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Solar Farm Pile Layout

tollejr3
(@tollejr3)
FNG Member

My company recently purchased a Vermeer PD10 pile driver for a solar farm project we have. My question is what is the beat method of layout for this solar work sounds like the industry standard is gps but is that gps rover layout or using machine control. I know some companies have used total station layout on smaller projects. Any information on this type of work would be greatly appreciated.

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Topic starter Posted : August 20, 2021 8:34 am
Tim V. PLS
(@tim-v-pls)
200+ posts Member

Rover layout, nails and feathers.

A robotic total station for small area is quicker - latency of measurements is quicker. That is, as soon as you plumb the rod, you have a go-to (delta north/east) distance. However, with huge area for laying out, multiple setups virtually eliminates the benefit of total station.

 

I'm currently doing support for a solar project that has `65,000 piles. There are about 30 drilling machines on the project.

Another company has the pile layout contract, but I've talked to their crews and closely observed how they're doing this work. It's all about production, getting points in the ground.

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Posted : August 20, 2021 10:21 am
Chris Bouffard
(@chris-bouffard)
500+ posts Member

In my mind, it all depends on the tolerances expected.  I have laid out smaller solar projects and always used a TS because I was staking and generating cut sheets with tight vertical tolerances.  

When doing layout, I will use VRS RTK for rough grading but always go terrestrial when staking for finished grades.  Sometimes hundredths matter, sometimes they don't. 

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Posted : August 20, 2021 1:05 pm

dmyhill
(@dmyhill)
1,000+ posts Supporter

Buy an RTK system and start putting in stakes!!! What could go wrong?

(most likely issue: datum)

I did some consulting with a firm that was trying to build robotic installation and maintenance machines for solar projects. Getting from Web Mercator to something I can layout on the ground was something they were working on with the software. Not sure where it ended up... 😉 

This post was modified 10 months ago 2 times by dmyhill
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Posted : August 20, 2021 1:11 pm
Tim V. PLS
(@tim-v-pls)
200+ posts Member

The company I've been observing is using 2 one person crews. Each person has a rover and is loaded down with nails with color coded feathers in carpenter pouches. The feather color indicates the type of pile. Horizontal layout only. The exception to horizontal only is one point with an elevation about every 3000 points. The pile driving crews bench off this elevation point with a laser level to drive the piles to the correct elevation.

Each layout person sets in the range of 500 to 600 points per day with the goal of being around 1000 points ahead of the pile drivers. (Talking to the other company's surveyors, they say they have a friendly competition to see who get more set each day.)

I bid the layout work. I hadn't done this type of layout so I asked many questions on what the scope of work is. I was told by the project manager every nail had to be within "1/8th inch, with an elevation on every point." So that's how I bid it, with a per point price.

The company with the winning bid had worked on several of these types of projects in the past and came in with a per point price of less than half of my price. Now that I see how they're doing this, I can see why.

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Posted : August 21, 2021 11:15 am
Rover83
(@rover83)
1,000+ posts Member
Posted by: @tim-v-pls

Each person has a rover...Horizontal layout only...one point with an elevation about every 3000 points...pile driving crews bench off this elevation point.

I bid the layout work...I was told by the project manager every nail had to be within "1/8th inch, with an elevation on every point." So that's how I bid it, with a per point price.


GIF
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Posted : August 21, 2021 5:13 pm

Tim V. PLS
(@tim-v-pls)
200+ posts Member

@rover83 

Well... it reiterates to me, project managers often don't really know how the work gets done. Typically I would talk to the superintendent - if they have experience, they know. In this case I didn't.

But now I know more. Watching and pondering, I might have a couple of ideas to increase efficiency. So, next time, now that I know the going price, I can bid to win.

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Posted : August 21, 2021 6:16 pm
DDubya
(@ddubya)
10+ posts Member

I am surprised here, having laid out concrete piles and presuming your production is on a faster scale. Forgive my ignorance in advance, please.

Whether it is GPS or granny, you are working from control, and after that, nothing can beat a total station, matter of fact, not a robotic, because I would lay out in chunks and tape in between, my instrument man and me turning and burning.

Another thought is building a frame, or rack, a template, whatever, that you can throw down over points laid out for those in between.

I laid out an auger-cast pile job with a jig my boss told me to make for cluster piles. It was just an isosceles triangle made from 2x2’s I flopped around after centerlines were established. Fun!

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Posted : October 28, 2021 9:43 pm
kotuku4
(@kotuku4)
100+ posts Member

Contractor should have rtk machine control. If necessary a surveyor or sitech gets it up and running and does some quality control.

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Posted : October 28, 2021 11:13 pm

MightyMoe
(@mightymoe)
5,000+ posts Supporter

I've done many rammed earth column projects, similar to the project described. Think about the construction process. There is no reason to carry elevations on the drill stake. It's gone with the turn of the drill. Elevations need to be some distance away. The ground should be graded before setting points but that's usually a rough grade staking or machine control.

This post was modified 8 months ago by MightyMoe
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Posted : October 29, 2021 3:16 am
Bill93
(@bill93)
5,000+ posts Member
Posted by: @tim-v-pls

500 to 600 points per day with the goal of being around 1000 points ahead of the pile drivers.

That's less than a minute each, all day long, except for water and bathroom breaks. Moving right along.

How many of what kind of pile drivers can drive and reposition at that rate?

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Posted : October 29, 2021 5:26 am
Chris Bouffard
(@chris-bouffard)
500+ posts Member

I just complated a smaller solar field layout project with about 400 piles.  No elevations were needed.

Initial control was brought in via VRS RTK and tightened up into a constrained network after cranking some angles with a TS.  All the layout was done with a two man crew running a TS.

Call me an old fart set in my ways if you will but I don't allow my crews to do any layout with RTK unless the accuracy tolerances allow for a tenth or two of slop.  My crews often moan and groan when they can't use RTK but the last thing I want to hear from a job Super or PM is that my measurements are all over the place.

When fingers start pointing, I want to be able to produce a field book print out and the x, y, z deltas of my design/as staked points to shut down the blame game immediately.

I have no problem using RTK for building digs, boring locations and any other rought location work or grading but when it comes to layout work, I want my points to land on a knats ass, as much as humanly possible.  I'll take quality over quantity all day long.

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Posted : October 29, 2021 12:46 pm

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