The collapse of a suspension cable bridge in Gujarat’s Morbi, which killed around 140 people, has evoked strong political slur from West Bengal’s ruling party Trinamool Congress, but has also turned out to be an eye-opener for the state government considering the state’s record of the bridge collapses.
In the words of a senior engineer with the state public works department (PWD), who refused to be named, “while politics is in it’s place, the thoroughly undesirable tragedy at Morbi has at least pressed the panic button for the department to have a fresh review of the conditions of the bridges and flyovers in the state”.
On Tuesday, the state PWD minister, Pulak Roy called an emergency meeting of the top bureaucrats and engineers of the department to have a review of the conditions of the bridges and flyovers.
According to Roy, in the meeting spot decision was taken to thoroughly rebuild two major bridges in the state. The first being the Birendra Sasmal Bridge over Kangsabati River connecting Midnapore and Kharagpur towns in West Midnapore district and the second being the Coronation Bridge, also known as Sevoke Roadway Bridge over the Teesta River connecting Darjeeling and Kalimpong Bridge in north Bengal.
At the same time, the minister has also ordered that the health of all the bridges and flyovers in the state be checked and a report be tabled within a month. He also sought details on the bridges where plying of heavy vehicles can create hazards or tragedies.
While that is the official decision of the meeting and the official versions on this count, there had been some revelations that transpired during the course of the review meeting. Sources said that as per the preliminary findings there are around 45 to 50 bridges in different corners of the state, which are between 50 and 60 years old, where simple patchwork or even thorough renovations will not work out and need to be thoroughly rebuilt to make them safe for vehicle movement.
“The estimated cost of doing that will be around Rs 3,000 crore, which is currently a big amount for the state PWD department considering the financial constraints imposed on the department,” a department official present in the meeting said.
IANS talked to a couple of structural engineering experts to have a clear understanding of the technical factors where and when a bridge or a flyover needs to be thoroughly rebuilt instead of undergoing renovation or patchwork.
According to founder-director of Citius Infracon Private Limited and structural engineering specialist, Anindita Moitra Das, generally the life span of a bridge or flyover is determined on various parameters of Indian Standards (IS) which start from 35 years.
“This duration of the life span is dependent on various parameters like weight varying capacity and the quality of material used, among others. At the same time, there are different parameters by virtue of which it has to be decided where plying of heavy vehicles would be allowed and where not. The monitoring, maintenance and renovation should be an ongoing process starting from the day of its inauguration till the end of its life span as per the IS parameters concerned, when the bridge needs to be thoroughly rebuilt. Unfortunately, in India such detailed processes are not followed in most cases,” she said.
Another city- based structural engineer, Pradipta Mitra said that the factor that determines the weight-carrying capacity of a bridge or a flyover is the base- strength of that bridge or flyover.
“Certain major and traditional bridges like Howrah Bridge, Second Hooghly Bridge, Nivedita Setu or even some smaller bridges like Dhakuria Bridge or Gariahat Bridge have extremely strong bases and hence can carry the weight of heavy goods vehicles or passenger vehicles. On the other hand, Maa flyover that connects the city with the Eastern Metropolitan Bypass might be an extremely long one, but does not have that strong a base for allowing movement of heavy vehicles. Again, the strengths of the bridge or flyover bases depend on the quality of materials used. And yes, whether strong base or not, constant monitoring and maintenance of the bridges and flyover are necessary during the entire interim period till such constructions come to the end of their life-spans” Mitra added.
On March 31, 2016 just before the West Bengal Assembly elections a steel span of the under-construction Vivekananda Road Flyover at Girish Park in North Kolkata collapsed killing 27 people.
On September 4, 2018, the Majerhat Bridge in the southern outskirts of Kolkata collapsed killing three people.
On March 3, 2013 a huge portion of the Ultadanga flyover in the Eastern Metropolitan Bypass that connects VIP Road with the Netaji Subhash Chandra Bose International Airport in Kolkata. However, no one was killed in the mishap.