[Chicago Skyscrapers, 1934-1986, published by University of Illinois Press, is out now–available on Bookshop.org and Amazon.com, among other outlets.

Gateway Center I-III (SOM, 1963-72)

Weeks after the Hartford’s opening in April 1961, Bruce Graham’s concerns about predatory New York developers and architects proved relevant.  Erwin Wolfson, chairman of Morse Diesel and the leading figure behind Manhattan’s Grand Central City, disclosed plans to invest $200,000,000 in air rights developments over Union Station’s riverfront railroad tracks, stretching four blocks between Madison and Van Buren.  Mayor Daley had arranged the deal, bypassing the city’s Planning Commission and surprising the Commission’s chair, Ira Bach, who nevertheless expressed support, pointing out that it would represent a “major step” in realizing the Central Area Plan.[i]  Air rights projects like the Prudential, the Merchandise Mart, and the Daily News Building had made Chicago a pioneer in developing infrastructural space.  Grand Central City (later Pan Am) followed Chicago’s lead by developing the space over that station’s tracks in New York and was being built to designs by Emery Roth, Walter Gropius, and Pietro Belluschi even as Wolfson worked out the deal in Chicago.  At fifty-nine floors and nearly 3 million square feet of space, that project’s bulk and its “clumsy” connections to the surrounding streets were drawing withering criticism, though.[ii]  Concerned about initial reactions to the Grand Central project, Daley pressured Wolfson to employ Chicago architects and demanded that the development include “abundant” urban amenities along the River.[iii]

Wolfson hired Skidmore, Owings, and Merrill’s Chicago office, and they presented a scheme for the northernmost parcel in November 1961—an 18-story rectangular block running parallel to the river, occupying just half of the site, and set atop an elevated pedestrian plaza.  In deference to Bach’s association with the Central Area Plan, Wolfson suggested that, if the city moved ahead with the Transportation Center, the building could be built on the block to the south.  Wolfson was confident enough in the market and the site’s proximity to the Station that he announced the project would start without a confirmed major tenant.[iv]  “My reputation is at stake,” Wolfson told the Tribune in January 1962, committing to the project and predicting demand in the neighborhood for at least a million square feet.[v]

Wolfson died of cancer in June 1962, however, throwing the project into doubt.  His air rights options ran out, though the railroads and the city expressed interest in renewing them.[vi]  New York-based Tishman Realty and Construction took over his leases, keeping SOM on board and hiring Arthur Rubloff as their local agent.  Tishman was more ambitious than Wolfson had been. SOM released a revised design for them in January 1963, showing a 20-story steel frame clad in glass and black metal set on a riverfront promenade with plazas at the Madison and Monroe ends of the block.  An inset glazed lobby and projecting I-beam mullions made this design SOM’s strictest Mies’ interpretation yet, though with blue-green heat-absorbing glass that contrasted with the otherwise dark palette.  Office floors within extended north and south from a central core and the structure was tuned to the position of tracks below, with three track-spanning 45’ bays in the east-west direction and fifteen smaller, 18’ bays running north-south to reduce spans and, thus, vibration from trains underneath.[vii]  All told, Gateway I would contain 750,000 square feet and cost $20 million.[viii]

Reassured by Daley’s personal role and the promise of new investments in the West Loop, First National and Continental Illinois led Gateway’s financing.  This first tower broke ground in September 1963, as Tishman reported that 14 stories had been leased and that a second building, south of Monroe, would follow suit.  Originally planned as a four-story transportation center to meet the Central Area Plan’s goals, Tishman was so convinced of the market that it re-conceived this second phase as a twin to the first.[ix]  This first building opened in February 1965 and the second, a strict copy, broke ground that December.[x]  Steelwork for Gateway II began rising in the spring, of 1966, and Gateway I filled that August, with IBM, Weyerhaeuser, and Monsanto taking space in its upper floors.[xi]  Tishman began looking for the next logical expansion, taking an unfortunate cue from New York’s Penn Station, where they had been consultants for Madison Square Garden and Penn Plaza, projects that involved the demolition of the McKim, Mead, and White Penn Station.  In March 1967, Tishman vice president Perry Herst announced that the third phase of Gateway would rise above Union Station’s boarding platforms, replacing the stone, steel and glass head house from Graham, Anderson, Probst, and White’s 1922 structure.  This, Herst explained, would keep the development contiguous, rejecting a proposal from the city to build farther west in the West Madison urban renewal district.[xii]  Objections from Chicago’s burgeoning preservation movement failed to convince the City to stop the demolition.

Tishman presented SOM’s preliminary plans for the third Gateway Tower in February 1969—initially a steel frame with aluminum and glass curtain walls, much like the first two buildings, but with different proportions—a square plan of 35,000 square foot floor plates extended to 35 stories.  Much of SOM’s work went into weaving Union Station’s pedestrian access and baggage services through the structure, but as the design progressed, Graham brought Fazlur Khan in to consult on the structure as well.  Khan had, by this point, engineered so-called tube structures for the Hancock and Chestnut-DeWitt apartments (see Chapters 6 and 8), and he proposed the ‘composite tube’ to address the unique problems of Tishman’s site.  Perimeter walls of steel columns encased in structural concrete would form a stiff exterior shell. In contrast, a lightweight, more flexible structure of steel alone would support its interior—a more literal interpretation of the Monadnock’s hybrid.  The exterior shell alone would provide lateral resistance, eliminating heavy shear walls that would have interfered with the tracks below. Light steelwork supporting the center of the building could be supported on smaller, shallower foundations, limiting the amount of deep caisson work required between tracks.[xiii]  Tishman’s executives approved the idea, and Khan’s revised design began to take shape in early 1970.[xiv]

Tishman’s optimism was borne out as the third Gateway building topped out in 1971 when insurance brokerage Marsh & McLennan leased the top eight floors for 20 years—at $36 million, the largest commercial office lease in the city’s history.[xv]  That paralleled the Chicago Mercantile Exchange’s announcement that they would occupy a dedicated trading floor in an extension to the new tower, a cross-braced, cantilevered structure on Jackson Street.[xvi]  A new concourse for Union Station, meanwhile, swapped the spatial drama of the old, glass-roofed head house for 30,000 square feet of underground concessions and corridors on two 12’-0” stories between track and street level. 

As the complex opened in January 1972, Tishman announced the fourth and fifth Gateway buildings for the riverside site south of Gateway III, including a long-anticipated heliport and the half block just west of the second building.  But these were delayed by economic uncertainty and the politics of the 1970s—Tishman would not complete the final two Gateway blocks, designed by a new generation of SOM architects, until the 1980s.  The three original buildings continued to attract tenants, but they also came to stand for SOM’s formulaic approach.  The three buildings’ relentless grids and the simple replication of the second structure left critics unimpressed. Paul Gapp, while acknowledging the “cool and proper” Miesian design of the first two, thought the “uncomely” third phase was unforgivable given the demolition of Union Station’s concourse and its replacement with “ugly…lower-level spaces.”[xvii]  The three buildings served as effective backdrops, however, to the riverfront promenade, christened “Riverfront Plaza” as the first two buildings opened.

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[i] Thomas Buck, “Skyscrapers Planned on Air Rights Site.”  Chicago Tribune, July 20, 1961.  3.

[ii] Edgar Kaufmann, Jr., “The Biggest Office Building Yet…Worse Luck.”  Harper’s Magazine, May 1, 1960. 220.

[iii] Thomas Buck, “Skyscrapers Planned on Air Rights Site.”  Chicago Tribune, July 20, 1961.  3.

[iv] “Wolfson Group Plans Transit Hub.”  The Wall Street Journal, Nov. 17, 1961.  24 and James M. Gavin, “$20,000,000 Skyscraper First Air Rights Project.”  Chicago Daily Tribune, Nov. 17, 1961.  C7.

[v] James M. Gavin, “City Skyscraper Plan Definite—Wolfson.”  Chicago Daily Tribune, Jan. 14, 1962.  A9.

[vi] “Attempt in Chicago to Build on Air Rights is Being Re-Evaluated.”  Wall Street Journal, July 2, 1962.  24.

[vii] “Train Yard Towers.”  The Architectural Forum, Vol. 128, no. 2.  March, 1968.  73.

[viii] “Start Construction of First Gateway Center Building.”  Chicago Tribune, Sept. 18, 1963.  C5.

[ix] “Start Construction of First Gateway Center Building.”  Chicago Tribune, Sept. 18, 1963.  C5.

[x] Alvin Nagelberg, “2d Gateway Building to Rise.”  Chicago Tribune, July 30, 1965. C7 and “Begin No. 2 building in Gateway Center.”  Chicago Tribune, Dec. 2, 1965.  G7.

[xi] “Start Plaza Twin’s Steel Construction.”  Chicago Tribune, May 29, 1966.  E5 and “Occupancy is Completed in 1^st Gateway Building.” Chicago Tribune, Aug. 28, 1966.  E1.

[xii] Alvin Nagelberg, “Tishman May Build Over Union Station.”  Chicago Tribune, Mar. 1, 1967.  E6.

[xiii] “Massive Core [sic] Supports Thin Steel Frame.”  Chicago Tribune, Nov. 22, 1970.  E1 and “Innovation at Gateway Center.”  Chicago Tribune, May 23, 1971.  D1.

[xiv] Richard Ellis and David Billington, “Construction History of the Composite Framed Tube Structural System.”  Proceedings of the First International Congress on Construction History. (Madrid, January, 2003).  799-810.

[xv] Alvin Nagelberg, “Gateway Lease a Record.”  Chicago Tribune, Mar. 25, 1970.  D9.

[xvi]“Future Mercantile Home.”  Chicago Tribune, May 19, 1970.  C7.

[xvii] Paul Gapp, “River’s Newest: One Works, One Doesn’t.”  Chicago Tribune, Apr. 15, 1984.  K28.

[Chicago Skyscrapers, 1934-1986, published by University of Illinois Press, is out now–available on Bookshop.org and Amazon.com, among other outlets.

Lake Point Tower (Schipporeit and Heinrich with Graham, Anderson, Probst and White, 1965-1969)

Chicago’s most visible residential tower, rising 645 feet from the base of Navy Pier, sprung from a cladding detail and a helicopter flight, matching a dramatic, undulating curtain wall and technical developments in air conditioning to a singular lakefront location.  Owned by Chicago Dock & Canal, the site was occupied by declining warehouses and factories adjacent to the obsolete Navy Pier.  Chicago’s port facilities’ move to Calumet drew industry with them, though, and the area’s loft structures gave way to parking lots.  By the early 1960s, Chicago Dock & Canal was more real estate company than active port, selling its land to developers who hoped to transform the grimy, polluted acres of fill and asphalt into a desirable residential neighborhood.

Lake Point Tower’s developers and architects were part of a growing network of skyscraper experts centered on Chicago.[i]  William Hartnett, a New York lawyer assisting Herbert Greenwald on Metropolitan Structures’ Mies-designed Newark apartment project, worked with Charles Shaw, an Alcoa employee who was develop prototype aluminum housing and high-rise components in St. Louis.  Alcoa was considering a demonstration project on the Dock & Canal property and Hartnett and Shaw invited architect George Schipporeit to join them on a helicopter tour of the site in 1962.  Schipporeit, a Nebraska native, came to Chicago in 1955 studying at IIT before going to work for Alfred Caldwell and then Mies.  He had worked on curtain walls with integral fan coil units for Mies’ Newark and Detroit projects before moving to St. Louis in 1960 to work with Shaw at Alcoa’s Cupples subsidiary.[ii]  After joining Shaw for the aerial tour, Schipporeit recalled thinking that the property was “the best site in the country.”[iii]  Alcoa passed on the opportunity but Hartnett and Shaw formed their own development company for the site and, after finding initial schemes by Perkins & Will unimpressive, Hartnett turned to Schipporeit, who in turn brought his IIT classmate John Heinrich on board.  Heinrich (1928-1993) had been a field architect for Mies on Lafayette Park; he took Schipporeit up on his offer of “the biggest gamble in the world.” Hartnett and Shaw brought Los Angeles-based Fluor into the project as financiers, while Schipporeit and Heinrich associated with Graham, Anderson, Probst, and White for technical assistance and with William Schmidt for structural engineering.[iv]

The site, east of Lake Shore Drive between Illinois and Grand, was massive but “marooned,” in Schipporeit’s words, a half-mile from Michigan Avenue.  Zoning would allow over 1230 apartments, they estimated.  Wanting to leave as much open space as possible, Schipporeit and Heinrich accommodated these within a point tower rather than a slab.  Given the site’s extraordinary views they developed a cruciform plan with rounded corners to provide lake and skyline panoramas.  Set diagonally at the far eastern end of the site, atop a podium containing parking and a landscaped deck, the four wings of the tower were to radiate from a central core.  As the design progressed, Fluor grew concerned about renting so many units at such a remote site.  Marina City, they pointed out, had only 900 units and Outer Drive East just 945.  One of Fluor’s executives suggested slicing one arm of the cruciform off, leaving a three-lobed form that reduced the number of apartments, offered more open views and greater privacy, and—with some fine-tuning—eliminated inefficient fire stairs at the corridor ends of the four-armed scheme.[v]  Schipporeit and Heinrich took to this idea, first laying out a three-lobed plan around the site’s east-west axis, accessed by long automobile ramps from the west end of the site.  They found the resulting form “too static.”  By rotating the tower 120°, however, so that one arm pointed due north, the tower fit more comfortably on its base, allowing more generous space for automobile access from Grand Avenue, an enclosed drop-off they developed with an open skylight in the roof, offering a dramatic, upward view of the tower. 

The scheme’s three arms implied a triangular core— structurally efficient but difficult to arrange.  Schipporeit and Heinrich turned its elevators toward a central lobby on each floor that led through the core’s corners to radial hallways, with fire stairs and service shafts wedged into the triangle’s vertices.  The apartments were laid out to maintain an even depth tangential to the corridors and core walls.  The resulting soft transitions from the tower’s curved corners to its long re-entrant curves created a sleek form that, wrapped in a black aluminum and dark glass curtain wall, was arresting and allusive.  Critics would compare this curving glass wall to Mies’ 1922 Glass Skyscraper’s curving concrete floors and transparent glass walls. Schipporeit and Heinrich were happy to claim this lineage, but this was a superficial comparison.  Mies’ early schemes would have stood just 30 floors tall, less than half Lake Point’s height, and he never developed mechanical services or lateral bracing for them.  Their floor-to-ceiling glass curtain walls without intermediate mullions remained infeasible even in 1965. 

Schipporeit and Heinrich’s curtain wall experience with Mies gave them a good understanding of their infiltration, condensation, and thermal problems.  Schipporeit recalled constant visits to the Esplanade Apartments to survey and propose fixes for leaks.  Improved extrusions and sealants addressed these problems but combining code-required natural ventilation with mechanical heating and cooling loaded curtain walls with functions that competed for space.  Schipporeit had developed integral, knee-height cabinets for the Detroit and Newark projects that could accommodate either fan coil units or operable, grilled apertures supplying fresh air.  He and Heinrich adopted this detail for Lake Point Tower, with cabinets that alternate between housing electric fan coil units and screened openings, both integrated with the curtain wall sill panels.[vi]  Each window panel runs from one cabinet’s top to the next floor, framed by two horizontal mullions for each story, all set behind a screen of vertical aluminum I-beams.  The result is a delicate, woven texture like the Esplanade and Commonwealth curtain walls—but wrapping an evocative form.  The same cladding panel repeats more than 11,000 times and the building’s lack of sharp corners means no special detailing was needed, as in Mies’ towers, to end one plane and begin another.[vii] 

The undulating tower was topped by a rooftop mechanical unit and, above that, a circular pavilion containing a private lounge for residents.  At the base, the podium was designed to accommodate 700 cars and retail facilities within a minimalist brick box—often criticized for its forbidding, 30-foot-high walls, which were more appropriate in the building’s original context of grim industrial buildings and abandoned docks.  The base does contain one piece of immense structural drama—the 108’ clear span that forms the automotive drop off and leads on to the ‘rotunda’ on the Grand Avenue side, while the podium’s roof houses a garden designed by Caldwell.

At 70 stories, Lake Point was one of several Chicago structures to claim the title of world’s tallest reinforced concrete structure.[viii]  William Schmidt, Chicago’s most prolific flat-plate concrete engineer, designed the tower’s core walls to taper from 30” at the base to 12” at the 56^th floor, above which they are replaced by simple columns.  Eight-inch lightweight concrete slabs connect to the core and columns with reinforced joints to form a monolithic, wind-resistant structure.  Schmidt specified high-strength concrete throughout the columns and core walls, minimizing their bulk and weight, and these savings allow the entire building to sit on a layer of good hardpan 90’ below the surface, tied to the core walls with a 24’ deep grade beam.  Schmidt deployed a network of strain gauges throughout the foundations and superstructure to test his calculations after the building was occupied, making the building a laboratory for wind engineering for years after its completion.[ix]

Crane Construction began work in November 1965 as the project faced protests upset at its intrusion on the lakefront.  Lake Point was the third project to be built east of Lake Shore Drive, after Outer Drive East and Solomon, Cordwell, and Buenz’ Harbor Point Tower, both at the end of the extended Randolph Street.  For decades, Chicago builders had a gentleman’s agreement that no construction would take place between the Drive and the actual Lake—not that there were that many potential sites wedged between the two—and Lake Point drew pointed arguments about the tradition of a public shoreline.[x]  These were matched, however, by genuine fascination as the tower grew out of its foundations at the rate of a floor every three days, reaching the 16^th story by October, 1966 and the 29^th by January, 1967.[xi]  Construction was slowed by a building trades’ mechanics strike in January, 1967 and the operating engineer’s strike that spring.  But by the end of 1967 the structure was topped out, with Daley praising the project’s “young entrepreneurs for another fine edifice for the future of urban living.” By then it was occupied by over 100 tenants, who moved into the lower floors as construction continued above them.[xii]  More than half of the building’s units were leased by the time upper floors were completed in April 1968.  Its rooftop lounge— “a masculine flavor carried out in a French Norman interior”—and a street-level steak restaurant sealed the building’s appeal when they opened in 1970.[xiii]

Lake Point Tower won the local AIA chapter’s top architectural award and was one of fourteen projects recognized with national AIA awards in 1970.  Hartnett and Shaw planned expansions of the original in 1965, when Schipporeit and Heinrich proposed two duplicates of the three-armed tower to the south and west of the original and in 1971, when they modeled three boomerang-shaped slabs flanking the entry to Ogden Slip.[xiv]  None of these proceeded beyond massing studies, but Schipporeit and Heinrich did collaborate with Hartnett and Shaw on one other large project, the 22-story State National Bank at Orrington and Davis in downtown Evanston (1968-69), a more doctrinaire Miesian prism, after which Heinrich left to pursue teaching full time.[xv]  Schipporeit continued designing commercial and residential towers, including the 13-story Eisenhower Tower in Maywood (1973), the mid-rise Atrium Village on Division Street and 18-story One Rotary Center in Evanston (1977), the 33-story Asbury Plaza in River North (1981), and the 38-story Lake Shore Tower on east Ohio Street (1986).  His design for the Cor-ten clad parking garage north of Mies’ IBM Building (1974) wrapped vertical cladding elements around the elevated sweep of Wabash Ave. in a subtle nod to IBM’s vertical mullions, repeating in principle the visual effect of Lake Point Tower’s articulate aluminum piping.

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[i] See the outstanding Edward Windhorst and Kevin Harrington, Lake Point Tower: A Design History.  (Chicago: Chicago Architecture Foundation, 2009) for an authoritative, detailed history of the project.

[ii] “Build a Room with Aluminum Panels?: Versatility Noted.” The Christian Science Monitor, July 06, 1962. 12.

[iii] Interview with George Schipporeit, Illinois Institute of Technology Architectures Studios.  10 October 2012, 1600-1800.

[iv] “Lake Point Tower: The First Skyscraper With an Undulating Glass Wall.”  Architectural Record, Vol. 146, no. 4.  Oct., 1969.  130.

[v] “How High to Build?  Need Tells.”  Chicago Tribune, Feb. 8, 1970.  E1 and Edward Windhorst and Kevin Harrington, Lake Point Tower: A Design History.  (Chicago: Chicago Architecture Foundation, 2009).  6.

[vi] Display ad, “All Electric Design [Lake Point Tower].”  Architectural Record, Vol. 146, no. 4.  Oct., 1969.  278-279.

[vii] “Lake Point Tower: The First Skyscraper With an Undulating Glass Wall.”  Architectural Record, Vol. 146, no. 4.  Oct., 1969.  130 and “Tallest Apartment Tower Will have Aluminum Skin.” New York Times, June 4, 1967. 1.

[viii] “Chicago Keeps Building Them High with Concrete.”  Chicago Tribune, May 15, 1966.  F1.

[ix] “New Tower to be a Giant Test Station.” Chicago Tribune, Jan. 9, 1966. 1-e1 and Barbara Schmidt Hornkohl, “The Structural Engineer: A Retrospective of the Engineering of William Schmidt” in Nancy Gavlin, ed., Engineering in the City of the Century. (West Lafayette: Purdue University, 1998).

[x] “On The Streets.” Chicago Tribune, Oct. 28, 1965. 1-e9.

[xi] Alvin Nagelberg, “Reveal Floor Plans, Rent Schedules for Lake Tower.”  Chicago Tribune, Oct. 7, 1966.  D11 and “Construction Lags: 70,000 Men Off Job.”  Chicago Tribune, Jan. 28, 1967.  B7.

[xii] Alvin Nagelberg, “Lake Point Twinkles on Skyline.”  Chicago Tribune, Dec. 9, 1967.  D7; Alvin Nagelberg, “Lake Point Topped Out.”  Chicago Tribune, Dec. 29, 1967.  C9; and Glenn Fowler, “Eager Tenants Lived in Tower as it Went Up: Tenants at Topping-Out.” New York Times, Feb. 11, 1968. 2.

[xiii] Kay Loring, “Lake Point Tower Opens Continental Restaurant.”  Chicago Tribune, Aug. 2, 1970.  F5.

[xiv] Alvin Nagelberg, “Plan Lake Shore Dr. Apartments.”  Chicago Tribune, June 23, 1971.  C9.

[xv] “Developer Tells Need for Evanston Tower.” Chicago Tribune, June 18, 1967. 1-d1.

[Chicago Skyscrapers, 1934-1986, published by University of Illinois Press, is out now–available on Bookshop.org and Amazon.com, among other outlets.

Executive House. (Milton M. Schwartz ,1959). 

Hotels were one of the last sectors to resume construction in the Loop after the twenty year building hiatus; by the end of the 1950s, no new dedicated hotel building had been built in downtown Chicago since Holabird and Root’s 23-story Chicagoan was built as an extension to the Morrison Hotel, on West Madison, in 1932.  Seeing an overdue opportunity developer George S. Lurie, along with his partner, Jerrold Wexler and two local lawyers, spent much of the decade assembling parcels on Wacker Drive at the northward bend in the River.[i]  In 1956, working with Draper and Kramer, they arranged a $3,500,000 loan from Aetna Life Insurance to cover 50% of their costs.  In June of that year, they announced plans by Milton M. Schwartz, then enjoying the acclaim from the attention given to his 320 Oakdale and Constellation apartment towers, for a 37-story skyscraper containing a unique mix of units that blurred the distinction between apartment and hotel.[ii]  Apartment hotels had a long and mixed history in Chicago—they formed a critical supply of short- and medium-term housing for middle class workers who were able to afford daily or monthly leases but preferred not to commit to longer contracts.  Most were built to provide studio—or, in the term of the day, ‘efficiency’—units, with small kitchenettes that were typically supplemented by cafes or restaurants.  Their appeal to young singles was apparent in constant controversy over their construction.  Often opposed by neighborhood organizations who feared the moral implications of night clubs and large groups of unmarried residents, they saw a gradual change from single-sex to co-ed in the 1950s along with more of an appeal to the lifestyle benefits of the arrangement.  Lurie and Wexler, though, claimed a different motive. In talking to investors, they found reluctance to fund pure residential development in the Loop itself.  More certain of the market for business travelers, and recognizing the aging stock of hotel rooms downtown, Aetna had been willing to fund a ‘hotel’ but not an ‘apartment’ project, and the investors carefully announced the project as a ‘luxury hotel’ while instructing Schwartz to design the building with kitchenettes in every room.  The investors signed a management contract with Condado, a Chicago hotel company, and gradually recognized that the central area was “vastly underbuilt in the apartment hotel field,” where efficiencies and kitchenettes were associated with flop houses on skid row more than with luxury living.[iii]

The hotel’s program reflected Lurie and Aetna’s hedged bets on the future of downtown living; more than 85% of the building’s 448 units were studios—essentially hotel rooms with kitchenettes—providing for both hotel guests and for longer term renters.  A restaurant and café on the ground floor replicated the usual apartment hotel amenity, while a cocktail lounge on the roof offered views of the city and, because of the project’s siting, of the River’s main branch.  All interiors were provided with air conditioning, and a 200-car garage in the basement could be rented daily or long term—as at the Constellation, Schwartz specified an automobile elevator to save space.  Wexler and Lurie proposed rents that reflected the additional services that the hotel arrangement provided—at $150 per month for a studio, rents were about a fifth higher than rates for high-end rentals within walking distance of the Loop and daily rates of $16 were similarly aggressive for local hotels.[iv]  But tenants and guests would receive more than access to parking, bars, and a restaurant; finished in ‘gleaming metal and glass’ and with balconies providing fresh air and views, the freshly-named Executive House would also, its backers argued, appeal to the growing taste for urban living among young residents.  Initial inquiries were promising; Loop corporations were particularly avid, signing long-term deals for units on what Wexler called the “New York basis,” where company personnel and guests could be put up in their dedicated units while visiting on business.[v]  But responses from prospective hotel guests were also strong, and Condado recognized another potential market in tourist and executive families, who would find the suites and kitchenettes particularly attractive.[vi]  Ultimately, just eight of the building’s 37 floors were reserved for permanent residents.

Schwartz initially proposed a cylindrical design for the site but, as at 320 Oakdale, he faced stiff resistance from financial backers for such a radical scheme and instead focused, again with structural engineer Henry Miller, on maximizing views and efficiency.  The site was a particularly narrow one, restricted at the rear by Holabird & Root’s 1932 Automobile Club building.  Schwartz and Miller’s plan responded with a tightly integrated reinforced concrete structure that relied on shear walls placed ever 40 feet to stiffen a 20 x 20 column grid.[vii]  Four centrally located elevators were tied directly to the concrete structure (a mistake that would plague the development with excessive mechanical noise until renovations in the 1980s), across a double-loaded corridor from two interwoven staircases that occupied a single fire shaft.  At the ends, one-bedroom suites took up the leftover site dimensions with subtle angles that wedged as much lettable area into the parallelogram of a site; the result was a supremely efficient floor plan of fourteen units per floor—six studios and two one-bedrooms, ten of which had balconies, six of which overlooked the River.[viii]  Miller’s design was, briefly, the tallest reinforced concrete structure in the United States, and, at 37 stories, the slab was, also briefly, Chicago’s tallest residential tower.[ix]  Interiors of the furnished units, along with the hotel lobby and restaurant, were designed by Morris Lapidus, then riding the popular success of the Miami Beach Fontainebleu, specified gold-upholstered settees to complement blue-green and gold finishes throughout the ground-level restaurant and bar.[x]  The “Executive Dining Room and Lounge” was pitched not only to guests and residents, but to the downtown business community as “an atmosphere of muted magnificence” in the “ultra-modern new 40-story skyscraper hotel.”[xi]

Lapidus’ trademark excess occurred within a project that featured notable technical advances in its foundations and cladding, as well as its record-breaking structural design.  The building broke ground, with Mayor Daley in attendance, at the end of January, 1957, and right away the job site attracted attention for its caisson drilling technique.  Schwartz, shocked by the poor safety record of foundation excavation in the city, demanded that the contractor, C.A. Tharnstrom & Co., use a French Benoto drilling machine that relied on its own dead weight to screw 3-1/2 foot diameter steel tubes into the ground, after which soil could be safely extracted by bucket from within.  The method eliminated the need to send workers into the fragile excavations—though Schwartz insisted on being lowered, himself, to take samples once the machine hit bedrock, but it also handled ground water more readily than traditional methods and it lessened noise and vibration, both critical on the tightly confined site.[xii]  The Benoto machine was a success, drilling on average one caisson a day over a two month period over 110 feet deep.

Surrounding Miller’s reinforced concrete structure, Schwartz designed a glistening stainless steel skin that functioned as both enclosure and, on the building’s balconies, as a parapet.  Grand Rapids-based Haskelite manufactured the metal panels, laminating 26-gage stainless sheets to 4’ x 8’ foam cores 1” thick.[xiii]  These were held in place by aluminum z-bars and steel angles connected to embedded plates in the adjacent concrete slabs, all of which provided a precise, even surface that had none of the oil-can effect that marked Inland Steel’s cladding, a few blocks away.[xiv]  The resulting elevation was, like Schwartz’ 320 Oakdale, expressive of its slab construction, presenting a powerful horizontal grain to the river that was capped by the asymmetrical cocktail lounge with bright neon signage—a sleek, stylish contrast to the art-deco rocket of Lincoln Tower next door.  Fully enclosed units in the center of each floor formed a light vertical counterpoint, but Executive House’s overwhelming sense was that of cool, trim horizontality, emphasizing its views out and over the River and City instead of the grasping skyward reach of the earlier generation. Executive House proved enormously popular; Schwartz’ careful planning and Lapidus’ interiors did, in fact, appeal to the broad range of business travelers, families, downtown professional singles, and corporate guests that Wexler and Lurie had imagined, and the building filled with eager residents and guests even as construction finished in February, 1959.[xv]  While the building itself enjoyed continued success due to its location and its amenities, its namesake parent company—renamed to reflect Executive House as its flagship property—floundered in the late 1960s after disastrous expansions including an airport hotel in San Francisco and resorts in Puerto Rico and the Caribbean.  The company filed for bankruptcy in 1971, but Wexler and his company maintained an interest in the building.  Under management by Ramada in 1986 the building underwent a renovation that enclosed the original balconies and replaced Schwartz’ original clear glass with deeply-tinted, blue-green panes that have obscured the original, more elegant proportions.[xvi]  The project’s success was proof that there was a strong market for both hotel and residential construction downtown; it also extended the height to which reinforced concrete seemed viable in skyscraper construction. 

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[i] Ernest Fuller, “Work Begins on Downtown Apartments.”  Chicago Daily Tribune, Jan. 31, 1957.  D7.

[ii] Ernest Fuller, “Plan Skyscraper on Wacker Dr.: Tallest Apartment House in City.”  Chicago Daily Tribune, June 21, 1956.  3.

[iii] Ernest Fuller, “Many Inquire of Leases in Wacker Bldg.”  Chicago Daily Tribune, Mar. 25, 1957.  C5.

[iv] Ernest Fuller, “Many Inquire of Leases in Wacker Bldg.”  Chicago Daily Tribune, Mar. 25, 1957.  C5.

[v] Ernest Fuller, “Many Inquire of Leases in Wacker Bldg.”  Chicago Daily Tribune, Mar. 25, 1957.  C5.

[vi] “Loop to Have 1st New Hotel in 2 1/2 Decades.” Chicago Daily Tribune, Sep 27, 1957. 1-c9.

[vii] “New Hotel in Midwest Offers Unusual Facilities: Executive House, Chicago, IL.”  Architectural Record, Vol. 125, no. 5.  May, 1959.  215-218.

[viii] “New Hotel for Chicago’s Loop [Executive House].”  Architectural Forum, Vol. 3, no. 2.  August, 1959.  124.

[ix] “New Hotel in Midwest Offers Unusual Facilities: Executive House, Chicago, IL.”  Architectural Record, Vol. 125, no. 5.  May, 1959.  215-218.

[x] Richard J.H. Johnston, “Chicago’s New Hotel Ready to Open.”  The New York Times, Jan 25, 1959.  X31.

[xi] “New Hotel for Chicago’s Loop [Executive House].”  Architectural Forum, Vol. 3, no. 2.  August, 1959.  124; and “Executive House Announces the Opening…” Display ad, Chicago Daily Tribune, Feb. 28, 1959.  18.

[xii] Ernest Fuller, “Many Inquire of Leases in Wacker Bldg.”  Chicago Daily Tribune, Mar. 25, 1957.  C5; see, too, Schwartz Oral History, ARTIC [????]

[xiii] “Executive House Steel Face Shines in Dark.”  The Chicago Defender, Jan. 31, 1959.  4.

[xiv] “New Hotel in Midwest Offers Unusual Facilities: Executive House, Chicago, IL.”  Architectural Record, Vol. 125, no. 5.  May, 1959.  215-218.

[xv] “Guests Filling New Hotel as Work Goes On.”  Chicago Daily Tribune, Jan. 10, 1959.  B5.

[xvi] Karl Plath, “Executive House Puttin’ on the Glitz to Edge Rivals.”  Chicago Tribune, Sept. 13, 1987.  [????]

31 December 2022 Update: The State of Illinois has sold the 23-acre site on which the Santa Fe silos (now known as the Damen silos) stand to the owners of MAT Asphalt, a company with a checkered history of influence and community relations in Chicago. MAT’s owner has indicated they intend to demolish the silos and redevelop the site sometime next year.

Some loyal readers will know that, alongside my research on commercial high-rise construction, I’ve very happily gone down a rabbit hole the last few years chasing the history of the city’s grain elevators–Chicago’s “other” skyscrapers. That’s a comparison that was made by many at the time–Inland Architect said in 1896 that “the first sky-scraper was a grain elevator,” and when the Montauk was built in 1882, at 130 feet it was shorter than seven of the grain elevators that lined the River at the time.

That history is, I hope, going to be the subject of a published paper sometime next year–the city’s elevators were instrumental in its role as a financial center, and even though there are only a handful of structures left–and none from before 1900–their influence can be seen in Buckingham Fountain, IIT, Wacker Drive, and the U.S. Supreme Court…it’s a doozy of a story.

But they also impacted building as a whole, pioneering technologies that were adapted by commercial skyscraper architects once they’d proven themselves. Mechanical transport, temperature monitoring, and pile foundations all saw proving grounds in grain elevators, sometimes decades before their application in buildings for people.

One of the most influential pieces of technology transfer came from Chicago engineer John S. Metcalf, who constructed one of the first concrete grain silos in Indianapolis, and who was commissioned by the Santa Fe Railroad in 1906 to build silos and an elevator for their freight yard at Damen Ave. and the Chicago River. Like most elevators, this one was designed to buffer the flow of grain from points west, arriving by rail, by providing storage and a docking facility for lake barges that could carry the grain to points east. Its location, two miles upstream from downtown, speaks to the congestion that was plaguing the River by this point, but it also illustrates the position of Chicago as place of exchange and transfer–the Santa Fe was one of over 100 elevators built before the Depression that allowed the city to absorb the influx of corn, wheat, and other grains from the midwest and Plains states.

Metcalf’s innovation was to apply a new material–reinforced concrete–to the problem of grain storage. Concrete was fireproof, a big improvement over the timber elevators that had been constructed throughout the 19th century, but one that required skilled carpentry to build the cylindrical formwork needed to build silos that could, by incorporating hoops of reinforcing steel, resist the fluid pressure of a hundred or so feet worth of vertically piled grain. In 1904 and 1905, Metcalf patented a system of moving formwork that used donut-shaped forms, about four feet tall, to pour one day’s worth of concrete at a time. The next morning, after a pour had cured to a working strength, laborers would crank the forms up another four feet, using steel rods embedded in the concrete as rails to support the forms and their attendant scaffolding platforms, and to assure that they rose truly vertically. Scientific American referred to Metcalf’s innovation as ‘quite as simple as it is ingenious,’ as it reduced costs for concrete construction below those for steel.

Metcalf built thirty-five silos out of concrete for Santa Fe in 1906, paired with a head house constructed of timber that housed the elevating machinery and the ‘marine legs’ that could take grain up, or discharge it, into waiting barges. In 1932, the wooden head house burned, but the concrete bins were unharmed by the fire and the railroad commissioned Metcalf to rebuild the head house in concrete. Both of these structures–the original 1906 bins and the rebuilt 1932 head house–are extant but in ruins, abandoned by the railroad in the 1970s and taken over since by the State of Illinois. Given the importance of slip-form construction to concrete high rises, Metcalf deserves more credit than he’s ever had as the inventor of this system. He also, along with engineer Jason MacDonald, also of Chicago, deserves recognition for building an astonishing number of slip-formed concrete elevators throughout the United States and Canada, and for revolutionizing the type; after Santa Fe, all grain elevator construction in Chicago, and most of it throughout the midwest, switched from timber to concrete.

The Santa Fe is one of just four pre-WWI elevators left standing in Chicago–in addition there are two along the Calumet River and one (threatened) in the West Loop. Metcalf’s pioneering bins are the most visible of these, though, as they can be seen from the Stevenson Expressway and the Orange Line CTA. They deserve some sort of landmark designation as one of the last links to the most important trade in the city, and for their own quiet beauty–the end elevation of the 1906 bins is, frankly, something a lot of architects would be happy with today.

Happy to report that the Construction History Society of America will a) hold its next meeting from 22-24 June, 2023, and that b) the University of Illinois at Urbana-Champaign will host it.

This is a happy change in schedule–since 2006 we’ve held biennial meetings based on what had been a relatively relaxed flow of new research and papers. Over time this proved to be a bit awkward whenever the triennial International Congress synced up with us. Since the next ICCH is going to be in 2024 (in Zurich, more info here), and since the American field has grown quickly, the CHSA Management Committee has decided to hold annual meetings in subsequent years, filling in the gaps between the every-three-year International gatherings.

Marci Uihlein and I will co-chair next Spring’s meeting on the (beautiful) campus of the University of Illinois at Urbana-Champaign. We have a website that includes the just-released call for papers, also included below. More to come on keynotes, tours, and social events, but for the moment mark your calendars and please share this CFP widely. Our meeting this past summer at Kennesaw State in Georgia was a demonstration of how far the field has come in the Society’s brief existence and we’re looking forward to even broader participation from preservationists, historians, architects, engineers, and general enthusiasts…

8TH CHSA MEETING – JUNE 22-24, 2023 – UNIVERSITY OF ILLINOIS AT URBANA CHAMPAIGN

Construction History Society of America announces CALL FOR ABSTRACTS for the 2023 Biennial Meeting on Construction History

Held at the Illinois School of Architecture, at the University of Illinois at Urbana-Champaign

June 22-24, 2023

We invite researchers and practitioners from all aspects of the history of construction to submit paper abstracts on subjects for the 2023 Meeting on Construction History, to be held in Urbana-Champaign, Illinois. The meeting will be hosted by the Construction History Society of America and the Illinois School of Architecture at the University of Illinois at Urbana-Champaign and follows successful meetings of the CHSA held in Marrietta, GA (2022), Seattle, WA (10th Anniversary Members’ Meeting 2017), Austin, TX (2016), Minneapolis MN (2014), Cambridge MA (2012), Philadelphia PA (2010), and Atlanta GA (2008).

ABSTRACTS FOR PRESENTATION

Abstracts will be compiled in a hard-copy catalogue to be distributed at the meeting.  Presenters will be asked to give their talks within 20-minute time slots.  A curated Proceedings, including completed papers of 4000-6000 words, will be assembled and edited by the Scientific Committee following the conference.

Additionally, CHSA encourages authors to also submit full papers to Construction History according to their publication schedules. The submission of an abstract for the CHSA Meeting does not exempt papers from the Journal’s review process. 

EACH ABSTRACT MUST INCLUDE: 

• authors’ names and institutional affiliations
• an abstract of 300 words.
• key words (selected, if possible, from the list of topics and subjects),
•   a one-page curriculum vitae indicating contact information, status, laboratory affiliation if relevant, and publications or other relevant work for each author.
• All presentations must be in English.
• 4-5 learning objectives, for use in AIA CES documentation.

ABSTRACT TOPICS MAY INCLUDE:

• Construction and engineering in Chicago and other regional cities

• Rural and agricultural construction, particularly in the Midwest

• The role of education in the building professions, especially in the region

• History and construction of specific projects

• History of the building trades or specific builders

• Organization of construction work

• Wages and the economics of construction

• The development of building codes and regulations

• Trade unions and guilds

• Military or Army Corps of Engineers

• Structural analysis and the development of structural forms

• Development of construction tools, cranes, scaffolding, etc.

• Building techniques in response to their environments

• Building materials, their history, production and use

• History of services (heating, lighting etc.) in buildings

• The changing role of the professions in construction

• Building archaeology

• Computer simulation, experimentation and reconstruction

• Use of construction history for dating of historic fabric

• Recording, preservation and conservation

• Construction in architectural writing

• The role of construction history in education

• The bibliography of construction history

• The theory and practice of construction history

IMPORTANT DATES:

Dec. 15, 2022                                                Abstract Deadline

TBD.                                                          Online Registration Open

Mid-Feb., 2023                                             Author Notification

April 15, 2023                                                Author Registration Deadline

June 22-24, 2023                                           Conference

The saga of Helmut Jahn’s State of Illinois Center/Thompson Center seems to be coming to a happy end for preservationists and Loop advocates with the news that Google will buy, renovate, and occupy the building (headline writers can’t resist adding “after long search…”)

Google’s move reverses a worrying trend of disinvestment as commercial tenants have been leaving the Loop in droves as remote work has encouraged alternative locations and office arrangements. Anchoring the center of the city with a few thousand employees is a good thing for transit, for retail and dining establishments, and for the city in general.

From a preservation point of view, it remains to be seen whether Google lives up to the not-totally-fulfilled promises of the 1986 building. Always a public favorite, access to its glass atrium and rotunda (stunning but environmentally dubious) is in question, as are its iconic Miami-Beach-on-Clark-Street curtain walls and postmodern? deconstructivist? follies that worked better as axonometric drawings than public sculpture. Jahn’s original curtain wall design was supposed to combine structural glazing with insulated glass, but this proved beyond the capabilities of manufacturers and installers in the 1980s. With Google’s deep pockets maybe this gets revived, though the basic physics of its southwest southeast-facing, 14-story glass atrium can’t help but present environmental challenges. (Thanks for the correction, Kevin G.–your proofreading merit badge is on its way…)

Less heralded but equally good news, IMHO, is the announcement that the State will decamp from the Thompson Center to the “old” Harris Bank/BMO tower a few blocks south. Designed by SOM and built in the early 1970s, it’s a vastly underappreciated example of the firm’s most rigorous work, with a finely tailored stainless steel curtain wall and central core elevators that are effectively suspended above the ground floor lobby and accessed by escalator, leaving the space wide open. It’s a subtle building, and hemmed in enough by its neighbors on La Salle Street that it’s hard to notice, but worth a look–especially as it presents a neat contrast with the first Harris tower, also by SOM, on the eastern end of the block. That was designed by Walter Netsch, a rare skyscraper by him, and the contrast between the gothic-like tracery of Netsch’s tower and the robust, if latent, classicism of the later one, by Bruce Graham, is pretty clear.

State of Illinois had a complex history. It emerged as the last, long-delayed element of Mayor Daley’s plan to keep Federal, City, and State offices downtown and as the sole piece of the ill-fated North Loop revitalization plan championed by Arthur Rubloff. If that had gone through, much of the area east and north of SOIC (including, unbelievably, Rapp & Rapp’s iconic Chicago Theater) would have been razed, replaced with megablocks and skywalks that, in hindsight, would have been disastrous. Jahn and then-governor James Thompson both saw the utility in producing a striking, press-release-worthy building, but making the complex geometry and giant atrium work proved difficult. The project suffered cost overruns, declining support in the local press, and serious thermal and water infiltration problems. Budget cuts eliminated new furniture and even doors on private offices–one wag at the Tribune noted that, finally, the State was living up to its promise of “open government.” But the atrium and basement food court (a new innovation in 1986) were immediately popular with workers and the public–the building regularly was cited as both the “most hated” and “most loved” building in the city.

If Google keeps some public access, if it leverages its ownership into much-needed improvements to the CTA station attached to the Center, and if it invests in restoring or replacing the building’s cladding, this will prove to be a good thing. I’ve written critically about the efforts to landmark and salvage the Thompson Center before–I think the costs and consumption needed to keep energy-hogging buildings alive and running has to be taken into account when we have these conversations–but if Google is picking up the bill and if it’s willing to keep the best aspects of the building while fixing the most difficult this could be a win…

It’s been a great irony that, with all the traveling to see Nervi buildings I had not–yet–been to the one closest to my home base. St. John’s University in Collegeville, MN hired Marcel Breuer to masterplan their campus in 1953 and the central church, with its iconic bell tower, was the centerpiece of Breuer’s extensive work on the campus. Its design and construction paralleled that of the UNESCO conference hall, which Breuer designed with Nervi and Bernard Zehrfuss from 1955-58. (The best design history of the structure is Victoria Young’s Saint John’s Abbey Church: Marcel Breuer and the Creation of a Modern Sacred Space (U of Minnesota Press, 2014).

The two projects have immediate similarities–but also key differences that are interesting as insights into two very distinct but related careers. UNESCO has always seemed important to me as a moment where two really thoughtful approaches–Breuer the International Style modernist and Nervi the process- and pattern-oriented structural engineer–merged for a very brief moment and profoundly influenced one another. Breuer emerged from the projects as a confirmed brutalist, interested in the expressive power of exposed concrete and robustly displayed structure, while Nervi’s work expanded into more sculptural (if far more restrained) territory.

UNESCO on the left, St. John’s on the right. Both house a large assembly space under a folded concrete plate roof–the corrugations give thin concrete planes the depth necessary to act as beams, and you can see that both structures rely on deep, stiff connections between vertical and horizontal members to become portal frames. Breuer clearly appreciated the architectural impact of the folded plates–their deep recesses create a strong pattern of light and dark that gives both spaces rhythm and scale. Crucially, though, the folds run the long direction of the UNESCO space while they run the short direction of St. John’s–perpendicular to the liturgical axis:

The effect is recognizably gothic–the structure emphasizes the march down the aisle to the altar, which is notably open and pushed forward into the congregation as an early experiment in what would become standard design in post-Vatican II churches. So far, so good. Nervi thought that gothic churches represented a high point in structural and architectural integration, and would have been entirely on board with Breuer’s sensibilities here.

How those corrugations landed, though, was a matter of contention. Breuer wanted the heavy roof to sit above strips of windows that would illuminate the sanctuary from ground level–making the concrete appear to float. Again, not unlike gothic structure, but look at where the folded plate/portal frames land. Their loads are collected by a deep concrete girder that carries them over apertures to the bearing piers. That’s a bit of structural gymnastics of the sort that Nervi criticized heavily. A good gothic builder (or, for that matter, Roman or Greek) would have “put solid above solid,” both a recipe for structural efficiency and for visual satiety. Syncopating the structural rhythm of the plates and windows does make for a striking visual–but for Nervi this was a distraction from the otherwise holistic conception of the structure and space. While he wrote–extensively–about UNESCO, Nervi rarely mentioned St. John’s, and from correspondence it’s clear that he considered this a less successful manifestation of the folded plate idea than the conference center in Paris.

Nervi was farther from Collegeville than Paris, of course, and that shows (perhaps) in the quality of concrete. As a contractor, Nervi’s knowledge of formwork and mixes was extraordinary and the craft that went into the surfaces of his poured-in-place work is rarely given the credit it deserves. UNESCO’s concrete shows the level of fine detail that would have come from having that knowledge going into design, specs, and site supervision. St. John’s concrete is far rougher, and Breuer was happy to have the random color differences and rough surfaces that would come to typify brutalism on display. Both approaches work, and Breuer’s late career would take this acceptance of concrete ‘as-stripped’ much farther.

So, a far less “pure” Nervi work and one that relied more on his calculation than design instinct. That doesn’t take away from the sheer architectural power of the Abbey, though–Breuer on a good day could produce genuinely awe-inspiring spaces with the best of them, and you can see him starting to stretch his sculptural and spatial instincts as well, beyond the relatively straightforward efforts in his houses to that point. In particular, the balcony, set up on cantilevered piers and grazing but not touching the back wall of the sanctuary, is a tour de force, or, really, a tour de forces, that is almost Wrightian in the way it compresses and explodes as you move under it:

The bell tower–easily the best-known piece of the composition–contains something of a tribute to Breuer’s collaboration with Nervi. Its base is recognizably splayed, reflecting the shape of the Eiffel Tower, which sits at the opposite end of the Champ de Mars from the UNESCO building.

Collegeville is about a 70-minute drive northwest on I-94 from Minneapolis and well worth the trip, especially if your traveling companion knows to recommend the bear claws at Nelson Brothers Bakery in Clearwater. If you can throw in a Twins or St. Paul Saints game or two, so much the better.

Architecturefarm has been offline while we relocate our main offices to our new ‘east coast’ location (in the words of an Iowa neighbor, to whom Illinois might as well have been Massachusetts when we moved in). Still, lots to report and ponder about the last semester, which was sort of bookended by two righteous quarry visits.

Our hotel studio this year was based in Rome, amongst the Nervi Olympic projects–full details to come, but the highlight was a field trip that we felt needed to make up for our students’ two years of being stuck at home. In addition to Rome, we took them to Florence and (split-squad) to Venice, Bologna, and Mantua, exactly the sort of whirlwind tour that I’ve usually tried to avoid. In this case, though, we agreed with the studenti that an antipasti tour that whetted their appetites for more, future travel was only too appropriate.

My teaching partner, Lee Cagley, offered Carrara as a day trip. This has always been a bucket list stop for me–picturing Michelangelo stomping around picking the perfect piece of marble is irresistible (even if apocryphal), but Lee’s background in high end hospitality design came with connections that made a day there even more extraordinary, with a Land Rover tour throughout the mountains, lunch in the foothills, and a back of house visit to a shop that let us see the marble get gradually refined from massive blocks into architectural and sculptural pieces.

My seminar class on building history puts stone construction near the very start of the syllabus, comparing it with timber in the way that materials not only have to be fabricated and assembled but also harvested. Timber is relatively easy, but stone obviously requires another orbit of technology–cutting, shaping, transporting, etc. Seeing the scale of the operation and how challenging it is even with giant machinery puts a lot in context and makes it clear that proximity and the existence of good paths or roads to get the stuff off the mountain and into the shops were determinant factors in stone architecture. (Watching giant trucks hauling multi-ton blocks down cliffside gravel roads from the back of a Land Rover drives this home rather well…)

Base camp included an open-air museum of quarrying techniques, replacing those giant tractors with…wedges and water, an ancient technique still used into the early 20th century that relied on the expansion of wetted wood to crack large pieces into more manageable sizes:

A slightly different vibe this past month at the 2022 Biennial Meeting of the Construction History Society of America at Kennesaw State in Georgia, where tour day involved descending into the pit of an aggregate quarry. At Carrara, aggregate is what happens when they hit a bad vein or a stone breaks poorly–a way to salvage what they can out of what would otherwise be an expensive bit of rock. Marietta is all gravel, all the time–one of hundreds of local quarries that provide the raw material for roads and highways instead of finish stone for buildings. And while the scenery wasn’t quite coastal Italy, the scale was still impressive.

Both places naturally spur questions about extractive industries and renewability–seeing the amount of earth carved away and scaling it to a century in Marietta’s case or a couple of millennia at Carrara makes it clear both how abundant the raw stuff of building is in the earth and the expenditure of raw power it takes to remove it. Students on the tour in Italy asked a lot of hard questions about the impact on the local environment, and that pipe in the middle ground of the Georgia quarry is there to pump a pretty toxic brew of ground water out of the pit and into a treatment facility. The scale of the equipment also makes it clear why building and buildings account for 50% of our energy consumption:

Any chance to get students, in particular, to see the roots of their choices is an important part of understanding the larger contexts of what we as architects do, so Carrara was a great moment. It was also part of a milestone semester, in that it was the last time Lee and I will teach our integrated hotel studio together; he’s off to enjoy a well-earned retirement. He and I have enjoyed five years of coaching teams of interior designers, architects, and landscape architects into working together, finding overlapping interests, subtly clashing value systems, and the frustrations and rewards that come with trying to meld all of those into coherent pieces of design. Have we swept a few Hospitality Design student competitions along the way? Made wrong turns and ended up on the wrong continent? Hiked bands of students up a volcano or along the shoulder of an Italian autostrada? We have. I’ll miss watching Lee at work, as he’s been a truly brilliant studio instructor, someone who has taught me as much as he has our students.

Very happy to report that I’ve accepted an invitation to join the University of Illinois’ School of Architecture as a Visiting Professor for the 2022-2023 academic year. Champaign-Urbana will be a great base camp as Chicago Skyscrapers, 1934-1986 finishes up–the School is just a few blocks from its publisher, the University of Illinois Press. Once the book is out in the world I’m hoping for many opportunities to talk about it in and around Chicago, which will be a short train ride away.

A short ride and a familiar one. Illinois is my alma mater and Champaign-Urbana is where I grew up. That train ride was a key element in early, formative trips to Chicago, and it’s been an enjoyable reprise to take it down to campus for studio reviews over the last few months. Those reviews have featured great work and Temple Hoyne Buell Hall has been full of impressive energy each time. I’m looking forward to being a part of that, teaching alongside some good friends and at least one of my undergrad professors, as well as completing the new book in particularly appropriate surroundings.

Thanks to all who have made this happen…

Our rough schedule for the Structures Zoo course is to go from heavy to lightweight, introducing students to more and more exotic structural types as we go (sort of like going from the goats in the petting zoo up through the penguins, orangutans, and eventually the lions…) We’re closing in on the end of the semester, and the last lab or two should be doozies, but the more recent one definitely turned a corner as we went from membrane structures to what I think of as networked structures.

The paradigm for these is the geodesic dome, invented by (or, really, rediscovered, packaged, and marketed by) Bucky Fuller. The evolution of the dome through his initial attempts at Black Mountain College (and, I think, at Chicago’s Institute of Design, but that’s another post), shows a gradual refinement from structures based on flat members arranged in “great circles” that failed, to geometric patterns that arranged nodes around a spherical surface, connected by multiple linear elements. The result was a structure with vast redundancy–like a monolithic concrete structure, a true geodesic presents a nearly incalculable number of potential paths for gravity and lateral forces to take. As a result, it functions very much like a shell structure, but with nearly all of the weight removed.

Exotic enough, but all of those elements are sized to take either tension or compression. A particular variant of the geodesic experiments, (pictured at the top) involved figuring out how to organize the linear elements so that compression and tension could be isolated–in other words, placing the heavier, compressive elements only where they were needed and rendering the rest of the dome in thinner, lighter, tensile elements–cables.

The instigator of this idea was Kenneth Snelson, who went on to a career as a sculptor and consultant for all sorts of projects employing this principle. But Fuller also co-opted it, calling it “tensegrity” and (depending on who you believe) claiming it as his own. While geodesics were a bigger business success, tensegrity ranks higher on the exotic structures spectrum because of the uncanny openness the principle creates:

Super weird-looking, right? But also completely stable. If you start at the base, you can see that the structure is based entirely on triangulation–think of it as a three-dimensional truss. Each compression element has its ends stabilized by three cables, fixing those two points in space. As long as you can trace those cables through other, similarly fixed points back to the foundation (the nice, boring equilateral triangle at the bottom), the whole thing is stable–at least mathematically.

So, on the desktop, using wood stirrer sticks for compression elements, regular string for tension, and duct tape to make joints, you can very quickly and simply build a network of triangulated members, finding stability where you can and fixing points by watching where the structure is floppy or where it feels fixed. Student teams started with sterilite boxes, and quickly realized that the secret to building these is that you have to go down to go up–that some tension elements want to pick up gravity loads by reaching down (thus ensuring that they’ll always be in tension), while you can use the compression elements to gain height–with impressive results. A second ‘family’ of cables stabilizes the compression elements’ upper ends, fixing points of triangles to give the whole structure geometric stability.

One team went with a precedent study, building an analogue version of the structure that held up the (now-demolished) Georgia Dome. You can see the “go down to go up” principle at work here as the structure “climbs” a series of (red) compression elements to gain height. Again, there’s some missing rigidity in the short axis, but they’ll get there.

These get impressive pretty fast–here’s Rob admiring that first team’s finished product, a cathedral-like tower of sticks that seems to float almost by magic, even if you know the trick (also, in the background, ace knitterbot sculpture by ace ISU digital fabrication team, for inspiration).

The Georgia Dome is still among the best examples of the principle at work in practice, and its limitations are apparent when you start poking at these models–even with all of the triangulation you’re dealing with inherently flexible structures, and once you realize that you have to design for wind-related lateral forces and uplift in addition to gravity the deflection issues get more difficult. But the results are, to say the least, visually compelling, and tensegrity’s material efficiency is remarkable.

So, what’s lighter than light? That’s this week’s lab…