Dual grade laser setup

[neikris]

We have a dual grade laser with a d4 with accugrade. We are having a hard time setting up the dual grade the way we want. Here is an example of what we are having a hard time with. Say we have a buiding site 100' long. We are putting a surface drain down the side of it say 20' from building. Now the building is level. The surface drain has a 1% grade so that is the y axis. Now we have a 1% from building to high point of surface drain. Normally I would get my flow line done for surface drain first then set the side slope grade every 20' and blend the rest. Is there a way to set the dual grade up so I can do both without changing side grade every 20'? I may be over thinking it. But I can't get anyone around here to explain it to me. We just bought the system and we are trying to learn it. We have a single slope laser so not totally laser stupid. But any help would be greatly appreciated. Thank you for the help.

 

[brianbulldozer]

I am not familiar with accugrade but If I assume what you are doing is grading using your laser as reference and not GPS. If I understand correctly, you have 0.2' of fall from the building to the high end of the drain (1% slope x 20'). The drain slopes 1% from the high end to the low end which is 1.0' over 100', so at the low end it is 1.2' below the building level. This means the slope is 6% (1.2' / 20') from the building at the low end. It looks to me like the area you are trying to grade is not a plane with slope in two axis (which is what your laser can do), but is instead a warped surface. What you are calling the y axis has 0% slope at one side (the building) and 1% slope at the other side (drain flowline). The x axis has 1% slope at one end (high side) and 6% slope at the other (low side). If you hold a piece of paper in your hands and tip the front side down and then tip the right side up without twisting the paper, this is the kind of surface your dual slope can produce, but as soon as you start to twist the paper you cannot replicate this surface with a laser. If your system is GPS then forget everything I just said.

 

[Acivil]

No matter how many axis a slope laser is capable of it can only be used practically on strait plane work.... that 1%-6% slope is essentially a twisting slope so a laser will be useless unless it is used to shoot in top (edge of building line) and toe (surface drain line) of slope then the face is done freehand or string line. Same goes for road grading... you can set it up to work strait slope sections of the profile, but it's useless in vertical curves. Essentially the same thing bulldozerbrian said.

 

[Randy88]

Neikris, did you get a helpful answer, I read your question and was seeing something completely different and was trying to figure out how it was working out for you. If you didn't get something that worked, let me know, I understood your question a completely different way and have some different ideas that might help better.

 

[Machine head]

Well it seems obvious to me that what you what to do with A dual grade laser is unachevable. The easiest way to achieve production is to set out and prep your cross fall off your building using your grade laser on any 1 axis . Once you have completed cross slope re set your laser for your drain excavation and way you go. Ain't rocket science, might take you half a day But quicker than tring to prep all at once you will get your knickers in a knot.

 

[Machine head]

Btw that's presuming the heal of the slope stays level with the building slab.

 

[correysmith32]

How would you use a laser as a reference and not a gps on a dual grade laser? I've been wondering about that, if using the laser instead of the gps will make a difference. The company that I work with don't use that type of concept, we usually use a gps. http://www.eastcoastlasers.com.au/reception/shopdisplayproducts.asp?id=12&cat=Dual+Grade+Lasers