When the unthinkable happens:
Collapse and destruction of some of the tallest towers
in the world|
In advance, I would like to make the following statement.
The basics of this section were written and published in early 1998, years before the september 11 attack on the World Trade Center in New York City and the disastrous tsunami in south-east Asia.
Shortly The High-Rise Pages will publish an in depth article about the social and economical impact of the destruction of iconic buildings such as the World Trade Center Twin Towers. This section however mainly comments an other kind of disaster: the collapse of TV-Towers.
The sky is the limit?
Many high-rises all over the world stand tall as if they were built
to last forever. Sometimes the faith we have in our engineering skills
is crushed in a split second by the powers of mother nature,
by fatal human mistakes, and even by evil human intellect, as the world witnessed on september 11, 2001, during the attack on the twin towers of the New York City World Trade Center.
Unfortunately, also many men have lost their lives
during construction of some of the tallest towers in the world.
On this page you will find several stories that show you the
devastating results of high-rise disaster and remind us to the fact that
the sky is the limit, but not at all cost...
Is tower-collapse a rarity?
Thursday october 23, 1997, the WLBT TV-tower near Raymond
Mississippi collapsed, killing at least three Canadian workers.
These brave men were working at 1500 ft. when the tower came down.
At 609,3 m (1999 ft.) WLBT TV-Tower was the tallest structure in
Mississippi and one of the tallest structures in the USA.
A tragedy like this raises the question: How tall can we go?
And if this is the result of building 2000 ft. tv-towers,
shouldn't we draw a line somewhere? The point is, this disaster
is no rarity. Tower-collapse happens more often than you think.
For example have a look at this website. It shows the
collapse of a 305 m (1000 ft.) tower in 1982.
Several men died at this horrible event.
The site includes much information, a lot of pictures,
and even mpeg-files of the collapse.
In 1978 the 491 m (1610 ft.) WJJY-TV Tower in Illinois was hit by an extremely strong winter storm.
It tragically collapsed!
In 1996 disaster struck in Montgomery when the 242 m (793 ft)
WCOV-TV Tower was
totally destroyed by a tornado. In 1997 an other extremely tall
structure collapsed. A 606 m (1989 ft.) tower
came down, killing at least one man.
Here's an other one.
Collapse of towers has been studied by Nathan Mulherin who wrote a paper
about this subject called Atmospheric Icing and Tower Collapse in the United States.
Very often it is mother nature that causes high-rise disaster.
But it seems that man-made high-rises can cause severe
damage to nature as well. Millions of birds appear to die every
year because they crash into skyscrapers.
Here are some more links providing you with information about
Once, the Citibank in New York City
threatened Manhattan because it was in danger of collapsing.
Furthermore, read about the
devastating bombing of
Oklahoma City and
the breaking windows of the John Hancock Tower in Boston.
Some articles about
designing structures to resist explosions.
You can learn more about Tsunamis at:
The Great Tsunamis of 1992-1996 and the USC expeditions.
Ed West on tower-collapse
In 1998 I have been contacted by Ed West from Iowa.
Ed has been working for 25 years in the
engineering department of KCRG-TV and recalls some dramatic
events concerning collapsing tv-towers.
The rest of this page shows various of these disasters and some very
close calls as described by Ed West.
Ed concludes with good news, and that is that technology and
regulations concerning these tv-towers have rather improved
for the past years. Let us hope this will make these towers a safer
place to work at.
This is what Ed had to say:
"In our TV market area we have had three tall towers go down
and two other towers have had very close calls over a period of many years."
"WMT-TV (now KGAN-TV) lost the first tall tower (about 1600 feet above
the ground) to be constructed in our area. It is located near Walker,
IA. This occurred during initial construction. The tower was nearly
complete when a temporary guy cable parted during high winds.
No lives were lost. The tower was rebuilt right away."
"Our (KCRG-TV) 2000 foot tower near Walker, IA went down in the early
1970's about a year before I began working for them. The tower was
being strengthened to allow one of the Iowa Public Television stations
to mount their antenna on our structure. The strengthening involved the
replacement of diagonal braces and other structural members. While
working at about the 500 foot level the temporary cross brace used while
the old cross members were removed gave way causing the tower to fall.
5 lives were lost."
"KWWL-TV, an NBC affiliate, lost their 2000 foot tower near Rowley,
IA in the early 1980's. This was caused by a combination of ice on the
tower and guy cables and high wind. The guy cables began "galloping"
and they finally failed. No lives were lost."
"KCRG-TV nearly lost it's 1100 foot auxiliary tower near Hiawatha, IA
in the late 1970's when a small single engine aircraft collided with the
tower under poor visibility conditions during daylight hours. The pilot
appearently saw the tower and tried to turn away when one wing struck the
tower structure between the top guy cable and the one below it. About 6
feet of one wing was left embedded in the tower causing considerable
damage to the tower structure which was repaired over the next several
days. Three members of one family lost their lives when the aircraft
crashed a short distance away, narrowly missing several mobile homes in
a mobile home court."
"Another disaster in this area was narrowly avoided when a 1200 foot
tower was being constructed for Iowa Public
Television at a site near West Branch, IA. A friend of mine was working
on the tower at the time and told me the story later.
The tower was complete and ready for the antenna to be set on top of the
tower. The crew waited for a relatively calm day since this is a fairly
delicate operation. The antenna was hoisted and was being set in place
and the bolt holes aligned when the three man crew on the tower heard a
"crack" above them. They looked up and saw that the "picking eye" had
broken. The "picking eye" is a large eye attached to the antenna to
allow the hoisting cable to be attached so the antenna can be hoisted to
the top of the tower. This left a several ton antenna over 100 feet
tall balanced on the top plate of the tower with no support.
Fortunately they were able to get the bolts in place and tightened
before a gust of wind could unbalance the antenna. The Good Lord does
smile on us sometimes."
"There have been a few more tall towers in the midwest United States come
down. The most usual cause of structural
failure in this area is a combination of ice and wind. Recent
regulations use a newer method of computing ice and wind loading when
doing the structural engineering calculations for new tower
construction. This should reduce such problems in the future. In the
last 15 years or so the technology of guy cable "snubbing" and "damping"
devices has also improved. This is reducing the danger of ice and wind
causing "galloping" of guy cables leading to guy cable failure."
Dramatic tower-collapse in 1992
Recently, Ed contacted me again, because he recalled another
dramatic example of tower-collapse in the mid-west of the US.
We can learn so much from people like Ed, because he's one of the
guys who actually worked on these towers himself. Thanks again Ed!
"In mid July of 1992 a 425 foot self supporting tower collapsed during
a very heavy rainfall and high winds. This was a commercial tower that
leased space to many business in the area for their communications
needs. There were 38 antennas and associated transmission lines on this
one tower. It fell on an adjacent building 225 feet away that housed a
small manufacturing firm. This tragedy resulted the death of one worker
in the building and the serious injury of another."
"According to news accounts there would have been many more people in the
area damaged by the tower if there had not been a meeting going on
elsewhere in the building. Damage to the building and contents was
estimated to be at least a half million dollars."
"Two technicians who have worked on the tower said that it was
seriously overloaded, and from looking at it over the years I would
agree. Quoting from a news story: "Technicians from a service company
told their boss that there were too many antennas and it was too
complicated to work on. The workers said it was so bad they didn't want
to climb it again."
"One of the concrete footings was pulled out of the saturated ground,
and bolts securing the tower to the footings were broken loose from the
concrete. The tower was inspected each year, but structural analysis was
not part of those inspections. It is my opinion that regulations should
be in place to require a structural study each time equipment is added
to such towers."