Council on Tall Buildings and Urban Habitat
 

Blue Cross-Blue Shield Tower, Chicago
Posted August 2012
Blue Cross-Blue Shield Tower was recognized as a nominee in the 2010 CTBUH Awards Program.
Other Featured Tall Buildings

The Blue Cross Blue Shield corporate headquarters was the first building in Chicago to be built up in phases, adding 24 stories on top of the pre-existing 33.

Location
Chicago
Completion
2010
Height
227 m (744 ft)
Stories
54
Primary Use
Office


Owner/Developer
Health Care Service Corporation

Design Architect
Goettsch Partners; Lohan Associates

Structural Engineer
Magnusson Klemencic Associates; Chris P. Stefanos & Associates
MEP Engineer
Cosentini
Contractor
Walsh Construction

Blue Cross-Blue Shield Tower is a unique combination of a build-to-suit headquarters and a multi-tenant office tower in downtown Chicago. The design concept defined an initial building to serve a company’s immediate needs and planned for vertical expansion in the future. Thus the building was constructed in two phases, with the second phase of construction occurring on top of the fully operational phase one, without interrupting existing tenant operations. The project’s 33-story, first phase was completed in 1997 and in 2006 the decision was made to proceed with the initial plan and add 24 stories on top of the existing building. Nearly a decade separated the two phases of construction.

Figure 1. Overall view after Phase 1 completion, 1997
Figure 2. Interior open stair

The initial foundations and structure were designed and constructed to support the fully expanded building. Additional riser space also was provided to accommodate independent mechanical, electrical and plumbing systems for the expansion floors. In order to allow the cooling towers on the roof of phase one to continue to serve the building during construction, a three-story gap from the 30th to the 33rd levels was left during construction. Once the new cooling towers were in place, 24 floors above the originals, the old cooling towers were removed, and cladding was applied. This space now serves as a mid-building conference center, providing necessary additional meeting and training space.

Figure 3. Diagram showing the vertical expansion

Figure 4. Detail of the elevator layout (View Larger)

Vertical shafts to accommodate the high-zone elevators that service phase two of the project were accommodated in phase one as large atrium spaces that ran the height of the building alongside the low-zone elevator banks along the north wall. Local open stair cases are also located along the northern wall to promote inter-floor interactions without dependency on the elevators.

Figure 5. View from Millennium Park of the tower in the Chicago skyline
The entire exterior of the building is clad in glass, stainless steel and stone—all materials that both aged well and were easily matched as the building expanded. As a result of this design planning, there is no visible distinction between the old and new portions of the building, providing a seamless, integrated expression that now achieves its full height and appropriately fits into the Chicago skyline.

Related Links
CTBUH Skyscraper Center Profile:
Blue Cross-Blue Shield Tower

Download the Blue Cross-Blue Shield Tower 2010 CTBUH Awards Book section
2010 CTBUH Awards Book

The CTBUH would like to thank Goettsch Partners for their assistance with this article. Photography © Goettsch Partners, James Steinkamp Photography, Scott McDonald - Hedrich Blessing, and Marshall Gerometta