‘We need to find out whether any structural element has got fatigue.’
‘We want to increase the lifespan of the bridge.’
The iconic Howrah Bridge is due for a comprehensive health checkup after close to two decades.
The custodian of the bridge, the Syama Prasad Mookerjee Port, Kolkata (SMPK, formerly Kolkata Port Trust), is already engaged in discussions with the National Technology Centre for Ports, Waterways and Coasts — an incubation centre at the Indian Institute of Technology- Madras that works as the technology arm of the ministry of shipping and IIT-M.
Once the scope of work is defined, a call may be taken on roping in external experts if required.
The last major health audit by RITES for the British-era bridge spanned from the middle of 1980s and till early 1990s.
Based on the recommendations the work was executed by an executive agency which completed it in 2005.
“The time has come to take up a health check-up again,” says SMPK Chairman Rathendra Raman. “It’s due.”
The exercise is different from the maintenance work or check-ups that the port routinely undertakes.
“You may be going to the physician every day. But then there may be a time when you need a thorough check-up,” says Santanu Mitra, senior deputy chief engineer, SMPK.
A K Mehera, deputy chairman, Haldia Dock Complex, amplifies, in steel structures, there is a concept called fatigue. “We need to find out whether any structural element has got fatigue.”
The Howrah Bridge, the sixth-longest (third-longest at the time of launch) cantilever bridge opened to the public on the night of February 3, 1943. A tramcar was the first vehicle to roll down the bridge.
Almost 90 per cent of the steel was produced by Tata Steel (then the Tata Iron and Steel Company); the fabrication was done by Braithwaite, Burn & Jessop Construction. Some of the steel and special items were made in England.
Built over the river Hooghly, the bridge connects Kolkata and Howrah and is one of the busiest cantilever bridges with around 100,000 vehicles and 150,000 pedestrians using it on a daily basis.
Though heavy vehicles have been shifted to the Vidyasagar Setu (or the second Hooghly bridge), it’s a major connectivity especially if the Howrah station is considered, Mehera says. “That is why we are engaging with consultants because we want to increase the lifespan of the bridge.”
Earlier, paan-spit and bird droppings were found to have damaged the health of the hangers.
In 2011, an inspection showed that spitting had reduced the thickness of the hangers from six millimetres to less than three millimetres.
At that point in time, fibreglass covering was provided for the hangers, Mehera said.
Every 6-7 years, SMPK also does an extensive painting of the bridge which also gives protection. And every time the painting is undertaken, the bird droppings are also cleared.
The last painting job happened in 2015 and took about six months.
About 120 labourers and painters were engaged on a daily basis to complete it.
The next is due after monsoon this year and is estimated to cost Rs 2.8 crore (Rs 28 million).
Apart from the Howrah Bridge, SMPK is also planning to float a global tender for maintenance of the Bascule Bridge.
“We have written to the ministry; as soon as we get permission, we will float a tender,” says Raman. “This will increase the life of the bridge.”
Feature Presentation: Rajesh Alva/Rediff.com
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