We've recently started a multi-phase project in a 52 floor steel skeleton building that was built circa 1929. The entire interior has been gutted to bare slad/walls. There's line of sight access to only the 1st floor on one side of the building, most windows won't open and there is only one column of windows which have a long sight to an adjacent building for a mounted target. We need H & V throughout the building, including 6 sub grade floors. I've read everything on every forum about high-rise work and have done a number of them from start but this, with it's extremely limited access and existing slabs adds a new twist to it all that's got my mind working overtime.
Thus far we've:
-Set BM's 2 floors below grade and 6 up using the Jesse Kozlowski trig leveling and our 1" MS60. Luckily we had open escalator runs to use for this, closed each leg as we went. With BM's set @ existing slab core holes we double checked between floors with a steel tape, don't think I'll ever use an auto level again!
-Ran a perimeter loop around the block, closed out a little than 1:185,000 (5.4ppm).
-Set points throughout 1st floor, each one tied back into perimeter loop.
Now the X,Y needs to move upwards...
We have a Wild NL luckily but very limited options for line of sight after the escalators end at the 6th floor except random core holes.
Would cores additional cores be the best route or are there other options?
Any advise or ideas will be greatly appreciated!
Yes, cores would be best route. I know a company in TX are doing high rise with cores. The developed a system using clear plex glass over the cores to mark a plumb point. They don't use a NL, instead a Total station or Robot with a 90å¡ optical and they remove the instrument handle. They actually traverse straight up floor to floor.
I made these with the same idea in mind, using the NL and a Leica PL3 to go up & down as needed. My worry is that once we're up a few floors we'll have no ability to check outside of the building to make sure we haven't gone astray.
There will be no tower cranes and after 88 some years there shouldn't be any settling, any thoughts about diurnal movement from thermal loading? The building has a stone fascia so the steel members won't be getting any direct sun.
We transferred positions inside a dam from the surface to an air gallery located inside the dam through small shafts at each end. I used a T2 (newer model, with compensator) with 90å¡ eyepiece, with a Plexiglas plate at the top. We took multiple readings at 90å¡ spacing around the circle. We repeated the measurements a couple of months later, and we were under 3 mm on the second round versus the first. I had done elevation transfers in each shaft a couple of years ago using a steel tape with a bucket of water (20 lbs) at the bottom. I have a Wild ZNL, but it is out of adjustment, and the T2 worked well. I haven't used the ZNL in a number of years, I don't remember how far out it is. I do remember that we sent it somewhere for adjustment but they were not able to get it adjusted, not sure why. Someone recently sent me the manual for the ZNL, and it does not seem that difficult. I also did a transfer in a 300 foot vertical mine shaft a number of years ago with the same equipment (T2 and eyepiece), and used a gyrotheodolite at the bottom.
A few years ago we had to bring in NAVD88 elevations inside some dam intake towers to the water level gages, and we repeat that measurement each year or two in the deformation surveys we do at the dams. The initial measurements were done in the middle of winter, in some cases in single degree temperatures. One thing I found was that the towers "shrink" with the cold, with higher elevations in the warmer months, and lower elevations in the colder months. They are concrete towers, but probably have lots of steel in them as well. So I think a building with a steel skeleton will expand and contract vertically with temperature.
Luke J. Crawford, post: 407637, member: 11382 wrote: We've recently started a multi-phase project in a 52 floor steel skeleton building that was built circa 1929. The entire interior has been gutted to bare slad/walls. There's line of sight access to only the 1st floor on one side of the building, most windows won't open and there is only one column of windows which have a long sight to an adjacent building for a mounted target. We need H & V throughout the building, including 6 sub grade floors. I've read everything on every forum about high-rise work and have done a number of them from start but this, with it's extremely limited access and existing slabs adds a new twist to it all that's got my mind working overtime.
Thus far we've:
-Set BM's 2 floors below grade and 6 up using the Jesse Kozlowski trig leveling and our 1" MS60. Luckily we had open escalator runs to use for this, closed each leg as we went. With BM's set @ existing slab core holes we double checked between floors with a steel tape, don't think I'll ever use an auto level again!-Ran a perimeter loop around the block, closed out a little than 1:185,000 (5.4ppm).
-Set points throughout 1st floor, each one tied back into perimeter loop.Now the X,Y needs to move upwards...
We have a Wild NL luckily but very limited options for line of sight after the escalators end at the 6th floor except random core holes.Would cores additional cores be the best route or are there other options?
Any advise or ideas will be greatly appreciated!
Glad its you and not me! Good luck! I think you will be amazed at how random the error will be of individual components of the building, such as the plumb line of an elevator wall as you go up. My 2 cents, Jp
Jp7191, post: 407752, member: 1617 wrote: Glad its you and not me! Good luck! I think you will be amazed at how random the error will be of individual components of the building, such as the plumb line of an elevator wall as you go up. My 2 cents, Jp
We are a little short handed, a lot actually, want to join us?
leegreen, post: 407647, member: 2332 wrote: Yes, cores would be best route. I know a company in TX are doing high rise with cores. The developed a system using clear plex glass over the cores to mark a plumb point. They don't use a NL, instead a Total station or Robot with a 90å¡ optical and they remove the instrument handle. They actually traverse straight up floor to floor.
Thank you!
Get one of these(attached). Saves a lot of time, go up 12 floors at a time.
I agree with Ken's post above. Cores with a Quad 1000 works great. Set 2 targets outside the building to check in to. Get a new one though as the early models had heating issues.
We just ordered one of these.
Have been using a Leica NL to center over core then replace the NL with target. 6 floors up and still checking within .006' to ground level. Long way to go but hopefully it'll stay tight.
Do you have access to the elevator shafts?
Mike Falk, post: 411340, member: 442 wrote: Do you have access to the elevator shafts?
No, a few are still active, the rest have work platforms in them and are walled up. The elevator banks are all gated & locked.
For outside targets it's equally as difficult. We have only one long LOS down a perpendicular street but only the bottoms of the windows open and we've been told that what upper sashes which are fixed can't be removed. This limits our Z angle LOS. Just really a difficult spot.
The Quad 1000 does not measure vertical distances? So what's the advantage of this against a properly leveled total station with a 90 scope?
FrancisH, post: 411631, member: 10211 wrote: The Quad 1000 does not measure vertical distances? So what's the advantage of this against a properly leveled total station with a 90 scope?
In my opinion : N
ot stuck with an eyepiece on the TS and don't need to pop off the handle. Also, the TS isn't tied up on another floor setting targets which takes 2 people. With the laser you can set targets solo if needed or add more for travel kits as younwork along without moving the TS floor to floor.
We were informed today that we'll be getting no more cores. They'd like us to run from 5th to 52nd up stair wells, all of which have multiple landings/halls/corners leading to horribly un-balanced legs. We explained the inevitable detriment to quality and nearly tripling of time per floor to no avail.
Luke J. Crawford, post: 412919, member: 11382 wrote: We were informed today that we'll be getting no more cores. They'd like us to run from 5th to 52nd up stair wells, all of which have multiple landings/halls/corners leading to horribly un-balanced legs. We explained the inevitable detriment to quality and nearly tripling of time per floor to no avail.
1. Be sure you get paid regularly every cycle.
2. Hopefully someone here will chime in with some wording regarding accuracy and precision that you can get the owner's rep to sign indicating their understanding.
Brad Ott, post: 412924, member: 197 wrote: 1. Be sure you get paid regularly every cycle.
2. Hopefully someone here will chime in with some wording regarding accuracy and precision that you can get the owner's rep to sign indicating their understanding.
Billing is not my department, for the better I think.
I am very curious as to what others think would be a reasonable expectation of accuracy given the circumstances. It seems hard to imaging getting anywhere close to what could be achieved with cores and the NL.
Perhaps you can push for control of the elevators during off hours in order to do the work.
If you have time try poking around on Leicas website if I remember there were some articles about alternative methods for vertical construction.
party chef, post: 412983, member: 98 wrote: Perhaps you can push for control of the elevators during off hours in order to do the work.
Elevators are all off limits. Some being removed and others refit. They all have working platforms at most floors.
