TEHRAN -- Part of a ramp to the historical Si-o-Se Pol Bridge has collapsed as result of excavation for the Isfahan Metro on Monday.

In January 2010, by redirecting the original course during excavation work, structural damage was done to the western end of a tunnel for the Isfahan Metro near the Si-o-Se Pol Bridge, which dates back to the Safavid era.
Thus, the Isfahan Metro was forced to stop excavating after many cultural heritage enthusiasts and experts have protested because of possible negligence by the tunnel contractor.
Excavation was resumed last week, an unnamed source told the Persian service of CHN on Tuesday.
The tunnel-boring machine has excavated 70 to 100 meters, the source added.
Officials of the Isfahan Municipality, which owns the Isfahan Metro project, visited the Si-o-Se Pol Bridge, denying any connection between the collapse and the excavation for metro.
They announced that water pipes had burst, but only workers and machines of the Isfahan Municipality and the Isfahan Metro were observed at Si-o-Se Pol. No employee from the Water and Wastewater Organization were present at the bridge.
Si-o-se Pol, also known as the Allahverdi Khan Bridge, is one of a small number of Isfahan’s historical bridges spanning the Zayanderud River.
The construction of the bridge began in 1602 by order of the Safavid king Shah Abbas I.
The Isfahan Metro officials have said that the city’s metro will be operational by 2012.
Other metro lines under construction are threatening monuments located on Chahar-Bagh Street as well as in Naqsh-e Jahan Square, a complex of Safavid-era monuments registered on the UNESCO World Cultural Heritage List.
In 2001, UNESCO rejected the Isfahan Municipality’s request to construct tunnels beneath Chahar-Bagh Street and Naqsh-e Jahan Square.
Despite rejection by UNESCO and opposition by the Isfahan Cultural Heritage, Tourism and Handicrafts Department, the project’s tunnels were bored.
Experts believe that vibrations caused by metro trains passing underneath the monuments will cause damage to nearby historical sites.