John Hancock Tower vs 71 South Wacker Building

Comparing the John Hancock Tower and the 71 South Wacker Building is compelling because they were both designed by Pei Cobb Freed & Partners, yet they stand in different cities (Boston, MA and Chicago, IL), and were completed over two decades apart.

What this will allow us to see, is how the same firm's approach adapted to different places in different periods of time.

The John Hancock Tower is clearly the larger tower of the two, both in terms of height and number of floors. It rises to 791ft (241m) with 60 floors above ground, while the 71 South Wacker Building reaches 679ft (207.1m) with 48 floors above ground.

John Hancock Tower also offers more total built-up area, a total fo 2,809,378 sqf (261,000m²), which is about 1,044,378 sqf (97,026m²) more than what the 71 South Wacker Building offers.

Of course, each project may have faced different briefs or regulatory constraints, which we don't really know about and could also explain the outcome.

The John Hancock Tower was designed in the International Style style, while the 71 South Wacker Building reflects the principles of Contemporary.

The John Hancock Tower represents a late expression of the International Style, a style already in decline in 1976 when it was completed. By contrast, the 71 South Wacker Building followed the then mainstream Contemporary, embodying the dominant architectural direction of its time.

With 29 years between them, the comparison also reflects how quickly architectural priorities can shift from one dominant language to another.

Both the John Hancock Tower and the 71 South Wacker Building were designed to serve as commercial towers, and that has remained their main use since their completion, serving similar roles in the urban fabric.

The 71 South Wacker Building also provides 163 parking spaces.

The two towers rely on different structural systems, reflecting distinct engineering strategies.

The John Hancock Tower uses a Frame structural system, which relies on a regular grid of columns and beams to sustain its weight, while the 71 South Wacker Building uses a Framed Tube In Tube system, that combines a strong central core with a perimeter tube of columns.

Yet, when it comes to their facade, they both employed the same solution, a Curtain Wall facade.

A curtain wall is a non-load-bearing facade hung from the structural frame. It is anchored to floor slabs and transfers only its own weight and wind loads, allowing for sleek, glassy exteriors.