Hi all. I am about to begin a project where we are going to try and shoot for an Fmin 156 flatness floor. It's a 20'x400' long strip of concrete. We are using engineered lumber for the form work. We are trying to get this thing as flat as possible. As far as leveling I am planning on shooting the forms with a trimble dini level taking shots every 5 feet until hopefully I could get this thing perfectly flat. Do you guys have any suggestions or ideas. All opinions are welcomed
Can the forms be filled with water to check their levelness?
Dave Lindell, post: 420000, member: 55 wrote: Can the forms be filled with water to check their levelness?
Im sure we could arrange that somehow.
That is an intensely flat floor in addition to being level. Not that perfectly level forms are not a very important start, but how do you get a finish that good?
Steve
The finish is the easy part. We have great finishers. The setup needs to be perfect for this to be successful. We run pans, tow behind bump cutter then combo blades and finally poly blades made out of UHMW (Ultra-high-molecular-weight polyethylene) to give it that extra shine
Just what do you call FLAT ? Give a realistic value; like + or - 1mm or something in the 400 feet.
JOHN NOLTON
no more than + or - .5mm elevation changes within 30cm to achieve fmin 156 floor.
What application calls for such flatness?
narrow isle way high speed lift trucks that go up to 50 feet in the air. [MEDIA=youtube]Rh-rG0JaUiU[/MEDIA]
That's going to be quite the goal. I would be sweating every detail; mix design, screed straightness, condition of the blades and disks on the power trowels. Are you using a laser screed? Will the edge forms have a nosing? etc.
What is the tolerance for the total length of the job? That is what I would like to know.
400 feet (121.9 + meters) + or - what?
JOHN NOLTON
Fu3l3r, post: 420009, member: 11864 wrote: The finish is the easy part. We have great finishers. The setup needs to be perfect for this to be successful. We run pans, tow behind bump cutter then combo blades and finally poly blades made out of UHMW (Ultra-high-molecular-weight polyethylene) to give it that extra shine
Poured a bunch of concrete in a former life but never with that level of precision. To my way of thinking leveling the forms is the easy(er) part. Maintaining form quality along the length of the form to your tolerances during the construction process would be more difficult. I am assuming your finishing system indexes itself from the tops of these forms. So, if I drop a piece of rebar on them and dent the top of a form it is likely to show up in the finish.
Anyhow, laminated lumber forms would work well if your labor force understands this and takes great care not to damage them. If I had to do several jobs like this I might have a set of steel forms that never went out to the 'other' less critical jobs and were handled with care.
Surveying wise, you might have to use a digital level if for no other reason than the crosshairs may be thicker than 0.5mm at +/-200 ft with an auto level. Or maybe a pipe level.
Steve
Fu3l3r, post: 420009, member: 11864 wrote: The finish is the easy part. We have great finishers. The setup needs to be perfect for this to be successful. We run pans, tow behind bump cutter then combo blades and finally poly blades made out of UHMW (Ultra-high-molecular-weight polyethylene) to give it that extra shine
What am I looking at in that picture? Is that taken on the day of the pour? I'd love to see a video of that process.
Once you watch the video you get some idea of what you want. You want the pour to be continuous. If the depth of pour is one foot you are looking at near 300 yards of concrete (around 25 trucks?). If you pour 20 feet wide you need some special equipment to reach that far. I am quite sure you know all this.
You also have a very good idea about leveling; checking the forms every 5 feet should work.
Have you checked on specifications DIN 15185 and DIN 18202/05.86 ?
Once your pour is done just call in one of the Concrete Grinding Companys that finish the job.
Checking the systems that diamond grind they claim they can grind to 1/16 of an inch in 50 linear feet.
Also it looks like you want level and not flat.
