Khaju Bridge (Pol-e Khaju) is one of the historic bridges of Isfahan on Zayandeh Rood. Walking on this bridge, especially at night can be one of the most memorable moments of your life. The night life on and around the bridge is also exciting. There are many bridges crossing Zayandeh Rood, but Pole Khaju is especially significant and is known the most beautiful bridges in Isfahan. The structure was listed in the national heritage sites in 1931 with ID number 111.
It is located in east side of Sioseh Pol and has a magnificent view in terms of architecture and its decorative painting and tilework. The bridge was built on the order of Shah Abbas II on the ruins of Hassan Beyk Banna’s bridge from the Timurid period. It which links the northern and southern banks of Zayandeh Rood. On the eastern side of the bridge, there are two stone lions, which are probably the symbol of the Bakhtiari army of Isfahan during the Safavid era. The distance of the bridge from the river bed is about eleven steps. The pass way of the bridge is made on delicately carved bricks. It has 23 arches, and is 133 meters long and 12 meters wide.
There are several sluice gates under the archways, regulating the water flow of the river. When the sluice gates are closed, the water level behind the bridge is raised to facilitate the irrigation of the many gardens along the river upstream of the bridge. The upper level of the bridge, which is the main central path was meant to be used by horses and carts, while the passersby could use the vaulted paths on either side.
The interesting fact about the bridge is that unlike other bridges, the foundation of Khaju bridge needs water for stability. There is a stone near the two stone lions in the norther part of the bridge that serves as a compass to indicate the direction of Qibla.
During the excavations that were done for the restoration and reconstruction of the bridge in 2009, the exquisite and old tombstones with strange carvings were discovered most of them, however were damaged during the excavation but the remainders are now kept safe in Takht-e Foolad Museum.
Proportion principle is an important factor in architecture that creates asymmetry and visual beauty. Pol-e Khaju is an axample of this principle; a linear organization of repetitive spaces with the same function. There are 21 halls under the bridge, located separately from one another with the main middle space that connects them. The size and proportion of this middle space is designed in a way that it supplies the light as it provides visitors with the view from the two sides of the bridge. The bridge is 150 m in length, 12 m in width with 21 streams and 26 closures or springs. It is a four-story bridge with two upper side-pathways and 51 chambers. The height of the bridge from top to the closures is 20 meters.
Aside from bricks in the façade and pebbles and cobbles used in river bed, stairs, and the pathways paving other materials used in Pol-e Khaju include sarooj, tiles and wood.
Sarooj: a traditional water-resistant mortar, a mixture of clay amd lime with specifc proportion. It is a very suitable material for bridges due to its resistance against water.
Tile: it is used mostly for decorative purposes throughout the bridge. The clay brick tiles known as Haft Rang (seven colored) is a glazed clay brick.
Wood: wood is used for temporary water structures. In Khaju Bridge it is used at the back side for the valves that would create a lake behind the bridge.
Benefits of the bridge as a dam
The lake behind the bridge served as a magnificent view along with the surrounding gardens. Sometimes water contest would be held in the lake; swimming, boat rowing and so on.
The lake would serve as a reservoir during the seasons with water shortage.
At time of the tides, the streams branching from the lake would take the water to downstream gardens.
When the gates were closed, the pressure of the water would drive the mills.
The Khaju Bridge has two eastern and western sides, each with a building called Shah Neshin or Royal Section with several decorated rooms. The building was meant to be a temporal residence for the royal family and the monarchy guests who would visit there or attend an event (e.g swimming or boat rowing matches inside the water).