Architectural treatment

Finding a suitable architectural expression for the frame building gave architects two separate problems:

In working with a framed structure, architects had to consider two important issues, namely:

• the expression of the steel frame (as distinct from the heavier masonry counterpart)
• finding a suitable composition for the tall multistorey building.

In this respect it is interesting to compare two of Jenney's buildings:

• First Leiter Building, Chicago (1879) in which the elevation was simply and clearly divided by columns and slightly recessed spandrels which carried three bays of windows separated by light mullions. But, despite this light, frame-like appearance, the masonry columns were actually self supporting.
• The Home Insurance Building, a later structure, with its 4+3+4 division of the elevation by large piers.  It had wide brick mullions between the windows giving it much more of the appearance of a loadbearing masonry building. It was not until the building was demolished that it was realised that the walls were carried by the frame.

The strength and slenderness of the steel frame presented the opportunity to lighten the feel of the ground floor.

Later, in his Second Leiter Building (1889-91), and his Fair Store (1890-91), Jenney returned to the lightness of the elevational treatment of the firstLeiter Building. Jenney's Fair Store building makes a play of the light frame and heavy cladding to give the appearance of a freer ground floor level.

If iron beams and columns were now able to carry the weight of the masonry, then the verticals within the elevation need no longer be carried through to the ground. One might imagine them instead interrupted by girders. This appears to have been done in Jenney's Fair Store where the piers dividing the elevation are interrupted at second floor level and their load apparently distributed over three columns, while at the ground floor there is a return to the original column spacing. However, illustrations of the building during construction show that this is a trick. The columns are continuous, the effect simply produced by building the masonry piers on the upper floors much wider than was necessary to protect the columns.

What is seen in many examples from around this period is a lightness on the store front ground floor with a relatively heavy treatment of the office floors above.

Buildings which made a particular play of a more open ground floor arrangement include the following:

• The Guaranty Building by Adler and Sullivan (1894-95)
• TheStock Exchange Building again by Adler and Sullivan (1893-4)
• The Gage group of buildings (1898) principally by Holabird and Roche, (the last building of this group is by Sullivan).

In the Gage group the buildings have piers thinned down to a minimum, emphasising the slenderness of the loadbearing members that was achieved with metal construction. The architects used that same slender treatment of columns in their McClurg building but all the spandrels were set back from the columns.

Perhaps the most successful expression of the slenderness of the steel frame at this time was Sullivan's Carson Pirie Scott store, where the elevation was a series of simple frames.

A feature which became popular was the bay window.

Freitag commented that, "With the introduction of steel construction and veneer methods came the demand and possibility of constructing the bay windows, a feature which has become more or less prominent in modern office building and hotel design."

These bay windows, which were not carried below the first floor level, were constructed by cantilevering supporting frames from the spandrel girders.

Jenney, in hisManhattan Building, also used the technique filling the elevation with bay windows as a way of getting light into the building. However, the clearest expression of this technique came with Burnham and Root'sReliance Building of 1894, which used terracotta cladding over the frame to give a lightness to the form.

An architectural design approach for high rise buildings gradually developed.

Sullivan explored the treatment of high rise buildings such as the Wainwright Building, St. Louis (1890-91).

In this building and the Guaranty Building, Buffalo (1894-95)  he looked for an expression of the function of the building rather than an expression of the steel frame that supported it.

Sullivan, who wrote The Tall Office Building Artistically Considered (1896), took a conservative approach for his early buildings. The auditorium building which he did with Adler was very traditional in its external treatment in spite of the innovative structural arrangement within.

With the need for fire proofing there could be little direct expression of the iron and steel in the skyscraper.

Although Jenney exposed the iron at the doorway of his Manhattan Building  elsewhere it was confined to occasional galleries beams where architects could show an interest in the expression of this new material. Furness in Philadelphia, for example, as early as 1871 exposed the iron beams that carried the masonry walls of his Academy of Fine Art, and in the UK a similar use of iron is to be seen in the St. Pancras Station Building, London. 

In Europe  interest focussed more on an expression of the use of the material for which the visual and structural problems were quite different.

The architectural development of steel structures around the turn of the century in Europe needs to be considered separately from its development in America because, although there was no use of tall skyscraper buildings, steel was still used in construction and there was, if anything, a greater interest in an expression of the use of the material in Europe. Of course, the visual and structural problems were quite different.

But it was in Paris  that a number of offices, workshops and department stores explored the architectural possibilities of the new material in a series of buildings along the Rue Reamue in Paris. These were built between the years 1895 and 1903, and were, stimulated by an architectural competition. Here the complete steel and glass facade was achieved in the offices of Le Parisien where closely spaced, riveted columns carry deep spandrels under the windows, and dramatic oriel windows just under the roof.

There was a similar dramatic use of iron and steel structure in interiors.

Eiffel and Boileau had built the iron and glass structure of the Bon Marche in 1876 and other department stores were to follow this lead. Today, exposed structure can still be seen in the Samaritain store in the Rue Rivoli with exposed girders and columns decorated partly with wrought iron work, but also with fake iron castings which are actually plaster.

Of this period it was Horta in Belgium who is best remembered for the extensive use of iron and steel in both the elevations and the interiors of the Maison de Peuple. Nevertheless, the limitations imposed by the need to protect steelwork against fire continued to limit its direct expression in multistorey framed structures.

But the ball was rolling, and by the early 1920's Rudolf Schindler, working on the west coast of USA, was able to encapsulate the architectural mood that the potential of the iron and steel frame had generated:

"Architectural forms symbolize the structural functions of the building material. The final stage of this development was the architectural solution of the steel skeleton; its framework no longer a symbol. It has become a form itself"