Columbia Center vs Two Union Square

Comparing the Columbia Center and the Two Union Square is interesting because they both stand in Seattle, WA, and were completed within 4 years of each other, but they were designed by different architects.

This offers a unique glimpse at how rival designers approached projects in the same city during the same era.

The Columbia Center is clearly the larger tower of the two, both in terms of height and number of floors. It rises to 932ft (284m) with 76 floors above ground, while the Two Union Square reaches 741ft (226m) with 56 floors above ground.

Columbia Center also offers more total built-up area, a total fo 1,538,161 sqf (142,900m²), which is about 372,722 sqf (34,627m²) more than what the Two Union Square 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.

Both the Columbia Center and the Two Union Square were designed in line with the aesthetic conventions of the Modern style.

Both buildings were completed when the Modern style was already past its peak. This makes them feel like late echoes of the movement, more reflective of continuity or nostalgia than of cutting-edge design at the time.

Both the Columbia Center and the Two Union Square 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 towers provide significant parking capacity, with Columbia Center offering 700 spaces and the Two Union Square offering 1100.

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

The Columbia Center uses a Frame structural system, which relies on a regular grid of columns and beams to sustain its weight, while the Two Union Square 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.