All of these tall buildings in New York that I have reviewed were constructed with ‘boxed” construction, that is, while they had iron skeleton framing in their interiors, they still had masonry bearing walls/piers supporting the exterior. We have seen that this even included the 309’ tall World Building, whose walls at grade were 7’-4” thick. (Yes, Bradford Gilbert’s structure for the Tower Building was completely iron-framed, but this due more to expedience given the slender depth of the site than a straight-on attempt to build an all-skeleton framed building.) In fact, with the exception of Jenney’s 16-story Manhattan Building, I have shown that all of Chicago’s skyscrapers up to this point also had at least one masonry bearing or party wall. I posited that the reasons for this were two-fold: first, that Chicago’s building code required a masonry party wall for fireproof reasons, and second, economics, that is, a masonry bearing wall was cheaper than an iron-framed wall. The Manhattan was the exception, and this was due to the fact that an iron-framed party wall on both interior lotlines was less expensive because the two neighboring buildings contained printing businesses, and the cost of underpinning these to strengthen their respective foundations (in money and time) was prohibitive. Jenney had no choice but to erect the first tall building in Chicago that relied solely on an iron frame. My analysis of its structure, however, showed it to have been slightly “jerry-rigged,” that is, its structure wasn’t a systematic approach to a free-standing tall building but rather an empirical solution to the foundation problem.
The Masons had assembled the entire quarter block at the northeast corner of Sate and Randolph, with alleys on the north and east, i.e., like the Rookery; there would be no party walls required. Unlike the Rookery, the Temple was planned to be twice the height of the Rookery. There was no way of avoiding the facts, that is, a 20-story masonry bearing wall on Chicago’s soil would sink to China, as the Auditorium’s tower was proving. It was finally the moment to take on LeRoy Buffington’s challenge (v.4, sec.3.1). Could a free-standing skyscraper be built solely with a metal skeleton frame? Burnham, Root, E.C. Shankland and George Fuller would be the first to attempt to build Buffington’s iron skeleton-framed Cloudscraper, first proposed some two years earlier, and as such, it’s design and construction engendered great interest in the American press, equally in the Midwest as well as on the East Coast. It marked the end of the beginning phase in the development of the American skyscraper. Francisco Mujica, in his early history of the skyscraper published in 1930, stated that the Masonic Temple was “the first really important skyscraper in history.” A statement my research most emphatically supports.
Structurally, the Masonic Temple would fulfill Buffington’s prophesy in the Cloudscraper. A twenty-story steel frame with no supplementary rigidity provided by any bearing walls. Lateral stability was gained with the same system that Burnham & Root first tried in the Chicago Hotel: two lines of continuous diagonal bracing that were located on either side of the elevator bank that also supplied the columns for the long, clearspan trusses over the Masonic spaces in the upper floors. The diagonal bracing extended for two floors, typically intersecting the intermediate floor at a column connection. Very concerned about the overall stiffness of the frame, Burnham & Root’s engineer E.C. Shankland employed two-story iron columns that were arranged in an alternating pattern so that half of the columns in each floor were always continuous at that point. (This practice continued to be used in many skyscrapers up through the World Trade Center!) The foundations were detailed as the by-now standard construction of a concrete pad upon which were placed steel beams (one of Root’s many technical firsts). Shankland had calculated the amount of settlement he expected once the building had been completed and set the elevation of the top of the footings this much higher than the desired final elevation for the ground floor (again, a standard practice by then), expecting to bring the behemoth to a smooth landing…
The three-story triumphal-arched entry posed a significant structural problem in that there were two columns that carried the load of the seventeen floors above the arch that had to be transferred to the sides of the arch so that the opening would be column-free. Shankland placed a 25 ton, 7’ deep by 43’ long box girder immediately above the arch to carry the column loads over to the adjacent columns. (There is some irony in having to use a seven-foot deep steel beam so that an arch with this depth would have no loads to carry except its own self-weight…) The Chicago Tribune realized that the city’s builders had invented a new “type of the American school of Architecture, the masonry is only to protect the real supports of the building, steel beams.” (Once again, there are no similar claims made in contemporary accounts of the Home Insurance Building’s construction.) I’ll take the opportunity here to point out that the Tribune had called this the “American school of Architecture,” to reinforce my argument that there were, indeed, those in Chicago during this period that were aware of, and encouraging the development of a modern style of architecture in Chicago, i.e., the Chicago School of architecture..
FURTHER READING:
Hoffmann, Donald. The Architecture of John Wellborn Root. Baltimore: Johns Hopkins University Press, 1973.
Hoffmann, Donald. The Meanings of Architecture: Buildings and Writings by John Wellborn Root. New York: Horizon, 1967.
Monroe, Harriet. John Wellborn Root; A Study of His Life and Work. Park Forest: Prairie School Press, 1966.
(If you have any questions or suggestions, please feel free to eMail me at: thearchitectureprofessor@gmail.com)
The Architecture Professor 