Rumi Darwaza ‘most vulnerable’ to earthquake

Can we imagine Lucknow without the iconic, imposing structure of Rumi Darwaza? Perhaps not, but in the event of an earthquake in the state capital, which falls in the seismic zone III, the 1784 AD structure built during the regime of Nawab Asaf-ud-Daula would be among the first monuments to come crumbling down.

This conclusion was drawn from a recent study carried out by the department of civil engineering of Indian Institute of Technology, Kanpur (IITK), whose experts defined the majestic monument as the ‘most vulnerable standing monument of the city’.

“Its fast decaying state is posing a grave threat to the monument. On the basis of facts that came to the fore during tests we carried out early this year, the monument might be an easy victim to any seismic event,” Durgesh C Rai, professor at IIT-K, told HT.

In the seismic evaluation carried out under Rai’s guidance, students of IIT-K found that the seismic load carrying capacity—that decides the behaviour of the structure at times of earthquake—of the ‘masonry arch gate’ was below the average mark.

“In an ideal condition, the

IT IS IMPORTANT THAT THE ASI ENSURES QUALITY WORK AT THE MONUMENT TO ENHANCE ITS STRENGTH SO THAT IT BECOMES STRONG ENOUGH TO WITHSTAND ANY FUTURE SEISMIC EVENTS

DURGESH C RAI, IIT-Kanpur professor

seismic load capacity of Rumi Darwaza should be at least 21% of its weight whereas the actual capacity was estimated at 17%. It’s far less than the seismic demand for the monument falling in seismic zone III,” said Rai.

Often referred as the Turkish Gate, Rumi Darwaza is 60-feet tall and built using Lakhauri bricks and ‘lime-surkhi’ mortar.

It is said that delegates accom- panying the British army in 1858 had referred the stretch from Rumi Darwaza to Chhatar Manzil as the most beautiful cityscape — even better than that of Rome, Paris, London and Constantinople (Istanbul).

However, over the years, vagaries of the weather have taken a toll on Rumi Darwaza. Vibration caused by frequent vehicular movement has further added to the damage.

In the seismic evaluation, the team of experts had also carried out an on-site ambient vibration testing to measure the dynamic property such as its frequencies by placing sensors at four different levels in both longitudinal and lateral direction of the monument.

“It was found that the excitations of the structure could be largely due to the vibrations caused by vehicular movement and also due to environmental loading,” Rai said.

These measurements were used to calibrate the computer model used to compute seismic demand on the monument.

In the tests, the latest Complex Mode Indicator Function (CMIF) technique was used under which the sensors were installed at the monument to calculate the vibrations. “We also used a threedimensional model of the monument using ABAQUS software to calculate accurate figures,” he said. The maximum stress, Rai said, was found at the base of the structure and also at the junction of the arch pillar. Other than this, maximum stress also occurred at corner openings and junctions of the arch pillar. “And this is not a good sign,” said Rai, adding, the information has also been shared with the ASI for future references.

“It is important that the ASI ensures quality work at the monument to enhance its strength so that it becomes strong enough to withstand any future seismic events,” said the IIT-K professor. When contacted, PK Mishra, superintending archaeologist, Lucknow circle, said, “We are using the best quality mortar available for maintenance and repair of the monuments.”