Correct procedure to blue topping ahead of motor grader?

[chrismatin]

Can someone explain to me how to properly set blue top stakes ahead of using a motorgrader. And at what time during the pad, paving area or road to set them? Also do I leave the material a little high or low, before setting stakes. I'm trying to improve my grades before turning over to concrete/asphalt subs. We use trackloaders & skid steers as of now, to get within a 1"-2". Need to get much closer to stay in business/reputation.

Many thanks

 

[oceanobob]

The last one to measure it always finds a problem with the previous. That being said, we place these stakes on a pattern or grid, top of wood is set low so one half (or a bit less) of the whisker is exposed when grade is attained.
Hope this helps as I don't know exactly what is a blue top, as we have small wood stakes with a whisker on them and the whisker can be orange or white typically. No blue. Sorry if this is something else and not what you are wanting.

 

[chrismatin]

Yes helped Tks. So sounds like grade is left high to blade/cut down to bluetop/ whisker stakes. Wonder if it's best to compact or leave loose, until exact grade is achieved?

 

[Operator4100]

wow! I haven't heard that in term in years brings back lots of memories, I used to work for a bridge company and we dealt with that some, from what I remember on the road work when you got your sub-grade up close to grade the survey crew would set what was called blue top grades stakes on the shoulder of the road so the grader wouldn't cut them out and you could go back to them to check grade , they were probably about 50' apart not sure of that though, the base material was put down in 2 to 3 layers, each layer compacted to spec's. I was told back then if you could blue top running a grader you got top pay, no such thing as GPS or lasers then!!!

 

[Scrub Puller]

Yair . . . chrismatin. It always used to be that finished grade was achieved by cutting down to level . . . in other words the fill was put in and compacted a fraction high and then cut off to the "bluetops" which were short hardwood stakes pounded down to level.

On road work the local practice was to stake the centreline and shoulder every hundred feet giving line and level.

There was an offsider with the grader to broom away the dust. With our top notch grader hand we would end up with a shiny surface and three lines of bluetop dots.

They do it different these days of course with GPS and laser and the practice of cutting down to level seems to have gone by the board as well.

I believe it shows up in the finished jobs with pavement failure seemingly being accepted as normal instead of the exception.

Cheers.

 

[old-iron-habit]

My dirt subcontractor is currently fine grading the first phase of the parking lot at the hospital we are building. This week they have been using a brand new rental D6 hi track with lasers on it that follow the curb apron. Looks good to the eye but we will see Monday when the surveyors come pack and set the blue tops. The thinking part comes in when you still need to know what curbs your machine needs to be aligned with for proper flow. I'm not convinced they got it down yet. A good grader hand would have done it in 8 hrs and they have been there 2.5 days and not done yet. It does work real good in the 30 ft roadways. I'll keep you posted on how it comes out.

 

[R.D.G013]

Over here for subdivisional roads we use pegs set 1 metre behind back of kerb with finished pavement levels on them and use a string line to pull across the road from one side to the other, work out the hight of the centre depending on the amount of cross fall, measure down with a tape and use a spray can of paint to mark the cut or fill required to get to the grade required. Example + 5 is 50 mm to go up to F L, or -8 is 80 mm down to F L, F L being finished level. A road that is 6 mtr wide with 3% cross fall will be 90 mm higher in the crown than at the sides. The kerb crew then use the same pegs to set up their line for the kerb, grader then trims for kerb working of their string line, once the kerb is in everything is measured from the top of the kerb, when final trimming it is from the lip of the kerb, for 30 mm asphalt, gravel would be trimmed 30mm down from lip of kerb and 30 mm low in the crown the asphalt would then bring the road up to finished hight.

 

[R.D.G013]

Forgot to say everything is compacted and left slightly high before the final trim, the final trim is the last thing to be done before asphalt goes on.

 

[chrismatin]

Understood thanks. No GPS systems here, just wanting to learn ol school way of fine grading efficiently. I realize it takes time/ learning, but would like to be knowledgable. I would be glad to budget for surveyors to set blue tops, we do not have a total station. Are the surveyors normally who sets blue tops for a small/mid size Sitework contractor? My company has a couple of lasers & transits.

 

[old-iron-habit]

Most surveyors set the blue tops with a robotic total station working off the cad design drawing. I have not seen a surveyor in 5 years that did not use robotic instruments. No reason you could not set them with a builders level if you have your layout and grid set up. Just takes a little more time and two people instead of one.

 

[Landclearer]

When we do roads or parking lots, the surveyor comes in and sets offsets with grade(cut or fill). Depending what it is we measure from his stake figure our grade from his cut or fill then set our own bluetops. We set ous so the top of the wood is grade and always make sure there is a little cut. It is a real pain trying to fill and compact around blue tops.

 

[RoadMan1775]

For roads I like to leave the material a bit high, not much just enough to trim off. The road should already be compacted before setting the final bluetops. I usually set them every 50 feet. If you have a vertical curve this can change. I set a row on centerline. And one on each side with the appropriate cross slope figured. Once it is trimmed I like to run a rubber tire roller over top of it. Really looks nice.

 

[Scrub Puller]

Yair . . . RoadMan .

Really looks nice.

Gotcha there mate. Sounds like you work they way we used to work here forty odd years back.

If you see my #5 post I mentioned that I believe road surfaces have to be overfilled and cut down to grade.

There is a certain sense of satisfaction in looking at a finished section so hard it cut off shiny in the afternoon sun with the bluetops just showing.

Ah to be young again. (big grin)

 

[Radrock]

How times have changed... I have blue topped many roads and streets using blue tops and some with the whiskers too. Here in Missouri it is pretty rocky and hard to set the hubs. Many changed over to just setting hubs and then pulling strings to grade . Then we went to sonic master to grade off of a string line or laser for a building pad. Now we are using a robot total station that I use on a dozer and 140M blade. It even has it's setback though. Probably a good thing we use it as the bubble in my butt is about wore out haha