Odd Benchmark

[+Airmapper]

I'd like to hear from some benchmarkers and see what you think about this description I found for an Airport survey marker. I plan on logging it sometime soon. (I'm known at the airport, no security issues.)

 

"THE STATION IS A PUNCH MARK IN TOP OF A STAINLESS STEEL DRIVEN INTO THE GROUND AND ENCASED IN A 3 FOOT SECTION OF GREASE FILLED PVC PIPE AND SURROUNDED BY A 5-INCH PVC PIPE WITH A LOGO CAP STAMPED --- LOGANPORT 1989---."

 

Why would a stainless steel marker need to be surrounded by a pipe filled with grease? I'm sure there is a purpose for the setup, but does anyone know why they went to so much trouble setting this marker?

[foxtrot_xray]

I'd like to hear from some benchmarkers and see what you think about this description I found for an Airport survey marker. I plan on logging it sometime soon. (I'm known at the airport, no security issues.)

 

"THE STATION IS A PUNCH MARK IN TOP OF A STAINLESS STEEL DRIVEN INTO THE GROUND AND ENCASED IN A 3 FOOT SECTION OF GREASE FILLED PVC PIPE AND SURROUNDED BY A 5-INCH PVC PIPE WITH A LOGO CAP STAMPED --- LOGANPORT 1989---."

 

Why would a stainless steel marker need to be surrounded by a pipe filled with grease? I'm sure there is a purpose for the setup, but does anyone know why they went to so much trouble setting this marker?

Uuuh... note that it doesn't say what it IS, just describes it...:

"...TOP OF A STAINLESS STEEL DRIVEN INTO..."

 

...a Stainless Steel...? What? A stainless steel fridge? Oven? Microwave? Rod?

 

Me.

[holograph]

That would be a stainless steel rod driven into the ground. It is surrounded with a grease filled pipe so that the heaving of the ground won't tend to pull it out and change the elevation of the top of the rod. There a quite a few of such stations.

[+Black Dog Trackers]

GC2731 is a steel rod type marker. There will be a 5-inch logo cap. The cap will likely be on a hinge and you just pry open the cap with a screwdriver and then you'll see the rod. Take 3 pictures - a distant picture with the logo cap in view, and note the direction of the shot, a closeup picture of the rod with the logo cap open, and a real closeup of the rim outside the logo cap where the designation "LOGANPORT" is.

[+Airmapper]

Thats what I thought, these were supposed to be descriptions.

 

I looked at a description for another benchmark on down the runway, it says it is a stainless steel rod, I assume the other one is the same.

 

There are three benchmarks along the runway, all have seperate descriptons, and I reckon I get to log them as three different marks.

------

 

I'll try and take those photos like that when I log them. Thats interesting about the grease securing the rod.

I guess since this is an airport they secured the rod with extra measures so it would be accurate for possibly expanding the runway or other construction.

Edited September 15, 2005 by Airmapper

[DaveD]

NGS puts the sleeve filled with environmentally friendly grease around the upper portion of many rod marks to reduce the effects of surface motion in the upper meter of soil. This is especially important in areas that are susceptible to frost heave.

[StripeMark]

I've noticed that most marks set in Minnesota the last couple years are also set in this same manner. Yes, it's so the ground can rise and set with frost and the rod stays in the same place.

[+Airmapper]

Now when I find it I might be able to explain why it's built like that, the Airport manager (my flight instructor) may already know where they are as he is listed in the description as thier caretaker. Thanks, I'll try to post here after I find and log them.

[+Airmapper]

I found all three marks on the runway, two were of the type mentioned. Stainless steel rod. I could see the top of the rod, I assume it goes down 3 feet or so. The mark halfway down the runway was a regular disk set in concrete. The last one down the runway had a witness post, this is the first one I've seen, without it I woulden't have found the mark. I paced off the distance and started prodding around, found it under grass clippings.

Thanks for all the info.

Airmapper

[+Black Dog Trackers]

The rod probably goes deeper than 3 feet. Check out what this one says!

[+Airmapper]

Man! 38 feet, he might as well drill for oil, I bet that one hasn't drifted far.

[Z15]

These type marks are usually of more imporatance and thus the added measures to make them less subject to enviromental conditions affecting the stability of the mark.

 

Airports and CORS stations is where you might find these..

 

AA8048 ***********************************************************************

AA8048 FBN - This is a Federal Base Network Control Station.

AA8048 DESIGNATION - PORTAGE A

AA8048 PID - AA8048

AA8048 STATE/COUNTY- MI/HOUGHTON

AA8048 USGS QUAD - OSKAR (1975)

AA8048

AA8048 *CURRENT SURVEY CONTROL

AA8048 ___________________________________________________________________

AA8048* NAD 83(1994)- 47 13 37.82095(N) 088 37 31.04750(W) ADJUSTED

AA8048* NAVD 88 - 192.928 (meters) 632.96 (feet) ADJUSTED

AA8048 ___________________________________________________________________

AA8048 X - 104,103.487 (meters) COMP

AA8048 Y - -4,338,042.251 (meters) COMP

AA8048 Z - 4,659,069.331 (meters) COMP

AA8048 LAPLACE CORR- -7.93 (seconds) DEFLEC99

AA8048 ELLIP HEIGHT- 159.42 (meters) (06/11/02) GPS OBS

AA8048 GEOID HEIGHT- -33.55 (meters) GEOID03

AA8048 DYNAMIC HT - 192.961 (meters) 633.07 (feet) COMP

AA8048 MODELED GRAV- 980,783.6 (mgal) NAVD 88

AA8048

AA8048 HORZ ORDER - A

AA8048 VERT ORDER - FIRST CLASS II

AA8048 ELLP ORDER - FOURTH CLASS I

AA8048

AA8048.This is a reference station for the UPPER KEWEENAW 1

AA8048.National Continuously Operating Reference Station (KEW1).

AA8048

AA8048.The horizontal coordinates were established by GPS observations

AA8048.and adjusted by the National Geodetic Survey in September 1995.

AA8048

AA8048.The orthometric height was determined by differential leveling

AA8048.and adjusted by the National Geodetic Survey in July 2002.

AA8048

AA8048.The X, Y, and Z were computed from the position and the ellipsoidal ht.

AA8048

AA8048.The Laplace correction was computed from DEFLEC99 derived deflections.

AA8048

AA8048.The ellipsoidal height was determined by GPS observations

AA8048.and is referenced to NAD 83.

AA8048

AA8048.The geoid height was determined by GEOID03.

AA8048

AA8048.The dynamic height is computed by dividing the NAVD 88

AA8048.geopotential number by the normal gravity value computed on the

AA8048.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45

AA8048.degrees latitude (g = 980.6199 gals.).

AA8048

AA8048.The modeled gravity was interpolated from observed gravity values.

AA8048

AA8048; North East Units Scale Factor Converg.

AA8048;SPC MI N - 272,895.291 7,876,915.700 MT 1.00003831 -1 10 29.1

AA8048;SPC MI N - 895,325.76 25,842,899.28 iFT 1.00003831 -1 10 29.1

AA8048;UTM 16 - 5,231,690.617 376,962.287 MT 0.99978605 -1 11 35.5

AA8048

AA8048! - Elev Factor x Scale Factor = Combined Factor

AA8048!SPC MI N - 0.99997501 x 1.00003831 = 1.00001332

AA8048!UTM 16 - 0.99997501 x 0.99978605 = 0.99976107

AA8048

AA8048 SUPERSEDED SURVEY CONTROL

AA8048

AA8048 ELLIP H (09/21/95) 159.44 (m) GP( ) 2 1

AA8048 NAVD 88 (06/11/02) 192.93 (m) 633.0 (f) LEVELING 3

AA8048

AA8048.Superseded values are not recommended for survey control.

AA8048.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.

AA8048.See file dsdata.txt to determine how the superseded data were derived.

AA8048

AA8048_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TCT7696231691(NAD 83)

AA8048_MARKER: I = METAL ROD

AA8048_SETTING: 59 = STAINLESS STEEL ROD IN SLEEVE (10 FT.+)

AA8048_STAMPING: PORTAGE A 1994

AA8048_MARK LOGO: NGS

AA8048_PROJECTION: FLUSH

AA8048_MAGNETIC: N = NO MAGNETIC MATERIAL

AA8048_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL

AA8048_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR

AA8048+SATELLITE: SATELLITE OBSERVATIONS - July 17, 2001

AA8048_ROD/PIPE-DEPTH: 15.5 meters

AA8048_SLEEVE-DEPTH : 1.20 meters

AA8048

AA8048 HISTORY - Date Condition Report By

AA8048 HISTORY - 1994 MONUMENTED NGS

AA8048 HISTORY - 19951212 GOOD MNDT

AA8048 HISTORY - 19960519 GOOD NGS

AA8048 HISTORY - 19960709 GOOD NGS

AA8048 HISTORY - 20010425 GOOD MIDT

AA8048 HISTORY - 20010717 GOOD MIDT

AA8048

AA8048 STATION DESCRIPTION

AA8048

AA8048'DESCRIBED BY NATIONAL GEODETIC SURVEY 1994 (CFS)

AA8048'STATION IS LOCATED ABOUT 11 KM (6.85 MI) NORTH OF HANCOCK, ON THE EAST

AA8048'SIDE OF THE CONFLUENCE OF PORTAGE LAKE AND LAKE SUPERIOR, AT THE WEST

AA8048'END OF A CLEARED AREA ON THE WEST SIDE OF BEAR LAKE ROAD ABOUT 0.08 KM

AA8048'(0.05 MI) NORTH OF A CABLE GATE AT THE OLD COAST GUARD STATION, IN THE

AA8048'NORTHEAST 1/4 OF SECTION 28, T 55 N, R 34 W. OWNERSHIP--US COAST

AA8048'GUARD, ROUTE 1, BOX 81, HANCOCK MI 49930. CONTACT DICK OTT PHONE

AA8048'906-482-5620 IN HANCOCK, OR JIM GLAZ, USCG SAULT STE MARIE PHONE

AA8048'906-635-3262.

AA8048'

AA8048'TO REACH FROM THE CENTER OF THE U.S. HIGHWAY 41 BRIDGE BETWEEN HANCOCK

AA8048'AND HOUGHTON, GO NORTH, THEN WEST ON HIGHWAY 41 FOR 1.66 KM (1.05 MI)

AA8048'TO A FORK. KEEP LEFT, WEST, THEN NORTH ON STATE HIGHWAY 203 FOR 14.03

AA8048'KM (8.70 MI) TO A CROSSROAD. TURN LEFT, WEST, THEN SOUTH ON BEAR LAKE

AA8048'ROAD FOR 0.48 KM (0.30 MI) TO A CABLE GATE AT THE OLD COAST GUARD

AA8048'STATION. PASS THROUGH GATE AND CONTINUE SOUTH ON PAVED ROAD FOR 30 M

AA8048'(98.4 FT) TO A SAND ROAD ON THE RIGHT JUST NORTH OF A ONE CAR WHITE

AA8048'GARAGE, TURN RIGHT AND GO WEST-SOUTHWEST FOR 0.2 KM (0.10 MI) ON SAND

AA8048'ROAD TO A GRASS LANE ON THE RIGHT. TURN RIGHT AND GO NORTHWEST THEN

AA8048'NORTH ON THE GRASS THEN SAND LANE FOR ABOUT 0.15 MI (0.24 KM) TO THE

AA8048'STATION ON THE LEFT.

AA8048'

AA8048'STATION MARK IS A PUNCH HOLE TOP CENTER ON A STEEL ROD ENCASED IN A

AA8048'PVC PIPE WITH LOGO CAP SET IN A CONCRETE POST FLUSH WITH THE GROUND.

AA8048'IT IS ABOUT 117.0 M (383.9 FT) WEST OF CENTER OF BEAR LAKE ROAD, 35.3

AA8048'M (115.8 FT) WEST OF THE WEST CORNER OF 1 M (3.3 FT) BY 1.5 M (4.9 FT)

AA8048'SQUARE CONCRETE BASE FOR AN ANTENNA, 44.5 M (146.0 FT) EAST OF METAL

AA8048'RETAINING WALL AT EDGE OF WATER, 2.9 M (9.5 FT) WEST OF THE CENTER OF

AA8048'SAND LANE, AND 1.1 M (3.6 FT) EAST-SOUTHEAST OF A FIBERGLASS WITNESS

AA8048'POST.

AA8048

AA8048 STATION RECOVERY (1995)

AA8048

AA8048'RECOVERY NOTE BY MN DEPT OF TRANSP 1995 (DKH)

AA8048'THE MARK WAS RECOVERED IN GOOD CONDITION AS DESCRIBED. RECOVERY NOTE

AA8048'BY DAVID K. HERDER, TYPED BY J.E.M.

AA8048

AA8048 STATION RECOVERY (1996)

AA8048

AA8048'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1996 (RPB)

AA8048'RECOVERED AS DESCRIBED.

AA8048

AA8048 STATION RECOVERY (1996)

AA8048

AA8048'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1996 (GAS)

AA8048'14.0 KM (8.70 MI) NORTHERLY ALONG STATE HIGHWAY 203 FROM THE JUNCTION

AA8048'OF U.S. HIGHWAY 41 IN HANCOCK, THENCE 0.4 KM (0.25 MI) WESTERLY ALONG

AA8048'BEAR LAKE ROAD, 103.3 M (338.9 FT) WEST OF THE ROAD CENTER, 85.4 M

AA8048'(280.2 FT) WEST OF THE NORTHWEST CORNER OF THE MOST WESTERLY OF 2

AA8048'SMALL BUILDINGS, 54.8 M (179.8 FT) NORTH OF BENCH MARK 2065, 32.8 M

AA8048'(107.6 FT) WEST OF THE SOUTHWEST CORNER OF A FENCE ENCLOSING AN

AA8048'ANTENNA, AND 1.1 M (3.6 FT) EAST OF A WITNESS POST. NOTE--ACCESS TO

AA8048'THE DATUM POINT IS THROUGH A 5-INCH LOGO CAP. THE SLEEVE DEPTH DOES

AA8048'NOT MEET THE SPECIFICATIONS FOR A CLASS A MARK. THE MONUMENT IS ON

AA8048'PROPERTY OWNED BY THE U.S. COAST GUARD, ROUTE 1, BOX 81, HANCOCK, MI

AA8048'49930, TELEPHONE NUMBER (906) 482-5620.

AA8048

AA8048 STATION RECOVERY (2001)

AA8048

AA8048'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2001 (SHN)

AA8048'RECOVERED IN GOOD CONDITION.

AA8048

AA8048 STATION RECOVERY (2001)

AA8048

AA8048'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2001 (ASK)

AA8048'THE STATION WAS RECOVERED ON 07-17-2001 IN GOOD CONDITION AS DESCRIBED

AA8048'BY NGS.

AA8048'

Edited September 24, 2005 by Z15

[+bicknell]

I found all three marks on the runway, two were of the type mentioned. Stainless steel rod. I could see the top of the rod, I assume it goes down 3 feet or so.

I believe these are "driven to refusal". That is, they drive the rod in, hook up a new section, drive it in, lather, rince, repeat until it doesn't drive in any more.

 

I wonder what the average length ends up being....I suspect some are < 10', some > 100'.

[Difficult Run]

I helped my father set many USGS benchmarks in Michigan in 1972/73. We used copper coated steel rods which were 5-6 feet in length. They were driven by hand with a sledgehammer. Subsequent rods were added (brazed together) with a copper sleeve to join the next rod. This continued until a large obstruction (buried rock) or soil density stopped any further depth. The final step was to hacksaw the excess rod off and braze the tablet on top. Generally, the total length of those rods averaged 25-30 feet. Care had to be taken in setting the rod perfectly vertical and not breaking the joint or sleeve. I remember a few that didn't meet this requirement. Those broken rods stayed in the ground, as we had no equipment to remove them.

 

Why all the fuss about driving long rods in the ground?? This was necessary due to the thickness of the aluvial deposits formed in the ice age.

 

Fond memories of growing up.

 

- Mitch -

[Bill93]

I can see why the rods are stable vertically, but what I've wondered is how they can be used for horizontal position with sufficient sideways stability.

 

It seems like they can wiggle a hundredth of a foot just if you wipe off the disk (on those that have a disk attached). and I don't think I'm disturbing them any more than many other causes. It would be really easy for them to be moved sideways by shifting soil (due to animal burrows nearby or differential compaction as mowers and construction equipment drive by. There is one in the Benchmark Photo thread that GH55 found with a root pushing it sideways.

 

Are these really as good as the old concrete posts in the horizontal direction?