GIS as means of construction operations optimization 6

[clems05]

Hello,

I am currently in school and am doing a research project on the use of GIS to optimize earthmoving operations. Having been on projects where sometimes amounts greater than 6M CY are moved, i most definetly see reason and feasibility for implementation of such a system that can aid in scheduling, estimating, (by creating a dynamic production rate database among many reasons) and all around improvement of data flow between take-off, scheduling, surveyors, PMs, etc. Be forewarned, in my mind, this is purely conceptual. The idea first came to me after reading a thesis,

http://fire.nist.gov/bfrlpubs/build02/PDF/b02095.pdf

ANyhow, I am curious if this sort of thing is in use in any related form that someone may know of. Also, i am currently devising scenarios in which a system like this would be used. As examples, a dynamic production rate database or the ability of GIS to take data from surveyors or a GPS equipped dozer and and relate that to geotechnical data to create more accurate volume counts and potentially real-time relations to Actual Cost of WOrk Perofrmed (ACWP) and Budgetted COst of WOrk performed (BCWP). I relize I am not doing very well on communicating what it is I am talking about, but even if you're unsure, I would appreciate your input. Input regarding scenarios where this sort of system could potentially be of use would be awesome and greatly appreciated.

Thanks,

Robert Hardison

 

[LCruiser]

GPS controlled equipment is definitely the wave of the future. A proper analysis of existing vs. final topo and the best optimization algorithm will be invaluable. One problem is not just in minimizing hauls, but in minimizing magnitude of haul with respect to available and reality based haul equipment - roughly 3 or 4 types of haul: dozer, (loader,) scraper, and truck, with truck broken down into 10 wheeler, truck and pup, and semi, with others broken down by size and maneuverability. A long dozer haul is more expensive than a short scraper haul that can be longer. As you can see, it's entirely project specific.

I don't mean to discourage you, I'm talking about the optimal solution, and there is a *lot* of room for improvement in what is used out there.

What you are trying to do will be extremely valuable. I would suggest considering using a CAD based system vs. a GIS system, with flexibility with regards to equipment availability (based on owned equipment).

Keep us posted!

 

[cvg]

I agree with the CAD recommendation as I have yet to see a contractor with GIS capabilities. Many will hire engineer subconsultants to do the earthwork calcs, but again probably no GIS capability. I think the tricky part would be getting the contractors to buy into the process as most probably have little knowledge of what GIS is.

 

[francesca]

I think that a lack of GIS capability with contractors should not be discouraging. The DOTs would be most likely to utilize such a tool, particularly on long road jobs where they will be trying to optimize costs associated with road cut-and-fill volumes and where to get/dump cut and fill material (use a borrow pit/dump site or transport to elsewhere on the project). I have witnessed that the DOT can have a huge pebble-in-a-pond effect with consultant software capability, as with the prevalence of Microstation in TN at TDOT's bidding.

As long as surveying is done with respect to state plane co-ordinates, or the conversion factor is known, it should be easy to integrate the data into GIS. A bounty of data should be available.

 

[clems05]

Iam thinking GIS because of its capabilities in handling databases, and the use of the Avenue language to create add-ins etc more specific to the job. THere is also the potential for modeling, not as advanced as say hydraulic modeling of some kind, but the capability does exist for the GIS component to trened things out with a push of a few buttons. An example could be in the scheduling aspect, with regrds to an obstruction in the proposed haul route, which a dgn or dwg would be used by the GIS to pick out a proposed haul route and schedule it more accurately taking into account soil types, haul road surface types, material being hauled, obstructions, could be viewed in 4D and a near infinite number of other factors could be accounted for in the scheduling process. In a linear project, creation of mass-diagrams would be the simplest example i can think of that would benefit.

rth

 

[clems05]

What is the current method of tracking production values for fleets of 777s or the like? Has anyone heard of using RFid tags to monitor their movement past a point on a haul road. THis can in turn be dumped into something like an excel file for load counts and other production values. This excel file could then be used by the GIS to determine unit weights of the soil where it was cut from (via data received from earthmoving equipment using GPS grade control). This could ultimately aid in preparing CO or just a real value of banked material moved.

 

[jheidt2543]

Just a couple of thoughts to add to the above:

1. I think the larger earthwork contractors are always looking for productivity increases and they would be the ones that would support your GIS idea. The smaller firms generally don't have the capital to invest in "untried" methods.

2. Have you thought of contacting an equipment manufacturer like CAT or Terrex to help with the research?

3. The agrecultural industry uses GIS in a number of ways for soil testing, planting and harvesting. Some insight might be had from contacting IH, Deer or other AG company that currently uses the method.

 

[EngEnv]

Robert,

Just a very quick, hopefully useful, hint. If you finally go for a ESRI-based GIS, I would recommend programming your add-ins in Visual Basic, rather than Avenue (thus using more recent versions of the software). Interface with other applications, ease of communication, flexibility and capility of the programming language, future developments are among the reasons why.

 

[woodleigh]

I worked on a 2 mile long complete new two lane highway through rolling terrain where the contractor used sitevision by trimble, go to this website for the specifics on the system, your sure to find more than you need.

http://www.trimble.com/sitevision.shtml

The contractor had the complete finished grade plane down loaded into this system and didn't request any stakes. As I was in the role of adminstering the contract(inspection, etc) and not at all familiar with this system, nor outfitted with a backpack unit to check grades, I had my survey crew stake the job the same as any other job, slope stakes, and finish grade stakes. Our specs were basically + or - 6" on cut and fill slopes, and 0.05' on the subgrade plane. I was totally impressed, what I found was that on embankement and cut slopes, the were within an 1" of where they wanted to be, and it always high on the cut slopes, and low on the embankment slopes (thus reducing the actual excavation by almost an average of 5" over the entire job in the slope areas, exclusive of the area under the new pavement structural section. We used a hand generated mass diagram to figure where the balance points were. When it came time to check subgrade and base rock grade, over the 2 miles of roadway (~every 50'), we found only two spots that were about 1/2" high on base rock grade. We had the grader outfitted with the gps system pull up on itand set the blade down, and it agreed with what we figured by pulling a stringlines and stabbing grades.

They also had it mounted in dozers, and compactors. I believe trimble claims accuracys within 1" but I found it to be alot tighter (which is probably due to the real time kinematic grade calc's always having alot of satellites in site).

As this equipment constantly figures the coords of the two gps units mounted directly over the corners of the blades, and knowing distance down from the gps unit to the bottom corners of the blades cutting edge, it continously would calc their coordinates. As I recall, the only issue was that there was nothing mounted to the equipment which could figure the grade of slope the equipment was traversing, and thus always projected the two points down through a perfectly plumb plane. At the normal profile grades of the roadway 3,4, 5% etc, the error was negligible, but when the equipment was trackwalking side slopes up or down a 2:1 etc, when it should have been projecting on a plane perpindicular to the side slope, it assumed it was in a plumb plane through the gps unit pts. As this is a simple math problem, the manual calc to figure the adustment was simple.

With respect to economics, I recall making rough calcs to what I believed to be a break even point in the costs of this gps equipment to pay for it self due to savings on grade setters and stakeing,increased effiency of earthwork equipment. This job had about 150,000 cy of roadway exc. and total cost was about $4,00,000. As I recall, according to my rough calc's., it would have taken 3 to 4 similiar jobs to pay for the equipment they purchased. As they get alot of earthwork projects in the bay area, they obviously could justify it. I was very skeptical about this process, but was very amazed at how will it worked. Not sure what you are really asking, just putting my two cents worth of experience in.

I am also another subdivision project in the hills which was using this system. As this project had a whole lot of pads. As this project would have required alot more gradesetter hrs / cy exc/emb, I think its safe to assume purchasing the equipment would likely pay for itself alot quicker.

 

[clems05]

In doing this economic anaysis, were you able to also look at increase in production rate or did you just factor in savings in surveying services? What sort of increase in productivity did you see?

THanks

 

[woodleigh]

That was 4 years ago, I don't recall. I think I factored in 1 to 2 additional gradesetters for 4 to 5 months, and some increased efficiencys of the earth work equipment, etc. I didn't account for the cost of installing it on the equipment. Also, once the equipment is owned, moving it from one piece of equipment had to be handled by a consultant to the contractor, If I remember correctly, I believe the firm which installed prep'd the data was Worldwide Surveys out of Northern California.

Do some searches for sitevision by trimble, you likely can find a whole lot of contacts.

I am also aware of a job where they used this near my home. Here is a link to an article about it.

http://www.cadinfo.net/editorial/eldorado.htm

 

[Snatch]

I have just came off a earthworks contract with a difference between with volumes of 20000 cubic metres. We had a difference of 5% and all parties (consultant, contractor & client) were happy to split the difference.