On 11/23/2012 8:00 PM,
hanc...@bbs.cpcn.com wrote:
> On Nov 21, 6:34 pm, danny burstein <
dan...@panix.com> wrote:
>
>> Err, those of us familiar with the situation are well aware
>> that simply holding the WTC to _standard_ NYC building code
>> would have saved quite a few lives, even if the structure
>> still collapsed.
>
> In what ways did the WTC fail to meet NYC bldg codes in effect at the
> time of construction?
Here is just a small smattering of the easily available loads of
objective reports and analyses that serve to indict any number of
officials and experts:
NYC Dept. of Buildings: No Records for Pre-9/11 WTC Elevator Rebuild,
One of the “Largest, Most Sophisticated” Ever
By Aidan Monaghan
9/11 Blogger
July 20, 2011 – Originally Published June 16, 2011
The New York City Department of Buildings (DoB) has reported within a
June 6, 2011 Freedom of Information (FOI) response, that no records
could be located regarding the following request for information
pertaining to the massive elevator modernization project underway at
World Trade Center buildings 1 and 2 until the very morning of September
11, 2001, one of the largest ever [1]. The DoB governs elevator
construction and use within New York City.
An April 15, 2011 FOI appeal request sought:
“Permits or certifications provided by the NYC Department of Buildings
regarding elevator modernization/renovation work performed at the former
World Trade Center buildings 1 and 2 during the 1990s and 2000s.”
The DoB’s June 6, 2011 FOI answer reads as follows:
“BIS shows no elevator records for the time period in question.”Organic
Oregano Oil Blend 125X125
The DoB’s Building Information System (BIS) “is the Department of
Buildings’ main database. The database was put into production in 1984
and supports Department functions with respect to: … Application
Processing (application submission …)” [2]
The DoB’s description of its role regarding elevator installation and
use within New York City: “The Department of Buildings’ Elevator
Division oversees the use and operation of New York City’s elevators”.
[3] Such duties include the receipt and issuance of construction
applications and permits:
“Applications and Permits; New Installations or Major Upgrades; File an
Elevator Application (EA) to install a new device or perform a
substantial upgrade, alteration, replacement or modernization to an
existing device.” [4]
The New York City building code regarding elevator construction reads as
follows: “SUBCHAPTER 18 ELEVATORS AND CONVEYORS; § [C26-1803.1] 27-1001
Permit required. – No construction, alteration or removal shall be
commenced until a written work permit therefor shall have been issued by
the commissioner” [5]
“Dear Mr. Monaghan
The New York City Department of Buildings (“the Department/DOB”) is
in receipt of your April 15,2011 letter appealing the Department’s
February 28, 2011 letter that acknowledged receipt of your FOIL request
letter and advised you that it was currently working to determine if it
had any of the requested documents.
DOB’s letter further advised that it would notify you within 30
business days regarding the status of your request. You are treating
this determination as a constructive denial based on the fact that the
Department did not provide an update within the 30 days as stated, and
that the Department is still working on your request.
Your FOIL request asked for the following DOB records:
“Copies of inspections and certifications records issued by the New
York City Department of Buildings, pertaining to construction projects
performed at the World Trade Center Buildings 1 and 2 between January
2000 and January 2002.”
“Permits or certifications provided by the NYC Department of
Buildings regarding elevator modernization/renovation work performed at
the former World Trade Center buildings 1 and 2 during the 1990s and 2000s.”
According to the Department’s Building Information System (“BIS”),
there was a complaint registered on January 11, 2001 at 1 World Trade
Center, but the Department did not inspect in view of a lack of
jurisdiction. Nor are there records of the Department having inspected 1
World Trade Center during the time period in question for any other
reason. There are no records of complaints filed or inspections
conducted at 2 World Trade Center for the period requested.
The Department of Buildings records show no violations issued
during that period, so there would be no certification records.
BIS shows no elevator records for the time period in question.
Therefore, the Department has no records responsive to your request.
This constitutes the Department’s final determination.”--
http://theintelhub.com/2011/07/20/nyc-dept-of-buildings-no-records-for-pre-911-wtc-elevator-rebuild-one-of-the-%E2%80%9Clargest-most-sophisticated%E2%80%9D-ever/
----
The tube-frame design, earlier introduced by Fazlur Khan, was a new
approach that allowed more open floor plans than the traditional design
that distributed columns throughout the interior to support building
loads. The World Trade Center towers used high-strength, load-bearing
perimeter steel columns called Vierendeel trusses that were spaced
closely together to form a strong, rigid wall structure, supporting
virtually all lateral loads such as wind loads, and sharing the gravity
load with the core columns. The perimeter structure containing 59
columns per side was constructed with extensive use of prefabricated
modular pieces each consisting of three columns, three stories tall,
connected by spandrel plates.[31] The spandrel plates were welded to the
columns to create the modular pieces off-site at the fabrication
shop.[32] Adjacent modules were bolted together with the splices
occurring at mid-span of the columns and spandrels. The spandrel plates
were located at each floor, transmitting shear stress between columns,
allowing them to work together in resisting lateral loads. The joints
between modules were staggered vertically so the column splices between
adjacent modules were not at the same floor.[31]
The core of the towers housed the elevator and utility shafts,
restrooms, three stairwells, and other support spaces. The core of each
tower was a rectangular area 87 by 135 feet (27 by 41 m) and contained
47 steel columns running from the bedrock to the top of the tower. The
large, column-free space between the perimeter and core was bridged by
prefabricated floor trusses. The floors supported their own weight as
well as live loads, providing lateral stability to the exterior walls
and distributing wind loads among the exterior walls.[33] The floors
consisted of 4 inches (10 cm) thick lightweight concrete slabs laid on a
fluted steel deck. A grid of lightweight bridging trusses and main
trusses supported the floors.[34] The trusses connected to the perimeter
at alternate columns and were on 6 foot 8 inch (2.03 m) centers. The top
chords of the trusses were bolted to seats welded to the spandrels on
the exterior side and a channel welded to the core columns on the
interior side. The floors were connected to the perimeter spandrel
plates with viscoelastic dampers that helped reduce the amount of sway
felt by building occupants.
Hat trusses (or "outrigger truss") located from the 107th floor to the
top of the buildings were designed to support a tall communication
antenna on top of each building.[34] Only 1 WTC (north tower) actually
had an antenna fitted; it was added in 1978.[35] The truss system
consisted of six trusses along the long axis of the core and four along
the short axis. This truss system allowed some load redistribution
between the perimeter and core columns and supported the transmission
tower.[34]
The tube frame design using steel core and perimeter columns protected
with sprayed-on fire resistant material created a relatively lightweight
structure that would sway more in response to the wind compared to
traditional structures such as the Empire State Building that have
thick, heavy masonry for fireproofing of steel structural elements.[36]
During the design process, wind tunnel tests were done to establish
design wind pressures that the World Trade Center towers could be
subjected to and structural response to those forces.[37] Experiments
also were done to evaluate how much sway occupants could comfortably
tolerate, however, many subjects experienced dizziness and other ill
effects.[38] One of the chief engineers Leslie Robertson worked with
Canadian engineer Alan G. Davenport to develop viscoelastic dampers to
absorb some of the sway. These viscoelastic dampers, used throughout the
structures at the joints between floor trusses and perimeter columns
along with some other structural modifications, reduced the building
sway to an acceptable level.[39] --wikipedia
----
A principal factor limiting the loss of life was that the buildings
were one-third to one-half occupied at the time of the attacks. NIST
estimated that if the towers had been fully occupied with
20,000occupants each, it would have taken just over 3 hours to evacuate
the buildings and about 14,000people might have perished because the
stairwell capacity would not have been sufficient to evacuate that many
people in the available time. Egress capacity required by current
building codes is determined by single floor calculations that are
independent of building height and does not consider the time for full
building evacuation.
Due to the presence of assembly use spaces at the top of each tower
(Windows on the World restaurant complex in WTC 1 and the Top of the
World observation deck in WTC 2) that were designed to accommodate over
1,000 occupants per floor, the New York City Building Code would have
required a minimum of four independent means of egress (stairs), one
more than the three that were available in the buildings. Given the low
occupancy level on September11,2001, NIST found that the issue of egress
capacity from these places of assembly, or from elsewhere in the
buildings, was not a significant factor on that day. It is conceivable
that such a fourth stairwell, depending on its location and the effects
of aircraft impact on its functional integrity, could have remained
passable, allowing evacuation by an unknown number of additional
occupants from above the floors of impact. If the buildings had been
filled to their capacity with 20,000 occupants, the required fourth
stairway would likely have mitigated the insufficient egress capacity
for conducting a full building evacuation within the available time.
Evacuation was assisted by participation in fire drills within the
previous year by two-thirds of survivors and perhaps hindered by a Local
Law that prevented employers from requiring occupants to practice using
the stairways. The stairways were not easily navigated in some locations
due to their design, which included "transfer hallways," where evacuees
had to traverse from one stairway to another location where the stairs
continued. Additionally, many occupants were unprepared for the physical
challenge of full building evacuation.
The functional integrity and survivability of the stairwells was
affected by the separation of the stairwells and the structural
integrity of stairwell enclosures. In the impact region of WTC 1, the
stairwell separation was the smallest over the building height—clustered
well within the building core—and all stairwells were destroyed by the
aircraft impact. By contrast, the separation of stairwells in the impact
region of WTC 2 was the largest over the building height—located along
different boundaries of the building core—and one of three stairwells
remained marginally passable after the aircraft impact. The shaft
enclosures were fire rated but were not required to have structural
integrity under typical accidental loads: there were numerous reports of
stairwells obstructed by fallen debris from damaged enclosures.
The active fire safety systems (sprinklers, smoke purge, fire
alarms, and emergency occupant communications) were designed to meet or
exceed current practice. However, with the exception of the evacuation
announcements, they played no role in the safety of life on September 11
because the water supplies to the sprinklers were damaged by the
aircraft impact. The smoke purge systems operated under the direction of
the fire department after fires were not turned on, but they also would
have been ineffective due to aircraft damage. The violence of the
aircraft impact served as its own alarm. In WTC 2, contradictory public
address announcements contributed to occupant confusion and some delay
in occupants beginning to evacuate.
For the approximately 1,000 emergency responders on the scene, this
was the largest disaster they had even seen. Despite attempts by the
responding agencies to work together and perform their own tasks, the
extent of the incident was well beyond their capabilities.
Communications were erratic due to the high number of calls and the
inadequate performance of some of the gear. Even so, there was no way to
digest, test for accuracy, and disseminate the vast amount of
information being received. Their jobs were complicated by the loss of
command centers in WTC 7 and then in the towers after WTC 2 collapsed.
With nearly all elevator service disrupted and progress up the stairs
taking about 2 min per floor, it would have taken hours for the
responders to reach their destinations, assist survivors, and escape had
the towers not collapsed.
Objective 3: Determine what procedures and practices were used in the
design, construction, operation, and maintenance of WTC 1 and WTC 2.
Because of The Port Authority's establishment under a clause of the
United States Constitution, its buildings were not subject to any state
or local building regulations. The buildings were unlike any others
previously built, both in their height and in their innovative
structural features. Nevertheless, the actual design and approval
process produced two buildings that generally were consistent with
nearly all of the provisions of the New York City Building Code and
other building codes of that time that were reviewed by NIST. The loads
for which the buildings were designed exceeded the New York City code
requirements. The quality of the structural steels was consistent with
the building specifications. The departures from the building codes and
standards identified by NIST did not have a significant effect on the
outcome of September 11.
For the floor systems, the fire rating and insulation thickness
used on the floor trusses, which together with the concrete slab served
as the main source of support for the floors, were of concern from the
time of initial construction. NIST found no technical basis or test data
on which the thermal protection of the steel was based. On September 11,
2001, the minimum specified thickness of the insulation was adequate to
delay heating of the trusses; the amount of insulation dislodged by the
aircraft impact, however, was sufficient to cause the structural steel
to be heated to critical levels.
Based on four standard fire resistance tests that were conducted
under a range of insulation and test conditions, NIST found the fire
rating of the floor system to vary between 3/4hour and 2hours; in all
cases, the floors continued to support the full design load without
collapse for over 2 hours.
The wind loads used for the WTC towers, which governed the
structural design of the external columns and provided the baseline
capacity of the structures to withstand abnormal events such as major
fires or impact damage, significantly exceeded the requirements of the
New York City Building Code and other building codes of the day that
were reviewed by NIST. Two sets of wind load estimates for the towers
obtained by independent commercial consultants in 2002, however,
differed by as much as 40 percent. These estimates were based on wind
tunnel tests conducted as part of insurance litigation unrelated to the
Investigation. --
http://www.nist.gov/el/disasterstudies/wtc/wtc_about.cfm