 
CRANES (MACHINE HISTORY)
The principles of operation of today's CRANES is taken for
granted, however, we thought you might be interested in learning a
bit about the history of Cranes and their development into the
modern age of technology. Cranes are lifting machines
equipped with a winder, wire ropes or chains and sheaves that can be
used both to lift and lower materials and to move them horizontally.
Put in basic terms, they use one or more simple machines to create
mechanical advantage to enable the movement of loads beyond the
normal capability of a human.
From the ancient Egyptians to the Greek and Roman
Empires following through to the Middle Ages, the Industrial Revolution
and into technologies available today, the concepts and ideas inspired
by mankind's requirements to be able to lift heavy loads in order to
construct towering buildings and enable other large scale engineering
feats to become possible, is a fascinating source of reading material.
We hope you enjoy and find useful, the information provided. There are also a large
number of photographs to view and download.
ORIGINS OF MODERN DAY CRANES
CRANES AND THE
CONSTRUCTION OF THE HOOVER DAM
Hoover Dam, once known as
Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the
Colorado River, on the border between the U.S. states of Arizona and
Nevada. When completed in 1936, it was both the world's largest
hydroelectric power generating station and the world's largest concrete
structure. It was surpassed in both these respects by the Grand Coulee
Dam in 1945. It is currently the world's 35th-largest hydro-electric
generating station.
 When the construction of the Hoover Dam began in 1931, more than 5000
people were brought in to work on it. Although construction
actually began on the Hoover Dam in 1931, site testing for the project
had begun early in the 1920's. The necessity of such a dam had been
obvious for at least two decades, and the idea had been brought forth in
administrations from Teddy Roosevelt onwards.
The cycles of drought and flood
in the American southwest incapacitated the growth of the agricultural
industry; it was felt that a dam that could control the Colorado River
would also provide hydroelectric power, eventually rendering the dam
self-financing.
The growth of Las Vegas and Southern California as major
metropolitan centers also depended, to a large extent, on the
availability of water and power.
When the Swing-Johnson bill detailing the Hoover Dam project passed in
Congress in 1927, construction companies around the country began to
look over the proposals. Most agreed that the plan was too ambitious,
too difficult, the landscape was too unforgiving, and the technology not
advanced enough to build a dam of that size. Still, in March of 1931
five bids were made on the project; Six Companies, Incorporated--a
conglomeration of half a dozen smaller construction companies won the
job with a bid for $48,890,955, a figure only $24,000 over the Bureau of
Reclamation estimate.
Because the dam site was so remote, the first job was to lay roads and
railroad lines, and amass materials needed around the site. Men were
hired on at the Six Companies office in Las Vegas, and the real work
commenced. Much had to be accomplished before the concrete was poured.
The Colorado River, most importantly, had to be diverted.
Four diversion
tunnels were cut over a period of a year through the bedrock of Black
Canyon; when complete, these were lined with concrete. Two cofferdams were built just upstream from the dam site to protect the
construction site from flooding. The construction of the upper cofferdam
started in September 1932, before the river was diverted. A temporary
horseshoe-shaped dike protected the cofferdam on the Nevada side of the
river. After the Arizona tunnels were completed, and the river diverted,
the work was completed much faster. Work on the foundation excavations required removing
approximately 1,500,000 cubic yards of material and was completed in
June 1933.
Once the cofferdams were in place and the construction site dewatered,
excavation for the dam foundation began. For the dam to rest on solid
rock, it was necessary to remove all the riverbed's accumulated erosion
soils and other loose materials until sound bedrock was reached.
Due to
the dam’s arch and gravity design, the side-walls of the canyon would
bear the force of the impounded lake. The load of the water in the
storage reservoir is resisted by both the gravity/mass of the dam, and
by the arch of the dam pressing against and into the side walls of Black
Canyon.
 The two vertical foundations for each of the arch walls (the
Nevada side and Arizona side) had to be founded on sound "virgin" rock;
free of the cracks and the weathering that surface rock of the canyon
walls had from thousands of years of weathering and exposure. Suspended
"high scalers" laboriously chipped and
shaved at the rock walls of the canyon, creating a smooth surface to
which the dam's walls would adhere. It was the job of high scalers to
hang dangerously by rope above the canyon to blast and remove weakened
and loose rocks from the face of the Black Canyon cliffs where the ends
of Hoover Dam would join.
Following the diversion of the river, the floor of the canyon was
dredged down to bedrock. Only then could the pouring of the concrete
begin. A major problem with a structure as large as the Hoover Dam was
the cooling of the concrete. Engineers calculated that the massive
amount of concrete would take over one hundred years to cool; when cool
the dam would crack, rendering it useless. To avoid this, the dam was
poured in rows and columns of blocks. Refrigerated water was pumped
through the blocks in pipes, and the pipes were then shot full of
concrete, rendering the dam a true monolith in entirely one piece. The dam
itself was completed two years ahead of schedule, in 1935. Power
generation began in 1936 and turbines continued to be added until 1961,
when the last one went on line.
The completion of the dam drew massive crowds for
Dedication Day, September 30, 1935. Franklin D. Roosevelt delivered the
address, calling the Hoover Dam "an engineering victory of the first
order, another great achievement of American resourcefulness, skill, and
determination."
CRANES
HISTORY - HOOVER DAM POLICE DEPARTMENT
 The Hoover Dam Police Department has been a part
of Hoover Dam from the very beginning of the project in the early 1930s.
In addition to managing the formidable technical challenges associated
with building this engineering wonder, the Bureau of Reclamation also
addressed safety, security and law enforcement issues from the very
start of construction.
Because the project was located on lands that were ceded by the State of
Nevada to the federal government, maintaining order at the site was a
federal responsibility. Initially, this enormous task was assigned to
just one man, Claude Williams, a United States Marshal. Williams had
oversight of the entire federal reservation, consisting of about 115
square miles, including the dam site, the construction camp, and Boulder
City, the permanent community built 7 miles from the dam to house
project workers, Six Companies officials, and Reclamation's
administrative offices.
In August 1931, just a few months after construction started, a workers
strike forced the federal government to address the need for a larger
crew to maintain security and protect government property. The U.S.
Attorney General authorised Reclamation to deputize 15 to 20 men, with
the possibility of expanding the force should an emergency arise. The
strike ended quickly, 5 days after it began, but the need for an
ongoing police presence at the site was recognised.
Within a few weeks, Reclamation established a
temporary police force of 9 employees, all deputised as U.S. Marshals.
Oversight was divided between 2 ex-soldiers with police experience. Bud Bodell was Chief of Police within the Boulder City limits and Claude
Williams was Chief Ranger on the rest of the reservation, including the
construction areas. Williams was also responsible for the "gateway" at
the reservation boundary, just west of the Boulder City limits, where
all persons wishing to enter were required to show identification.
As construction of the dam proceeded and thousands of men and their
families made their way to Boulder City desperately seeking work, the
matter of preserving order became a greater concern. In 1932, Walker
Young, the construction engineer for Hoover Dam, and Frank Crowe,
general superintendent of Six Companies, Inc. (the builders of the dam) expressed the need for an adequate police force at the site. In 1933,
a court case between the state of Nevada and Six Companies questioned
the extent of the federal government's responsibilities for law
enforcement on the reservation. Following this event, the Department of
the Interior issued regulations prescribing new limits of authority for
policing the Boulder City reservation for the rangers employed by the
Bureau of Reclamation.
CRANES
HISTORY - HOOVER DAM TOURISM
 Thousands of
visitors from all over the country and world flocked to the barren
landscape to view the new engineering wonder and rapidly-filling
reservoir, Lake Mead. As a federal engineering agency unaccustomed to
hosting tourists, Reclamation teamed up with the National Park Service
to address these new demands. In 1936, the two agencies signed an
agreement whereby the Park Service agreed to be in charge of developing
what was then the world's largest artificial lake for recreational
purposes (and what is today, Lake Mead National Recreation Area - the
nation's first national recreation area), and Reclamation accepted
responsibility for tourist facilities at the dam and powerhouse.
Reclamation established a guide service to tell the story of the dam to
the hundreds of tourists coming to the site in those early years.
Since construction of the site was generally complete by 1936 (some work
on the powerplant continued into the 1960s), Reclamation focused its
safety and security concerns on the dam and power plant.
But as European conflicts increased in the late 1930s, and as threats to
America's national security increased, so did security measures at
Hoover Dam and the role of the Hoover Dam Police Department. In 1939,
all private boats were banned from Black Canyon (where the dam was
constructed), and restrictions were placed on dam employees and
visitors. Employees could only enter the dam for their specific duty
times, and were not allowed to escort anyone else without specific
authorisation. Visitors taking tours were under much closer supervision,
and no one was permitted to enter the facility with a package larger
than a lunch box or small camera except at the discretion of the chief
guide. To enhance these measures, Reclamation increased its ranger
force by several men.
Following the attack on Pearl Harbor in 1941, security was again
reinforced at Hoover. As a major supplier of electricity to the U.S.
defense industry, the dam was deemed to be a prime military target.
Several concrete and steel bunkers, camoflagued in a veneer of local
rock, were quickly built overlooking the dam. Soldiers manned these
bunkers (known as "pillboxes") and a squad of riflemen was perched in
the canyon walls 24 hours a day. Civilian vehicles were also escorted
across the dam by the military, and additional lighting, gates,
barriers, doors, alarm systems, and fencing were installed throughout
the site.
Today, only one of the pillboxes remains, but the security and safety of
Hoover Dam and its employees and visitors continues to be paramount.
Events over past decades have required security measures to again be
reinforced, and the Hoover Dam Police Department has enhanced its
officers' expertise and specialised skills, and its technical
surveillance capabilities, to meet the new law enforcement challenges at
the site. The Department also partners, as needed, with private security
contractors, the National Park Service and local law enforcement in
Arizona and Nevada to meet the increased demands for overall physical
security and emergency response at the dam.
The Hoover Dam Police Department is proud to maintain the legacy of
providing for the safety and security of this engineering wonder and
those who visit and work in it each and every day.
112
people died during the initial construction of the Hoover Dam, which was
completed in 1935. There are different accounts as to how
many people died while working on the dam and who was the first and last
to die. A popular story holds that the first person to die in the
construction of Hoover Dam was J. G. Tierney, a surveyor who drowned
while looking for an ideal spot for the dam. Coincidentally, his son,
Patrick W. Tierney, was the last man to die working on the dam, 13 years
to the day later. Ninety-six of the deaths occurred during construction
at the site. However, another surveyor died prior to construction, while
surveying a potential location for the dam, and these statistics do not
include other incidental and coincidental (heat stroke, heart failure,
etc.) deaths during construction.
The dam, an engineering wonder and national icon, is essential to
life in the American Southwest. The water from its reservoir irrigates
more than a million acres of land in the U.S. and Mexico, and supplies a
population of
more than 20 million in 3 states. Additionally, the dam produces
more than 4 billion kilowatt-hours of electricity a year, and provides
safe transit for more than 14,000 vehicles each day.
CRANES
AT WORK ON HOOVER DAM
BYPASS BRIDGE
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AUSTRALIAN
CRANE &
MACHINERY
PTY. LTD.
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AUSTRALIA |
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