Grade Control Systems - Excavation & Site Work - Contractor Talk

Grade Control Systems

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Old 03-12-2010, 10:29 PM   #1
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Grade Control Systems

I have been researching and looking into grade control systems lately and wanted to see if I could get owner feedback from somebody on the site. I appreciate operator feed back but I am really looking for owner feedback on cost savings/production multilpliers and so forth.

My company is not super large but not a ma and pa type of business either. Our bread and butter is Public Works/ Federal Projects conducting site work for new construction. We seem to land a lot of work through one specific General Contractor that I have been pretty much working steady with for 2 years and a lot more of that work is on the local army post. Most jobs range from $100k (the smallest) to $1M. With the damn unions continuing to push prevailing wages higher and higher (laborers are now $40.03 hr) and bid prices staying low I am looking for a way to cut out labor in grading operations while pushing production higher. We don't do alot of roads/highways but do have some larger town house developments negotiated out once the market turns around (those contracts are not part of the decision for this purchase). We don't usually place the top course for paving (paving contractors like to do that around here and the general likes for me to exclude it) so most of my grading is curbs and subgrade for buildings and parking lots. I am looking at purchasing a Trimble CS900 with single gps or maybe with single laser augmentation gps for a 09 komatsu d51 (or 07 komatsu d37). I already have a trimble GL720 dual slope laser but the set up can be a pain in the ass and you still have a labor grade hopping all the time.

I know at the price (30k) you can have a laborer do a lot of grade hopping but with the gps I can buy out my grading portion of the survery time from the general (sometimes as much as 10k per job) and not have to worry about a brain fart when setting hubs or setting the grade rod when doing cuts. With being a younger company (4 years old) i evently will be the Prime contractor for work with the USACE but right now im building a reputation with them since that sometimes goes farther than your price when they consider contracts. So even though right now im not doing much road/highway work it is in the near future (probably 3 years or so).

So what i am looking for is pros and cons to using these systems before i step up and drop 30k that could buy me another 35 sized mini or down payment on a new grader.
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Old 03-13-2010, 09:25 PM   #2
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Re: Grade Control Systems

Aloha from Hawaii! I have used, set up, and managed many grade control systems myself and for other companies here. I worked with most system brands including Trimble, Topcon, TDS, etc. And most set ups like Laser, position sensor, Sensor location, GPS and Robotics. There is much you need to know before you cough up any $. I will give you my 2 cents, and will limit this post to full GPS machine control systems only to try and keep it short. So here we go:


The sales man will really push the sale on you even if he knows that the system is not right for your company. If you try and demo a system it will seem to look and perform perfectly, but here are some things that he will not tell you until after you commit to buying the system:

You need to hire a computer tech fluent with AUTOCAD, and survey savvy to create 3D models needed to run the grade control for every job. (you can subcontract this out, for a fee of course)

You need a full time field person to run and maintain the system. (e.g. software upgrades come out at least once a month, hardware once a year)

GPS will not work in mountainous areas and under heavy vegetation.

The GPS accuracy is 0.05 of a foot (5 hundredths). What he doesn't say is that its plus or minus 0.05'. That means this morning it could be 0.05 low, but in the afternoon its 0.05 high, so now your grade is off by 0.10'! (accuracy also depends on where you are located)

You still need a surveyor. A surveyor still needs to verify or establish the horizontal and vertical control needed to calibrate the GPS system. You also need a survey savvy person to calibrate the GPS for every job.

You need to periodically, at least twice a day, check the accuracy of the system. This is because the earth and the satellites are always moving. Which brings us to:

So you still need a grade checker/setter! One of the main advantages of GPS is a stake-less job-site. If the system breaks down and there isn't a stake on the site what are you going to do?

If you need to finish grade and match any existing surface, like curbs or sidewalks, GPS is useless. This is because GPS cannot match existing surfaces. This is true even if GPS was used to set the elevation of the curb. THERE IS ALWAYS A VARIANCE WITH GPS, ESPECIALLY ELEVATION!

The most common sales pitch used by the salesman is this:

"Grade control will make your bad operators good, your good operators better, and your best operators untouchable."

What they don't tell you is that it doesn't show bad operators how to work the material properly. e.g. the gravel they are spreading is right on grade, but all the fines are left where they started, and all bones where they stopped. The problem is is that they think that they did a good job just because there work is on grade.

GPS machine control does nothing to help operators with the basic techniques of MOVING, EXCAVATING, OR EMBANKING material. It should be only used as a device to increase productivity by minimizing over excavating, second guessing, etc.

If the operator is computer illiterate, or refuses to learn how to use the computer, the system is useless. This is very common with the older operators who never learned how to use computers, and who are ironically the best operators, because of all of there experience. BTW I personally know old timers running machines without grade control that still outproduce operators with GPS.If your operator cannot understand basic plan reading and interpret contour lines, they will never exploit the full potetial of the system. Its like putting a performance chip in your pickup and keeping it on the lowest horse power setting because you don't know how to put it on a higher setting. Its way better than stock, but you're not getting the fullest potential out of it.

It can take up to week to properly outfit a machine for grade control use. Even if it comes "GPS grade control ready".

Of course there is the good. Probably all of the good things you've heard about GPS are true. I focused mainly on the "bad" because that is most likely what you haven't heard. But machine control is definitely a advantage in the right situations.

I like to compare full GPS machine control to a D11 dozer:

Remember GPS machine control is the "D11" of the grade systems. On small jobs i can take longer to set the GPS up that it does to finish the job. Likewise, you wouldn't put a D11 on a one acre job site where the dozer cant even turn around, regardless of the D11's production rates.

You wouldn't buy a D11 to work part time. Just like a D11 a full blown GPS needs to work every day to be worth the investment.

With that said install the GPS on the most used machine you have, with the exception of an excavator. I do not recommend GPS on an excavator, the ocala system (with laser) and paint on the ground, works WAY better. You can also switch the hardware between machines if you can only afford one set.

Lastly, if you can use it everyday, have the manpower to support and understand it, have an operator that can exploit every advantage it has, a GPS system will be worthwhile ten fold.

But remember going back to the D11 reference; you wouldn't buy a D11 if your grading parking lots and drive ways, don't have an operator to run it, a mechanic to fix it, money to put fuel it, and the personnel to maintain it!

GPS is not the only option. There are lots of options available for you requirements. There are so many systems out there to match conditions and budget needs.

There are a million more things I can say, but I do not want to have an endless post. If you have any questions please let me know and this goes for anybody reading. I will be happy to help in any way I can.


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The Following 6 Users Say Thank You to Hanalike For This Useful Post:
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Old 03-13-2010, 10:45 PM   #3
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Re: Grade Control Systems

That answered almost every question I had about Grade Control systems. You just saved me coutless hours dealing with a salesman and trying to read through the bs. Thanks a bunch.
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