California Surveyors Forums

I've always assumed that they were all the same size and length. Is that true? Seems that I was told once that they were 30" long. Can anyone verify that for me?

I found some of those lying on the ground in Rincon, San Diego County (never set). Memory is they were 4' long.

Northern CA
Seen different lengths, also some have a steel rod wire
on the top (which I would measure to), others do not.

It's cool that I can see a couple of these concrete monuments sticking out of the ground next to the RW fence corners while driving southbound on Hwy. 71, just north of the 91 in Corona/Chino area.

I have some Humboldt County area 1951 highway plans that show 3'-6". I don't know if these were supplied to contractors by the State, or built by the contractor. Either way, there I guess there could be variation. Caltrans surveyors should be able to pull up as-builts or give you some insight on your particular location.

Johnston: the trouble is Caltrans has absolutely nothing, no maps, no field notes, to document the two CHC mons we've found. Flying kind of blind here.

someplace I have a spec sheet of the old monuments, I will try to find, but from memory, 36" long was the standard.

I have an AS-Build sheet that shows the monuments. They are 3' 6" with a 3/16 copper wire that is 6" long. I got this from a District 1 Surveyor. He told me that the contractor often fabricated them on site using these spec sheets. Hope this helps, it is a little hard to read.

Pete

Attached is a paper that talk more in depth of the "C" mon and it's use.

with a 3/16 copper wire that is 6" long

I came across a CHC monument on West Capitol Avenue in West Sacramento that was broken off at the top. The exposed part of the copper wire was at least 8" long, and it was still anchored in the undisturbed portion of the monument below. I think the 6" wire length specification was a minimum rather than a no-more-no-less requirement.

Good Morning Lee;

Give me a call. Maybe I can help you out.

510-286-5267

Thanks for the paper on use of C-Mons. Do you know which district this came out of, and if those pre-1967 procedures were followed state wide? For any retracement survey that paper is a good reminder that there might be a convoluted history of measurements of varying accuracies that resulted in that original monument in the ground.

Here is a detail of the 6x6 monument from the state and a monument article from 1914.
The article was published by the California Highway Commission in the
"CALIFORNIA HIGHWAY BULLETIN VOLUME II JULY 1, 1914 NUMBER 1"
The detail of the 6x6 was taken randomly from as built plans.

forgot attachment!

I thank you all for your comments and especially for the articles and sketches. Looks like the weight of opinion is that they were 3'6" long, buried with 6" exposed. With the caveat that, since contractors were often involved in the setting of the monuments, adjustments could have been made in the field.

Working for Caltrans for 6.5 years, and my involvement with the Mount Diablo Surveyors Historical Society, in my quest for information on Caltrans C-Mons several years ago, these were not always set by a survey crew, rather engineers as references for "Construction Monuments". They may or may not be accurate, so be cautious.

Does anyone know who JLG3RD is? I've been trying, unsuccessfully, to contact him as I would like to know where his attachment ("Addendum to Chapter 6") came from. I think it is a valuable document but what's the source? For some reason my attempts to send him a "private message" will not go through. He hasn't responded.

Any chance anyone has those attachments and can put them up again? It looks like the attachments aren't available anymore.

Here are the docs I saved from this thread last year. Note that I am told that the "Addendum to Chapter 6" was authored by a Caltrans Surveyor as part of an in-house training session.

Thanks for reposting them. Valuable info to have.