The Chennai multistoried tower’s recent collapse
killing 60 odd poor construction workers, in my view, is an incident that was
waiting to happen. May be this is Chennai’s first, in terms of the magnitude,
but unless effective steps are put in place in double quick time, this won’t be
the last. Even before the debris in this site was removed it was followed by
another collapse near Redhills where a huge compound wall fell killing eleven
poor people including children . Read on and you will know why such incidents
are going to be repeating themselves in the forthcoming days, though I hate to
say this !
As for collapse of the multi storied building,
several views are flying thick and fast and various theories are floating
around. One says the developer got additional sanction for extra floors even as
the work was in progress and he went on to add five more storeys without
bothering so much about the need to strengthen or re-do the foundations and RCC
columns which will be loaded almost twice the load earlier designed for.
Another theory says being proximate to lake bed and
given the unsuitable type of foundation system (rather than deep piles to take
it upto the rocky layer deep below), the soil gave way and resulted in this
catastrophe.
Another view is that the quality of designs and
construction was below par and did not meet the codal provisions.
Many are blaming the CMDA for sanctioning extra
floors through some exemptions which would not have happened without the
ability of the developer to play the system. While one doesn’t know if the
CMDA’s system of approvals has been compromised, it need not necessarily mean
it led to the collapse, for this body sanctions the construction based on its
compliance with land usage norms and its conformity to the development control
regulations and nothing more. Checking the engineering designs and soil conditions
or suggesting changes in design are beyond its jurisdiction , expertise and
mandate. In fact CMDA’s approval for such developments expressly state that the
structural design and construction are in the realm of the developer and CMDA
is in no way responsible for the same !
May be if the building construction was already on
when the additional floors were sanctioned, the CMDA could have got an
undertaking from the structural designer that structure already executed is
capable of taking the load from 11 storeys rather than 6 storeys as per the
original approval. I do not know if this was done or not. If insisted upon this
would have ruled out one possibility for the failure. In any case it was not
CMDA’s task to examine the structural stability of the building.
It is said the structural designer who gave the
designs was not associated with the project right after approvals and someone
else has been looking after the structural aspects. It is also said lot of
changes have been effected at site in terms size and positioning of the
structural elements like columns and beams.
Be these as they may be, I have some small but
nevertheless relevant questions:
a) How is
that an ex-bank employee turned developer feels confident (over confident,
rather) enough to construct such a tower all by himself without the help of
senior architects and structural designers ?;
even after the original designer opted out of the system,it appears the
developer went on with a make shift arrangement for this most important
component of such huge buildings. Amazing confidence indeed , but at what cost
?
b) How is
that a person who is said to be a draughtsman acted as the structural engineer
in-charge during the construction ?
c) How is
that the well heeled buyers go for such developers whose background is hardly
impressive when it comes to developing such high-rises ?;
d) How is
that none of the buyers took an engineer from his/her side to understand how
the construction was being carried out and if indeed such inspections took
place, how come no one could fathom such deep flaws ?. After all if I am buying
a property and am not technically qualified, I would take such a help from some
known engineer and try to understand if my investment is safe.
e) How is
that none of the bank engineers who must have visited the site in connection
with the property loans, suspect anything wrong at all ?
The collapse of the system :
Till a decade back there was always a lurking fear
in the minds of designers, contractors , builders and soil analysts with regard
to structural and soil aspects. If the
design assumptions and the site conditions do not tally, the issue used to be
referred to the concerned expert who would visit the site and take a call
suitably which might involve complete re-design as well.
Designers used to decide how a design ought to be in
so far as important aspects like type of foundation, size and layout of
columns, extent of reinforcement and such technical aspects are concerned. Over
the years with rapid computerization and commodification of designs, no
designer has a ‘feel’ of the structure or the site; .Hawk eyed architects and
design engineers used to visit the site frequently and spot even minor transgressions
and had the authority to correct them.
The resultant product would be a robust development where there will be
no room for such nasty surprises.
These days there is
proliferation of designers and the latter bend over backwards to please
the new crop of bossy and purely profit driven developers; designers try to
display their ability to give ‘ competitive & economic’ designs rather than
safe designs with adequate margin for
errors in execution, so that they remain in the reckoning of the private
builders; given these and the falling returns from this profession and the
rapid pace of construction which permits no periodical meetings or changes to
suit site realities as they emerge, the architects & designers have largely
lost their space and authority in the project sites. Site engineers used to
exercise vigil to ensure there was no compromise in the quality of works
–especially in the case of RCC elements !
During the past decade or so, many developers and
project promoters, have developed a tendency to outguess the structural
engineers in terms of how a beam/column/foundation should be sized , what type
of reinforcement is to be used , what should be the depth of the foundation and
the like. They may have a degree in finance or marketing or HR or may not even
any educational qualification to speak of and would not be able to tell the
column from a beam, but nevertheless they venture with their ‘suggestions’ and
‘judgments’ as to what constitutes a good structural design; if not challenged ,
they even go overboard with their ‘gnan’
on electrical engineering, HVAC, fire protection and the like.
Some meek structural designers try to satisfy the
whims of these characters and design inadequately sized columns and foundations
with minimal reinforcement with a prayer in their lips.
Where such poor designs is further compounded by
poor soil conditions and defective work practices leading to weaker structural
elements, then it becomes a disaster waiting to happen !
Simultaneously execution standards have gone haywire
with the steep fall in the standards of engineering education!! We have site
engineers who do not know how many millimeters constitute one meter or vice
versa ! This is no exaggeration as I have come across several engineers with
such astounding levels of ignorance. Obviously one does not expect them to
ensure quality work at site.
Therefore the above failure is symptomatic of a
deeper malady and setting it right is
going to be a long and tortuous process, if at all we start working on this !
The simple truth is that there are no simple and
quick fix solutions !!
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Engineering Project Consultancy & Property
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