Willis Tower vs Gas Company Tower

Comparing the Willis Tower and the Gas Company Tower is compelling because they were both designed by Skidmore, Owings & Merrill, yet they stand in different cities (Chicago, IL and Los Angeles, CA), and were completed a decade 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 Willis Tower is clearly the larger tower of the two, both in terms of height and number of floors. It rises to 1450ft (442m) with 108 floors above ground, while the Gas Company Tower reaches 748ft (228m) with 52 floors above ground.

Willis Tower also offers more total built-up area, a total fo 4,499,999 sqf (418,064m²), which is about 2,718,251 sqf (252,534m²) more than what the Gas Company Tower offers.

The Willis Tower also concentrates more floor area on its site, indicating a higher floor area ratio.

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 Willis Tower was designed in the International Style style, while the Gas Company Tower reflects the principles of Postmodernism.

Both towers were built when their respective styles were already past their prime. This makes them feel more like late continuations rather than groundbreaking statements, showing how architectural traditions can linger even as tastes shift.

Both the Willis Tower and the Gas Company Tower were designed to serve as commercial towers, and that has remained their main use since their completion, serving similar roles in the urban fabric.

Both the Willis Tower and the Gas Company Tower rely on a Frame structural system.

A frame structure uses a grid of columns and beams to carry the building's loads. This frees the walls from structural duties, allowing for flexible floor plans and larger windows.

They also employ the same type of facade, 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.