Searching for Daylight in a Diagonal Urban Grid. A Commercial Office Building in San Francisco Financial District focusing on Daylighting and Structure


Zahra Hosseinabadi
North Carolina State University


Jeffrey Wayne Place
North Carolina State University


This winning project is a well-researched design for a high-rise, a fitting typology to celebrate and investigate steel construction. The project is believable and presented with rigorous analysis, achieving a high level of design and technical development. Particularly, the exploration of daylighting strategies, such as the light shelf, is interesting and enhanced spatial qualities. The drawings begin to illustrate how the building might be constructed, and the initiative to consult with a structural engineer noticeably added to the success of the project. 


A Commercial Office Building in San Francisco Financial District focusing on Daylighting and Structure   

Light, vegetation, and human scale are three profoundly important criteria for creating more humane tall buildings.  These issues were strongly emphasized in this design project.  Technology is also an inevitable aspect of design for tall buildings and it was strongly addressed in this design process.

Designing for our future cities, architects must strive to integrate fast-emerging design tools into their design process to more successfully integrate technical and human concerns.  Evidence-based design solutions should shape the foundation of our design thinking in order to have sustainable architecture.

This project involved a design process that went back and forth between key design issues, such as daylighting, structure, circulation, and energy efficiency measures.  Based on this process, the San Francisco tower is a 40-story building that uses the VALRAy Daylight Projection System installed in the façade in order to maximize the sunlight for stories of 10-40. The lower 10 floor don’t have VALRAy, because they are not getting enough beam sunlight to make it worthwhile.  The structural geometry was designed to not be a barrier for sunlight and to accommodate an open south corner for communal sunspaces.  The VALRAy Daylight Projection System and structural elements complement each other in the façade.

The city grid is oriented in such a manner that the corners of the building are N, S, E, and W.  The south corner is special, because of the following factors:

  • Solar movement provides bright sunlight from the southern sky during the wintertime.
  • The urban context provides the best solar exposure at the south corner.
  • The south corner of the building is at the intersection of the two adjacent roads, which provides a good place for the building main entrance, which has been inset from the corner to provide extra walking space to accommodate the dense pedestrian traffic at the corner.
  • The south corner is the ideal location for communal sunspaces providing view of vegetation for the building occupants.

The floor plans are organized symmetrically about the North-South diagonal of the square floor plan, thereby honoring the solar symmetry and the symmetry of the adjacent streets.

The floor is a 12”-deep, flat slab made of light-weight concrete and having voids filled with recycled plastic (as per invention by Skidmore Owings and Merrill) to reduce the cost of concrete and the weight of the slab.

The shallow floor slab allows the economy of a low floor-to-floor dimension and, at the same time, a high floor-to-ceiling dimension for enhanced daylighting and light airy spaces.

The access floor system accommodates efficient and comfortable distribution of conditioned air and distribution of electrical and electronic utilities to all spaces.

Evidence-based design was supported using the following software design tools:  Climate consultant, Ecotect, and Multiframe were used for daylighting and structure analysis.