third studebaker building to be converted…

IMG_0199In the “I don’t think you know what you have” category, word from ChicagoRealEstateDaily.com today that 2036 S. Michigan Ave. has been purchsed by Marc Realty and is slated for conversion into apartments.  The article notes that the building was “once home to a Studebaker showroom…”

Well, and how.  This was actually the third downtown building occupied by Studebaker–the first, designed by S. S. Beman and finished in 1885 was converted in the early 20th century into what’s now the Fine Arts Building.  And the Second Studebaker Building, also by Beman and finished in 1896, is now part of Columbia College.  Both of these were designed as showrooms, offices, and repair facilities, and they show pretty clearly the difference between loft-style buildings built in the 1880s (lots of stone, relatively small windows), and those built during the glass glut of the 1890s (windows and, um, not much else…in this case some fairly narrow cast iron spandrels and mullions).

The history books all know both of these, but it was this third Studebaker building, completed in 1910 and designed by William Walker, that may have represented the most radical construction of the three.  Concrete construction had infiltrated Chicago by this point, but it had mostly been used in column-and-girder construction that really mimicked steel framing.  Here, engineer Theodore Condron expanded the idea of a “paneled slab,” or a flat slab with shallow drop panels along girder lines and mushroom caps that transferred loads to hybrid columns of steel and concrete below.  This had been explored in a fertilizer plant in Hammond, Indiana, but at seven stories the Third Studebaker represented the tallest experiment in such construction to date.

studebaker III 1909_Page_12Flat slab construction implies a significant problem in transferring the dead weight of very heavy concrete slabs into relatively thin columns; while the column’s cross section itself may be enough to bear such a load, there is always a tendency for the column to punch through the thin slab above it.  This shear condition was addressed in early construction with very large mushroom caps, or with concrete girders that effectively spread the shear load out throughout a deeper section.  Both of these took up space and were difficult to form, however.  Robert Maillart developed early advances in flat plate construction in Switzerland that relied on reinforcing and more tightly defined mushroom caps around 1910-1912–the third Studebaker represents a slightly cruder, but more immediately soluble approach that sought instead to minimize the depth of bearing girders with extra reinforcing.  Not, in the eyes of modernist historians, the major leap toward the Corbusian dom-ino slab, perhaps, but an approach that eased the minds of building authorities in Chicago, at any rate.

Perhaps even more interesting, however, is the fact that the shallow girders in these panelized slabs were conceived not as individual girders spanning from column to column, but as continuous elements that spanned over each column.  This made their actual loading, as well as that of the columns below, far more difficult to calculate, but it contributed to the overall stiffness of the frame, an advantage that eventually made concrete a viable alternative to steel in tall construction.  While steel elements had been detailed with moment connections at the columns, the inability to splice beam flanges to one another across columns meant that they still behaved, in part, as simply supported elements.  With continuous steel reinforcing over the top of columns, however, the paneled slab system was less prone to deflection, and more naturally resisted lateral loading.

Writing in 1907 as the design was being completed, Condron noted that there were several advantages to the “paneled slab,” advantages that would prove important in the coming decades:

“The advantages gained by this paneled slab design are:

1) An improved form of construction whereby great strength and carrying capacity are attained with an economical expenditure for material and labor.

2)  A construction in which the stresses due to dead weight and all applied loads can be accurately determined.

3) A minimum depth of floor and a consequent reduction in the height of the building.

4) An improvement of the illumination of the rooms by the elimination of dark ceiling shadows; and

5)  A reduction in the expense of installing a sprinkler system.”

These last three were particularly important in the wholesale adoption of flat plate (with occasional drop panel) construction in high-rise residential construction.  Concrete dominated the burst of apartment building in the 1920s for precisely these reasons–with minimal ducted services, ceilings could tightly hug the floor slabs above in apartments, and this gain in sectional efficiency promised extra daylight and shorter floor-to-floor heights.

Condron also explained the system as basically a deep slab construction with a layer of concrete in the middle removed, where it would do the least work structurally.  Thinking of it this way, he estimated that the Third Studebaker design saved roughly 3.5 million pounds of material–a straight cost savings, but also a reduction that allowed smaller columns and caissons.

studebaker III 1909_Page_08The planned conversion into residential units makes sense in terms of the city’s material history–one hopes that it might also provide a means to restore the original showroom at the base, at least on the facade…

Quotes and illustrations from Theodore L. Condron, M.W.S.E.  “A Unique Type of Reinforced Concrete Construction.”  Journal of the Western Society of Engineers.  Vol. XIV, no. 6.  Dec., 1909.  824-864.

Corso Francia

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Running behind the 1960 Olympic sites is a fairly modest highway overpass that connects the Via Flaminia to arterial roads north and east. It was part of the planning for the Games, and also part of Nervi’s commission. While it’s hardly as eye-catching as the Palazetto, it’s worth a look on its own.

The supports are made of in situ concrete. They’re wide at the base, and narrow at the top, as you’d expect in a viaduct that required some ductility. But it’s how they’re that shape that’s impressive. A constant theme in Nervi’s later work involves concrete supports that change section gradually along their length, in this case a very subtle transition from a broad diamond shape at their base to a square at the top. The resulting form is easy to define with a series of straight ruling lines–connect the corners of the top shape with the midpoints of the base, midpoints of the top to corners of the base, then divide the resulting line segments into equal parts, connect those with straight lines, and you have a series of curves surfaces defined by straight lines.

These shapes were useful to Nervi because they allowed rotational freedom in one direction at the top, and in the opposite direction at the bottom. Here, I suspect they were designed to allow the overpass deck to rotate slightly under differential loading while maintaining a robust, fixed connection to the foundations (happy to be corrected by the commentariat, here…)

Building for work to make these shapes, of course, was something of a trick. But looking closely at the concrete itself provides a clue:

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What you’re seeing there are the impressions left by nail heads sticking out of board-formed concrete–a leftover that would have been eliminated by higher standards in more architectural concrete. Here, in a highway overpass, they were apparently acceptable. Each support has three or four of these lines of nail heads, and I think these show that the form work consisted of narrow, thin boards, each of which was slightly twisted between nailing strips to achieve the gently curving surface. The edges of the boards, being straight, followed the ruling lines of the geometric shape, and the nailers were designed to force each board into a very slight twist, one that made up the difference between one ruling line and the next.

To me, this is a perfect example of Nervi’s clever form work detailing–he was consistently able to achieve stunningly complex forms with relatively crude methods. This was in part due to his insistence on maintaining a full concrete laboratory and yard on the outskirts of Rome, where he and his office could experiment with techniques and materials before they went on site. In this case, it would have been important to get the thicknesses of the boards exactly right, for instance–too thin and the hydrostatic pressure of the concrete would have warped the boards between nailers, too thick and the boards would have been too difficult to twist,

There are other, more impressive examples of these sectionally-transforming supports–the Palazzo dello Sport in Rome, also done for the Olympics, and the Palazzo del Lavoro in Turin, done about the same time, have quite different takes on the idea. I have tentative appointments to see both in the next couple of weeks, and. I’m curious to see whether the tell-the-tale nailer details are evident or not…

Stadio Flaminio

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The low-hanging fruit on the Nervi reconnaissance are the Olympic sites from 1960. The small arena (the Palazetto Della Sport), the Corsa Francia overpass, and the Stadio Flaminio are all within a stone’s throw of one another along the Via Flaminia, north of the city center.

All of them are more or less accessible–you can drive on the Corso, of course, but as an American tourist you’re more likely to walk under it to get to Renzo Piano’s concert halls. The Palazetto is home to Rome’s professional basketball team (yep, you read that correctly) but it’s also more or less wide open during the daytime, and I wasn’t the only architectural sightseer there yesterday.

Stadio Flaminio is less accessible, and a somewhat sadder tale. Designed as a setting for the field sports in 1960, it was intentionally intimate, with only 32,000 seats spread out along the entire perimeter. Nervi designed a main grandstand with a cantilevered roof that echoed his first major work, the football grounds in Florence, but with a more refined sense of materials and structural form–at the Flaminio, the roof’s long span is formed of folded precast plates, and supported by steel pipes instead of concrete arms. The remainder of the stadium is brilliantly engineered with a repeating structural frame whose shape changes at every interval to accommodate the constantly shifting section. This let Nervi tune the end zones and secondary grandstand to provide more seats in better viewing areas, and the result is a subtly curving, sensuous form that.

Unfortunately, it’s intimate scale has done it no favors recently. For a decade it served as the home for Italy’s national Rugby team, but plans to hold international championships there more recently fell apart as funding for renovation and expansion never materialized. Italy’s team now plays in the larger–though far less graceful–Stadio Olimpico across the Tiber, and even Rome’s local team has abandoned Nervi’s structure.

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And the structure has suffered from this desertion. There’s a lot of visible spalling, and plants have begun to take root in the concrete–early signs of gravely compromised material. There was a grounds crew working on the immaculately trimmed field, but there is a lot of work that needs to be done to rescue this one. Part of the goal with this research is to call attention to the disintegrating works of Nervi that are perhaps a bit more obscure–water towers, warehouses and the like that belie their humble functions with poetic expressions of static and constructive logic. Stadio Flaminio, however, is arguably one of his most visible works, and it’s more than slightly shocking to see it in obvious distress.