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Buildings
New
York's Building Code Reflects High-Rise Concerns
Recommendations
from 9/11 will be debated
(enr.construction.com - 05/31/04 issue)
By Barbara
A. Nadel
...and impact conditions at Battery
Park and other venues. Prototype solutions include a roadway
trench with compressible fill and a thin planting cover, which
can be used in open landscaped areas without being obvious.
When strategically located, the trench will stop cars and
trucks from accelerating toward potential targets. "These
public amenities merge security and urban design, without
creating a fortress for commercial tenants, commuters and
residents," says Stephanie Gelb, BPCA Vice President
Planning and Design.
The multidisciplinary design team developing
security solutions consists of Rogers Marvel Architects, Weidlin-ger
Associates Inc. (structural and blast engineering), Ducibella
Venter Santore (security), Langan Engineers, (civil, geo-technical),
and Sam Schwartz Co. (traffic engineering). Traffic-calming
devices that reduce vehicular speed and increase standoff
or setback distance from commercial buildings include raised,
textured cobblestone crosswalks, curb lines and curb cuts.
Standoff criteria, including vehicular size, speed, velocity
and traffic patterns, are critical at long, narrow streets
near high-risk targets. Road access, street layouts, ramps,
movable bollard placement, truck docks, turning areas and
speed-resistant elements are other factors when reviewing
perimeter security.
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Owners, especially in urban areas, can
protect buildings through a combination of standoff, redundancy,
progressive collapse prevention and hardening of critical
exterior elements that could be exposed to threats, say engineers.
Performing a vulnerability analysis and incorporating protective
design during early conceptual stages minimizes costs, especially
for new buildings, says Richard Tomasetti, co-chairman of
The Thornton-Tomasetti Group, New York City.
"The design threat is now a common
part of the vocabulary," says Tomasetti. "Architects
and engineers must understand how to address the design threat,
along with sustainability, wind, gravity, seismic, dead loads,
energy, mechanical, electrical and plumbing concerns."
When additional security is required,
structural engineers use computer modeling to determine redundancy
levels and minimize building renovations. Redundancy reduces
local effect of damage to one part of a building. Hardening
technology is appropriate when standoff and redundancy cannot
be addressed, especially for existing buildings. Laminated
glass and polymer film in window frames can reduce life safety
risks by preventing flying glass shards from injuring building
occupants.
As building security techniques are
absorbed into the industry mainstream, design professionals
and building owners must be aware of the potential liability
risks that arise when security needs increase. The standard
of care has changed since 9/11, beyond traditional concerns.
"Everyone must anticipate potential
areas of liability that were not apparent in the past,"
says Raymond T. Mellon, partner of the New York City-based
law firm Zetlin & De Chiara LLP. "The need for building
hardening against blast is obvious now. But owners should
anticipate ways to reduce the impact of a chemical biological
attack, for example, by ensuring mechanical air intake vents
are located above grade to prevent tamper-ing."
Design professionals can mitigate liability
risks by documenting all efforts to make owners aware of potential
threats and the recommended remedial measures and by shifting
the burden for noncompliance onto the owner. Although owners
may decide not to implement some or all of remedial measures,
architects and engineers are obligated to alert their clients
about possible design threats and solutions, Mellon says.
Owners cannot be forced to pay for recommended security measures,
but creating a paper trail will diminish further liability.
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