+Black Dog Trackers Posted June 30, 2005 Share Posted June 30, 2005 I was looking in the benchmark gallery and saw this. I first thought it was some crazy mistake, but apparently not. Quote Link to comment
+Red_Cedars Posted June 30, 2005 Share Posted June 30, 2005 That's an interesting cover, but the pictures are not of the benchmark. From the datasheet: 27-INCHES BELOW SURFACE, UNDER 8-INCH DIAMETER HANDHOLE COVER, LABELED, WATER, BEING HIGHEST POINT OVER CROSS IN BRONZE DISC SET IN CONCRETE, They need to lift the cover and look down another 27 inches. R_C Quote Link to comment
+seventhings Posted June 30, 2005 Share Posted June 30, 2005 It is an odd cover and probably the correct cover, but I agree with Red - should not have been logged as "Found". W Quote Link to comment
StripeMark Posted June 30, 2005 Share Posted June 30, 2005 Red_Cedars, That is exactly what I was thinking as well. That's what I did with http://www.geocaching.com/mark/details.aspx?PID=AB4130 and it was a full-sized manhole cover! Very interesting site indeed! Quote Link to comment
+Black Dog Trackers Posted June 30, 2005 Author Share Posted June 30, 2005 Yes I made the topic, hoping to entice a benchmark hunter to go there and try to take a picture of the actual disk! It'd be rather tricky to photograph I think. Quote Link to comment
ArtMan Posted June 30, 2005 Share Posted June 30, 2005 Many marks in DC are also below ground in vaults, usually under a small cover marked "SURVEY." Given the level of security consciousness in Washington, I've never tried to uncover one, even in the city's outlying precincts, for fear of ending up (forever?) in Guantanamo. Cleveland also seems to have placed lots of its marks under iron. Other cities as well probably adopted this technique to avoid vandalism and other threats. -ArtMan- Quote Link to comment
2oldfarts (the rockhounders) Posted June 30, 2005 Share Posted June 30, 2005 I'm not to sure that the cover can be easily removed to verify the disk. I believe it was stated somewhere here in the forums that they (the covers) are put in place with Hot tar to seal the covers in place. John Quote Link to comment
mloser Posted July 1, 2005 Share Posted July 1, 2005 Here was a similar situation I found: KW0934 The cover was easy to remove. The mark was just below grade however, not 27 inches down. Quote Link to comment
+Red_Cedars Posted July 1, 2005 Share Posted July 1, 2005 Yes I made the topic, hoping to entice a benchmark hunter to go there and try to take a picture of the actual disk! It'd be rather tricky to photograph I think. I'm originally from Michigan and would have LOVED that challenge when I was still there. That'd be a mark of personal interest to me, with it's assocication with the Big Mac bridge. If I were to try and take a picture, I'd probably rely on suplemental lighting and a pinch or two of corn starch. R_C Quote Link to comment
mloser Posted July 1, 2005 Share Posted July 1, 2005 I have a book somewhere about the bridge and it has a chapter devoted to surveying. Included is a low res map of all the survey points used during the bridge and how they were used. I am sure most were not submitted to the NGS but I think quite a few were. I wish I was there to search for some of them. Quote Link to comment
Z15 Posted July 1, 2005 Share Posted July 1, 2005 (edited) Does that book say anything about the C&GS doing work there to support the buidling of the bridge? I worked for 30 yrs for the MDOT and once saw a old in-house film back around 1986 on the building of the bridge in which I got the impression is was the C&GS that did triangulation around the straits of Mackinaw in support of the proposed bridge. Here is another mark on the North side, while I have never seen this mark, one of our surveyors said they used is some time ago for approah surveys on the North end. QK0249 DESIGNATION - A 2 QK0249 PID - QK0249 QK0249 STATE/COUNTY- MI/MACKINAC QK0249 USGS QUAD - ST IGNACE (1976) QK0249 QK0249'DESCRIBED BY MI DEPT OF HIGHWAYS 1954 (CTH) QK0249'STATION IS SITUATED 1.5 MILES WEST OF ST. IGNACE AT THE NORTHERN END QK0249'OF THE MOLE QK0249'SECTION COMPRISING THE NORTHERN APPROACH TO THE PROPOSED QK0249'STRAITS OF MACKINAC BRIDGE. QK0249'THIS POINT IS THE ORIGINAL NORTHERN POINT QK0249'DESIGNATING THE CENTERLINE OF THE BRIDGE AND QK0249'WAS ESTABLISHED BY THE MICHIGAN QK0249'STATE HIGHWAY DEPARTMENT. THE MARK IS A 2-BY 48-INCH IRON PIPE QK0249'WITH CAP, QK0249'WITH TRIANGLE AND PUNCHMARK INSCRIBED ON TOP. THIS MARK IS 8 QK0249'FEET BELOW THE PRESENT QK0249'GROUND LEVEL, ACCESS TO SAME BY BRICK-SIDED CIRCULAR QK0249'MANHOLE WITH STANDARD SEWER MANHOLE QK0249'COLLAR AND LID. THE PIPE QK0249'MARKER IS SET IN CONCRETE, WITH JUST THE CAP QK0249'PROTRUDING FROM THE CONCRETE. QK0249'UNLESS TRANSFERRED TO THE BRIDGE LEVEL LATER THIS MARKER WILL QK0249'BE QK0249'INACCESSIBLE AFTER THE BRIDGE IS COMPLETED. QK0249 QK0249 STATION RECOVERY (UNK ) QK0249 QK0249'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY UNK QK0249'1.5 MI W FROM ST IGNACE. QK0249'1.5 MILES WEST OF ST. IGNACE, MACKINAC COUNTY, AT THE NORTHERN QK0249'END OF THE MOLE SECTION COMPRISING THE NORTHERN APPROACH TO THE QK0249'PROPOSED STRAITS OF MACKINAC BRIDGE, THE NORTHERN POINT QK0249'DESIGNATING THE CENTERLINE OF THE BRIDGE, 8 FEET BELOW THE QK0249'PRESENT GROUND LEVEL, ACCESS TO SAME BY BRICK-SIDED CIRCULAR QK0249'MANHOLE WITH STANDARD SEWER MANHOLE COLLAR AND LID. A 2- BY QK0249'48-INCH IRON PIPE WITH CAP, WITH TRIANGLE AND PUNCHMARK INSCRIBED QK0249'ON TOP, SET IN CONCRETE WITH JUST THE CAP PROTRUDING. QK0249'NOTE-- UNLESS THIS MARK IS TRANSFERRED TO THE BRIDGE LEVEL QK0249'LATER, THIS MARKER WILL BE INACCESSABLE AFTER THE BRIDGE IS QK0249'COMPLETED. QK0249 QK0249 STATION RECOVERY (1956) QK0249 QK0249'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1956 (WNM) QK0249'THE STATION MARK WAS RECOVERED AS DESCRIBED AND FOUND IN GOOD QK0249'CONDITION. THE AREA IS QK0249'STILL UNDER CONSTRUCTION AND THE DESCRIPTION IS ADEQUATE AT THE QK0249'PRESENT TIME. QK0249' QK0249'MR. JACK KENNY, BRIDGE ENGINEER, STATES THAT THE CIRCULAR MANHOLE QK0249'THAT IS BUILT AROUND THE QK0249'STATION MARK WILL BE EXTENDED UP TO THE BRIDGE APPROACH AND THE QK0249'STATION MARK WILL BE PRESERVED. ---------------------------------------------------------------------------- QK0733 DESIGNATION - M 1954 QK0733_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TFR7668478456(NAD 83) QK0733 QK0733 HISTORY - Date Condition Report By QK0733 HISTORY - 1954 MONUMENTED CGS QK0733 HISTORY - 19950701 MARK NOT FOUND USPSQD QK0733 QK0733 STATION DESCRIPTION QK0733 QK0733'DESCRIBED BY COAST AND GEODETIC SURVEY 1954 (CTH) QK0733'NO DESCRIPTION SUBMITTED BY FIELD PARTY. QK0733' QK0733'STATION ESTABLISHED ON CENTERLINE OF BRIDGE BETWEEN THE END POINTS QK0733'A 1 AND A 2. QK0733'STATION WILL BE COVERED OR DESTROYED IN CONSTRUCTION OF QK0733'BRIDGE. QK0733 QK0733 STATION RECOVERY (1995) QK0733 QK0733'RECOVERY NOTE BY US POWER SQUADRON 1995 QK0733'MARK NOT FOUND. ------------------------------------------------------------------ QK0248 DESIGNATION - M QK0248 HISTORY - Date Condition Report By QK0248 HISTORY - UNK MONUMENTED MIDH QK0248 HISTORY - 1934 GOOD NGS QK0248 HISTORY - 20020605 MARK NOT FOUND MIDT QK0248 HISTORY - 20050604 MARK NOT FOUND USPSQD QK0248 QK0248 STATION DESCRIPTION QK0248 QK0248'DESCRIBED BY NATIONAL GEODETIC SURVEY 1934 QK0248'1.5 MI W FROM ST IGNACE. QK0248'1.5 MILES WEST OF ST. IGNACE, MACKINAC COUNTY, SET IN CONCRETE QK0248'AT THE EXTREME SOUTH END OF THE CAUSEWAY. A STANDARD QK0248'TRIANGULATION STATION DISK. NOTE-- THIS BENCH MARK WILL EITHER QK0248'BE COVERED OR DESTROYED WHEN THE BRIDGE IS COMPLETED. QK0248 QK0248 STATION RECOVERY (2002) QK0248 QK0248'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2002 QK0248'MARK NOT FOUND. Edited July 1, 2005 by Z15 Quote Link to comment
+Red_Cedars Posted July 2, 2005 Share Posted July 2, 2005 QK0249'DESIGNATING THE CENTERLINE OF THE BRIDGE, 8 FEET BELOW THE PRESENT GROUND LEVEL, ACCESS TO SAME BY BRICK-SIDED CIRCULAR MANHOLE WITH STANDARD SEWER MANHOLE COLLAR AND LID. To what extent could we as hobbyists be expected to pursue this mark! IF it's still there, it's more than 8 feet down inside a man-hole! Anybody but me balking at the idea of going down there? I suppose I might be pursuaded to look for the manhole cover though ... R_C Quote Link to comment
mloser Posted July 2, 2005 Share Posted July 2, 2005 The book says it was the G. Edwin Pidcock Company of Allentown, PA that did all the surveying. It describes 8 land based and 6 sea based towers. The sea based towers are of little interest, but the land based towers have some history--three were based on established triangulation stations, "some of them more than one hundred years old." There were two "on the Mackinaw City side, one at the starting point of the bridge, and the other exactly 10,405.038 feet west of that point. Three were located on the St. Ignace mainland proper, two of these being situated along U.S. 2: 10,858.443 feet apart, and used as the baseline for the triangulating operations. Two additional land-based stations were established on the St. Ignace causeway, one at each end. The eighth land-based surveying point was established on Green Island..." By looking at the decriptions I am thinking that QK0251 is one of the eight, and fairly certain that QK0740 is one of the older-than-100-year ones. It was "not found" by the Power Squadron in 1995 but they may not have read that it is 18 inches underground. QK0272 is along US 2, QK0728 is the only mark on Green Island. QK0779 appears to be another old one, reset. Maybe the two you show the datasheets for, QK0249 and QK0733, are the other two. By downloading the NGS datasheets based on the center of the bridge you could probably find all the ones set, or used in 1954 and get a good handle on which were used for the bridge construction. A little side note. While looking for the 1954 marks I found a few set in 1934 that say they will be destoyed when the bridge is constructed. This goes back to an earlier attempt to build the bridge. The Mackinac Straits Bridge Authority was given the right to investigate the feasibility of building a bridge (and to actually build it) in 1934. Obviously one of their early tasks was to survey locations for the structure. Because this version of the bridge was never built some of these marks, such as QK0250, may still remain (although that is a bad example because it appears to lie right in the center of the highway). Quote Link to comment
Z15 Posted July 2, 2005 Share Posted July 2, 2005 (edited) Those mentioned as set in 1934 are decribed in error we believe. I pointed that out to Deb on another A 2 some time ago and she researched it and cound not find when it was. 1934 should be 1954 as the desc implies the bridge was under costruction in 1934 which is was not, it started circa 1954 and opened in 1957. One mentions that no description was submitted by the field party. Although the bridge was envisioned way back in the late 1800s, Sen. Prentiss M. Brown, Sr., the "Father of the Mackinac Bridge," was the key figure in the bridge construction project. Governor-elect G. Mennen (Soapie) Williams was another strong advocate for the bridge and helped to create the Mackinac Bridge Authority in 1950. Steinman quote. The bridge designer was Dr. David B. Steinman and primary contruction firms were Merrit-Chapman & Scott and the American Bridge Division of U.S. Official Web Site Survey platform - October 21, 1954 Two members of the survey crew on Survey Tower #1 in the Straits of Mackinac during the placement of the foundations. Could I please have the name of that book, I would like to see if I can find a copy. Is this the book? The history and building of the Mackinaw Bridge by Paul M Johnson. If so it not easy to find on the net btw - that company still exists The Pidcock Company Civil Engineers · Architects · Land Planners · Surveyors 2451 Parkwood Drive, Allentown, PA 18103-9608 Edited July 2, 2005 by Z15 Quote Link to comment
mloser Posted July 3, 2005 Share Posted July 3, 2005 It is called Miracle Bridge at Mackinac, by David B. Steinman. I picked it up at a Boston bookseller last year for $10. It does mention a 1934 attempt to build a bridge but no work was done at all, so your theory about wrong dates is most likely correct. Quote Link to comment
+Harry Dolphin Posted July 7, 2005 Share Posted July 7, 2005 Do I file this under: Weird Benchmark Covers? Or: What Witness Post? The PVC end cap is, obviously, not a permanent cap. Stranger was the gentleman who came out of the house, and asked if there were a problem. You've never noticed that there is a witness post in your front yard?!? Duh... It does rather stick out a bit! KV3445 Quote Link to comment
mloser Posted July 7, 2005 Share Posted July 7, 2005 Mike, After all this talk about the bridge, there was a special on it on the History channel last night (July 5th). They even showed, briefly, one of the observation platforms. Are you interested in purchasing that book? Matt Quote Link to comment
Z15 Posted July 7, 2005 Share Posted July 7, 2005 (edited) I was thinking of finding a copy if I could. A local used book dealer is using his contacts to see if he can locate one. Do you have a source? i was told this book; The history and building of the Mackinaw Bridge by Paul M Johnson has a lot of interesting info also but its out of print and hard to find. Back in 1986ish I saw a in house MDOT movie (old) of the bridge that had much more information than what is out there on tape. The History channel did a complete 1 hr episode on the big mac. I saw it. I think I saw part of what you just seen as I recall it was about the 10 greatest bridges or was it engineering feats? Back in 1986 I attended a 3 day meeting held an the hdqts of the MBA in St Ignace and never paid a lot of attention to the history. They offered to take us to the top of the North bridge tower (as high as the Washington Monument) but being packed into that small elevator like a sardine was not anything I cared to do. Everyone who went raved about the view. I do know that just about every state and gov't police agency has radio antenna's up there. I knew the radio tech that set them up and serviced them. Edited July 8, 2005 by Z15 Quote Link to comment
mloser Posted July 8, 2005 Share Posted July 8, 2005 This show was an entire hour on the bridge and was well done, except they didn't mention surveying and benchmarks enough! Or at all really! I meant my copy. I bought it on a whim and doubt I will ever really read it in detail. I would rather someone who would enjoy it have it then keep it on my shelf forever, even though I do seem to collect books just for the sake of having them. Matt Quote Link to comment
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