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The bridge not too far: Elphinstone Road bridge is getting ready with army precision

Author: aditya anand
Publication: The Hindu
Date:  January 28, 2018
URL:   http://www.thehindu.com/news/cities/mumbai/the-bridge-not-too-far/article22545756.ece?utm_source=email&utm_medium=Email&utm_campaign=Newsletter

New railway foot overbridges are coming up with military precision: not surprising, since the Indian Army’s engineering corps are doing the work

The tragedy at Elphinstone Road made it clear that — among many other problems that plague the hugely overburdened Mumbai’s suburban train network — the foot over-bridges at that station and many others were completely inadequate for the volume of people using them. The bitter irony was that that truth was known; the Railways had cleared the building of a new bridge, but the paperwork, tendering and other processes mandatory for a government-owned organisation were happening at a slow bureaucratic pace.

After taking care of the immediate needs of the victims, the government made an unprecedented decision. On October 31, after the country’s Ministers of Defence and Railways and Maharashtra’s Chief Minister made a joint visit to the station, they announced that the Army would be constructing bridges for commuter use at three stations, and a set a January 31 deadline. (Of course this caused a bit of a brouhaha on social media, with members of the opposition asking if the Army would even be filling potholes hereafter.)

But for the corps assigned the task, the Bombay Engineering Group and Centre, informally known as the Bombay Sappers, it was simple: orders had been given, and they buckled down to it.

Initial strategy

For the Commandant of the Sappers, Brigadier Dheeraj Mohan, the task seemed straightforward. He had, after all, worked on constructing parts of the Line of Control, and a remote airstrip.

Brig. Mohan assigned three platoons the job: one each for Elphinstone Road, Currey Road and Ambivli. They were each headed by a bridge commander, and all under the command of a Colonel. In all, there were 150 members, each with a role to play.

The plan was to construct a Bailey bridge, a design invented in the UK in 1940 and used by the British army to great success in World War II, and also later in that war by the Americans. It is a design that has proved its value in peacetime too, using easily replicable and interchangeable parts, and simple to build with relatively small teams, with the additional advantage of the designs being able to scale up strength to handle more weight, as much as a battle tank.

Plan of action

The first site inspections revealed a challenge Mumbai residents know well: limited space.

The toughest one, the team knew, would be the bridge connecting Elphinstone Road on the Western Railway line and Parel on the Central Railway’s Main Line with each other and the roads on the east and west. “At Elphinstone Road, there was restricted space available between two tracks,” Brig. Mohan told The Hindu on a tour of the construction site at 1 a.m. on January 27, when his men launched a part of the bridge in under 30 minutes. “It was just three metres. And the bridge had to span across 13 tracks, both WR and CR lines.”

They immediately saw that an open foundation — simplistically, making a large excavation constructing the foundation, then filling it up — would not be feasible: there was no way that the Railways could stop operations for the time it would take to make the foundation. “The proximity of the tracks made us change it to a pile foundation,” Brig. Mohan says.

A pile foundation is used in situations where soil near the surface is poor, or when the structure being built is very tall or must bear heavy loads; it transfers the weight of the structure further down into the earth. But it is also useful in areas where the work space is limited. In simplistic terms again, it involves driving piles — hollow steel cylinders which are filled with concrete — into the ground and then building the structure on a platform attached to the piles. Brig. Mohan describes this method as the ultimate foundation possible for bridges.

Other obstacles

At Ambivli and Currey Road, there were other issues yet to be dealt with.

At Ambivli, Railway restrictions meant that a distance of 8.83 metres has to be kept from the mother platform. Also Brig. Mohan says, “We found that while the railway boundary ended at 7.50 metres, our foundation was going beyond that edge, and there were encroachments beyond. Fortunately, people living in the three houses agreed to vacate their homes.” The Army demolished those homes and will rebuild them later; meanwhile it is paying the residents ₹5,000 a month for the period of construction. “The wall of one of the reconstructed homes will come up on the pile foundation.”

Currey Road brought a different problem: local politicians were against one end of the new bridge coming down into a BMC playground, despite the plan being finalised and approved earlier. There were delays in handing the site over to the Sappers too. It took up to 40 days for the Railways and BMC to clear all obstacles and let the Army start doing its job.

Attacking the problem

The commanding officers began by setting up a committee to identify Army-approved private contractors to execute some aspects of the project, like the hiring of heavy-duty cranes to lift the pre-fabricated components.

Simultaneously, the men who would do the job did dry runs of the operation in models of the three sites built at their Pune base. Every move was planned and rehearsed so as to ensure minimal disturbance to the running of Mumbai’s lifelines.

Next was the task of procuring the construction material. The military-grade pure steel segments of the bridges are manufactured by Garden Reach Shipbuilders and Engineers Ltd (GRSE), Kolkata, the premier warship manufacturer for the Indian government.

The bridges can hold weights up to 30 tonnes, which can even withstand the passage of a Bofors field gun. “The bridges are actually meant for moving vehicles and equipment, not pedestrians,” Brig. Mohan says. “But we have incorporated it into our design.”

There are other adaptations of the basic Bailey bridge design, more usually used to span gaps, like over a river or a gorge. “The stairways will be the first of its type having pre-cast reinforced concrete slabs,” Brig. Mohan says. “This is something that the Railways have also now shown interest in.”
Thinking out of the box

The Sappers came up with other innovations too.

One is the use of spreader bars, a type of below-the-hook lifting device used to aid crane operators in picking up large, heavy pre-fabricated structure segments by distributing the load across more than one point, increasing stability. “Using spreader beams has enhanced our capability,’ Brig. Mohan says. “We can now launch such bridges during disaster management anywhere in the country, given that high-capacity cranes are also now readily available.” The other innovation is the canopy. “Army bridges are without roofs. Never has a Bailey bridge had a canopy in India. To adapt for commuter requirements, the bridge had to be given a roof, which meant the design had to be changed to make the structure stronger, as wind pressure had to be factored in. Since the chord reinforcements as suggested by GRSE were not at our stores, they were brought in from Pathankot.”

The Ambivli bridge will be finished first. There were tense moments there. “My blood pressure in December was really high,” Brig. Mohan confesses. The last crisis happened on January 25, just before the Ambivli bridge was completed. “When the landing platform was being fixed it was found to be interfering with the last transom.” A transom is a strengthening crossbar; the last one usually supports the ramp by which vehicles get on to the bridge. “Experts across the country were consulted, even as the panel remained hanging between two cranes for almost three hours. It was finally decided to remove the transom.”

From its first recce on October 28-29, till date, the Army has completed 80% of the work. The bridge at Ambivli was completed on January 26 and will be opened to the public on January 31. At Elphinstone Road, the work on the basic bridge structure started on December 25 and will have finished by January 28. The focus will then shift to Currey Road, where the girders will be laid on February 4; after that, it will take another 15 days to build the staircase, ramp and roof.

Mumbai will then have three new pedestrian bridges and understand what the term ‘war footing’ means.

The Bombay Sappers

Sappers are combat engineers. That is, infantry soldiers who perform military engineering duties, like building and repair work as well as combat duty. The word comes from the French saper, which means to hollow out, to scoop out, or in military terms, undermine. As recently as World War II, trenches were extensively used as land armies fought. Sappers were the ones who built those trenches.

The origin of Bombay Sappers dates back to the late 18th century when the Bombay Presidency of the British Raj set up several companies of Pioneer Lascars. (‘Pioneers’ was a way to describe the work they did, and ‘Lascar’ was a Portuguese word for sailors and military men from the subcontinent and south Asia.) In 1797, the British reorganised companies and absorbed the Lascars into a new Bombay Pioneer Corps. Separately, another group of engineer Lascars had been formed into the Sappers and Miners Company. After several reorganisations, all the companies were merged into the Bombay Sappers and Miners in 1840. As a reward for meritorious service in WWI, the prefix Royal was added to their name.

After Independence, they became a part of Indian Army’s Corps of Engineers, and have since been known as the Bombay Engineering Group and Centre. They are headquartered at Kirkee, Pune.

Their commanding officer, Brigadier Mohan says, “Everyone at work here is a tradesman: mason, electrician, driver, bulldozer operator. They have also in the past fought insurgency in J&K, killed militants, laid mines, prepared bridges for demolition, built bridges.”

Each of the platoons working on the Mumbai bridges has several priests from different religions offering them spiritual support. They also got a secular pep-talk. “The men were told about how the trust of people was our driving force,” Brig Mohan says. “We believe the biggest motivation is in paying tribute to lives lost in the stampede.”
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