Editorial: Raising the Stakes

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Having once spent time blue-topping hubs for I-40 west of Oklahoma City, I can probably safely say that wood pounding is something surveyors won’t miss when it comes to new technology methods—­like machine control. Last month I had the good fortune of moderating a panel on machine control at the annual New York State Association of Professional Land Surveyors conference in Albany. Attendees at the session (there were nearly a hundred) couldn’t have asked for a better panel of experts. These included: Harry Ward, PE, Daniel Streett, LS, PE, and Bruce Flora, LS. Ward runs Carlson College for Carlson Software, Streett is the director of the land surveying and CADD support sections for NYDOT, and Flora is a practicing surveyor in southeast Virginia.

Streett reviewed the way things are today: the horizontal and vertical aspects of a project are treated differently. That is, the focus is on the plan and profile and the cross-sections. Horizontal and vertical stakeouts are separate. Deliverables for the contractor include alignment strings and grade stakes. Inspectors use hand levels and measuring wheels. Quantities are determined from cross-section end areas.

Contrast this with automated machine guidance, in which the horizontal and vertical alignment is handled simultaneously, the 3D model allows for interference checks, no stakes are needed, inspectors use GPS, and volumes are quantified from the model. Auto-interpolation between model surfaces allows the machine operators to know the cut or fill anywhere, not just at the stake. For the contractor, benefits include no crew scheduling, stakes are not in the way, less experienced equipment operators can be used, checking is reduced, and re-staking is eliminated.

Flora, with 35 years of survey experience, including 10 years doing data prep for machine control models, commented that although the technology today is primarily being used for dirt moving, eventually curb and gutter, inlets and piping will be automated. He believes the best data prep people are former construction layout surveyors. Ten years ago he had five crews; today he has one, but most of the field people have been brought inside. This reduces scenes in which a crew is hunched over a roll of plans on the hood of the truck and the contractor asking, "Who’s paying for that?"

As an example of the value-added work, Flora discussed ways to use the model before the dozers are running, and ways in which even small contractors can benefit. These include computer work like checking the design for "constructability." For example, water flow analysis can eliminate ponding. Flora claims that even small contractors can benefit and said helping these contractors get up to speed will result in them giving you other un-automated survey work. Flora also claims that no dirt-moving project is too small to apply machine control.

Streett said that NYDOT has seen a 20-­30 percent savings on their projects. Ward told of another project where, because of the overall project time saved, the savings approached 50 percent.

Another valuable use of machine control involves project phases. It is common for dirt from one project phase to be stockpiled for another phase. If the equipment operators know exactly how much to remove and where to put it, overcuts–which require select material to be brought back in–can be eliminated. Flora mentioned that many times the model delivered by the owner is for the final surface, but that there might be as many as four other surfaces below that.

Ward discussed accountability, liability and certification of models. He charges one fee to allow his model to be used, another to make changes to the model, and yet another to allow the contractor to make changes. For the latter, liability also shifts–from the data prep company to the contractor.

Many like myself have been concerned that if construction staking is removed from the work we do, because there’s not enough boundary work, many companies will have trouble justifying the field people. But fear not. With machine control, the work will still be there, it will just be different, and survey expertise will still be needed. Of course the new technology does beg the question: What will machine operators aim for when there are no longer any stakes?

Marc Cheves is editor of the magazine. 

A 167Kb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE