TEHRAN – Safavid-era (1501-1736) arch bridges of Sikapol and Bozpol in the northern province of Golestan are planned to undergo some rehabilitation works in the near future, a local tourism official has said. 

A budget of two billion rials ($47,600 at the official exchange rate of 42,000 rials per dollar) has been allocated to the project, Jafar Khanduzi announced on Tuesday. 

Upon the order of Shah Abbas the Great (r. 1588 – 1629) thousands of kilometers of roads were constructed throughout the country during the Safavid period to stimulate trade and travels, the official explained. 

“One of these roads was the Shah Abbasi Road, which connected northern Iran to the central province of Isfahan over these two historical bridges, but most of the road has been destroyed over time,” Khanduzi added.

Though the construction of these two bridges and the road is over 400 years old, they are still in use despite needing major repairs, he noted.

The bridges and the road were registered on the national heritage list in 2019. 

An arch bridge carries loads primarily by compression, which exerts on the foundation both vertical and horizontal forces. Arch foundations must therefore prevent both vertical settling and horizontal sliding. Despite the more complicated foundation design, the structure itself normally requires less material than a beam bridge of the same span.

Arch bridges can be classified into deck arch bridges (featuring arches below the deck) and through arch bridges (those with arches above the deck, generally tied arches). In all arch bridges, the structural difficulty can be found in the minimization of the misalignment of the arch axis and the line of thrust, as well as a sufficient bending and buckling resistance. General design recommendations focus principally on the arch-to-span ratio, the arch and deck slenderness, and the number of hangers or piers.

Recent innovative arch bridges include high-speed railway (HSR) bridges, concrete-filled steel tubular and precast concrete arches, high-performance concrete or ultra-high performance concrete arches, and steel-concrete composite arches, and feature innovative erection methods. Recent research has been dedicated to the shape and magnitude of equivalent geometric imperfections, fatigue detailing, erection methods, reduction of the arch's self-weight, and new materials for arches, hangers, and ties.

Golestan is reportedly embracing some 2,500 historical and natural sites, with UNESCO-registered Gonbad-e Qabus – a one-millennium-old brick tower – amongst its most famous. Narratives say the tower has influenced various subsequent designers of tomb towers and other cylindrical commemorative structures both in the region and beyond. The UNESCO comments that the tower bears testimony to the cultural exchange between Central Asian nomads and the ancient civilization of Iran.

ABU/AFM