third studebaker building to be converted…

IMG_0199In the “I don’t think you know what you have” category, word from 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.

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