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A year ago, we investigated
the use of instruments and learned that views on their value varied
considerably according to the size of the projects. Those who were
frequently involved in big jobs (such as airports, highway construction
or expansion, or extensive industrial development) were familiar
with—and were users of—the impressive array of instruments
available as add-on helpers to site workers who have spent most
of their construction years with excavators, graders, loaders, and
scrapers. They used to rely on their own skill and judgment, on
stakes in the ground, or on other workers for precision. Has much
changed since then? In the last few months we asked contractors,
“When would you purchase lasers and instruments like those?”
The most common answer still is, “When the scope of our work
justifies them.”
Contractor Attitudes
Are Essentially Practical
An important aspect of the subject is revealed by Jim Hughes, CEO
of Building Ventures Inc. based in Cartersville, GA. “As a
small contractor, I have not found a need for the laser level,”
notes Hughes. “I still use a Nikon line-of-sight level, and
every now and then we need a transit. For that I use Topcon. The
line-of-sight level does not require me to spend a lot of time training
someone to use it, but the transit is another story. I am usually
the one who uses the transit.” His company is frequently engaged
in grading for drainage and site preparation. “I have a loader
that I use for most of my work. If the job demands it, I rent excavators
and scrapers, but none of the rentals has a laser level. We can
bring a slab to within one-eighth to one-quarter of a foot and can
create drainage falls in the same range. This is more than satisfactory
for our needs. A laser would be nice, but it is still way too costly
for me.” Other contractors, especially the one-, two-, or three-person
companies, agree with him. “Many say they can’t buy new
equipment just because it’s new; “especially in these
difficult times for small contractors, they must need it.”
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| A Cat
140H motor grader equipped with Topcon 3D-GPS automatic grade
control system |
“Lasers are indispensable,”
observes Maurice Piersol, president of Piersol Construction in Rosalia,
WA.
“Our on-the-ground
personnel use them every day. We buy only self-leveling lasers—usually
Topcon because we like their dealer support and price—but we
do have some Spectra Physics [SP] equipment. I feel the quality
of these old SPs is superior to any of the newer machines we own,
but lack of local dealer support has prevented us from buying additional
units.” Piersol Construction also has two machine-mounted receivers
on dozers, or they can be mounted on a grader with machine controls.
“For prebid work, I usually use a total station to verify jobs
if I need additional information,” adds Piersol.
“Some training is
required for the operators to become familiar with the specific
piece,” notes Barry Bender, president of Barry Bender Excavating
in Wellesley, ON. “We keep our equipment as simple as possible
to reduce the possibility of error. The equipment is only as good
as the operator. We tried more complex laser equipment in efforts
to become more efficient in our operations, but the operators didn’t
like it and that actually slowed down our operations because the
operators spent more time waiting for the equipment to catch up
with them.” He cites an example of an instrument that was supposed
to pick up the laser signal as the boom-mounted receiver passed
through the beam. It then would calibrate itself to indicate cutting-edge
elevation in any position. “The receiver wasn’t fast enough
to pick up the beam, so the operator had to pass it through the
beam several times till he caught it. That obviously slowed down
operations.
“My experience in
20-plus years of using laser equipment tells me to use the simplest
system available for the most satisfactory results. We would never
give up the laser equipment. We still try new pieces as they are
introduced, and we upgrade when something superior comes along.”
Bender’s comments echo those of many other contractors with
whom we spoke.
Combine Estimating
and Layout for Competitive Efficiency
“We often use laser instruments to do surveying on projects
before we bid,” relates Bender. “Most of our employees
use the instruments, in varying degrees. On the excavators, the
operators need to know how to set up and use basic laser transmitters
and receivers for foundation excavations and jobs like that. On
the bulldozers, we use them for level or slope work. It certainly
saves time by keeping the operators on their machines [instead of]
having to get out to check grades or waiting for someone else to
check the grades.”
Preparing your bid has
become both easier and more accurate since estimating software with
computer-aided-design (CAD) file import has become available. Combining
this accuracy with layout capability was a natural next step for
software developers. Products that can be used for bidding, as well
as for exporting data to the field, keep estimators and layout personnel
on the same page for the project. An example of this type of program
is InSite Sitework. “The program is designed to handle tough
takeoffs with ease,” observes Steve Warfle, product manager
at InSite Software Inc. in Rush, NY. “It uses common terms
that are familiar to site estimators so that a time savings over
a conventional hand takeoff of five to 10 times is easy to achieve.
With a good CAD file, a complex takeoff can be done in a half hour
or less.” InSite Software also supplies Field General, a product
that gives the contractor control of site layout, data collection,
and the machine all at the same time. Field General can interface
in real time with a robotic total station or a global positioning
system, or it can send point data to a conventional data collector.
The system supports offset staking for even more time saved. “Using
the CAD file, you can quickly stake the site with precision,”
says Warfle. “Then you take your bids won with InSite Sitework
right to the field.”
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| Fran
Cunningham's company is not large, but he believes he saves
many hours with the Field Generall Program. |
“I can set a hundred
stakes in an hour with Field General,” relates Fran Cunningham,
owner of Landmark Development in Auburn, NY. “Then I can go
to the next job and set 100 more stakes. I don’t have any operators
and equipment standing around waiting for layout stakes. The benefits
are obvious.” Field General exports surface models to Trimble
SiteVision 3-D, Leica 3D, and Topcon 3DMC systems. To verify work
done, shoot the site and InSite will calculate the cut and fill
to date. To handle the next phase, the contractor simply copies
the proposed to the existing and imports the next shot, and the
program calculates the new quantity. You can print cross sections,
3-Ds, and cut-and-fill maps to show actual excavation progress.
Does this sound too complicated for you? We found it interesting
and practical that InSite insists that potential purchasers of their
systems try them for 30 days before commitment.
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| At
this site, the grading controlled by Trimble instruments was
good enough to make traditional fine gradingun necessary. |
What Do You Look For?
What’s the menace that can interfere with any outdoor work
(or recreation)? Both project owners and contractors assert that
it’s the weather. If your site work involves people trudging
through mud and unstable ground conditions, the job will slow down
or stop. The right instruments can avoid that if you make sure your
instruments match the bad weather you might experience. Can your
controller and receiver survive being dunked in a typical construction-site
puddle? Can they survive falling off a 6-ft. supporting pole or
toppling from the top of a grader, a loader, or an excavator? Wind
and rain have probably stopped more construction jobs than anything
else has, but today’s best instruments are designed to shrug
off the whims of the weather and carry on. A word you will find
in many product descriptions is “rugged.” “Reliable”
is another; that usually refers to the laser’s constant accuracy.
For the Spectra Precision LL500 Slope Laser exterior horizontal
laser level, for instance, the vendor claims “stable accuracy
in even the most challenging environments.” This model offers
easy setup via a three-screw leveling system with compensated electronic
sensing. It is recommended by the manufacturer for roads and ditch
banks with up to 25% grade, storm drains, septic beds, parking lots,
and sloped floors. On the Snap laser receiver (a combination of
a survey rod receiver and a machine-mounted receiver), the housing
is made of Lexan to combat the most hostile weather and site environment,
and the LCD has a built-in strobe-light rejection so the display
is visible in all lighting conditions. The Snap receiver mounts
on the machine with a magnet; it has been used on backhoes, box
blades, skid-steers, excavators, and dozers.
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| The
details of the project are clear and easily understood with
InSite's software. |
The words used to describe
the Rugby 100LR, an automatic self-leveling laser for general construction
from Leica Geosystems, are “rugged,” “reliable,”
and “robust.” “The Rugby 100LR is a result of listening
to our customers,” states Dan Dykhuis, program director for
lasers in the Grand Rapids, MI, office. “It is built to be
rugged yet easy to use and can make quick work of concrete forming,
pad placement and framework, setting foundation and footings, as
well as elevation indication for heavy equipment.” It has a
working range of up to 2,500 ft., an automatic elevation alert function,
and a manual grade up to +/-10% with cross-axis self-leveling. It
levels automatically and quickly, has a simple five-switch keypad
that controls all the functions, and features a low-battery and
out-of-level indicator. “[The Rugby 100LR is built] along the
same principles that guided the development of the earlier product
[the Rugby 100], so customers can look forward to the same level
of reliability and robustness,” adds Dykhuis. “The Rugby
100 has received an overwhelmingly enthusiastic response from both
our dealers and customers worldwide. The co-molded housing of high-impact
plastic and rubber is as rugged as it looks.” The Rugby100LR
is the first Leica-branded product combining the heritage and expertise
of Laser Alignment and Leica Geosystems.
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| Bullseye
instruments attach to the earth-moving machine. |
Trimble (with mergers,
that name now includes years of experience in this field with Spectra
Precision, Laserplane, and Geotronics) makes an interesting and
significant point: “Our customers are supported by the industry’s
largest global service and support system, with partners who understand
the technology, the applications, and your business needs.”
What it is saying is that instruments are products that cannot be
sold the way many other items for contractors are; they are not
like hammers, pickups, or even most earthmoving machines.
Contractors frequently
mention that educated service personnel and knowledgeable sales
staff are essential to instrument purchases. Lack of good local
product support is a common reason for being disillusioned about
instruments. “That’s a shame,” remarks Richard Shimota,
a contractor in Bend, OR. “Poor support doesn’t necessarily
mean poor product, except to the customer.”
What Are the Main
Advantages?
In a practical vein, manufacturers point out that instruments can
improve the quality of a contractor’s work, use less skilled
labor (still in short supply and perceived in some regions to be
the most important need in our industry), and minimize downtime
and rework. They also say instruments can become significant tools
from the very beginning of a project, at the concept stage before
any blades have struck the ground or engines have been started.
When estimates are accurate and the work follows suit, some of the
not-so-obvious advantages to the contractor are better use of materials,
lower labor costs, and fewer occasions when well-paid workers are
wondering what to do next or how to correct a mistake just made.
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| Choose
instruments that can work in all types of weather. |
An example of how you
can save time and money recently occurred in the Netherlands. Dutch
contractor Kuypers Kessel had to build a new ring road with several
crossover sections, and there was railroad track nearby. That was
nothing new for the contractors, except that they were also testing
a new kind of sub-base material containing polluted soil. Kuypers
Kessel installed a Blade Pro 3D machine control system with an ATS
total station on a Caterpillar D6M dozer. The innovative sub-base
material comprises lightly polluted earth mixed with chemicals and
cement. The chemicals “store” the pollution while the
cement sets the mix like concrete. But the work must be completed
within a few hours and can take place only in dry conditions. The
original plan was to use the dozer with the Blade Pro 3D system
and then complete the fine work with a grader. In practice, the
results from the instrument-guided dozer were so outstanding that
the contract specifications were reached without the need for any
further equipment. “We have used Trimble machine control laser
systems for some years now to very good effect,” notes Harry
Kuypers, managing director of the contractors. “On this project,
we completed the contract quickly and accurately well within the
set time frame.”
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| Both
big and small projects can be faster and more accurate with
the right instruments. |
Progress in Small
Stages
One of the intimidating aspects of instruments in construction is
that some vendors and contractors believe you have to go straight
to the most advanced products available. Such products are also
the most complicated and require the most training. “Visual-indicate
machine control systems are a great first step into machine control,”
comments Mike Bank of Apache Technologies in Dayton, OH, which makes
and markets the Bullseye series of laser grade checkers, among other
products. “They are a simple way for contractors to further
save money using laser equipment they already own. Visual-indicate
systems are similar to handheld laser detectors in that they show
the operator the direction to move the cutting edge in order to
be on grade. The difference is that a visual-indicate machine control
receiver allows the operator to check the grade without leaving
the cab. These systems are easy to use and relatively inexpensive.”
To use a visual-indicate
receiver on a bulldozer or a grader, a pole is welded to the blade.
The cutting edge is then placed on-grade and the receiver adjusted
to indicate on-grade. The operator can then check grade continuously
during the earthmoving operation. When used on an excavator or a
backhoe, the receiver is mounted on the dipper stick, with that
mounting being either a pole welded in place or the magnetic mount
many manufacturers offer. The operator would then dig to grade,
place the bucket on the on-grade location, and attach the receiver.
The receiver is then adjusted to show on-grade, and the operator
continues his excavation. “When the operator wants to check
grade, the bucket is placed in the same position as it was during
setup,” adds Bank. “The dipper is placed in a plumb position,
and the operator observes the indication given by the receiver.
Some receivers automatically adjust for out-of-plumb, thereby increasing
the digging range.”
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| Topcon
RL-H2S rotating laser provides elevation control for grading.
|
One of the simplest systems
we came across was from LaserLeveling Inc. of Lutz, FL; it was developed
from a three-point-hitch scraper (the Grademaster). This company
has enjoyed particular success in recreational grading projects,
such as golf courses and ballparks. For the construction grading
package, LaserLeveling offers a three-part system: the grading system,
the laser, and machine control. Setup takes only minutes. “We
believe our system is simpler than most,” says Ray Joling for
the manufacturer. “Unlike traditional three-point box scrapers,
LaserLeveling’s scrapers use a unique rear-axle assembly where
the rear axle controls the height or elevation of the cutting edge
instead of the three-point hitch on the tractors [doing that]. This
design increases the efficiency and control of the scraper and turns
it into a precision grading attachment. Without this rear-axle system,
we would probably not attain our tight grade tolerances.”
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| The
operator can see exactly what he has done and what needs doing.
|
“Plenty of tools
have been available to measure grade, ranging from a simple pendulum
to digital displays with remote sensors,” says Skip Gosnell,
director of marketing at Rieker Inc. in Folcroft, PA. “While
these instruments work well to indicate the grade of a surface,
they only do one thing: indicate. It is up to the operator to control
the machine moving the dirt.” Why don’t some instruments
move the blade on a machine to keep a constant grade or the angle
of a trench? In the past, it was difficult to have any one sensor
do the job since conditions for trenching or grading would change.
If a blade hit a rock, the sensor might send an elevated reading
that would make the blade jump trying to react to the sudden input.
Electronic sensors have been damped, among other things, to try
to help alleviate some of the problems with jarring and vibration,
but this has made tilt or grade sensors slow to react to changing
surfaces—usually requiring the operator to make another pass.
“The solution was
not in the evolution of the sensors; it was in the invention of
the microprocessor,” continues Gosnell. “A microprocessor
can take information from a sensor and analyze it to see what it
should or should not consider before giving a command to move or
adjust a blade—much like a human understands that the sudden
jolt of a rock is only a rock. It does this so fast that the blade
remains on-grade.” Rieker’s RGC GradeControl system allows
an operator to dial in a set angle in degrees, percent grade, or
slope. Once in motion, the operator can fine-tune the controls,
depending on the application. The RGC GradeControl Inclinometer
package is designed to monitor slope and regulate both hydraulic
and pneumatic systems. Adjustments of grade setting in manual and
automatic control modes are done by simply pressing the “up”
and “down” arrows; the operator adjusts the setting during
operation for instant control. The “function” button allows
the user to select among pulse width, dead band, and gain, then
press the “up” and “down” arrows to calibrate
the selection. “Using smart microprocessor-controlled systems
like the Rieker GradeControl can increase productivity, but it can
also allow someone with far less experience to produce masterful
results,” concludes Gosnell.
Whatever your level of
interest, whatever your level of expertise, it seems that today’s
instruments, independently or in conjunction with other tools, can
increase the efficiency of your bidding, your productivity, and
your profits.
Paul Hull writes on
construction and environmental topics for several international
magazines.
GEC
- November/December 2003
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