Contractor requests points to be set for elevator walls at each level of a four/five story building (plus three levels of a parking structure). Currently the building is wood framed, leaving virtually no line of site to any of the three elevators at any of the floors to use conventional traversing from the outside.
Back in the day (the 80's for me) one of the commonly used methods to project a plumb control line up an elevator shaft was to use piano wire and a large plumb bob. That been said, I haven't had such the request since the 80's either.
Any suggestions on transferring a plumb line up an elevator shaft using modern equipment? I'm reluctant to want to use a builders laser line as a plumb line due to the inherent inaccuracies projecting five+ stories.
Thanks in advance!
-Kan
Two words for you
OR
Nice! I see one says 'Wild' and the other looks like it could be a 'Wild' (Surveyors Are Wild people! I still have the "sticker" on one of my old tool box's).
That being said...What name and model are these? I shall need one "ASAP!"
Thank You for the quick response.
"...Any suggestions..."
Yes. Only accept work that you are qualified to perform.
Of course! This will not be an issue. That is however, great advise for our profession!
> Nice! I see one says 'Wild' and the other looks like it could be a 'Wild' (Surveyors Are Wild people! I still have the "sticker" on one of my old tool box's).
>
> That being said...What name and model are these? I shall need one "ASAP!"
>
> Thank You for the quick response.
Top one is a Wild ZL and the Bottom one is a Wild ZNL, the top one is rated 1:200,000 and the Bottom one is rated 1:30,000. You can probably accomplish what you need with a right angle eyepiece. You're really not going that high.
Thanks, I'll check with a couple of my local Instrument suppliers for a possible rental. Side note, of the many "multi-story" buildings we have been the surveyor of record for in the Los Angeles area, it is the first request of it's kind to "layout" for the walls in an elevator shaft. On the other hand, we had to "asbuilt" finished walls of an elevator due to poor framing work, some eight years ago.
Kan,
I've done lots of elevator wall and stairwell control. Most were concrete walls with thickness between 8 and 12 inches. Lasers and plumb bobs are useless. Usually the outside has scaffolding planks in the way, the inside has a form system in the way, and the bottom inside floor has 2 feet of trash piled up. There's no way in hell I'd step foot anywhere inside the bottom, lest the next piece of trash hits me. So, using two total station setups, one on each side, a couple hundred feet away, I just put offsets on each level of pour. I usually have to get creative because of vertical rebars, but as long as I can check one redundant measurement and do a few tape checks, all is good. Keep in mind your tolerances. As for embeds and pour levels, I put a 5'AFF(Above Finish Floor) snap line around the outside that I can drop my steel tape to, between plank and wall, to bring up elevations.
Dave
> Kan,
>
> I've done lots of elevator wall and stairwell control. Most were concrete walls with thickness between 8 and 12 inches. Lasers and plumb bobs are useless. Usually the outside has scaffolding planks in the way, the inside has a form system in the way, and the bottom inside floor has 2 feet of trash piled up. There's no way in hell I'd step foot anywhere inside the bottom, lest the next piece of trash hits me. So, using two total station setups, one on each side, a couple hundred feet away, I just put offsets on each level of pour. I usually have to get creative because of vertical rebars, but as long as I can check one redundant measurement and do a few tape checks, all is good. Keep in mind your tolerances. As for embeds and pour levels, I put a 5'AFF(Above Finish Floor) snap line around the outside that I can drop my steel tape to, between plank and wall, to bring up elevations.
>
> Dave
You're obviously speaking from a Carpentry perspective.
During the concrete phases, up to the podium, I was able to layout the grids and elevators without problems encountering the typical obstructions as you mentioned. Now the project is framed up to the fourth or fifth floor and now they want to insure the elevator contractor has plumbed walls before they install. As mentioned earlier, it's an unusual request after surveying for dozens of multi-story buildings in recent years. The framing disallows for any grid control at those levels. I knew I needed the right instrument for the job. I'll probably have some of the plywood walls removed for redundant checks. I have several "Direct Reflectorless" target control around the site.
Thanks for your input!
>You can probably accomplish what you need with a right angle eyepiece. You're really not going that high.
How high would you trust a right angle eyepiece?
I really enjoy construction surveying, but transferring control more than a couple of stories up seems like a whole other art form. Just curious as to how it is done.
The instruments presented by Ralph Perez is the correct choice. I have used one of those, or one like it, to check for the plumb of a five or six story building a dozen years ago.
As for your question on accuracy at high levels..I establish 'Direct Reflectorless' control targets around a project and resect from them and checking independently to target that weren't utilized in the resection.
> You can probably accomplish what you need with a right angle eyepiece. You're really not going that high.
I've never run at a zenith angle of zero, but off the top of my head, is there any reason a properly-leveled theodolite set to zero Z wouldn't describe a small circle centered around the plumb line within its design accuracy limit?
