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Large
Binocular Telescope
Mount Graham International Observatory |
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PHH PRESENTS
A SIGHT BEYOND BELIEF |
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As a new
millennium dawns, a giant new telescope will begin to
observe the heavens in a way never before thought possible.
Located near the summit of
Mount
Graham
, a plateau high above the desert of southeastern
Arizona
, the Large Binocular Telescope (LBT) represents the
opportunity to pursue the age-old human quest to understand
the origin of the universe and all it contains.
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| The problem:
How to get a 10 million dollar, one of a kind,
largest in the world, telescope mirror up to the top of a
10,500 foot mountain peak, in one piece, on a road that was
built by the Works Progress Administration (WPA) in the
1930’s under the Hoover administration. That was the
challenge faced by Precision Heavy Haul, Inc (PHH) of
Phoenix
,
AZ
when they contracted to transport two major components of
the LBT from the Steward Observatory Mirror Lab at the
University
of
Arizona
in
Tucson
,
AZ.
, to the Mount Graham International Observatory (MGIO)
enclosure at the top of
Mount
Graham
, near
Safford
,
AZ.
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Upon final
construction of the first of two primary mirrors, with
winter weather conditions approaching, a journey up the
mountain needed to be completed in a timely manor to ensure
the entire LBT work scope stayed on schedule. All aspects of
a haul of this magnitude, from permitting to overnight
pullouts, must be coordinated and executed to perfection.
High winds and snow are not uncommon during the fall months
on
Mt.
Graham
, making hazardous traveling conditions a concern. A close
eye on the weather would dictate the window of opportunity
for each three-day haul.
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Three loads
were scheduled to be delivered to the mountain top. The
first
 component transported was a dummy mirror; used for
load tests. The second load was a mirror cell, which will
support the mirror on the telescope. The final load was a
parabolic mirror, the first of two primary mirrors for the
binocular telescope.
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| When the LBT
is fully operational, it will be the world’s most powerful
and advanced research tool in optical and infrared
astronomy, capable of imaging planets beyond our solar
system. This telescope will be nearly ten times more
powerful than the Hubble Space Telescope.
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The mirror,
8.4 meters (27 ½ feet) in diameter, three feet thick and
weighing 18 tons, is not self-supporting.
For transportation purposes it was supported in a
specially constructed
box having 280 pneumatic actuators that restrained and
cushioned it in every direction.
The mirror and box together were about 30’1” feet
square, 9 ½ feet thick and weighed about 55 tons. The cell,
which will support the mirror on the telescope is
approximately 29 ½ feet in diameter, 9 ½ feet thick and
weighs about 50 tons.
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| The mirror
is very expensive, required years to produce, and is quite
fragile. Therefore,
the University designed and built a dummy mirror out of
steel that closely modeled the real mirror in size, weight,
location of the center of gravity and stiffness.
Every operation that was to be performed on the
mirror had to be first performed on the dummy mirror, thus
allowing a check on the adequacy of the mirror box and the
transportation and handling systems.
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The route
from
Tucson
included 122 miles of interstate and state highway to the
base camp near Safford.
PHH loaded the mirror transport box and its
 precious
cargo at U of
A’s Mirror Lab, located in the campus football stadium.
The mirror-carrying convoy pulled out of the lab
hours before dawn, accompanied by 2 civilian and 25 police
escort vehicles consisting of University K-9 units and
Paramedics, Sheriffs Department, and Highway Patrol. The car
and motorcycle escorts formed a rolling blockade as the
mirror traveled down Interstate 10 and State Highway 191.
These officers provided both traffic control and
mirror safety as the convoy averaged 45 mph to the MGIO base
camp, located at the base of the
Pinaleno
Mountains
. A large number of law enforcement was utilized due the
history of threats made by environmentalist groups. Some
stating “A mirror will never make it to the top”.
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The team
arrived at base camp safely and faced an additional 29 miles
up the tortuous Swift Trail (HWY 366) to the mountain top.
Traffic control was strictly enforced by police units and
message boards along the route, allowing vehicles only to
pass at predetermined pullout points. This last 29 miles
averaged more than 5% grade over the entire length, with
some areas as much as 12%. There
were numerous switchbacks, with extremely short radii and
lateral slopes up to 22%.
In fact, 523 curves and switch backs were noted.
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The
Tucson
to base camp portion of the haul utilized a nine-axle
trailer. The load beams were high enough for the loads to
clear roadside obstacles, and low enough for overhead
clearance. All loads were supported horizontally on the
beams. The
Mount
Graham
portion of the road was much too narrow to
 accommodate the
components loaded in this manner. It was noted that most of
the road was a side hill cut with the bank on the right and
the canyon on the left. Further calculations determined that
if the loads were tilted up on the right hand side through
an angle of 60-70 degrees, they best fit the mountain
profile. At 60 degrees, the loaded height was 33’0”, the
width 21’ 3” and the center of gravity 17’10” above
the ground.
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The position
of the load versus the mountain was thus determined. The
challenge remained one of selecting the proper equipment
that would sustain that position, maneuverability, leveling
as required, and provide a comfortable factor of safety
against overturning.
It was obvious from the load and road requirements
that a European platform trailer would best fulfill the
needs. Selected for this task was a six-line Goldhofer for
its capacity, stability and maneuverability.
The twelve axles are normally grouped into three sets
of four in a triangular distribution that allows the trailer
to negotiate warped surfaces without significant effect on
the individual axle loads.
Alternatively, they may be grouped into four groups
of three in a rectangular load distribution.
This configuration has approximately 50% greater
lateral stability against overturning than the triangular
distribution, but introduces the problem of axle groups on
opposite corners tending to take the entire load on warped
surfaces. This tendency is modified by tire deflections and
twisting of the trailer frame and, more importantly, by
manually adjusting the hydraulic pressures in the four
groups.
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The high
center of gravity and large cross section made the load very
susceptible to overturning from side slopes or wind loading
or a combination thereof.
We therefore accepted the four-point loading
configuration along with its operational problems. It was
decided additional stability could be gained by adding
counter weight to the loaded configuration, placing the
combined center of gravity as low as possible.
The amount of counter weight was determined by
subtracting the weights of the load, the support frame and
the trailer from the rated capacity of the six axles on one
side. Thus, 70,000 pounds of 8 X 20 foot steel plate was
placed on the trailer deck, lowering the combined center of
gravity by 2 feet 10 inches.
This final configuration had a lateral overturning
angle of 16.6 degrees, an increase of 107% over a
three-point system without counter weight, and 30% over the
four-point system without counter weight.
It also has a safety factor of 2.6 against
overturning from a 75 MPH wind.
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The support
frame, designed, engineered, fabricated, and assembled to
the trailer by PHH had to accommodate both the mirror box
and the cell. The
loads varied approximately 6 inches in length and hard
points to which supports could attach varied by 10 inches in
the lateral direction. The
longitudinal difference was accommodated by designing bolted
trunnions that were sufficiently strong enough to support
the load over a substantial length.
The actual attachment to the trailer needed to be
easily connected during loading and unloading, yet meeting
the special requirements of each load.
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One problem
was that the four supports on the loads were fixed with
respect to one another as the loads were quite rigid.
The support points on the trailer, however, could
vary substantially from one another as the loads on the
four-axle groups varied with the road conditions and
corresponding hydraulic
 adjustments.
The trailer and support frame were quite limber yet
the loads were rigid. Therefore, if the corresponding points
of the trailer and the loads were joined rigidly together,
the variations in the trailer geometry would impose unwanted
forces on the loads. This
was solved by designing the frame and the trunnions from the
forces resulting from hanging the loads from the top
supports and resting either of the lower trunnions against
the frame. Thus,
as the trailer and frame distorted from the varied axle
group pressures resulting from the tortuous twists and turns
of the roadway, either of the lower supports could lift off
as required to accommodate the differences in distortion.
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The
four-point suspension system was less sensitive than
expected, and the trailer operator was able to maintain
pressure and level conditions within acceptable parameters
with rare stops for adjustments.
These adjustments happened most often on the unpaved
portion of the road where significant wash-boarding of the
surface existed. In these areas, three undulations of wash
boarding corresponded roughly to the axle spacing and the
amplitudes of oscillation about the longitudinal axis tended
to build up quickly. When
forward motion was stopped, the system returned to normal in
10 to 15 seconds. Experimentation showed that slightly
increased speeds improved the performance in these areas.
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| Power for
the moves was provided by a 2004 T-800 Kenworth tractor with
special low speed 8.40 ratio rear ends towing and a
Caterpillar 980 front-end loader pushing.
This equipment worked well together at speeds varying
from 0 to 4 miles per hour.
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Communication
was of the utmost importance in making the hauls as safe
 and
productive as possible. Fitted with voice activated radio
and head sets, the drivers of the tractor and loader were
able to compare RPM and speed to pull the grades
successfully. Identical sets worn by the trailer operator
and spotter allowed all members of the haul team to be
well-advised on what every inch of the route presented. One
police escort was on this private channel so all parties
involved were in constant radio communication.
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| Precision
Heavy Haul experienced one delay while moving the
components. During the second day of the mirror transport,
lead police escorts, radioed; they had encountered a group
of men with firearms and propane tanks along the route two
miles ahead of the load. When
the men resisted cooperating with law enforcement, the load
was stopped, for fear members of the haul and the priceless
mirror were in danger. Only after control was gained by
Police K-9 units, was the load allowed to proceed on, this
situation was resolved within one hour.
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Elevation
and time of the day dictated what temperature was to be
expected. It was not uncommon to experience a 40 degree
difference in the 7,014 foot assent in the 29 miles between
base camp and the observatory. Road
conditions remained clear with the occasional wet spots from
natural springs and overnight condensation. On the final
day, winds picked up as the load was three miles from the
enclosure, blasting the mirror with a sustained 50 mph wind
and gusts reaching 60 mph. The final stretch of road was the
steepest grade and provided no protection from the weather. Based
on the fear of an incoming storm, the decision was made for
the transport
team to continue on, only to find shelter from the stinging
wind and bitter cold once inside the MGIO.
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The dream of
a working telescope became a reality in late October of 2003
when PHH delivered two major pieces of the telescope. With a
mirror cell and
a parabolic mirror safely inside the
observatory, a sophisticated team of astronomers, engineers
and riggers will assemble one side of the binocular
telescope, making it operational. A much anticipated first
light is expected in the summer of 2004. PHH feels
privileged to be a part of this project, and is looking
forward to hauling the remaining mirror cell, mirror,
and
bell jar to the MGIO this fall.
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 Thanks to
many months of planning, state of the art equipment, and the
skills of everyone involved, the work was completed within
budget, on or ahead of schedule with no incidents or
accidents.
(PHH received the 2003 SC&RA
hauling job of the year for this project)
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PROJECT MAN HOURS
Survey and Planning 680 hrs.
Engineering 634.5 hrs.
Fabrication 712.5 hrs.
Transport Operation 984 hrs.
EQUIPMENT UTILIZED
(2) Kenworth T-800's License #AA23267, AB47195
(1) Trailking steerable 9 axle w/ load beams License #L79529, L79530
(1) Goldhofer THP/ SL (3 +3) License # M05824, M05825
(1) Caterpillar 980 wheel loader
(1) 300 ton Liebherr
(1) 140 ton Grove
(1) 120 ton Grove
LOADED DIMENSIONS
Steward Observatory, Tucson AZ. to MGIO Base Camp, Safford AZ.
PRIMARY AND DUMMY MIRROR IN TRANSPORT BOX
Gross weight 185,000 lbs.
Length 110'0"
Width 30'1"
Height 14'10"
MIRROR CELL
Gross weight 175,000 lbs.
Length 110'0"
Width 29'5"
Height 14'10"
MGIO Base Camp, Safford AZ. to MGIO, Safford AZ.
PRIMARY AND DUMMY MIRROR IN TRANSPORT BOX
Gross weight 307,436 lbs.
Length 111'10"
Width 21'3"
Height 33'0"
MIRROR CELL
Gross weight 297,436 lbs.
Length 111'10"
Width 21'3"
Height 33'0"
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For more
information and pictures, click below:
LBT
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