Have somebody can give me the advise,How to present to client the building vertically monitoring method statement, thank.
I would also be very interested in ideas about checking vertical of existing structure. I got a call yesterday from client asking to check vertical of launch tower building that was exposed to recent launch failure/explosion. I have a plan but this is not my regular type of service.
Thanks for any advice.
It is unclear to me whether this is about vertical motion such as settling, or about departure of a structure from vertical. Different problems, even if the cause could be the same.
For my problem these pictures should help.
Don't know about Mr. Chen and I kind of highjacked his post (sorry Kent Chen), but it seemed like a good opportunity to get feedback. I didn't consider your point.
I would set a minimum of two sets of permanent control, preferably 90 degrees from the direction of lean. Zero your gun, record your horizontal angle at the base and at the top of the structure from each setup. Observations once or twice a week will let you know if the lean is getting worse and at what rate. That is providing you can pick out the same target each time.
My $0.02
I did a job akin to this in Oklahoma a couple years ago. A water tower that had been in the path of a tornado. I made a table with a row for each support leg, a column for the height above ground that we measured, and each cell showing bearing and distance from the theoretical vertical.
The real trick was determining the center point of the round support legs, which we did by shooting (reflectorless) several points around their surface and using a best-fit-circle to determine the center point.
> It is unclear to me whether this is about vertical motion such as settling, or about departure of a structure from vertical. Different problems, even if the cause could be the same.
Absolutely correct. Further more, if the issue is "static" in nature, that is, slowly moving over time for whatever reason, it would require measuring displacement.
If dynamic motion is suspected, then the OP would be better off with one or more accelerometers mounted strategically on the upper floors.
did basically this a few years back now when the decision was being made on how to handle our infamous, still-unsolved governor's mansion arson.
was a multi-faceted job (the most thorough as-built i've ever done, and staking utilities was an exercise in human cruelty- more for the diggers than our crews).
but the point being for a while the structural guys weren't sure the thing could stand-up at all, let alone handle a sub-basement up remodel. we had control out the wazoo, and set up a pair of targets high and low at each corner that a crew went back and shot every other day. (this was about the same time our gubnor was out shooting coyotes on his morning jog.)
anyways- it didn't move much through the whole thing, not enough to worry anyone. that was an interesting job- i think the hardest part was finding 6 (out of our 30+ field hands at the time) crew members who could pass the security/credit screen to get on the actual grounds. heck, i even got a little grief with mine and while i'm no choir boy, i've never been in front of judge one in my life. oh, and you can rest assured that no 160 pound human being can be catapulted over the new perimeter fence from a distance inside the width of any adjoining right-of-way...
Settling is not an issue, departure from vertical because of a catastrophic event.
I would definetly 3d laser scan it if possible.
This would give you any departure from vertical easily identifiable in all 3 planes.
It would give an accuracy of within 2-3mm, but it would by far be the most efficient data collection technique and allows for future analysis if required.
Regards,
Tim
> I would definitely 3d laser scan it if possible.
It would be a terrific scan job. But we completed the field work in less than a day, the calcs took a couple of hours. Not worth an investment for this alone. Probably be the sort of thing that the Leica MS-50 would be great at.
My Bad..I meant to reply to this post!
I would definetly 3d laser scan it if possible.
This would give you any departure from vertical easily identifiable in all 3 planes.
It would give an accuracy of within 2-3mm, but it would by far be the most efficient data collection technique and allows for future analysis if required.
Regards,
Tim
I was asking about ambiguous wording in the original post, which has not been answered. Your meaning was clear in your hijack.