100 Mount Street

100 Mount Street
100 Mount
100 Mount Street

Making a distinctive addition to Sydney's growing north side business district, this office tower features an innovative cross-braced structure that is efficiently engineered to minimize the carbon impact of construction.

Project Facts
  • Status Construction Complete
  • Completion Year 2019
  • Design Finish Year 2012
  • Size Building Height: 147 meters Number of Stories: 34 Building Gross Area: 52,160 square meters
  • Rentable Area 40,893.00 sq m
  • Awards
    2020, Building, Design + Construction Building Team Awards, Building Design + Construction 2019, Architectural Design / Tall Buildings, Architecture MasterPrize 2019, Structural Innovation Award, Council on Tall Buildings and Urban Habitat (CTBUH) 2021, Award of Excellence – Structural Systems Design | AEI PPA, American Society of Civil Engineers (ASCE) – Architectural Engineering Institute (AEI) 2021, Best Overall Project Over $100 Million, American Society of Civil Engineers (ASCE) – Architectural Engineering Institute (AEI) 2020, Innovation Award, Council on Tall Buildings and Urban Habitat (CTBUH) 2020, SEAOI Best Project over $150 Million, SEAOI
  • Collaborators
    Architectus Enstruct Arup
Project Facts
  • Status Construction Complete
  • Completion Year 2019
  • Design Finish Year 2012
  • Size Building Height: 147 meters Number of Stories: 34 Building Gross Area: 52,160 square meters
  • Rentable Area 40,893.00 sq m
  • Awards
    2020, Building, Design + Construction Building Team Awards, Building Design + Construction 2019, Architectural Design / Tall Buildings, Architecture MasterPrize 2019, Structural Innovation Award, Council on Tall Buildings and Urban Habitat (CTBUH) 2021, Award of Excellence – Structural Systems Design | AEI PPA, American Society of Civil Engineers (ASCE) – Architectural Engineering Institute (AEI) 2021, Best Overall Project Over $100 Million, American Society of Civil Engineers (ASCE) – Architectural Engineering Institute (AEI) 2020, Innovation Award, Council on Tall Buildings and Urban Habitat (CTBUH) 2020, SEAOI Best Project over $150 Million, SEAOI
  • Collaborators
    Architectus Enstruct Arup

A landmark for Sydney’s business district

The design for 100 Mount Street is inspired by Sydney’s rich architectural landscape and shaped by SOM’s legacy of innovation in architecture and structural engineering. The 35-story office tower offers panoramic views of Sydney Harbor, the Sydney Opera House, and Sydney Harbor Bridge, while creating welcoming new public spaces and amenities at its base.

At ground level, the building’s offset core allows for a series of highly flexible, open-concept spaces, including a commercial lobby, café, and restaurant. These areas are sheltered from the elements by a nine-meter-tall glass wall. From the landscaped public plaza, with cascading steps and inclined pathways, visitors can access new shops and cafes at the lower street level, while a pedestrian route bisects the site to connect the building to nearby public transit.

100 Mount Street
The building incorporates public spaces and amenities at its base. © Brett Boardman Photography
100 Mount Street
A series of canopies and a 9-metre wall of glass identify the main entrance to the building. © Brett Boardman
100 Mount Street
100 Mount Street Lobby © Brett Boardman Photography
100 Mount Street
A café, and restaurant currently occupy the flexible open-concept spaces at ground level. © Brett Boardman Photography

The tower’s interiors are designed to maximize daylight and open space, with 6-meter column-free zones to the north and south. Together, the offset core and high-performance closed cavity facade allow for automatic daylight control and reduce glare, while maintaining maximum transparency.

100 Mount Street
Panoramic views of Sydney Harbor, the Sydney Opera House, and Sydney Harbor Bridge. © Brett Boardman Photography

Engineered for efficiency and elegance

The tower’s highly efficient structural system and exposed mega-bracing are designed to manage the building’s torsional response, while minimizing the size, cost, and carbon footprint of the bracing system. This design helped to reduce steel quantities by 10 percent for lateral loads, while also lessening the impact of vertical creep and shrinkage stresses. SOM’s structural engineers developed the innovative cross-braced exoskeleton structure by using topology optimization algorithms and classic structural analysis.

100 Mount Street
The optimal geometry of the bracing was the result of years of in-house SOM research. © SOM
100 Mount Street
The bracing geometry is derived from discrete typology optimization. © SOM
100 Mount Street
Concealed sliding central node details. Innovations discovered for 100 Mount Street are expected to influence the industry and lead to a new generation of composite concrete and steel megabraced tall buildings. © SOM

The tower features highly transparent glazing, subtly articulated by exposed structural elements. The elegantly proportioned bracing on the east facade gives the tower a distinctive identity on the North Sydney skyline.


Taking sustainability to greater heights

100 Mount Street reflects a commitment to sustainability that exceeds typical office buildings; it considers total life-cycle impact, in addition to targeting environmental ratings in design and operation. A range of strategies and systems, including chilled beam systems and motorized Venetian blinds, reduce the building’s environmental footprint. The office layout also prioritizes natural light, allowing for open and light-filled spaces. The project is targeting 5-star ratings on the Australian Green Star and National Australian Built Environment Rating Systems.

100 Mount is an embodiment of Sydney’s spirit of architectural innovation. SOM is proud to have continued this legacy, marrying it with our own history of innovation in skyscraper design worldwide.

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