The collapse of a suspension bridge in the Morbi of Gujarat has claimed more than 130 lives. The tragedy has raised questions about the British-era bridge’s design and structure.
New Delhi,UPDATED: November 1, 2022 9:00 PM IST
A British-era cable suspension bridge collapsed into the river on Sunday evening. (Image: Sanjay Samir / India Today)
By Rahul Gautam: The unlucky one Morbi bridge collapsed, which claimed more than 130 lives, has left the nation in great shock. After the collapse of the British-era bridge, questions arise about the structural design and engineering of the collapsed bridge.
To unravel the reasons behind the accident, India Today showed pictures of broken cables to Professor Mehtab Alam, Netaji Subhash University of Technology. Prof Alam has been teaching structural engineering to students for over 30 years.
Here are the excerpts from the interview:
Q: What would be the tensile strength of such a rope? What weight would it normally take if it were at full strength?
A: It is not possible to predict the total load capacity of rope in suspension bridges. It seems clear that the failure was sudden and it appears that the wires had no ductility (the property of metal related to its ability to be stretched into wire without breaking).
Q: Do you think the material used for wire could have been better?
A: I don’t know what material they used, what the grade was or what the breaking load was, but the broken wire shows that it lacked ductility characteristics.
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Q: Would the engineers have missed this danger signal a year ago when it was decided to give it up for repairs?
A: Very difficult to comment on. The responsible authorities should have gone through procedures and proper checks. Not sure if they got it right or not. But excessive loading seems to be the main reason for the collapse of the bridge.
Q: Many people have flatly ruled out the shaking/swaying of the bridge as a possible reason for the collapse. What is your opinion?
A: Jumping, shaking and swinging puts a lot of stress and strain on wires and cables. It could be one of the possible reasons behind the accident… Crowd should have been managed on the bridge.
Q: Even when hanging bridges collapse, is it normal for such strong steel cables to snap in half (rather than slowly tearing over time)?
A: There is no wear concept in suspension wires. When the final load is reached, failure is inevitable, breaking is inevitable.
Q: Would this “click” indicate that the steel cables were corroded or had lost strength for some other reason?
A: It’s not like that. I don’t think they were very corroded. It was recently renovated and I don’t believe the wires were corroded.
Q: If this was the condition of the bridge, was it right that the authorities recommended it for repairs, rather than demolishing it completely?
A: It’s not easy to talk about this, but renovated bridges should have been regulated and only the design load allowed. The crowd should be managed and activities such as dancing and swinging should not be allowed.
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