Delhi Government to Investigate Collapse of Roof at Brand New Airport

[SinoIndusFriendship]

Delhi Government to Investigate Collapse of Roof at Brand New Airport
Posted by: Mehul Srivastava on August 25

Shed a tear for Delhi’s residents. First, the city baked for months as the monsoons decided to skip a year.

Then, one hour of rain on Friday, and the city almost fell apart. 74 millimeters of rain – nothing close to Noah’s-Ark like – and roads flooded, electricity got knocked out, and a brand new $100 million airport sprung leaks, resembling a wedge of Swiss cheese more than the first stop for millions of passengers to one of the world’s fastest growing economies.

The airport shut down for over an hour in the middle of peak Friday evening traffic, as computers had to be shut down, planes were cancelled, X-Ray machines were wrapped up in plastic and passengers shared umbrellas indoors.

(This, btw, is the new terminal - the old one, now mercifully being shut down, came in second in Foreign Policy magazine’s 2007 list of the world’s worst airports, pipped to the finishing line by Dakar, Senegal’s standing-room-only terminal)

But unlike most storms, the one over the airport roof collapse hasn’t passed. Built by an Indian company called GMR infrastructure under India’s much-criticized public-private-partnership model, the new airport terminal was meant to be the first phase of Delhi converting itself into a truly global city. The government has ordered an inquiry into how exactly a brand new airport – this one opened in May 2009 for full service – falls apart after a one-hour thunderstorm.

It’s a big deal for the Delhi Government. In October 2010, hundreds of thousands of tourists, thousands of athletes and a few hundred media folks will descend on Delhi for the Commonwealth Games. To showcase itself to the world, Delhi set aside $12 billion for infrastructure programs, many of which now seem to be either behind schedule or below standard.

On July 13, a concrete pillar for the under-construction above-ground subway system in Delhi collapsed, killing six people. The next day, cranes being used to lift large metal beams flipped over from the weight, crashing the 200 ton metal beam to the ground. Nobody was hurt, thankfully.

While tales of India’s woeful infrastructure are legendary, the Indian government has always hoped that this was a thing of the past. By handing over construction to private operators, it had hoped to escape the criticism that government built infrastructure is often late, always ugly and usually too expensive. But Gammon, which is building the Delhi metro, and GMR, which is building the airport, are both well-respected Indian infrastructure companies - both declined comment since the incidents are under investigation – not fly-by-night operators.

Part of the problem is that there’s never enough time in India to catch up with the crushing growth of megacities like Delhi. Delhi roads will likely never be adequate – everyday, 200 new cars are registered, but new roads takes months to build. Even for the Commonwealth games, projects were handed out only recently, and then construction slowed as private builders found it tough to raise funds during the credit crisis (The government’s model spreads payments out over 30 years, with the private developer pocketing some portion of profits during that period, but upfronting the construction money itself).

Around the corner from my house in South Delhi, where the main Commonwealth stadium is being refurbished, work is still chaotic. A proposed parking lot is still a hole in the ground, the stadium itself is only halfway through repairs, and the metro lines that are meant to serve those locations are far from complete. Work will pick up, no doubt, as we get closer to the Games, as it happened in Beijing for the Olympics, but safety concerns will become even more important as developers work faster under the glare of an immovable deadline.

Related link: Delhi Government to Investigate Collapse of Roof at Brand New Airport - BusinessWeek

Delhi Government to Investigate Collapse of Roof at Brand New Airport - BusinessWeek

 

[eastwatch]

Design and construction both may be at fault for the collapse of a building roof. Design parameters consider the maximum runoff volume of storm water in, say, for the last 100 years. This volume is matched with an adequate roof slope so that rainwater does not accumulate on it. Then comes the selection of diameters of downward discharge pipes. These are so selected by calculations that stormwater does not accumulate on roof top.

Please note when there is a 30 cm high parapet around a roof, then the roof will be burdened with a 300kg/m2 additional load if somehow water accumulates to a full parapet height. This load is very large and the engineers do not assume this load when doing the design calculation for roof slab.

Now, even if the rooftop slopes and the discharge pipe diameters are adequate, the roof may collapse due to faulty design/construction of concrete roof itself. A less than adequate slab thickness as well as inadequate provision of re-bar (round or deformed steel bars) or cement may cause also a collapse. A thinner than required slab thickness and inadequate provision of re-bar or cement may be intended to cheat to earn additional profits.

I believe Indian engineers are capable, because their predecessors were directly taught and trained by the British teachers and engineers. However, I have noticed a few recent collapses during or after construction. I hope the investigation committee will find out not only the causes of collapse, but they should also recommend ways on how to prevent recurrences.