Equitable Building

Equitable Building
  1. About the Equitable Building in Chicago
  2. Architect and team
  3. Architectureal style
  4. Spaces and uses
  5. Structure and materials

The Equitable Building is an International Style skyscraper designed by Skidmore, Owings & Merrill, with Bruce Graham, Natalie de Blois as lead architect, and built between 1963 and 1965 in Chicago, IL.

Equitable Building is not the only name you might know this building by though. The building is, or has also been known as 401 North Michigan.

Its precise street address is 401 North Michigan Avenue, Chicago, IL. You can also find it on the map here.

At the time of the sale of the land owned by the Chicago Tribune, it was stipulated that the new building should have a plaza along Michigan Avenue to preserve the view of the Tribune Tower and the Chicago River. This plaza is now known today as Pioneer Court.

The Equitable Building embraces the international-style skyscraper that Mies, who at the time had a thriving career in Chicago and across the US, had envision and executed for the Seagram Building in NY before the Equitable Building, and much closer a few years later in 1970, just a couple blocks away, at the IBM Building.

Building's timeline

Construction begins
Construction completed
years ago

Architect and team

Skidmore, Owings & Merrill, with Bruce Graham, Natalie de Blois as the lead architect, was the architecture firm in charge of the architectural design.

Commonly known as SOM, the firm was founded in Chicago in 1936 and has grown to be one of the largest architecture firms in the world.

Even long after its founders passed away, SOM has remained at the top of worldwide architectural excellence by attracting visionary architects. Amongst their most notorious partners we find names such as Gordon Bunshaft, Bruce Graham, Walter Netsch, Adrian Smith, Myron Goldsmith or David Childs.

SOM has also managed to grow and evolve to tackle the architectural challenges of each time, whatever those might be, and today is committed to aspects as important as efficiency and sustainability, as core values of their designs.

With a legacy spanning decades, SOM continues to shape the skylines of cities around the world, and is a usual contestant in any competition or selection process to design large-scale or iconic buildings and structures.

Skidmore Owings Merrill

Skidmore, Owings & Merrill was in charge of the architectural design, however, architecture is a complex discipline, which usually involves many professionals from different fields, without whom this building would have not been possible. We will surely be leaving out a lot of names here, but at the very least we know that there was one other part involved, that was Equitable Insurance Company as the Main Developer.

Architectural Style

The Equitable Building can be categorized as an International Style building.

The international style originated in Europe in the early 20th century, and made its way to the US a couple of decades later when the rise of the Nazi regime forced figures such as Walter Gropius, Marcel Breuer, or Mies van der Rohe to flee Europe.

The International Style emerged as a response to the prevailing historicism and ornate architecture styles of the late 19th century, which according to a younger generation of architects didn't represent the new materials and construction techniques that were on the rise at the time.

Architecture in the early 20th century US was marked by the adoption of steel structures, modern construction techniques, and the rise of the skyscraper. As it turns out, this combination of circumstances created the perfect ecosystem for the International Style to flourish, becoming the to-go style for skyscraper designs during the mid-20th century, when American cities were growing fast.

The International Style’s legacy can not only be found in numerous iconic buildings across all major American cities, but also incorporated in contemporary architecture, which still puts a big emphasis on functionality and minimalism.

The Equitable Building was completed in 1965. By 1965 the International Style movement had already left its early days behind and could be considered a mature movement, which does not mean it was loved and accepted by everyone, on the contrary. The International Style was accepted by the architecture community way before it was by the general public, and it is therefore likely that the Equitable Building was not well received by everyone at the time.

Spaces & Uses

The Equitable Building reaches an architectural height of 456ft (139m). It has a total of 35 floors, which combined offer a total of 796,529 sqf (74,000m2) of usable space.

Ever since opening its doors to the public in 1965, the Equitable Building has mainly been used as Commercial space.

456ft (139m)

Materials & Structure

The Equitable Building uses a framed tube-in-tube structure , with steel columns and concrete slabs.

A framed tube-in-tube structure uses a central core, known as inner tube, which usually holds stairs, lifts and installations, and a perimeter of columns around it, which form the exterior tube. The interior tube is tipically more massive (often made of reinforced concrete), and the exterior tube is "lighter" (made of steel or concrete columns). Both tubes are conencted via horizontal elements which make up the floors and also transmit any horizontal froces from the facade to the core.

The facade of the building is load bearing. This is a direct consequence of the integration of the exterior "tube" into the facade, something which most framed tube-in-tube buildings do in order to liberate the interior space from structural elements and achieve a more flexible interior.

So the facade of the builing is techinically load-bearing, yes, however, in between the load-bearing colums we find a curtain-wall type of facade, which by itself would not be cosnidered load-bearing.

From an aesthetic point of view, the facade features an open ground floor, continued by a dark curtain wall.

The curtain wall is organized in 3 bays on the short side of the floorplan and 5 bays on the long side, which are determined by the structural pillars embedded into it. In each bay, bronze-tinted glass and aluminum spandrels, together with the style characteristic column coverings and vertical mullions create a repetitive rhythm both horizontally and verically.