Machine Control Machine Control GradingGrading

The Iowa DOT ExperienceThe Iowa DOT Experience

Michael J. Kennerly P.E.Michael J. Kennerly P.E.Director of the Office of DesignDirector of the Office of Design

Iowa Department of TransportationIowa Department of Transportation

BackgroundBackground

In March of 2003 we laid out several long In March of 2003 we laid out several long range goals for the Office of Design.range goals for the Office of Design.

One of our primary goals was to move from One of our primary goals was to move from our traditional 2D design environment to our traditional 2D design environment to designing in a 3D environment.designing in a 3D environment.There were several advantages cited for this There were several advantages cited for this move among them were:move among them were:

3D Renderings3D Renderings

Machine Control GradingMachine Control Grading

BackgroundBackground

We canvassed other state DOTWe canvassed other state DOT’’s to see what we could s to see what we could learn from their experience.learn from their experience.We met with contractors, equipment manufacturers, and We met with contractors, equipment manufacturers, and makers of the GPS equipment.makers of the GPS equipment.We also worked with the Center for Transportation We also worked with the Center for Transportation Research and Education (CTRE) at Iowa State Research and Education (CTRE) at Iowa State University on literature search of the state of the University on literature search of the state of the practice.practice.We had discussions with our software vendor about our We had discussions with our software vendor about our software capabilities. (At the time we were using software capabilities. (At the time we were using Microstation J and during this time transitioned to v.8)Microstation J and during this time transitioned to v.8)

What We LearnedWhat We LearnedThere were probably 5 to 6 other states in various stages of There were probably 5 to 6 other states in various stages of implementation of machine control grading at the time.implementation of machine control grading at the time.The meetings with the vendors, contractors and manufactures The meetings with the vendors, contractors and manufactures provided a great deal of insight on the issues, performance provided a great deal of insight on the issues, performance capabilities, and needs.capabilities, and needs.Although companies like McAninch had made great strides in the Although companies like McAninch had made great strides in the area this was still an emerging technology for many of the area this was still an emerging technology for many of the contractors in the state and the investment required was a concecontractors in the state and the investment required was a concern rn for several contractors.for several contractors.As a result we knew that a wholesale move to machine control As a result we knew that a wholesale move to machine control grading by the industry would take time and therefore we would grading by the industry would take time and therefore we would need to support both methods. need to support both methods. There were no national standards and little or no guidance from There were no national standards and little or no guidance from AASHTO or the FHWA.AASHTO or the FHWA.

What We LearnedWhat We LearnedThere were two companies that seemed to dominate the There were two companies that seemed to dominate the market, Trimble and Topcon. market, Trimble and Topcon. There was no one industry standard file formatThere was no one industry standard file format

Trimble Requires:Trimble Requires:Design Surface File: This is a conversion of the .TIN file to a Design Surface File: This is a conversion of the .TIN file to a Trimble Trimble format called .TTM.format called .TTM.3D Break Line File: This is an 3D Break Line File: This is an ““DXFDXF”” format that 3D line strings of all format that 3D line strings of all longitudinal elements.longitudinal elements.Survey Control File: This contains x,y,z coordinates for all priSurvey Control File: This contains x,y,z coordinates for all primary mary control points set by the IDOT (ASCII format)control points set by the IDOT (ASCII format)

Topcon RequiresTopcon Requires::Design Surface File: Provided in ASCII and LandXML format.Design Surface File: Provided in ASCII and LandXML format.3D Break Line File: This is a 2D file in our native DGN format a3D Break Line File: This is a 2D file in our native DGN format and nd contains line work for longitudinal elements (centerline, shouldcontains line work for longitudinal elements (centerline, shoulder line er line hang point etc.)hang point etc.)Survey Control File: This contains x,y,z coordinates for all priSurvey Control File: This contains x,y,z coordinates for all primary mary control points set by the IDOT (ASCII format)control points set by the IDOT (ASCII format)

What We LearnedWhat We LearnedProviding the information would not require a significant modification to our

design process.

What We LearnedWhat We Learned

• We now create roadway surface TIN files for the entire projectwhereas we only completed them at certain areas in the past.

• Although we do not provide surface models at some of the more complex areas like intersections, and bridge berms.

• Once the proposed design surface .TIN file is complete it can be written out to a number of formats.

What We LearnedWhat We Learned

• Our traditional cross section spacing of 1 every 100 ft in Rural areas and 1 every 50 ft in Urban areas was reduced to 1 every 10 ft.• We require a cross section at all changes in the typical sections, ditch grade points, as well as foreslope and backslope changes.• However; we do not generate cross section for the plans at 10’ spacing or provide geotechnical information on all of the cross sections.

The Machine Control Grading File for the Roundabout at The Machine Control Grading File for the Roundabout at the intersection of US 63 and US 34the intersection of US 63 and US 34

Current PracticeCurrent PracticeCurrently all of our major projects are developed with the Currently all of our major projects are developed with the ability to produce a file for machine control grading.ability to produce a file for machine control grading.The contractors can request the information along with The contractors can request the information along with the other bidding documents prior to the letting.the other bidding documents prior to the letting.The information is provided on a CD at this time, but we The information is provided on a CD at this time, but we are looking into the possibility of providing it through Bidare looking into the possibility of providing it through Bid--X or an ftp site.X or an ftp site.We do not charge contractors for the machine control We do not charge contractors for the machine control grading file, although there is a possibility Bidgrading file, although there is a possibility Bid--X could X could charge contractors a fee to obtain the information.charge contractors a fee to obtain the information.

Current PracticeCurrent PracticeWe have a Developmental Specification for Machine Control We have a Developmental Specification for Machine Control Grading DSGrading DS--01072 which is located at:01072 which is located at:

http://www.dot.state.ia.us/specifications/dev_specs/DShttp://www.dot.state.ia.us/specifications/dev_specs/DS--01077.pdf01077.pdf

The contract documents are setThe contract documents are set--up with an optional bid and the up with an optional bid and the contractor must select one of the following alternatives:contractor must select one of the following alternatives:

Alternative 1 Machine Control Grading and Construction SurveyAlternative 1 Machine Control Grading and Construction SurveyAlternative 2 Construction SurveyAlternative 2 Construction Survey

Construction Survey in Alternative 1 applies to the following:Construction Survey in Alternative 1 applies to the following:Staking for the embankment construction in the areas shown in thStaking for the embankment construction in the areas shown in the e project plans.project plans.Establishment of secondary control monuments.Establishment of secondary control monuments.Staking for construction of pipe culverts, RCB culverts, and briStaking for construction of pipe culverts, RCB culverts, and bridges.dges.Staking for entrances, dikes, and guardrail berms.Staking for entrances, dikes, and guardrail berms.Placement of finish grade stakes as defined in GPS Machine ContrPlacement of finish grade stakes as defined in GPS Machine Controlol

Project ExperienceProject Experience

The Sibley Bypass on IA 60 in northwest Iowa was let as a mandatory machine control grading project.

Project ExperienceProject Experience

The Sibley Bypass:

Length: 8.97 miles

Grading Cost: $9,053,965

Segment 1 and Segment 2

Anderson Construction Co.

Segment 3

Mathers Construction Co.

They both used Trimble

Segment 4

Van Buskirk Construction Co.

They used Topcon

Project ExperienceProject Experience

The shaded areas on the map highlighted by the arrows designate the areas were machine control

grading information was not available.

Machine Control Grading Information Limits Map

Project ExperienceProject ExperienceIn general these projects affirmed the direction of the IDOT in In general these projects affirmed the direction of the IDOT in support of the support of the grading industry and mutual efforts in advancing machine controlgrading industry and mutual efforts in advancing machine control grading.grading.Additional 3 dimensional GPS calibration points will be beneficiAdditional 3 dimensional GPS calibration points will be beneficial on future al on future projects andprojects and with an even distribution around the project limits.with an even distribution around the project limits.IDOT construction inspectors enjoyed the functionality of the GPIDOT construction inspectors enjoyed the functionality of the GPS rover for S rover for nonnon--machine control activities.machine control activities.The computer files we provided for machine control were used witThe computer files we provided for machine control were used with little h little modification, but the contractor still elected to create some admodification, but the contractor still elected to create some additional files for ditional files for their use. their use. A few small problem areas existed due to natural terrain that coA few small problem areas existed due to natural terrain that could be resolved uld be resolved with the introduction of additional GPS repeater radios.with the introduction of additional GPS repeater radios.A bulldozer equipped with GPS still cannot be expected to cut wiA bulldozer equipped with GPS still cannot be expected to cut within two thin two tenths of a foot most of the time.tenths of a foot most of the time. It's just the nature of the machines.It's just the nature of the machines. Most Most dozers are for rough work, perhaps finishing of road surfacesdozers are for rough work, perhaps finishing of road surfaces should be left to should be left to motor graders.motor graders.The files formats that we provided, ASCII, Land XML, & Trimble TThe files formats that we provided, ASCII, Land XML, & Trimble Terramodel erramodel meet the contractormeet the contractor’’s needs. s needs. File size was not a problem and that entire project could be loaFile size was not a problem and that entire project could be loaded and rapidly ded and rapidly used by the field equipment.used by the field equipment.Both of the construction control systems (Topcon & Trimble) usedBoth of the construction control systems (Topcon & Trimble) used on the on the projects satisfactorily completed the projects.projects satisfactorily completed the projects.The cost savings (or additional costs) have yet to be determinedThe cost savings (or additional costs) have yet to be determined. .

Ongoing IssuesOngoing IssuesAll areas of the grading project need to be included in All areas of the grading project need to be included in the surface models (berms, returns, etc.).the surface models (berms, returns, etc.).There needs to be a standard file formatThere needs to be a standard file formatWe need to revise the precedence of which documents We need to revise the precedence of which documents prevail, i.e. the plan or the electronic file.prevail, i.e. the plan or the electronic file.We want to develop a more efficient way of providing the We want to develop a more efficient way of providing the electronic files to the contractor.electronic files to the contractor.Our goal is to make the machine control grading files Our goal is to make the machine control grading files available for all projects requiring grading work.available for all projects requiring grading work.We are in the process of developing a statewide CORS We are in the process of developing a statewide CORS RTKRTK--GPS networkGPS network

For More InformationFor More Information

ContactContactKent Nicholson P.E. Assistant Design Engr.Kent Nicholson P.E. Assistant Design Engr.

Office of Design (Support)Office of Design (Support)kent.nicholson@dot.iowa.govkent.nicholson@dot.iowa.gov11--515515--239239--15861586800 Lincoln Way, Ames Iowa 50010800 Lincoln Way, Ames Iowa 50010

Wayne Mander P. E. Automation EngineerWayne Mander P. E. Automation EngineerOffice of Design (Methods)Office of Design (Methods)wayne.mander@dot.iowa.govwayne.mander@dot.iowa.gov11--515515--239239--18361836

Questions?Questions?