The second half of the 1920's was a period of prosperity for the city of Brünn, Germany (today Brno in the Czech Republic)(1). The city's architectural designers were ripe for the new Functional Architecture that was taking hold in Western Europe. A competition was announced in 1924 for the 26 hectare Exhibition of Contemporary Czechoslovakian Culture, Vystava Soudobé Kultury, which was to open in 1928 to celebrate the ten-year anniversary of the founding of the Czechoslovakian Republic(2). The architect M. Fuchs won first prize for the overall plan (see below left) and was also given the commission to design the pavilion for the city of Brünn. The commisions for the other buildings of the exhibition were then awarded by separate competitions.
The prize for the design of the main exhibition hall was given to Josef Kalous of Prague. His original design for the Industrial and Commercial Hall consisted of elongated buildings with a semi-circular, ribbed cross-section. The final parabolic form of the load-bearing structure was the result of the design influence of the engineer, Jaroslav Valenta(3). The two were able to provide a distinct monument which became the symbol of the exhibition.
The Industrial and Commercial Hall became a small complex of arched spaces in which all of the primary structural elements were reinforced concrete. The parabolic ribs of the two 124 meter long legs were laced together with a secondary structure of simple beams that had fields of glass block spanning between them. These met at a 30 meter diameter rotunda that was also of the same articulation. A remark was made in the press at the time concerning the disappointing effect of the interior space; "the dimensions of the arches are too massive due to our much too stringent building codes."(4) One must wonder if the resulting hall would still be standing if the ribs had not stood stolidly throughout the political upheavels.
When the hall is viewed from the outside, it appears as though the primary arches have been inserted within a box. These load-bearing elements peel away from the boxy skin of the hall at a point about three fourths of the way up their length. Prior to this point, the skin and the arches followed the same line, creating an effect which is quite dramatic. Noteworthy is an article which appeared in Wasmuths Monatsheft(4)in 1929, in which the parabolic form is harshly criticized as disquieting and nervous. This criticism seems to contradict the generally accepted opinion found in the literature at that time that the most logical form was also found to be the best formal choice.
The heavy beam, evident in the construction view above, provided the longitudinal stiffness for the structure. Thus, the box into which the arched ribs were set was the longitudinal stiffening element of the hall. It can also be seen that the formwork was the traditional wooden planking. The concrete was of normal strength and little mechanization was found on the building site.
The semi-circular form is not the best form for an exhibition hall. Van Doesburg(5) questioned the validity of the construction stating: "...one may question whether this construction in concrete, which somewhat resembles an iron construction imitated in concrete, is actually in order here." One must wonder whether he was questioning the use of the material concrete or of the structural form. If one accepted the view of these words, one would have to question the validity of the application of reinforced concrete to any skeleton frame structure.
The Hall in Brünn is another case of an exhibition hall that wasto be a virtual and real expression of the economic and cultural prowess of a community. The technology which was represented in the erection of the hall in Brünn was nothing new. Despite this, it was one of the earliest examples of the design of an entire structure with the combination of glass, glass block and reinforced concrete without an outer protective shell. The traditional gabled roof over the interior skin has disappeared. The Outside and the Inside have become one and the same element.
In this case, it is an expression of architectural intent, and not due to an advance in building technology. However, one finds the acceptance and desire for the Outside and the Inside not only to be expressed as one element, but also to be constructed as one element. This issue was critical to the later acceptance of the shell.