dougie doesn't wanna say "hate", and i don't particularly either, but i might be closer than he is...
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it's been a few years, but i got one of those emails earlier today from the civil on a big construction project:?ÿ "GC says the site grades are wrong on the survey."?ÿ "ugh" is the immediate reaction.?ÿ so then i open the attachment and see a bunch of hand written spot elevations that are "correct" on top of my contours.?ÿ they're all half a foot to a foot higher than what i'm showing.?ÿ funny, this is about the fifth time i've been through this in the past 20 years and somehow i always blow topos on the low side...
so i go back in, look at the raw data, look at the cad file, look at the deliverable.?ÿ everything seems ok at first glance. then i remembered i was given an old topo done by somebody else for a previous iteration of the site, done in a different datum.?ÿ but i xref it in anyways and see that i'm, like, CONSISTENTLY .7 higher across common shots- benchmarks, hardscape, and natural ground included.
then i go to the city data hub and pull their contours.?ÿ same datum as mine, lidar (so of course up close they won't look that good), just dropped them into cad and voila- practically on top of mine.?ÿ funny, two entirely different sources of independent info randomly match my survey in terms of relative topo.
time to start making phone calls.?ÿ call the GC project manager:?ÿ "i don't know, call my site guy."?ÿ call the site guy: "the excavator says it's y'alls' contours."?ÿ funny, nobody can tell me what the problem is, only that i'm wrong.
at this point there are about 3 or 4 red flags blowing in the breeze.
call the excavator, leave a voicemail "hi, i'm the surveyor for the honda site you guys are working on.?ÿ call me back at your earliest, etc..."
half hour ago i get the call.?ÿ now, i don't know what part of the voicemail the guy listened to, but apparently not the part where i stated i'm the surveyor, or A surveyor.?ÿ because as soon as i answer he starts talking.?ÿ and it occurred to me really quick to just shut up and listen.?ÿ and i proceed, for about the fifth time in the past 20 years, to get a 10 minute lesson from a dirt guy on how land surveying works.?ÿ and about 12 minutes in i hear what i knew was coming:?ÿ "see, if we estimate we'll have to haul off 100 loads and we get out on site and it turns out to be 170 loads, well that costs a whole lot of money."
it was at this point i interjected and let him know that i'm familiar with benchmarks, datums, contours, and redundancy, and that the topo he checked- that i did and that i drafted- had all of those things built in as well.?ÿ then i told him about the cad file and the city data.?ÿ i feel bad, cuz i think i aggravated some nervous response in him that set off his stuttering.?ÿ told him it was no problem, i had to send the guys three hours up the road tomorrow to set a couple rods, so dropping by his site that's only two hours up the road- but conveniently on the way- wouldn't be a problem.
hell, we might have screwed up.?ÿ i'll know in 24 hours.?ÿ but four other times in the past 20 years i've been wrong exactly zero times.
i really don't like dirt guys.?ÿ?ÿ
and it occurred to me really quick to just shut up and listen
word. ?ÿI love my job.
Be glad they call you and be worried about the one time you are wrong.
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@hpalmer?ÿ
they didn??t. The civil did. I had to chase them down. Since speaking with the guy I??ve now learned they??ve found ??bad? topos on a disproportionate number of sites they??ve done over the past few years.
I am of course vigilant, and human, and perfectly willing to accept that I have been and will be wrong.?ÿ
but there??s a definite slice of the excavation business around here that operates like this: pre-emptively carpet bombing their clients with ??bad survey? claims for the sake of future change orders and/or disclaiming of liability.
Does this happen to more or less match the difference between 29 and 88?
@flyin-solo preach! ?ÿA-men.
@holy-cow no.?ÿ interestingly enough, the old topo that i xref'ed in claims it is in NAD88, but doesn't spec a geoid.?ÿ this is in san antonio, where i don't work too often.?ÿ around here the shift from 09 to 12B was pretty noticeable in most cases, but certainly not .7
that said, the old survey i looked at certainly was goofy- it said it was based on illinois grid (?)?ÿ but again- in a relative sense i matched across it almost perfectly.?ÿ and i never opened that file before i set foot on site.
this excavator's survey has variations all over the map between .5 and 1.0.?ÿ and they claimed to have matched tbm and c&g elevations within hundredths.?ÿ it's ONLY the dirt they say we screwed up.?ÿ which is allthemore interesting when considering it was all shot with a fixed height rod.
I built the mc files for about 6 miles of 4 lane going cross-country that we are building now. Calibrated the site, shot in a couple of base poles, everything is checking. Up until about a year ago we used all Cat/Trimble equipment, but the Topcon guys have convinced them to try a couple of Komatsu excavators with their stuff on it ?ÿFiles and calibrations have to be converted, among other things. Got a call that the grade on a ditch was off about .8??. Top on guys were blaming it on the calibration, but the Trimble stuff was right on grade. Turns out there was an obscure setting somewhere in the Topcon stuff that had got changed.?ÿ
yep- and this speaks to another possibility i was considering prior to speaking with the guy- that it was, basically, chimps flying rockets.?ÿ because i've dealt with that too.?ÿ never forget the client who bought a brand new blade (never having owned one before) and a brand new MC rig for it.?ÿ convinced one of my PE partners to hand over the civil grading cad files.?ÿ?ÿ
took the guy about an hour to dig a nice tunnel where his main entry drive supposed to go...
Chimps Flying Rockets is now a permanent addition to my lexicon.
Dirt guys want more money than just number of trucks. Their fill never fluffs up to what they say and they always carry off more litter than they want. If they can convince the contractor you missed by a half foot, that's golden to their pocket book.?ÿ
"see, if we estimate we'll have to haul off 100 loads and we get out on site and it turns out to be 170 loads, well that costs a whole lot of money."
Yes, it certainly does. Hard to believe he's not aware that in situ material when excavated may shrink or swell by up to 50% after excavation depending on its geotechnical characteristics when loaded into trucks.?ÿ Surveyors measure volume not by truck, but by volumetrics in place, either excavation or compacted fill and sorry if the projected shrink/swell numbers are way out of whack (should be somewhat accurately estimated by the geotechnical engineer) but that's their risk.?ÿ ?ÿWe certify volumes in place, not truck counts, so I've never lost a battle with trucking contractors who claim the engineering earthwork woefully underestimated their efforts and my volumetrics were never in dispute.
Somebody once said to me (or maybe someone once should have said to me): "Contractor A will walk the site with the tender docs and work out how to do it, while Contractor B will walk the site with the tender docs and work out how to screw it."
while Contractor B will walk the site with the tender docs and work out how to screw it.
Yes. ?ÿIn my experience this one??s email signature line will say, ??have a blessed day.?
The liability thing is why I'm always shocked that contractors want to take on the staking themselves.?ÿ Back it the olden times they could blame us for everything because we staked it.
@brad-ott lmao. I??ll hold back from expanding upon this, but those guys?? business cards tend to be pretty?? entertaining as well.
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Kinda like the septic system people....
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Laughing all the way to the bank!
@jitterboogie is that a corn cowboy?