Mies van der RoheWe've all heard of Chicago's steel mills, now most of them gone, and we know it shapes our modernist buildings. It has inspired poetry, like "Smoke and Steel" by Carl Sandburg, and it has become symbolic of strength and endurance. For Chicago, as one of the world hubs for the industry, steel is iconic, and an essential element of our city's great history and architecture.

In my studies of Chicago architecture, I've always found the technological advancements of materials to be fascinating in its influence on the building possibilities of architecture. To start, the steel industry erupted here because of the geographical advantage to the Great Lakes, which were rich in iron ore deposits, and of course steel is an alloy of iron and carbon. In the 1800s the burgeoning industry appeared in Chicago, Joliet, and North Chicago. In 1901 New York financial mogul JP Morgan organized U.S. Steel, the largest corporation on the planet. A lot of this steel went towards making farm equipment, railroads, bridges, and most importantly to this blog post - buildings.

The first steel-framed building, and argued by some to be the world's first skyscraper, was William LeBaron Jenney's Home Insurance Building, completed in 1885. It used steel for its frame rather than cast iron, but people debate on the legitimacy of its "steel frame" because it still had a thick brick and stone exterior. It was torn down for the very art deco Field Building, now called the Bank of America Building, at 135 S. Lasalle St.

An early steel-frame skyscraper still around in Chicago is the Reliance Building on State Street, designed by multiple architects of the firm of Burnham and Root in 1890. Surrounding its wide plate glass windows you can easily see the columns of its framed supports, literally exposing how the material dictates the form of the structure. The steel frame revolutionized buildings by allowing for more space because of less need for clunky walls. The ability to have larger windows meant greater natural light and ventilation. Imagine that back then lighting technology was not very advanced, and bulbs let off a lot of heat during the pre-air-conditioning era. And perhaps most importantly the strength of the steel frame let architects build taller, such as to 15 stories with the Reliance Building. Masonry buildings generally cannot stretch higher than 10 stories or so.

But let's not get ahead of ourselves. In the 1930s  came to town and brought with him designs for his modernist architecture. Essentially he wanted to spare down buildings to their most basic elements, meaning no fluffy ornamentation or other unnecessary details. The vertical steel I-beams of his 860-880 Lake Shore Drive towers, for example, run up and down the outside of the building and show the steel structure to the world while also providing a visual harmony.

The Inland Steel Building cannot be ignored when speaking of a history of steel architecture in Chicago. I love talking about the significance of this building as a tour guide on my Loop Interior Architectural Tour. This elegant skyscraper used steel like an exoskeleton, making the steel columns on the exterior into the support for the structure so that inside the space has no interruptions of walls, columns, or even elevator shafts. Additionally the brushed stainless steel cladding illuminates beautifully with the light at various times of day.

Fazlur Khan innovated the tube structural system, which took various forms with his giant skyscrapers, such as the Willis Tower and John Hancock building, and most of these forms would be impossible without the strength of steel. Today the steel frame still has the sky as practically the limit in regards to height, especially with Khan's designs.

Steel is not just history in Chicago though. You can still peak at the process of steel forging if you bike or drive by A. Finkl & Sons Co., on Cortland St just East of the North Branch of the Chicago River. Architects are also always innovating with the material, such as the Solar EV Deck, designed by Adrian Architects. Located on Northerly Island, this super green, solar-powered structure charges electric/hybrid vehicles, shades them, and on top of that can collect rainwater for irrigation. Steel was necessary to support the heavy photovoltaic equipment.