On Thursday Mar. 31, around noon, the busy Rabindra
Sarani-KK Tagore Street crossing in the city of Kolkata, India (population 4.5
million) was crowded with shoppers and people having lunch in open-air
eateries. Crowds that a Westerner
would consider to be a mob scene are routine in the Indian subcontinent, and
the density of street-level shops makes many thoroughfares almost impassible by
automobile. To alleviate this
congestion, in 2008 the Hyderabad-based construction conglomerate IVRCL won a
bid to construct an overpass that would carry vehicular traffic above the
existing street. Construction
began in 2009 and was due for completion in 2012. But the firm ran into financial and land-acquisition
difficulties, with consequent project delays, and so last week one of the last
parts of the projected 2+ kilometer-long overpass was still under construction
above the street.
By Wednesday, Mar. 30, a long straight
section of the overpass was complete, and concrete was poured that night for a
section next to a turn at the crossing, where steel girders already were
suspended above the road. At about
12:25 PM Thursday, some 300 feet (100 meters) of the overpass collapsed onto
the street below. As of Apr. 2,
the death toll stood at 27, but more were missing and over 100 people were
injured.
While the cause of the collapse is under
investigation, the IVRCL firm has been charged with culpable homicide and three
members of the firm have been arrested.
This is after one firm representative termed the collapse "an act
of God."
The construction phase of any large
civil-engineering project is fraught with hazards that only good planning and
expert supervision at all times can avoid. As a civil-engineering professor interviewed about the
tragedy pointed out, right after a poured-concrete structure is set in place,
the weight of the newly poured material must be supported by temporary
scaffolding before the concrete sets.
In contrast to the finished product, which office-based engineers can
design at their leisure to withstand known stresses, temporary scaffolding is
erected onsite in an ad-hoc way, and may have hidden defects that would require
more engineering knowledge to avoid than the onsite construction workers and
supervisors have. It was
apparently one such defect that led to the disaster in Kolkata last week.
From videos shot during the collapse, it
appears that few if any pedestrian or vehicle barriers were in place to keep
people away from the construction site.
Admittedly, this would have been difficult, like temporarily shutting
down Times Square in New York City for construction. And businesses on the street undoubtedly would have
complained if large sections of the surface street had been blocked off,
impairing access to some shops.
But events have proved that the tradeoff would have been worth it, if
excluding traffic from under the most hazardous parts of the overpass during
construction would have saved lives.
While some commenters on Indian news sites
complained that such things are never allowed to happen in the so-called First
World, only a year ago I reported in this space about a similar but
smaller-scale accident involving overpass construction, right here in Texas. While a prefabricated-concrete-beam
overpass was being built over the busy I-35 freeway near Salado, Texas, a truck
carrying an overheight load struck one of the beams before it had been firmly
fixed in place. It shifted and
knocked down several other beams, one of which killed the driver of a pickup
truck. Again, this accident could
have been prevented by diverting traffic from underneath the overpass, but the
result would have been permanent miles-long backups on I-35 that might have provoked
angry citizens to mount a protest march at the Texas Department of
Transportation.
Any complex engineering project is a series
of compromises with safety, expenses, schedules, personnel, and other resources
all in the mix. In the West, a
relative abundance of resources has led engineering organizations to err on the
side of more money traded for more safety. In India, as the comparatively poor track record of fatal
building and construction collapses attests, getting the project done cheaply
sometimes takes priority over getting it done safely. India is a democracy, and it may be that the current level
of construction safety reflects an increased urgency to solve the nation's
civil-engineering needs faster and with fewer resources than Western-style
engineering would allow. It is bad
enough when a privately-owned building collapses. But a public-works project such as an overpass inherently
affects more people, and carries more potential for harm. This is why most public-works project
specifications require licensed professional engineers to supervise the design
phase. But the best designers in
the world will be unable to prevent onsite accidents if the people who actually
do the construction are not capable of understanding the hazards and
engineering challenges involved.
At least three members of the IVCRF firm
have been arrested in connection with the tragedy and charged with culpable
homicide. The degree to which they
are responsible is now going to be determined by the legal process, which may
take months or years. Regardless
of the fate of the engineers and managers involved in this accident, to prevent
future tragedies like this a sea change will have to take place in the entire
construction industry in India.
I have mentioned before a simple safety code
that was once emblazoned on bronze plaques in Bell System telephone exchanges
throughout the U. S.: "No job
is so important and no service is so urgent—that we cannot take time to perform
our work safely." That was
back when the Bell System was a monolithic nation-like organization, and it
could afford hundreds of bronze safety plaques. But everyone working in a business that creates potential
hazards for its own employees, and especially for innocent bystanders, can
afford to make the Bell System safety creed their own. And something like this could go a long
way toward making Indian construction sites and buildings safer places to be.
Sources: I referred to reports on the Kolkata
overpass collapse carried on the National Public Radio website at http://www.npr.org/sections/thetwo-way/2016/04/02/472797620/after-overpass-collapse-in-kolkata-firm-charged-with-culpable-homicide,
ABC News at http://www.abc.net.au/news/2016-04-02/indian-authorities-arrest-three-more-over-bridge-collapse/7294848,
the Times of India at http://timesofindia.indiatimes.com/city/kolkata/Kolkata-flyover-collapse-Its-an-act-of-god-says-builder/articleshow/51634766.cms,
The Week at http://www.theweek.in/news/india/what-caused-kolkata-flyover-collapse-experts-speak.html,
and The Wire at http://thewire.in/2016/03/31/photo-gallery-after-the-kolkata-flyover-collapse-26961/
and http://thewire.in/2016/04/01/kolkata-flyover-collapse-18-dead-over-60-injured-26907/. My blog article http://engineeringethicsblog.blogspot.com/2015/03/a-bridge-too-close.html,
"A Bridge Too Close," about the
I-35 accident appeared on Mar. 29, 2015.
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