Comparative Study of Facade Ornament, a factor in understanding of scale, Function and structural expression; (Case Study: modern and postmodern era)

Ornament, has a special role in the understanding of the user, in the scale of the building, its function, and structural expression, so that the amount of ornament used, the location and the relationship with the components of the building, make it an effective and special element in the history of architecture. Shortage of coherent studies between ornament and mentioned factors caused this research to done.  The question of whether ornament can influence the perception of the user in understanding the above factors is important. Therefore, the present research hypothesizes that in the periods of history, the ornament has been in the pursuit of goals such as functional clarity, scalability, and clarity in the structural expression, and in periods has disconnected with clarity of these factors. Previous studies have surveyed ornament from the point of geometric dimension and semantics without considering these three factors mentioned above. This paper has a comparative- analytical approach. Accordingly, the components of "scale", "functional clarity" and "structural expression" are described with a focus on the subject of "ornamentation" in the two periods of modern and postmodern architecture, were surveyed using content analysis and referring to written and visual sources of Architectural examples of each two periods (Famous works by vanguard architects). The comparison is carried out in two phases of qualitative (for some famous building) and quantitative (by a checklist) methods in architecture. Selecting and evaluating the selected statistical society was done in the form of a checklist. The criterion for completing the checklist was based on logical reasoning and the authors' assessment of the available evidence. In selecting case studies, at first 100 samples of buildings - 50 samples for each period - were selected as target samples. The reason for being targeted at this stage has had the selection of the appropriate works of the famous architects. Then, 50 cases (25 samples for each period) were selected randomly to achieve the validity of the samples which was used in the quantitative evaluation. Then, among the works of the indexes of the mentioned periods, some of them were purposefully explained the results and their quantitative description.  Finally, it was concluded, from quantities and qualities analysis, that the type of ornamental approach could play a role in understanding the scale, functionality, and structural expression. In modern architecture, the style of Chicago school, there is an organic approach to ornamentation, it has united with the materials and to increase the effective exposure of the three indicators considered in this article. Also, in modern European architecture, with the removal of ornament is emphasized on the clarity of the scale, building function and in the expression of the structure in most works of that period. But in postmodern architecture (initial and shell oriented postmodern), with the disconnection of the decorative shell with the interior space and orientation of the decorative wall to the environment and the effect of it, a different approach was seen and vice versa than in the previous two periods.