Bridges calm roaring rivers; that break their twists and turns and make their way to the other side of the river. But a bridge is not always like this, and sometimes it brings fear into the hearts of those who are afraid of heights. So, while a bridge can break the river’s roar and rush, it can also be frightful. The Shadirwan Bridge in Shushtar district, had such features in its ancient past.
In the northwest of Shushtar city, on a branch of Karun River and 300 m away from mizan dam, Shadirwan Bridge stands with a long history. Mizan Dam is a dam in Shushtar and a remnant of the Sassanid era that has remained stable until now. It is a realm that was of great value to the designers of Sassanid structures, and they created works there that are considered masterpieces of engineering.
During the reign of Shapur I, Sassanid, in 260 AD, 70,000 Roman prisoners were brought to Shushtar with Valerian to help build a bridge designed by Iranian engineers. The prisoners were placed around Dezful and assigned to build dams and bridges. That is why the late Shadirvan Bridge was sometimes called “Caesar Bridge” or even “Valerian Bridge”. Valerian, the Roman emperor, is the one whose statue is engraved in Naqsh-e Rostam and Tang-e Chogan, in the heart of Mount Mehr, and shows him kneeling before the Sassanid Shapur. He was defeated in the battle of Odessa by the Sassanid Shapur.
There was a legend that Valerian had brought a hill’s soil from Rome to Shushtar at the request and order of Shapur. It was from this soil that the Shadirwan Bridge and other structures were built. This legend existed because the soil of shushtar, where the Shadirwan Bridge was built is not suitable for building, and so the soil was brought from other places. It is also worth mentioning that after the bridge’s construction, Shapur ordered the release of the Roman captives. They returned to their homeland, Rome.
Features of the Shushtar Shadirwan Bridge
To build the bridge, the Sassanid engineers covered the bed through which the river passed with smooth and cut stones and metal fasteners. Thus, they made a bridge that is about 500 meters long. The bridge also had 44 large spans and 43 small spans. Of those openings only 9 are left in the north side of the bridge and 28 in the south side of the bridge. Of the many bridges built during the Sassanid era, Shadirwan Bridge is one of the most beautiful. The art used in constructing this structure shows the advanced knowledge of structural construction in Iran in those centuries. The Shadirwan Bridge, in comparison with other bridges in Iran, has a prominent place in various historical periods and has the aesthetic values of architecture and the use of structures. In the construction of the bridge, stone, mortar, and ash have been used. Carved stones can also be seen everywhere on the bridge.
Nearly 1800 years have passed since the construction of Shadirwan Bridge. It is clear that during this period, the flooding of the Karun River and floods and many other unpleasant natural events have damaged the bridge. In addition, human intervention has also been efficient in destroying parts of the Shadirwan Bridge. Hence, the bridge has been rebuilt several times in different historical periods. Historical documents testify that the Shushtar Bridge was restored during the reign of Buyids (in the fifth century AH), Safavids and Qajar dynasties, and there are signs of those reconstructions and manipulations in the body of the structure. During the conquest of Fath Ali Shah of Qajar and in the years that followed, this bridge was completely rebuilt and restored. Those reconstructions followed the works done by order of Safavid kings to keep the Shadirwan Bridge closed. The last restoration was done in 2001, and two spans of this bridge were reconstructed.
One of the most important uses of the Shadirwan Bridge was for the Sassanid army to cross from western Iran to the east. On the other hand, Shushtar Bridge established trade links between Iranian cities. However, building the bridge was not just for military purposes and to create trade routes. The Sassanids wanted the construction of the Shadirwan Bridge to calm down and raise the water flow and lead it to the Dariun River. The Dariun River is a tributary and a fantastic water canal built at the same time. This made it easier to irrigate the fields around the bridge, and many foundations were made for structures like this.
The Sassanids built the Shadirwan Bridge to be used also as a dam. Those who have done extensive research and studies on the Shadirwan Bridge believe that this bridge was part of a comprehensive plant built in that area; however, little is known about those engineering facilities, and we do not know their mechanism. It is also worth mentioning that mills were built next to the bridge, the wheels of which were moved by the force of water. Thus one can imagine how magnificent the Shadirwan Bridge was during its heyday.
What does Shadirwan mean, and why was that bridge called so? It has sparked many discussions, and several reasons have been cited. It is not possible to recount all those views here. Except that Shadirwan is a word with Parthian roots and has been given different meanings. Such as blinds, the base of structures, patterned and precious carpets and other examples. It is believed that because the floor of Shushtar Bridge was covered with cut stones and had a beautiful view, it was named Shadirwan.
Shadirwan bridge manifests the beauty of Sassanid art and shows a part of Iranian design and engineering in the distant historical centuries. Therefore, this bridge has a prominent and proud place in Iranian architecture.
* Using the website of “Sassanid researches” and also the article “Shadirwan Bridge” written by Emad al-Din Khazraei (Golestan Honar Magazine, 1387- No. 13).