This is not just another skyscraper post because the building above is not just another skyscraper. That’s the 1903 Ingalls Building in Cincinnati, photographed when it was brand new, and its mere existence badly messes up any simple narrative of skyscraper development.
Ingalls was the first skyscraper with reinforced-concrete structure. I firmly believe that there is no “first skyscraper” because there’s no way to create a definition of “skyscraper” that provides a meaningful first instance. Curiously, we know the first concrete skyscraper without any doubt – Ingalls – despite the lack of clarity about the overall situation. Simply put: there is no competition. At the time Ingalls was constructed, concrete buildings tended to be 3 or 4 stories high and usually with very low slenderness.
The original construction sounds like a nightmare. Continuous placement of concrete at high floors without pumps, without vibration, and with small batches is difficult enough that the construction rate of three floors per month doesn’t surprise me. Many steel frame buildings of that era had their frames built at two or three days per floor. In 1903, there was not yet consensus in the US about how to design concrete or what rebar should be, only competing proprietary systems. Ingalls was constructed using the Ransome system, which provided better bond between the rebar and concrete than any of the competitors (and better bond than is required today), which may have contributed to its longevity.
The details of the structural system of Ingalls explain why it was successful despite being built using quite primitive technology. The exterior walls are structural concrete, faced with brick and stone, and support most of the floor load. There is only one line of interior columns because the building is so slender; girders run between the long exterior walls and those columns, supporting filler beams parallel to the long walls. In short, the exterior walls act as shear walls for lateral bracing, and have a lot of dead load from the floors to help keep them in compression.
Here’s where modern categorization breaks down: by any rational standard, this is a bearing-wall building since the exterior walls are carrying most of the buckling’s weight. Except that we typically do not use the phrase “bearing walls” with regard to reinforced-concrete frames. We may talk about structural walls in concrete buildings – most often, but not always, in the core – but we generally reserve “bearing wall” for buildings with structural masonry walls. This linguistic issue doesn’t matter in one sense, since Ingalls functions regardless of what we call it, but the early history of skyscrapers is generally regarded as a move from bearing-wall structure to skeleton-frame structure. That change is often described as a move from masonry vertical structure to metal framing. There is no way to fit Ingalls into that story, but here it is, constructed 13 years after the first skeleton-frame buildings. In The Structure of Skyscrapers, I categorized the structure of early tall buildings by how they carried various loads, and using my system Ingalls is a bearing-wall building. If you categorize by looking at the exterior wall details, you reach the same conclusion.
The answer to this problem is simple. Some skyscrapers have bearing walls. That was true in the nineteenth century and it’s true today. And that, in short, is why I don’t believe that technology-based definitions of “skyscraper” make sense.
