PCS900 AccuGrade 3D Paving Training 3D Design Models & SVO/AGO & TBC May 2009 Phil Jackson CTCT Training Manager

Agenda 3D Designs Design Accuracy SVO / AGO Differential Compaction

3D Designs The design is critical If the design is wrong the surface is wrong Less important in grading “Because the paver can smooth it out” You are the paver The last chance to get it right

Design Types Parametric Roads TINs Grids Each have their strengths and weaknesses We must understand the strengths and weaknesses of each

Parametric Roads This is a road described by its design elements Horizontal Master Alignment Vertical Master Alignment Templates Superelevation Widening OR By Strings

Parametric Roads Typical Parametric Road

Parametric Roads Typical Parametric String Road

Parametric Roads This is the most accurate way to describe a road Problem is that every program does it differently Dozens of “road” formats to understand PCS900 / AccuGrade UTS for Asphalt Pavers does not understand any Parametric Road formats

TINs TIN is a Triangulated Irregular Network Or a mesh of triangles that describe a surface

TIN Models Again there are many different formats to describe a TIN Trimble uses several All work well in the program that designed them Some work in other programs PCS900 / AccuGrade uses the SVD format Proprietary to GCS, CCS, PCS, & AccuGrade

Grids Grids are rectangular (usually square) meshes where each intersection has a height assigned to it Very simple way to describe a surface But a coarse description

Grids Where is the valley or the ridge? Grid height may miss the high or low point Completely random with respect to the real features it describes 10 20 10 20

Design Format for Paving Don’t use grid data Unless you have a very special (unusual) case Try to get as “raw” a format as you can Get the parametric road data NOT a TIN of the parametric road Certainly not a Grid of the road Then use SiteVision Office or AccuGrade Office to produce the SVD/SVL files for the paver

How to TIN a Road – Use SVO or AGO or TBC A lot of programs can “TIN roads” Today, only SVO/AGO or TBC can produce an optimized TIN that is accurate enough Designed for optimum machine guidance

How NOT to TIN a Road This is an example of a TINed road where the sides of the triangles are one length on the straights and one different length in the curves A crude model that is OK for surveyors

How NOT to TIN a Road Take a Profile down the center of the lane Do you want to pave this surface?

How NOT to TIN a Road Problem: To make the triangles small enough to be accurate you get too many Large model Slow to query

How to TIN a Road – Use SVO or AGO or TBC Take a Profile down the center of the lane Do you want to pave this surface?

Trimble Exchange – An Engine behind SVO/AGO This is the program that SVO/AGO uses to intelligently TIN a road Very complex to design Reads over 30 different road formats Very easy to use So easy you don’t even know it is there Optimizes the TIN Lots of small triangles where the surface changes Few large triangles where the surface is constant

Trimble Exchange – An Engine behind SVO/AGO Lots of small triangles Few large triangles Triangle density also changes across the road Guarantees the surface to match to 1 mm Or whatever you set it to

Check Your Design BEFORE you start paving, check the design Look at the design in 3D Be careful that the 3D picture is a true representation of your final paving design It might be a 3D picture of the original data Which could be different Pull Profiles down the centers of the lanes The edges should be smooth in all cases Run the design in the Emulator to check what the operator will see

PCS900 / AccuGrade Design Formats PCS900 / AccuGrade only reads the SVD/SVL formats which are proprietary to Trimble and Caterpillar SVD describes a surface as a TIN SVL describes plan detail as lines, arcs, text, & Master Alignments

PCS900 / AccuGrade Design Formats Use either SVO or AGO or TBC to produce the designs for 3D paving

PCS900 AccuGrade 3D Paving Training Design for Differential Compaction May 2009 Phil Jackson CTCT Training Manager

3D Designs 3D Designs describe the final finished surface Grading systems use vertical offsets to build up to this surface The final asphalt lift is designed to finish at this surface But we must allow for compaction So we need to lay the asphalt high

Paving & Rolling

Asphalt Compaction & Designs 2D Systems lay a constant thickness over the base Therefore the compaction is constant Say: Design is 50 mm lift Mix gives 25% Compaction Therefore lay 66.7 mm Compact 25% Get 50 mm lift (66.7 mm - 25% = 50 mm)

3D Compaction Problem If you lay a thicker lift you get more compaction

3D Compaction Problem Design Asphalt Laid Asphalt Compacted Asphalt Design Base Actual Base

3D Compaction Solution Design Asphalt Laid Asphalt Compacted Asphalt Design Base Actual Base Measure the Actual Base and design the Laid Asphalt surface Load the Laid Asphalt surface as the design

3D Compaction Solution Lay the asphalt to the “Laid” Design Thicker over the hollows Then rolling will leave a smooth level surface

Differential Compaction Surface Good for long slow changes in thickness Bad for short sharp changes like potholes You can’t build or roll short sharp changes 

3D Compaction Solution Measure the actual base Use UTS & SCS900 Use AccuGrade Roller or CCS900 mapping Use GCS900 or AccuGrade mapping Process the design in Terramodel® Procedure is written up as a Trimble Construction Training Bulletin “The target audience is somewhat familiar with Terramodel, SiteVision® Office (SVO) and the process of collecting data, creating a model and using that model with SVO.”

How to create a differential compaction surface model using Trimble Terramodel When creating a surface model for the purpose of paving, frequently it is desired to adjust the surface for the effects of differential compaction or to make similar types of adjustments. This document will introduce the workflows and Trimble® Terramodel® commands that can be used to create differential models. The example project is a portion of an actual project simplified to demonstrate the technique. Users must consider many factors when modeling a job and this example may not reflect the density of the data needed to provide the desired accuracy.

High level summary of the workflow: 1. The user measures a surface of the original conditions. This can be done by collecting points and breaklines using Trimble SCS900 Site Controller Software. 2. The data is imported into Terramodel and an original surface is created. 3. The proposed surface is created. This can be done by importing from another format or using the design capabilities of Terramodel. 4. The difference between the existing and proposed surfaces is computed and saved as a difference surface. 5. The desired adjustments are applied to the difference surface. These adjustments can be a consistent depth or by applying a scale factor. 6. The difference surface is added to the proposed surface to create a target surface. 7. The target surface is transferred to the field system for construction. 8. The target surface is constructed and compacted with the resultant surface equal to the design surface.

How to create a differential compaction surface model using Trimble Terramodel Real Answer: It is a bit complicated but a competent data person can easily follow these instructions and produce the design PDF of this procedure will be distributed with the class material