The balanced cantilever bridge across Versova Creek is the latest refurbishment and strengthening project to benefit from Ramboll’s technical guidance and experience. The 49-year-old structure is a vital transport route connecting Versova and Mumbai to Gujarat and Delhi by road. In September last year the bridge was partially closed after cracks were noticed in the box girder. The bridge, which has two main spans of 114m, was undergoing a routine inspection as part of a state-wide bridge inspection programme following the Mahad bridge collapse in August that killed 28 people.
The rehabilitation of the bridge began in February after it was decided to undertake external pre-stressing using a technical solution designed by Ramboll in India and the UK. This involved introducing a compressive force to the concrete to counteract the stresses that result from the applied load.
On 13 May, the bridge was shut for 72 hours for observation while it was under full test load. After 18 hours there were no signs of distress in the deflection readings. The crack in the main span that originally caused alarm has now been repaired, and the traffic restrictions have been lifted.
Commenting on the load tests, Paul Jackson said: “As is often the case, the actual strains and deflections were less than predicted. The project is a very good example on how Ramboll can handle complex projects with tight deadlines with collaboration from Ramboll technical teams from India and around the world.”
Project Manager, Anoop Singh Jangi said: “This project is evidence of the close collaboration that exists between Ramboll’s offices in the UK and India office. When our strengthening solution was proof-checked by the Indian Institute of Technology, Mumbai, it was applauded as the only possible solution. The scheme received a lot of resistance during initial stages, and our persistence was key to its successful execution. The completed project is a big relief to motorists who were caught in heavy traffic on the approaches to the bridge. It has had an enormous impact, and raises awareness of who we are at Ramboll.”
The Versova Creek Bridge strengthening project is also a good example of how hidden defects that are hard to investigate can have very visible symptoms.
Paul is a contributor to (C764) ‘Hidden defects in bridges – guidance on detection management’, and is a speaker in a series of seminars promoting the new publication in the UK. Details here.
In ‘Look again at bridge inspection’, an article written for Transportation Professional - May 2017, Paul says: “There are some structures included in our bridge stock with defects that were hidden, so not considered in assessment. It is therefore realistic to imagine that certain bridges may be unsafe, even if they were assessed as ‘adequate’. In contrast, some that appear unsafe can be shown to be safe. Engineers should always consider the possibility of hidden defects and the new CIRIA report will help with this. Hopefully it will also alert more professionals to the issue of hidden defects. …Assessment, ‘failure mode’ analysis and an understanding of structural behaviour should all be considered together”.
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