3D Engineered Models for Construction Part I - Introduction September 2012 Part 1 Introduction1.

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3D Engineered Models for Construction

Part I - Introduction

September 2012

Part 1 Introduction

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What is 3D Modeling?

• Using a collection of intelligent computer objects that represent an original surface, in our case the design surface of a highway segment.

• The objects know their position in space and in some cases what they represent.

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To better understand the design and locate possible conflicts and/or errors in the design.

Why 3D Modeling?

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Courtesy of Iowa DOT

3D Transportation Model


Another 3D Model



3D Cartesian Coordinates

Part 1 Introduction Graphic courtesy of Curtis Clabaugh, WYDOT

Mapping Capabilities

Part 1 Introduction Graphic courtesy of Curtis Clabaugh ,WYDOT

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A High Level Benefit of 3D Modeling• Improves communication between the owner,

consultant, contractor, prefabricators, and materials suppliers

Part 1 IntroductionImage courtesy of FHWA

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• Easier to get stakeholder buy in• Identify possible errors before construction• Visualize subgrade and potential utility conflicts• Benefits to highway construction are similar to

those realized in Building Information Modeling (BIM)

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What are Some General Benefits?

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Virtual construction to assess issues and improve communication prior to breaking ground!

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Top Benefits for Owners

• Grade check 100% of constructed surface

• Locate as-built utilities on the fly• Improved industry perception• Material cost savings

Photo courtesy of FHWA


Top Benefits for Contractors• Save labor of setting string

line (paving) or stakes (grading)

• Stringless paving may limit need for traffic closures

• Increased productivity• Increased efficiency• Reduced labor costs



Top Benefits for A/E Firms

• Identification of potential constructability issues earlier in the design process

• Better value to clients• Improved accuracy in design• Visual model verification

provides design QC

Image courtesy of FHWA


Leaders in the Use of 3D Modeling

• Wisconsin DOT• Iowa DOT• North Carolina DOT• Caltrans• Land developers• Design-builders

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3D Engineered Models are a Building Block of the Digital Jobsite

Part 1 Introduction

Other Functions 3D Models Support

• Public outreach/marketing for projects• Utilities – coordination and early issue

identification• 3D mapping and data storage• Clash detection• Earthwork quantities


Challenges to Implementation

• Time investment from 2D to 3D

• Project selection – what characteristics to look for

• Coordination across key stakeholders (contractor, owner, designers, suppliers, etc.)

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• Where does “designing” stop and where does “detailing” begin?

• What becomes the legal record of the design?• Can a 3D model be part of the contract documents?• Can electronic plans legally represent the design?

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What Challenges Need Consideration?

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Project Development Considerations

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3D modeling allows the existing and proposed features to be seen geospatially.

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Plans and Evolution

• 2D plans with profile andcross-section

• 3D plans, electronic data files, and digital terrain models

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Using a 3D model, we now have the capability to design and build accurately everywhere.

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Limitations of 2D Plans in Construction

• Human error in reading plans• Conflicts are not readily apparent• No surfaces, just cross-sections• We traditionally design and build accurately

only at cross-sections

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Who

Complete Designin 3D from

Road Owner

2D DrawingsDOT Generates

2D drawings

Designin 2D from

Road Owner2D Drawings

ContractorCreation of3D Modelfor AMG

Surveying

StructuralRoad

Requirements(size, location,

ESAL, etc)& Prioritization

3D Model

Contractor Utilizes3D Model for AMG

DOT / Government Contractor

2D DataTransfer

3D DataTransfer

Several years old,

sometimes

Key Stakeholders and Process Elements

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• Develop incremental detail of a virtual model by working continuously in a 3D environment

• Extract the traditional 2D contract plans and bid item quantities from the 3D design model

• Export 3D data files for construction and use of technology applications in the field

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How is the Workflow Different from 2D to 3D?

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• A data package can be developed from the 3D model to support Automated Machine Guidance/Automated Machine Control“Plug and Play” equivalent once package is input to machine

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What Activities Can the Model Support?

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• A process where design software and construction equipment are linked to direct the operation of machinery with a high level of precision, improving the speed and accuracy of the construction process.

Part 1 Introduction

What is Automated Machine Guidance (AMG)?


Bulldozer Using AMG

Photo courtesy of David White , Iowa State University



What the Machine Sees

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• Stakes

• String Lines

• String Lines with Sensors

• Lasers

• GPS

• Total Stations

Types of Guidance Systems(Guidance Systems Evolution)

Part 1 IntroductionPhotos courtesy of FHWA

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• Provides visual guide/grade information

• Stakes set by surveyor

• Field personnel read stakes and guide machine operator

Using Stakes – Traditional Method

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• Allows for machine control along a non-level surface

• Line represents a design surface at a particular elevation

Using String Lines – Traditional Method

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• Lasers are used for elevations

• A light bar on the cutting edge of a grader allows for up/down positioning

• GPS can be used to determine X-Y coordinates and pinpoint a location

• Users need different accuracies (we need “survey” level accuracy for highway projects compared with lower accuracy for recreational use or mapping)

Using Lasers/GPS

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Scrapers, dozers, excavators, motor graders, milling machines, pavers

Automated Machine Control Applications

Part 1 IntroductionPhotos courtesy of David White, Iowa State University

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Earthworks

Part 1 Introduction

Photo courtesy of David White, Iowa State University

32Courtesy of Ed Jaselskis

Typical Concrete Paving Using AMG

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Typical Asphalt Paving Using AMG


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Grading

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Case Study Colorado I-70 Project

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Colorado DOT I-70: The Problem

• Expansive Soils Severe longitudinal undulations, rough ride, cracking

• Widely varying asphalt depths – average 15”

• Traditional mill/fill: consistent mill depth would maintain existing profile

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CDOT I-70: The Process

• No initial CDOT survey Contractor survey

• Specs allowed for AMG for milling

• Short timeline GPS survey – 5 passes at 25’ EB/WB

• CDOT used MicroStation InRoads optimization to create 3D model with milling depths to balance humps and dips

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CDOT I-70: The Project

• Concrete “Whitetopping” pavement design required 8” minimum asphalt for 6” concrete

• Full depth 9 ¼” concrete where < 8” asphalt remains after milling

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CDOT I-70: AMG Milling

• Robotic Total Station – 600’ intervals• Milling machine – automatically directed mill depth• Contractor’s surveyor performed independent check on original

and milled surface

Part 1 IntroductionPhoto courtesy of FHWA

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CDOT I-70: AMG Milling (cont’d)

• Operation manually monitored

• Screen reports deviation from pre-set milled elevation

• Track height adjusted automatically to meet milled surface profile

Part 1 Introduction Photos courtesy of FHWA

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CDOT I-70: AMG Milling (cont’d)

• Greatly variable milling depths

Part 1 IntroductionPhoto courtesy of FHWA

Image courtesy of FHWA

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CDOT I-70: Lessons Learned

• Colorado DOT– Better knowledge of technology prior to plan

preparation– Need survey control by owner during construction– More accurate initial survey – tie in boundaries

• Contractor– There should only be one 3D model– Boundaries were a problem – even in rural setting– 8% allowable concrete overrun is very tight– CDOT survey (pre-bid) more competitive bids

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Benefits – Quality Assurance, Cost Savings, and Schedule Savings

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Quality Assurance Without 3D Modeling

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Quality Assurance With 3D Modeling

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Who

Complete Designin 3D from

Road Owner

2D DrawingsDOT Generates

2D drawings

Designin 2D from

Road Owner2D Drawings

ContractorCreation of3D Modelfor AMG

Surveying

StructuralRoad

Requirements(size, location,

ESAL, etc)& Prioritization

3D Model

Contractor Utilizes3D Model for AMG

DOT / Government Contractor

2D DataTransfer

3D DataTransfer

Several years old,

sometimes

Data Transfer: Benefits, Procedures, and Challenges

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Trans XML

Autodesk

Bentley

Carlson

Trimble

Topcon

Leica

Preferred Import/Export Capabilities

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Leica

Trimble

Topcon

Autodesk

Bentley

Carlson

Another Import/Export Scheme

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Perceived AMG Benefits – Phase I Survey

Perceived AMG Benefits* Contractor Agency P/C Equipment Vendors

Labor savings (direct cost on projects) 96% 76% 80%

Environmental-Fuel savings N/A 36% 60%

Project schedule compression 86% 57% 93%

Avoidance of re-work (re-grading) 93% 60% 87%

As-built documentation 58% 57% 80%

Ease of constructability review 44% 49% 73%Jobsite safety 68% 44% 60%Safety of the traveling public N/A 31% 40%* Percentage of respondents choosing the benefit at the two highest risk levels

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Source: NCHRP 10-77

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Productivity Impacts

Productivity Gain Using AMG (%)

10 20 30 40 50

Fre

quen

cy

0

2

4

6

8

10

12

ContractorsVendors

Cost Savings Using AMG (%)

10 20 30 40 50

Fre

quen

cy

0

2

4

6

8

10

12

ContractorsVendors

>50

Ultrasonic12D Laser1

3D Laser1/GPS1 (89 to

101%)

Ultrasonic1 2D Laser1 3D Laser1

GPS1

GPS2

Notes: 1Fine-grading using CAT 140H motor grader (Jonasson et al., 2002) 2Trench excavation using CAT 330DL hydraulic excavator (Aðalsteinsson, 2008) 3Earth moving and fine grading (general values; not project specific) (Forrestel, 2007) 4Earth moving and fine grading project - Port of Brisbane (Higgins, 2009)

Notes: 1Fine-grading using CAT 140H motor grader - Overall unit cost (Jonasson et al., 2002) 2Earth moving and fine grading project - Port of Brisbane (overal cost savings) (Higgins, 2009)

GPS3GPS4

GPS2

GPS7

(265%)

5Bulk earth moving and subgrade fine grading using CAT D6N dozer (gain in the number of passes; Caterpillar, 2006)6Bulk earth moving using CAT 330D excavator (Caterpillar, 2006)7Base course fine grading using CAT 140H motorgrader (gain the number of passes; Caterpillar, 2006)

GPS6

GPS3

3Bulk earth moving using CAT 330D excavator - fuel cost savings (Caterpillar, 2006)4Bulk earth moving and fine grading using CAT D6N dozer - fuel cost savings (Caterpillar, 2006)5Fine grading using 140H motorgrader - fuel cost savings (Caterpillar, 2006)

GPS4

GPS5 (68%)

>50

GPS5

(107%)

Part 1 IntroductionSource: NCHRP 10-77

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McGraw Hill Smart Market Report – The Business Value of BIMImplementation of GPS Controlled Highway Construction Equipment

(Vonderohe, University of Wisconsin)AASHTO AMG Quick Reference GuideNCHRP 10-77

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Additional Resources

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• 3D Modeling can provide for increased efficiencies in projects by providing an intuitive user interface, identifying potential issues early on, and linking to cost effective construction methods such as AMG.

• Session II will focus on the application of these practices and components, along with challenges and project selection criteria.

Part 1 Introduction

Summary

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Charles Jahren, [email protected]

Douglas Townes, [email protected]

Chris Schneider, [email protected]

Questions?

Part 1 Introduction

3D Engineered Models for Construction Part I - Introduction September 2012 Part 1 Introduction1.

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