Based on comparative study of historic bridges of Isfahan

Document Type : Research Article



Continuation of experiences in the historical Iranian architecture used to traditionally pass from one generation to the next. The application of such experiences, when facing new requirements and situations, was a platform for a rebirth of new works, which were generally accepted by the society. Isfahan’s historic bridges are examples of the development of such processes which reached their peak during the Safavid era. This thrive, with building of new bridges  and restoring old ones, happened as a result of  economical prosperity and  growth in Isfahan, which was the capital of Iran during the Safavid era.  Khajoo bridge, among all others, has a different form and characteristics and these differences raise questions about the formation of this bridge.  This is based on the accepted concepts and experiences noted in the construction of other bridges at that time. Examples include common traditions and ideas taken into account in other bridges. Primarily, the present research studies the characteristics of Khajoo Bridge that have made it stand out among all other bridges and as well as the features that have led to the creation of a new set of behavioral and physical characteristics in the building. In order to find the appropriate answers to these questions, the researchers have focused on three basic architectural systems: function, physic and structure. By studying and comparing historic bridges in Isfahan with other bridges in Iran, it seems obvious that the success and the importance of these bridges can be best characterized by these basic architectural systems. It should be noted that these three systems are associated with Vitruvius three rules (effectiveness, stability and beauty).  The meaning of function in this research is related to the way the bridges were connected to the city, how they fitted in to the urban fabric, and how they communicated with the network of access points connected to the entrance and exit of the city. It is also important to identify the roles of the bridge and their special incorporated services since the bridges were not only built for transit purposes but they have also had other functions, as well.  The bridges have been used across history as a dam, a defense structure and as a space where people could gather, meet and socialize. They have also been used for channeling the water and helping with rotation of water mills, controlling waterways, and obtaining merchandise taxes. The purpose of analyzing physical form of the bridges is to identify the architectural result of function and what would become a shell, structure and shape of the building. This part of discussion includes the investigation on the division of the facade, plan and identification of corresponding areas. Also structural system in this research means analyzing skeletal structure and transition of forces. The approach of this study is basic.  The method of research is descriptive-analytical. The research data has been gathered through library sources and field observations. In this way, various traditions of building bridges in the region according to historical precedence were studied through the mechanism of comparative and mostly qualitative research.  In discussing the function, Khajoo Bridge similar to Shahrestan, Marnan and Allahverdykhan bridges, created connections to southern towns and villages. Also, during the construction period of Khajoo Bridge, the Zoroastrians were living in the adjacent neighborhood and this bridge connected this religious community to the city. Prior to that, there was a similar role identified between Marnan Bridge and the Armenian community.   On the other hand, Khajoo Bridge has a defined beginning and an end, attempting to connect citizens to Takhtefoolad. This property existed in Allahverdikhan Bridge (Dolatkhaneh Safavi to Hezarjarib) and Jooei Bridge (North gardens to Sadaatabad Garden and Ayenekhaneh and Haftdast palaces). In addition to its transmission role, Khajoo Bridge like Shahrestan, Marnan and Allahverdikhan Bridge had the role of a gateway to the city. Another function that was especially associated with this bridge was becoming the dam. Another feature is having different spaces in its different parts.  This property is affected by the concern to accommodate the presence of human in the space of architectural designs.  Such characteristic of the bridge began to take form with the creation and integration services. These spaces can also be found in Rahdarkhaneh in Shahrestan Bridge, Saqqakhaneh in Marnan and Allahverdikhan Bridge. Such attention to human presence in space, specifically in Khajoo Bridge, has been made by Combination Bridge with pavilion; creating eastern stairs, and platforms between arches and recreational space for the pedestrians. In discussing the physical form (body), the evolution of non-geometric and organic bridge (Shahrestan Bridge) to geometric bridge (Khajoo Bridge) has been highlighted in the present research. Among these bridges only Allahverdikhan and Khajoo Bridge have two level aspects with eastern and western facades due to their porous porches. In terms of division plans and facades, Khajoo Bridge has evolved as a sample for the bridges in the region specifically for its emphasis on the early, the middle and the end of the body.  When discussing the structure of the bridge, it is interesting to note that a design that had been used to make candle foundation in Marnan Bridge continued and evolved in Allahverdikhan and Khajoo Bridge. Another feature is the transmission of forces in Khaoo Bridge which is very similar to Allahverdikhan Bridge with some differences in the lower levels.  In fact, in Khajoo Bridge the lower platform occupies much more surface that leads to a better transmission of forces.In the end, the continuity of traditions in shaping the form of Khajoo Bridge has been detected. The results thereof are based on specific principles like the continuity of common traditions, as well as the conditions and the needs of the community. Identifying these can possibly be effective in applying conservation methods, as well as creating and giving life to architectural work, specifically to bridges.