D printing technologies to be able to produce tools and parts, locally.
• Leverage drone technology to provide fast and secure transportations of goods and people to and from the surrounding urban context.
• Leverage Building Automation Systems (BAS) by sharing (big) data across the region in order to adjust the building energy use in real time (using atmospheric data, occupancy load and types, date and time, etc.).

1. Shape: the proposed building form is created by wind flow and solar exposure.  The typical floor plate behaves like a symmetric airfoil oriented West to East. A quick air flow study shows that the prevailing West-East winds of South of Market create two areas of high speed flows, approximately at the widest point of the building.  There, small wind generators capture the faster wind motion. The airfoil then gently converges toward the East “trailing” edge, where a zone of very low speeds is created. In this area are located the building drone docks, sort of “air garages” from which airborne vehicles can safely take off.  The South facade uses PV Glass as the main curtain panel, for energy production. Toward the West, the space frame creates a gap which allows air to infiltrate the skin of the building, thus creating natural ventilation behind the southern facade.  Both PV Glass on the South and the curtain wall on the north are designed with the glass panels as flush to the frames as possible, in order to provide for a smooth surface for optimal wind flow.
2. Site: the San Francisco South of Market district still maintains its low rise industrial nature.  At the proper distance, the proposed CityScrapers can receive the wind and solar exposure they require to optimize energy production, while increasing density to a sustainable level without the overshadowing of the downtown district.  Also, safety for airborne vehicles routes require more clearances than normally available in downtown areas.
3. Structure: because point load supports (columns) and lateral bracing have overlapping roles (namely, they can both support vertical loads), vertical columns can be rendered obsolete. The proposed building uses two different structural exoskeletons, which are able to provide lateral support: to the South, a space frame onto which the PV glass are installed also supports the edge of slabs, while providing shear resistance; to the North, a recycle corten-steel frame also supports the edge of slabs while providing shear resistance.  Interior columns are angled to provide some degree of lateral support (if required); the core walls can thus be thinner since they have no shear resistive role.
4. Program: the proposed CityScrape hosts a mixed of residential, office, industrial, and agricultural programs.
5. Urban Context: the proposed CityScrape is connected to the city via airborne electric vehicles which make only a few minutes long trips to most of the city destinations, possible today with no additional advances in battery technology.  Also, the building is open to the public, and its ability to grow produce makes it a market place (beside a residential hub, and a work place).  Excess of food production can be redistributed to the adjacent neighborhood, also using short-distance micro supply chains.
6. Life Cycle: because of the speed at which technology advances, the building should be designed using an open, modular concept which allows it to be easily upgraded with the latest technologies in solar energy harvesting, wind generation, data gathering, gray and black water recycling, and more.  In other words, no system should be implemented today which cannot be easily upgraded tomorrow, since, in general, architecture greately outlives technology.

These are studies for the suspended steel staircase construction and design, at the South-East glazed corner of the building:

The following animation was produced using a Dynamo script which I created in order to animate Revit section boxes.  The animations were used to analyze the model and identify trouble areas and clashes throughout the model.