Understanding the 3D Construction Model · Flora Surveying Associates. ... drilling and piling...
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Engineering and Construction today with the Constructible Model Tim McClannahan, PE Trimble Navigation Bruce Flora, PLS Flora Surveying Associates
Understanding the 3D Construction Model · Flora Surveying Associates. ... drilling and piling operations and tracking 對mass haul operations. ... This screen capture \൳hows a
Engineering and Construction today with the Constructible Model
Tim McClannahan, PETrimble NavigationBruce Flora, PLS
Flora Surveying Associates
Presenter
Presentation Notes
Around the world Contractors are rapidly adopting 3D machine control because of the productivity, accuracy and efficiency improvements. The Design and Engineering community are facing the challenge of moving from paper deliverables to delivering 3D data that is useful, controllable and will result in savings for all stakeholders. The contractor now has the ability to add intelligence to the base design model which enables better decision making and more cost effective construction. This session will explain how design data is enhanced to become the Constructible Model. It will demonstrate how the model can be used to provide cost savings to the contractor across project lifecycle—machine control, compaction, drilling and piling operations and tracking mass haul operations.
3D Constructible Model What kind of data can be used and the advantages,
disadvantages and pitfalls What the contractor has to do to create a
constructible model How the contractor will the use the data for more than
just machine control
Presenter
Presentation Notes
There are three things I would like for you to learn about the 3D constructible model and then we will take a quick look at how one contractor has implemented the model on a relatively large transportation project.
Business Center - HCE
Presenter
Presentation Notes
The move to 3D machine control has been led by companies that develop GPS systems such as Trimble. The basic idea of machine control is that you can put a design on a small ruggedized computer in the machine and then by tracking some part of the machine such as the blade tips, you can provide information so that either the operator can position the blade relative to the design or the blade can be automatically controlled by the design. By seeing aspects of the design such as a cross section of the design or lines such as the edge of the pavement the need for stakes can be eliminated and productivity is greatly enhanced. In 1985 I moved from a small traditional engineering company to a small software company that created software for engineering applications. We created a product called Terramodel that allowed the user to perform survey calculations, do roadway design, subdivision design and all of the related drafting. Our claim to fame was in our ability to quickly create large point based surface models. As 3D machine control evolved this became one of the premier products for creating design models. Around the year 2000 our company was purchased by Trimble. About five years later we released the next generation of Terramodel which is Trimble’s Business Center – HCE. Initially Business Center just imported data and produced design models. Today it has evolved to support many aspects of the contractor’s workflows and needs. Today rather than just creating a design model we support a greatly enhanced construction model.
What Kind of Data can be Used? These are the least productive
for the contractor– Paper / hand entry
Tools designed for re-creation not design Add bore hole data or below ground surfaces to define
I find that more than ½ of the contractors use mostly paper and pdf files to do their planning and quantity takeoffs. Business center provides tools such as on screen digitizing to aid the contractor in transferring the design from paper to the computer.
Digitizing PDF Cross Sections
Presenter
Presentation Notes
When contractors are limited to paper or pdf files we provide tools so that cross sections of multiple surfaces can be traced in and used in conjunction with horizontal alignments to get volume estimates. Frequently this information can be used for initial planning and rough grading.
The Most Common Formats Survey
– Coordinate system definition– Site calibration– Points– Point clouds– Linework– Feature codes– Surfaces
CAD (.dxf, .dwg, .dgn, .ifc)– Lines– Points– 3D faces– Text– Blocks– Cross sections as lines
Presenter
Presentation Notes
When contractors do get digital data it is frequently in common survey or CAD formats. I consider CAD a dumb format because it can’t represent engineering objects such as spiral or parabolic curves.
The Most Feature-Rich Design (LandXML, .ttm, Bentley MX, 12D, GENIO,
3D model (.icm.dgn, .pro, .vce, .vcl)– Breaklines– Points– Surfaces– Alignments– Corridors / templates– Meshes– CAD
Presenter
Presentation Notes
Design formats can include engineering objects with spiral and parabolic curves. About 10% of the time contractors will get this more feature rich format. Last year we completed a project with Bentley Systems that enables the best transfer of data using their imodel format. This enables the transfer of the engineering objects along with more drafting data and meshes that are used to model objects such as bridges and guardrails.
Results from Importing Bentley’s .icm.dgn
Presenter
Presentation Notes
Because we developed this transfer jointly the import automatically creates corridors and the surfaces the contractor will need for construction. Surfaces are formed and used as a component in the corridor template. Note that in the template view that the lines within the surface are named. This gives the contractor additional information when used in the field.
Contractor’s To Do List: Now that you have the data, what do you have
to do?
Checking and Enhancing the Data
Even perfect data needs some help What you design is not what gets built Less than perfect data needs a lot of rework
by the contractor Contractors need much more than a finished
surface model
Presenter
Presentation Notes
There is a very small industry of people that make their living building models for contractors from design data. They will all tell you that a perfect design is almost unheard of. They will tell you that most designs can’t be built exactly as shown on the plans. The job of the model builder is to resolve any conflicts and create the model that reflects the sequencing of how the job will be built. Sometimes that means adding more information so that pavement drains. Sometimes that means making a more expensive material layer just a little bit thinner and the less expensive material just a little bit thicker, as long as it meets the specs.
Get the Coordinates Right Use the correct units and coordinate system,
Feet, US Survey Feet, Meters The proper coordinate system and calibration
must be sent to all field systems All systems must calculate the same
Organize the Data When creating data for the field you want the
minimum amount of data and choices Layers, linetypes, colors and names must make
sense for the field devices The work order tells the operator what to build where
Elevate the Data Frequently elevations are so unreliable that users will
first set all objects to a null elevation and then elevate every object.
Check for Errors The most common mistake is having one XY position
with two elevations The second most common is a design conflict with
crossing lines with different elevations
Clean up the Data Duplicate linework Gaps and overlaps of ends Too short at ends Wrong length Undesirable colors, layer, linetypes Arcs, spirals created as segmented lines No naming information No station information Blocks
Enhance the Data
Presenter
Presentation Notes
The top image shows a corridor with a surface created from a template applied at the beginning of horizontal and vertical curves The middle image shows a corridor with a surface created from a template applied at every 5 feet. The bottom image show the same corridor with the template applied so that the triangles model the template to within a specified tolerance. The goal of the model maker is to make the data approximate the design to a tolerance appropriate for the phase of construction.
Model How it will be Constructed
Presenter
Presentation Notes
The model the contractor wants to grade may not follow the bottom of the subgrade as per the design. The contractors bottom surface model won’t have this jog around the base. There are a hundred tweaks they make so that the design is constructible.
3D Model + ? 3D models for machine control and layout
– Points, lines, alignments, templates, surfaces Calculation of quantities Mass haul planning Sending work orders with subsets of the data
to field devices Real time surface tracking Compaction and pass count mapping Project tracking, linear scheduling
Presenter
Presentation Notes
Once the constructible models are built, how is the contractor going to use them? Within Business Center the contractor creates a work order to send to the field. That work order contains the design information and site calibration information needed to build a portion of the job.
Plan your Mass Haul
Presenter
Presentation Notes
On a transportation job the mass haul analysis can be critical. Within business center the contractor can establish haul ranges for equipment, designate offset borrow and waste sites, establish barriers, configure multiple strata surfaces with different properties and cost. The program can then determine the most cost efficient paths to move the material. This screen capture shows a particular haul range being selected in the mass haul diagram. The associated polygons in the plan view are automatically selected based on the haul range. These areas can be send to the machine control system so that the operator knows the exact boundaries that they should be working within. In the left panel we list all of the mass ordinates listed by material as well as total cut and fill.
Connect the Site
Presenter
Presentation Notes
Ultimately the constructible needs to be shared with other systems on the job. Trimble calls this the connected site. Business center synchronizes data with our cloud server called the Trimble Connected Community or TCC. Each machine or field controller can download designs and upload information as it is collected. From the office the contractor can see what files are in use and can be assured that the latest revision is being shared by all. The Location and health of each machine is monitored by our web based product VisionLink. Production can be monitored using both 2D and 3D information from the fleet. This information provides a near real time map of the surface of the project as well as volumes. When compactors are used temperature, pass counts, elevations and compaction values are recorded and can be viewed graphically or within reports.
Benefits of the Constructible Model Platform for machine control, layout, data
management, planning, quantity takeoffs Optimized for construction Understands GPS and field devices Reduction in re-work Minimal set-out Increased Safety Faster / easier data transfer Effective data management More effective planning Clearer monthly claim process Increased efficiency, decreased cost, increased profit
