Affecting Factors of Iranian Historic Bridges Architecture Generation on Uneven Areas

As architectural elements, bridges have served as connective structures since old times. The functional value of bridges is a reason why researchers have paid insufficient attention to environmental and climatic factors despite the fact that bridges are directly affected by contextual conditions in terms of their form and structure. It is not surprising that before bridges, as architectural elements, were constructed to overcome natural obstacles and in particular to pass across rivers and valleys, our ancestors used to face serious barriers that limited the expansion of human civilizations to other places. For instance, bridges that are built in areas with rugged terrain are characterized by fundamentally different criteria which require detailed research. Conducted through a descriptive-analytical and historical-comparative method based on comparative research, the present study aims to explore the formation of bridges in areas with rugged terrain in terms of the three principles of function, form and structure. The findings suggest that in mountainous areas with rugged terrain, bridges are often built over valleys to facilitate transportation, hence, lacking any sign of decoration or embellishment in the formal aspect. In addition, maintaining a solid structure and strong foundation work via the use of stone and bricks are of special importance. In conclusion, special topographic features in mountainous areas lead to specific subtleties in the bridge structure. In terms of function, bridges in areas with rugged terrain are built, in the first place, to facilitate transportation across natural obstacles, which made it impossible or difficult to pass across. From the physical perspective, because bridges in areas with rugged terrain are mostly built for their function and role in communication, less attention is paid to decoration. After all, in terms of structure, foundation work, subgrade construction and reinforcement for resistance and durability are of crucial importance to make possible the transportation of vehicles and pedestrians, all of which require the application of solid materials in mountainous areas with rugged terrain.