chicago skyscraper of the week–continental I

Continental-National Insurance was a Chicago-based firm, organized in the 1890s, that purchased the Straus Building on Michigan Avenue in 1943–and then quickly outgrew its 600,000 or so square feet of floor space. In 1960 the company announced two schemes for expansion to the west, along Jackson Street–one saving Holabird & Roche’s 1912 Cable Building in February and another, demolishing the Cable and two other adjacent structures, in September after the neighboring owners realized they would be ‘boxed in’ by Continental-National’s expansion plans.

The schemes were designed by C.F. Murphy & Associates, which had just undergone a tidal change in personnel. Murphy, the titular head of the office, was not an architect–he was, instead, perhaps the greatest business development operator Chicago has ever seen. He had his start in 1912 as Daniel Burnham’s personal secretary, and rose through the ranks of Burnham’s successor firms, finally emerging with partner Sigurd Naess as Naess + Murphy in 1947. Naess was a conservative designer, best known for the fairly stodgy Prudential Building, and after his retirement in 1957 Murphy emulated Burnham in hiring a stable of young, talented designers who would go on to design many of the city’s postwar landmarks.

Among them were two IIT graduates, Jacques Brownson and James Ferris, who brought a staunch belief in Miesian aesthetics from their backgrounds. Together, they tackled Continental’s program, which called for vast, open offices to allow for efficient communication among their huge clerical staff and for easy re-organization. Brownson and Ferris addressed this with unusually large, 42′-0″ column bays organized around a tightly-planned central core, leaving each level with around 19,000 square feet of usable space.

Typical Floor Plan, from Architectural Forum, May, 1963.

But those large structural bays presented a problem in that they required deep girders, and Continental-National’s other requirement was that the floors in the new building be contiguous with those in the Straus to provide easy circulation throughout. Murphy’s structural engineer responded with 27″ deep beams with unusually heavy sections that allowed large openings toward the center of each one to accommodate the building’s s double-duct mechanical system. The result was a compact floor sandwich–just 37″ total–within the Straus’ comparatively tight 12′-0″ floor-to-floor height.

Construction view showing openings in beams. Architectural Forum, May, 1963.

That was clever enough, but Brownson and Ferris’ Miesian leanings led to further innovation in the building’s integration of cladding and structure. Frustrated with the need for fireproofing around steel members, they looked for ways of expressing the building’s steelwork in a more direct fashion than the attached I-beams that had become Mies’ trademark cladding solution. “I like to see what really is,” Brownson later explained, “what goes on with things.” Their solution was to take advantage of a loophole in Chicago’s building code that required “bearing” structural elements to be fireproofed. This, they argued, left out wind bracing, allowing a building’s lateral system–provided it took no gravity loads–to be left unprotected.

Brownson and Ferris laid out a scheme that provided a fully self-supporting gravity system–the heavy column and internal girder in the detail above–but then detailed 3/8″ steel cover plates that served as the outer formwork for the fireproofing concrete that would be poured around these elements. These cover plates were designed with welded studs that made them monolithic with the concrete and, through another set of welded studs, with the columns and girders themselves. Exposed on the exterior, these cover plates became part of the welded frame’s lateral system–Roche relied on them to take some portion of the structure’s wind loads–but they also served as exposed cladding. They thus fulfilled three integrated purposes–lateral resistance, formwork, and facade.

Brownson and Ferris added vertical find to the spandrel panels to maintain flat surfaces against the fluid pressure of the poured concrete that align with stainless steel mullions framing the building’s continuous windows; they also detailed shadowgaps behind the column covers that reveal the thin nature of the steelwork overall. These details helped to articulate the building facade as a series of layers that offer a sense of cross-grain and hierarchy, with the column covers set out farthest and the girder edges, window mullions, girder plates, and glass all set back in a coordinated sequence that reads like a tartan grid of vertical and horizontal lines:

The result recalls the layered facades of 19th century lofts, especially those by Holabird & Roche, where this trick of layering horizontal and vertical elements produced visually rich elevations like that of the Gage group:

Continental opened in 1962 to wide critical acclaim. The Chicago chapter of the AIA called it “the finest commercial building of recent years” and Progressive Architecture explicitly noted its adherence to “the principles of the 19th Century Chicago School.” Carl Condit wrote about the building frequently, citing its “peculiar combination of force and dignity” and also praising the inspiration that it clearly drew from past, local examples. “The articulated walls of the Continental addition are so emphatically drawn” from such forebears as Ayer McClurg or Schlesinger and Mayer, Condit argued, “as to make it seem as though the long discontinuities between past and present had never existed.”

Brownson would go on to expand upon many of the Continental’s cladding and structural ideas in the Civic Center, which came into Murphy’s office as a joint venture with SOM and Loebl, Schlossman, and Bennett while Continental was on the drawing boards. Ferris would jump ship several years later when Graham, Anderson, Probst, and White won the commission from Continental–then renamed the CNA Group–to design the much taller (and much more colorful) expansion to the south along Wabash.

from Progressive Architecture, Sept., 1963

Sources:

  • “13 Buildings in Chicago Area Win Honors for Their Architecture [Continental 1].  Chicago Tribune, Apr. 10, 1964.  17
  • “Big Bays in Chicago. [Continental I]”  Architectural Forum, Vol. 118, no. 5.  May, 1963.  121.
  • Commission on Chicago Landmarks, Preliminary Landmark Recommendation: Continental Center, 55 E. Jackson Blvd.  (Chicago: City of Chicago Department of Housing and Economic Development, 2011).  13, 15.
  • Carl Condit, Chicago 1930-70: Building, Planning, and Urban Technology.  (Chicago: University of Chicago Press, 1974). 
  • Carl W. Condit, “The New Architecture of Chicago.”  Chicago Review, 17:2/3, special issue on New Chicago Writing and Art.  1964.  111-112.
  • “Evolution of the High-Rise Office Building.”  Progressive Architecture, Vol. XLIV, no. 9.  Sept., 1963.  155.
  • James M. Gavin, “Continental Shows Off New Skyscraper.”  Chicago Daily Tribune, July 24, 1962.  C6.
  • “Steel Plate Exterior Serves as Cover for Fireproofing [Continental].”  Architectural Record, Vol. 132, no. 2.  August, 1962.  156

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