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Buildings
Volunteers Sought to Inspect WTC Steel
(enr.com
10/25/01)
By Nadine M.
Post
The new president of the Structural Engineers
Association of New York (SEAoNY) issued a call for volunteers to
form a rotation at the two scrap yards in New Jersey receiving steel
from the World Trade Center's twin 110-story towers. The purpose
is to assist the American Society of Civil Engineer's WTC Building
Performance Study Team in its search for steel from the floors that
the airplanes hit and the steel that was subsequently fire-damaged.
A group of ASCE-team engineers spent a couple of recently—during
the team's first field trip to New York City—at the salvage
yards. "We were crawling through steel" but did not find
any pieces from the impact or fire area, said Edward M. DePaola,
SEAoNY's president and a principal of Severud Associates, New York
City, at SEAoNY's annual meeting in New York City, Oct. 24.
DePaola announced that SEAoNY has joined the ASCE team studying
the failure mode of the trade center buildings and the performance
of others that were affected by the collapses, along with the Federal
Emergency Management Agency, National Fire Protection Association,
American Institute of Steel Construction and other organizations.
Saw-Teen See, the managing principal at Leslie E. Robertson Associates,
one of the successor firms of the WTC's structural engineer of record,
provided information to the study team, of which she is a member,
on markings that identify the steel for those areas under scrutiny,
said DePaola. Each piece of steel in the towers was stamped with
its location in the building, he added. The team knows the impact
floors, so the goal is to find the marking on the steel for that
area, he added.
DePaola is trying to set up a continuous rotation for two months
at the two salvage yards so that engineers can examine the steel
before it is cut into 1-ton pieces and sent off for recycling.
SEAoNY organized its members who served as volunteers to aid the
rescue and recovery effort in assessing the structural stability
of the debris, shoring safe routes for equipment and assessing damage
to some 400 area buildings. The SEAoNY teams are under the direction
of LZA/Thornton-Tomasetti, the New York City-based structural engineer
in charge of the effort for the city's Dept. of Design and Construction.
"We learned that the angle of repose of rubble is 127o,"
said W. Richard Mahoney, SEAoNY's outgoing president and chief of
the structures division for M.G.McLaren, West Nyack, N.Y.
DePaola said the third structural assessment survey of the buildings
surrounding Ground Zero is complete. The only change is that the
damaged Winter Garden at the World Financial Center has been switched
from red to blue, meaning that it can be salvaged. He also reported
that the city has reduced the size of the cordoned-off zone around
the WTC site and that many of the yellow-tagged buildingsÑthose
with the least amount of damageÑare being "handed"
back to their owners.
DePaola also asked the nearly 140 structural engineers at the
meeting, many of whom were among the 400-plus volunteers at the
site, for any photographs they took of the debris pile or observations
they made during their shifts at Ground Zero. He asked for similar
information on the buildings still standing around Ground Zero,
also under study.
Currently at Ground Zero, SEAoNY has two teams of a pair of engineers,
each working a 12-hour shift, assisting the contractors with structural
concerns about equipment placement and other isssues affecting debris
removal. That is down from four teams of four engineers each, also
around the clock, in the days immediately following the terrorist
attacks.
To better prepare to assist authorities in future terrorist attacks
and other emergencies, SEAoNY has worked out a plan to get its engineer-members
trained by the Federal Emergency Management Agency. "Most structural
engineers do not learn about fire damage [in school]," said
DePaola. But at Ground Zero, engineers were being asked by the fire
department whether it was safe to go under "teetering and tottering"
steel, some of which had been damaged by fire. "There are FEMA
classes for this," he said.
He also said that SEAoNY has made contact with the city authorities
to work out protocols for assistance in future emergencies, as volunteers.
A draft memo of understanding is being crafted that will "talk
about our preparedness and provide contacts in the event of future
emergencies," he said, adding he is not talking about a scaffold
collapse, but an "event" that requires more engineers
to assist than the buildings department has on staff.
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