Precision and skill: Expert team retrieves tanker dangling on Vadodara bridge 27 days after collapse

From the makeshift control room set up in a prefabricated cabin in Gambhira to specialised pneumatic marine airbags, horizontal cantilevers and strand jacks on standby even as multiple drone cameras kept promptly ready to monitor the operations — the task to retrieve the chemical tanker hanging on the broken bridge since July 9, was all about meticulous calculations and probabilities.

On Tuesday, Dilipsinh Padhiyar, a resident of Nani Sherdi village in Anand district’s Borsad taluka, who was undergoing treatment for his injuries, succumbed, taking the toll to 22. On July 9, Dilipsinh was on a two-wheeler, returning from his night shift at a pharma company in Bharuch, when the bridge collapsed. Dilipsinh was among the four injured to be initially rescued. Another injured person, Narendra Parmar, had also succumbed to his injuries during the course of the treatment.

On Tuesday evening, almost four weeks after the bridge collapsed, leaving the chemical tanker hanging with a drop of about 50 meters on the separated span, MERC Vishwakarma retrieved the tanker, flawlessly executing the operation from 900 meters away without any human presence around the tanker.

Of firsts and challenges

Not only was it a first for the district administration where usual rescue services involving heavy cranes could not be pressed into action but even the marine emergency team was working on retrieving a road transport vehicle stranded on a collapsed river bridge for the first time instead of the usual salvage operations carried out in waters along the Indian coastline. With the structure of the bridge compromised and the movement of heavy machinery restricted, MERC experts deployed marine technology to retrieve the vehicle.

On Tuesday, the fourth day since the experts arrived in Anand district — the truck could now only be accessed from the Gambhira end — a team of experts began the deployment of the pneumatic roller bags (marine airbags) in the undercarriage of the truck. After several hours of preparation, including inflating the roller bags, personnel wearing safety harnesses, the physical deployment of the roller bags started. Once fitted to the necessary height aligned with the existing bridge span, the team of workers returned to the end of the bridge, leaving the rest to the remotely operated cantilevers and strand jacks.

MERC Director Ketan Gajjar told The Indian Express that the task of raising the tanker to align it to the road surface was the first step in the challenge, especially as the bridge had no strength and was surrounded by water. Gajjar said, “The process appears to be simple but it is complex as the deployment of roller bags requires proper methodology and equipment to make the system work effectively and safely. It is a task for an expert as things can go wrong immediately if the placement is not right and the vessel (vehicle) does not lift in the right manner… Once the pneumatic bags were successfully deployed and the vehicle was in an upright position to be safely pulled out, the next step was carried out… The execution was done with a combination of lifting with the marine bags as well as pulling with the strand jacks. We had brought in a payload of 200 tonnes from Mumbai to complete the task of extracting the truck.”

The director said that with human safety as the first priority, the deployment of the bags was done manually. “We could not use any hydraulic machines as the bridge is compromised and human safety is priority. So, the team manually placed the bags. The personnel who worked on the task were from the rigging team, hydraulic jack pulling team as well as engineers… Not damaging the bridge further was also a big challenge.”

Gajjar elaborated that meticulous calculations were crucial in determining the sizes of the components to be pushed under the tanker, given its unique bottom structure, which differs significantly from that of a typical sea vessel. To facilitate the operation, a smaller roller was strategically positioned under the bulkhead, where the tanker was most inclined, while a larger roller was pushed under the centre floor frame.

“Given the fact that unlike at sea, this deployment is on a bridge that has a fractured segment precariously holding position, we also needed to fasten the pneumatic bags to the bridge rails while inflating it to ensure that they do not roll away during the process or it could cause a major accident with the vehicle… Our experience of years means that we immediately calculate the necessary combinations to execute the task in a fast, effective and safe manner,” Gajjar added.

As per the protocol, the MERC team initially assessed the situation, the position of the truck as well as the strength load required to lift and align the truck to the centreline of the bridge.

Gajjar said. “The first day was spent inspecting the truck’s position, the height at which it needs to be lifted to align the wheels to the road surface of the existing portion of the bridge in order to successfully be able to pull it out… The process requires detailed calculation as it is a rare case of a road transport vehicle needing marine emergency response. Since the local authorities had assessed that bringing heavy cranes or equipment close to the tanker is impractical, it can remotely be pulled out only using the marine salvage technique… We had placed all equipment outside the bridge, 900 meters away,” Gajjar said.

The company then began setting up its other equipment, in aligned positions, including the strand jack and the horizontal cantilever that will allow the team to complete the process of pulling out the vehicle without human intervention at the spot. An engineered horizontal cantilever was used to steer the vehicle in alignment to the bridge and a horizontal driven strand jack, which utilises a hydraulic grip and pull force, was used for the calibrated pulling of the truck from the spot. “The horizontal movement is precisely controlled and helps move the vehicle upright as is the need in the present situation as we have to be careful that pulling out of the truck does not damage the existing bridge rails,” Gajjar said.

Anand District Collector Praveen Chaudhary told The Indian Express, “The tanker was successfully retrieved and it has been now placed standing on the existing span of the bridge. The MERC team paid their obeisance to the Mahisagar river after completing the task. They did not charge anything for this service, dedicating their work towards the society… we are grateful for the same.”