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Surveying Question

Old 04-18-2012, 05:53 AM
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I know there are probably some surveyors out here that know the trade and it's products well. I am looking to purchase a total station to use for building layout. I work for a GC, we will have surveyors give us a few points but I am buying this total station so my guys can take it from there. What is the best, in terms of ease of use, on the market? At my old company we used topcon so I am familiar with those. Thoughts?
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Old 04-18-2012, 05:59 AM
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Find a Topcon 313 in good condition and have it calibrated. Several shops close to your location that will calibrate and certify its accuracy.
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Old 04-18-2012, 06:10 AM
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For construction, a basic TopCon will do, and you have the added benefit of having used one before.

If you desire sub-arc-second precision & a robotic unit so only one person is needed, you will need to open the wallet up for a top of the line Trimble, Leica, or Sokkia unit.

If I may suggest, simply showing your guys how to shoot is not going to guarantee they do it properly. Spend some time and get someone to give them a "Total Station for Dummies" course, so they can have a basic understanding of what is behind the task they are doing. They don't need a course in geodetics or trigonometry, just a simple "why we do this".

As far a brand, well, that's YamahavsMercuryvsEvinrude territory.




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Old 04-18-2012, 06:26 AM
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As always...it depends. What kind of work are you doing?
If staking curb, storm and sanitary sewer and perhaps exterior building corners with offsets, you can't beat a robotic instrument. We have two Trimble robots.

If you are going to be lining up bolt patterns for columns, a robot will work, but you will need to have an instrument man turn the angle and give line along the column lines. Robots don't work well in this area unless you use them as a conventional instrument. I know this from experience.

Another, piece of advice....train your crew accordingly so they can think on their feet and not be just button pushers. They need to know and understand what they are doing or your buying concrete if they screw up.

Surveying is a profession, not a trade.

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Old 04-18-2012, 06:35 AM
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We are in the process of also hiring a layout guy with surveying experience. Layout is the single most critical start to a job, not going to just turn a couple guys loose with a gun. I am a project manager and myself and the superintendent will go out and verify some random points as we get going. Also I ran across a Topcon dealer that also sells Leica and he recommends the Leica. They have a builder model that will do what we want.
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Old 04-18-2012, 06:50 AM
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pmichael might know but do you have a network of Continuously Operating Reference Stations (CORS) in your work area? It would not be a replacement for a Total Station but it does have some advantages.

I would add Nikon to Snapper Heads list also.

What software and data collector do you use?
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Old 04-18-2012, 06:58 AM
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I'm guessing for general layout the TopCon would work great. Honestly...how accurate can you build a building corner? BUT....you sure better know how to setup and utilize a coordinate system, and the control that has been established for a project, and how that relates to the plans. THAT'S the issue we deal with on just about every freakin project it seems.
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Old 04-18-2012, 07:21 AM
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man we just spend the $1500 or so on each project and hire a surveyor...
they'll come out, verify benchmarks, set our corners, etc

we do use an instrument for excavation & concrete elevations but i'd rather use a professional for the site layout
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Old 04-18-2012, 08:00 AM
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Originally Posted by cgrand View Post
man we just spend the $1500 or so on each project and hire a surveyor...
they'll come out, verify benchmarks, set our corners, etc

we do use an instrument for excavation & concrete elevations but i'd rather use a professional for the site layout
It's not going to be $1,500 for the layout for this beast. We would probably spend $20K or more. That is just one job. We have several going on. Plus the layout guys can do much more than just layout.
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Old 04-18-2012, 08:41 AM
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Originally Posted by pmichael View Post
Surveying is a profession, not a trade.
Give this man a cigar.


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Old 04-18-2012, 09:18 AM
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Topcon seems to be the most user friendly in my opinion.

You may want to consider what cgrand mentioned. It will not only be the cost of the instrument, but to be effective and accurate you will need some version of autocad and someone to operate it. This means all the equipment cost, plus software and your layout guys salary. I am a survey manager for a survey/engineering firm and have converted many of the large contractors in our area to using us instead of hiring their own. We give them a lump sum price for all layout usually when they are bidding the job. About 90% of our business is layout. Find one you trust and build a relationship. Just something else to think about.
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Old 04-18-2012, 02:14 PM
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Originally Posted by cgrand View Post
man we just spend the $1500 or so on each project and hire a surveyor...
they'll come out, verify benchmarks, set our corners, etc

we do use an instrument for excavation & concrete elevations but i'd rather use a professional for the site layout
I couldn't agree more.

However, quite a few of the contractors in our area are going the route of hiring their own staff for stake out work. We used to do quite a bit of stakeout work for contractors, but not so much now. I have also pretty much quite bidding on the work because its tough to compete with the surveyors that are working out of their home with low overhead, which is fine for them, just tough for a brick and mortar firm to compete with that.

One thing I will caution you on. Your layout of the interior stuff should be fine, but if you are starting from the property line, you should get a LS to do it, so your not in danger of violating any surveying rules and regulations in either Virginia or North Carolina. This could impact your comapny's contractor license if you get busted.

Regarding the poster suggesting using GPS based on a VRS system. I would not recommend this due to the fact that RTK GPS has an accuracy of +- 4cm in the vertical component. Might be ok for rough staking horizontal items, but not for elevation work for curb, sewer etc.

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Old 04-18-2012, 02:38 PM
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Originally Posted by pmichael View Post

Regarding the poster suggesting using GPS based on a VRS system. I would not recommend this due to the fact that RTK GPS has an accuracy of +- 4cm in the vertical component. Might be ok for rough staking horizontal items, but not for elevation work for curb, sewer etc.

PM
I was thinking about horizontal layout and cut/fill for earthwork. Although the local DOT does allow dual frequency GPS receivers for both vertical and horizontal survey.

I know that we do not fully utilize the software and equipment we have but I was shocked last month when I went to a jobsite and the contractor had $30k or more worth of equipment and software and had the electronic cad files and did not know how to use it.

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Old 04-18-2012, 02:53 PM
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We generally always hire a surveyor. Unless you are self performing foundations and need to layout footings, walls, anchor bolts and the like, it's not worth the risk. Have somebody else assume the risk of laying out something wrong.

However, I did survey for a number of years and out of college I was a field engineer. We used either Sokia (very user friendly) or Topcon, they are both great guns and should suit you well.
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Old 04-18-2012, 03:00 PM
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This will all be building layout after a LS gives us a couple points. Lots of anchor bolt layout and tons of interior layout. Thanks for all the input. This is my opinion is what makes THT a great site. Tons of different people with completely different backgrounds that all are brought together because of one common interest.
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