India Abroad

09-19-2003

At the halfway stage of the federally-mandated probe into the collapse of
the World Trade Center on September 11, 2001, neither Dr. Shyam Sunder nor
Dr Shankar Nair has reason to doubt the structural merits of the Twin
Towers.

Their investigations, thus far, point to a combination of uncontrollable
fires and inadequate fire-proofing as the reason for the towers collapsing.

"We have not arrived at definite conclusions yet," Dr. Sunder, lead
investigator on the National Institute of Standards and Technology probe
told India Abroad.

"But our investigation shows the weaknesses in the fire-proofing system.
The towers withstood the impact of the planes that hit them, but they
crumbled after the fire that ensued."

The 24-month, $16 million study helmed by Sunder will continue for another
year before submitting its report; the NIST, under whose aegis the study is
being conducted, is a non-regulatory agency of the Commerce Department's
Technology Administration.

As chief of the Construction and Materials Research Division at NIST, it
fell on Sunder to lead the probe into the disaster.

Sunder has, as and when required, called on the expertise of outside
experts to facilitate his probe. Thus, the contract for the analysis of the
structural system was given to Teng Associates of Chicago, with Dr. Shankar
Nair, as principal structural consultant.

Dr. Nair, grandson of former Indian foreign secretary KPS Menon, is a
senior vice president at Teng and an acknowledged expert on tall
structures.

Ironically, part of Nair's brief, as chairman of the Council on Tall
Buildings and Urban Habitat from 1997 to 2001, was to assure people of the
safety and structural solidity of tall buildings.

Nair says structural system analysis includes design, analysis, and
behavior of high-rise steel buildings, lateral (wind) and gravity systems,
connection design, structural redundancy, and load redistribution; each of
these elements has to be probed, individually and collectively, to figure
out how and why the Towers collapsed in such dramatic fashion, and within
such a seemingly short period of time.

American Airlines Flight 11 had crashed into the north tower of the WTC at
8:45 am; United Airlines Flight 175 crashed into the south tower at 9.03
am. The south tower collapsed at 9.50 a.m. and the north tower, at 10.29
a.m.

Dr. Sunder's study is limited to WTC Buildings 1 and 2 (Twin Towers) and
WTC Building 7, and will focus on the construction, the materials used and
all of the technical conditions that contributed to the WTC disaster.

The Twin Towers and WTC 7 are the only known cases of total structural
collapse in high-rise buildings where fires played a significant role;
hence, says Sunder, the study is important in the sense that it provides
previously unavailable data.

"The investigation is going well, we are getting very good co-operation
from various government agencies and the city of New York," Sunder told
India Abroad.

He believes the fires, and not the planes, caused the collapse. "If there
had been no fires after the planes hit the towers, they would have stayed.
But we cannot say for how long," he added.

Steel, Sunder points out, does not melt easily. The WTC fires were unusual,
in that temperatures reached peaks of 1,600 degree Celsius, where a typical
fire can produce temperatures touching 1,100 degree Celsius.

"What happened here was something unimaginable," Sunder says; he adds that
steel loses its strength under such intense heat; it does not burn, but it
softens, and then gravity and the sheer weight of the structure does the
rest.

The jet fuel in the planes could not, by itself, have caused the collapse.
The fuel, Sunder says, burnt out in less than ten minutes; by then,
however, it had ignited the contents of the thousands of offices housed in
the twin towers.

Sunder believes as and when the probe is completed, its findings could
result in improvements in future constructions. "But we are not a
regulatory agency," he says, making the point that his team will not
mandate any improvements. "It is for the private sector to utilize the
findings of the investigation."

Given the nature of his job, Sunder has had to make multiple visits to
Ground Zero. "Each time it was a sobering experience. Loss of human life is
sad thing."

"The investigation itself is overwhelming, there is no precedent for an
investigation, of such magnitude."

Sunder was all praise for Nair who, he said, is a noted expert on the
structural aspects of tall buildings; his probe, Sunder felt, would benefit
from Nair's expertise.

Nair for his part agreed with Sunder's assessment that the Towers were not
themselves at fault.

Lack of adequate safeguards, Nair felt, was a crucial reason. "Even now, we
don't have a sound system of fire proofing to avoid such catastrophes. So
the technology available during the construction of the towers was not up
to the mark."

Though the probe is a year from completion, Nair says on the basis of work
done thus far architects planning to construct such tall buildings in
future need to provide for improved was of evacuating inhabitants in case
of problems.

At the WTC, he points out, thousands were trapped on the upper floors; to
rectify the problem in future, exit systems should be separated from the
building proper to provide for easy escape.