14 | MARCH 2019 | Claims Magazine | PropertyCasualty360.com
Unusual construction issues
Citibank Center, which is presently
named 601 Lexington, quickly became
a New York City landmark when it was
built in 1977. The building was noteworthy both because of its 45 degree-angled
top and the fact it stood on stilts that contained its bottom nine stories.
Why stilts? In 1905, St. Peter’s Evangelical Lutheran Church moved to the proposed building site of Citibank Center.
While church leaders agreed to the
church’s demolition, they required a new
church be built in its place. Furthermore,
they required the church be freestanding.
By building on stilts, Citibank Center
could be placed above the church.
To accommodate the church struc-
ture, the stilts had to be located at the
midpoint of each side of the building
rather than at its corners. This caused the
building to be less stable than it would
have otherwise been. To account for this
decreased stability, a chevron bracing
structure was used. This, in turn, caused
the building to be unusually light. As a
result, it would sway in the wind. To
quiet the building down so occupants
would not feel like they were at sea, a
400-ton tuned mass damper was placed
at the top of the building.
In 1978, a Princeton University civil
engineering student contacted the building’s structural engineer to report her
findings that the building could be toppled by wind damage. While the structural engineer had accounted for damage
from perpendicular winds, he had not
accounted for quartering winds that were
far more damaging given the building’s
unusual design. What’s more, the tuned
mass damper ran on electricity. In the
event of a blackout caused by a damaging
storm, the damper could be lost when it
was needed most.
There was more bad news on Lexington
Avenue. The construction company had
received approval to switch from welded
joints to bolted joints, to save labor and
material costs, without the structural engineer’s knowledge. In addition, the construction company used New York City’s
truss safety factor of 1: 1 instead of the
column safety factor of 1: 2. Both actions
increased the building’s vulnerability to
Fearing property damage, reputation
damage and economic losses, a plan to
weld two-inch steel plates over the building’s 200 joints was hatched in secret.
Six weeks into the work, which was performed after the conclusion of the workday, only half of the job was completed as
Hurricane Ella formed off Cape Hatteras
and pointed at New York City. While
emergency evacuation plans were filed
with New York City, again without the
public’s knowledge, the storm eventually
headed out to sea.
There is an awful lot to unpack in this
Construction Defects Affect a
New York Landmark
According to the International Risk Management Institute (IRMI), a construction defect is defined as “a deficiency in the design or construction of a building or structure resulting from
a failure to design or construct in a reasonably workmanlike manner,
and/or in accordance with a buyer’s reasonable expectation.” IRMI goes
on to differentiate between dangerous defects threatening life and
limb, and passive defects threatening neither but that can result in lost
value or increased cost from correcting the defect.