Ill South Wacker

Chicago, USA
2005

Goettsch Partners
www. gpchicago. com

On the corner of Michigan Avenue and Wacker Drive, a bronze marker in the pavement locates the spot where the U. S. Government built Fort Dearborn in 1795.

The Fort’s location, at the mouth of the Chicago river on the south western shore of Lake Michigan, made it ideally suited as a trading post during the nation’s expansion from east to west.

This early hub was the forerunner of modern Chicago which still routes approximately 50% of the countries rail freight through the city. Chicago’s growth from an 18th century trading post to a 21st century city of skyscrapers has been punctuated by many challenges and innovations. In 1871, the Great Fire burned most of Chicago’s timber structures to the ground, however, the city was quickly and tenaciously re-built. During this process the U. S.A.’s first skyscraper, the ten

storey steel framed Home Insurance Building was erected in 1885.

Ill South Wacker’s 53 storey structure (Fig. 1) is now a part of this pioneering tradition. Developers, The John Buck Company and the architects Goettsch and Partners (who had previously collaborated on the nearby UBS Tower) designed 111 with sustainability and LEED certification as their primary goals.

The resultant building totals 1,457,000 square feet distributed over 53 storeys of flexible, efficient office space with each floor plate being entirely free of interior columns. The building’s central core (Fig. 1) provides the means to fully span 50 feet to east and west and 60 feet to north and south (Fig. 3).

88 111 South Wacker | Chicago | USA | Fig. 1 above | Fig. 2 opposite

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The street level base of the building presents a stunning, seamless transition from the external plaza to the internal lobby (Fig. 2). The lobby is enclosed by a non-reflective cylindrical glass wall retained by one inch diameter vertical cables.(Fig. 6, Fig. 9)

The public facade of the central core is textured and faced in marble. The core is encircled by a spiralling vehicle ramp which facilitates access to the upper garage levels. A stepped, illuminated ceiling covers the underside of the ramp, rising to the soffit level at 44 feet above the plaza. The radiating pattern of the ceiling is reflected below in the marble lobby flooring. It continues outside the glass wall in the granite sett external plaza, up to the edge of the road kerbs.

This design feature and the ultra-transparent glazed facade, blurs the boundary between interior and exterior, creating the illusion of an uninterrupted single continuous space.(Fig. 11). The lobby also houses a restaurant and shop area (Fig. 4). Above the lobby, seven levels of parking

provide space for 389 cars for both public and tenant use (Fig. 7).

Other facilities include a double height conference centre at the mid-elevation of the building and a fitness centre on the 10th floor. Wacker Drive provides access to the building’s loading docks and additional levels of parking.

Multiple telecom risers, plant rooms and customised emergency power provision are all designed to attract discerning tenants to this state of the art building. Ill South Wacker also boasts direct elevator access for mid and high – rise occupiers (Fig. 4).

Ill South Wacker | Chicago | USA | Fig. 7 above left | Fig. 8 above right 93

Ill South Wacker was the first project to attain the LEED Gold certification for a building core and shell. To achieve this, the construction process was required to minimise both energy consumption and material usage.

The primary strategy was to enable the structure to re-use the existing caissons and foundation walls which had remained on the site.

Additionally, both high performance glazing and insulation were incorporated into the design of the building envelope (Fig. 9, Fig. 10). This was then capped by a high-tech, green roof.

Internally, the Heating, Ventilation and Air Conditioning (HVAC) plant employs low temperature air distribution incorporating automatic dehumidification when required. The system reduces duct and shaft sizes by 10%, increasing valuable net lettable areas. The HVAC and lighting systems are digitally controlled to increase comfort and minimise power consumption.

The selection of non-feature materials focused on products with a high recycled content. All of these initiative contributed to the high level LEED certification.