1. MC3D V1.1 - Match-Cast 3D Geometry Control Software
For Precast Concrete Segmental Bridges
Today, we’ll review the features of the MC3D Geometry Control Software developed by Interactive Design Systems
By Interactive Design Systems

2. MC3D Overview Segmental Construction Short Cell Casting
Match-Casting Technology
Geometry Control
We’ll talk briefly about applicability of the MC3D software. Namely, segmental construction and match-casting technology for the short-cell casting

3. Segmental Construction
Bridge built-up with multiple elements
Precast Segments
Geometry locked-in at precast yard
Geometry Control is critical
In a segmental bridge, the structure is built-up with multiple elements, or segments. For precast segmental, the final geometry is locked-in at the precast yard, and therefore a precise geometry control is critical

4. Short-Cell Casting Segments Cast One at a Time
Ensure that the segments fit together
Fixed Bulkhead
Match-Cast Segment
In the short-cell method, segments are cast between a fixed bulkhead and another segment – or a floating bulkhead for the first segment – the starter segment.

5. Match-Casting Technology
casting segment between a fixed form and its neighboring segment
Move to Match-Cast Position
Cast Next Segment
Move to Storage
The already cast-segment is placed in “match-cast” position in order to cast the “wet-cast” segment

6. Geometry Control monitor the casting operations
establish “as-cast” curves step-by-step
verify that the actual superstructure geometry is in close agreement with the geometry described in the design documents
The goal of the geometry control is to monitor the casting operation in order to produce the geometry required in the design documents

7. Typical MC3D Project Precast Segmental Balanced Cantilever Erection
Span-by-Span Erection
The method of match-casting concrete segments is applicable to a variety of projects, primarily for balance cantilever and spa-by-span types of girder erection

8. Balanced Cantilever
Here is an example of balanced cantilever erection. Casting is progressing on both sides of the pier segment.

9. Span-by-Span
In the span-by-span approach all segments of a span unit are cast in sequence – casting upstation or downstation (up-chainage, down chainage)

10. Understanding Geometry Control
Positioning Match-Cast is critical
Match-cast position is function of previous segment As-Cast compared to Theoretical
MC3D Computes Match-Cast “Set-up” based on As-Cast Coordinates
Set-Up is a set of 4 bolt elevations and 2 horizontal offsets for the Match-Cast Segment
Let’s talk about important aspects of the geometry control and the methodology: The positioning of the match cast segment is critical since it determines the relative position of the segments with one another. Again, the final geometry is locked-in at the time of casting of the wet-cast segment. MC3D uses the “as-cast” coordinates (i.e. the calculated general coordinates resulting fro previously cast segments) to determine the “Set-Up” of the match cast segment. The set-up is basically a set of 4 elevations measured in the local system of the casting-cell and 2 horizontal distances that are used to accurately locate the match-cast segment in it’s required position for casting of the wet-cast segment.

11. Roadway Geometry Horizontal Curve Profile Grade Line
Super-elevation and Transitions
Camber Values
The final geometry of the girder of course, is based on the basic roadway geometry – horizontal alignments, PGL, cross-slopes (superelevation) and transitions. In addition, a final camber is added to elevations to account for long term deflections under all permanent loads.

12. 3D Spine Curve
The result is a “3D spine curve” that can be fairly complex and difficult to achieve

13. Bridge Segmentation Casting Set
In order to process a set of segments, MC3D users need to “segment” the structure in multiple groups of segments that will be cast together using the match-casting method. In MC3D parlance, these portions of structure are called casting-sets. The basic assumption is that the fixed bulkhead is always placed in the direction of casting, arbitrarily referred to as “North” for the purpose of MC3D. In this example, the direction of casting changes for each side of a cantilever, and therefore the location of the fixed bulkhead is done accordingly – which determines the “virtual” North to be used as a reference for MC3D coordinates.

14. Control Points Base Points General Coordinates Bolts for Elevations
Hairpins for Alignment
2 Bolts on East Line
2 Bolts on West Line
2 Hairpins – North/South
The final geometry is provided to the program in the form of “base points” general 3D coordinates calculated form the base roadway geometry, the assumption of the bulkhead placement and the added camber values. These coordinates must be computed very accurately for the program to meet accuracy requirements. Specifically, the bulkhead plane must be always be perpendicular to the segment centerline – we’ll review the assumptions a bit later

15. Control Points
Here is a picture of the concrete segments (wet-cast and match-cast) in position in the cell – showing the location of the “control points” – bolts and hairpins (sometimes also called “rivets” and “stirrups”), so these terms are interchangeable.

16. General Coordinates Z (Positive Upward) W = U ^ V Vector Product w v
An important basic assumption is that the general system of coordinates in which the segment coordinates are computed and provided to MC3D must be an orthogonal system compliant to the “right hand rule”. In other words, a 90 degrees rotation of the X axis toward the Y axis produces the Z axis oriented upward. This is equivalent to saying the positive elevations are upward. We will see later that the local cell system must also be oriented this way. v
Y (North) u
Positive Rotation Rz
X (East)

17. Casting Bed - Fixed Bulkhead Assumptions
Orthogonal Local System
Local x is centerline positive toward South
Local y connects East and West Base Points – Positive toward East
Local z is vector product of unit vectors z = x y
LOCAL z MUST BE POSITIVE UPWARD
The local system of the casting-cell (or casting-bed) is shown on this picture. Basically, the centerline axis oriented from the bulkhead toward the match-cast segment is the positive x axis (i.e. positive from North to South). Then the y axis is located so that the vector product x*y produces a positive z (elevation) directed upward. This is extremely important since it will determine the location of the “East” line and the West line of bolts. For a balance cantilever, this orientation obviously changes when casting up-station or down-station.

18. Understanding Setup and Survey
So the result in the casting cell is the orientation of the local coordinates system shown here – in relation the fictitious North and South – and therefore the East and West Linces.

19. Casting-Set Definition
a portion of the project for which the concrete segments are precast as a unit
all segments will be match-cast against previously cast segments
“Starter Segment” usually cast between the “Fixed” bulkhead and a “Floating” bulkhead.
Base Dimensions A, B and C
Here is the definition of a casting set we’ve already discussed. The first segment is usually called the “Starter” segment. The starter must be cast between a fixed bulkhead and a floating bulkhead, or another segment. For each casting set, there is a set of 3 dimension types, that must be defined for all segments. Let’s review

20. Casting-Set Base Dimensions
C Dimension
The A, B and C dimensions are shown here – except the C dimension which was not shown on this drawing and that I added. The dimensions (in fact A North and A South) define the longitudinal distance (along the local x axis – or centerline) from the joint to the bolts. For each segment, they are supposed to be the same for the East and West line – but can be different on the North and South sides. MC3D assumes that the A distance are mostly constant – but can vary as just described for each segment. The “B” is the lateral distance from centerline to the East and West Lines. This distance must be the same for all segments. Finally the C distance is the North and South distance from joints to the horizontal control points or hairpins (or stirrups). As the A distance the C distance is assumed to be mostly constant for all segments but can be redefined for each segment – North and South

21. Base Dimensions A: Offset from Joint to Bolts (Rivets)
An (North) and As (South) may be redefined for each Segment
B: Offset from Centerline to Bolts (Rivets)
B is constant (East and West Line) for a Casting-Set
C: Offset from Joint to Hairpins (Alignment Stirrup)
Cn (North) and Cs (South) may be redefined for each Segment
Here is the definition of the basic A B C offset dimensions

22. Reference Planes control based on a theoretical “Reference” plane
survey bolts (rivets), which cannot be placed perfectly in the reference plane, are measurements of the location of the plane rather than its actual definition
The Match-cast method is based on relative location of local coordinate systems of the Wet-cast segment and the match-cast segment. This is also referred to as “Reference planes”. The reference planes, are the xOy planes of the local coordinate systems previously defined. The actual top surface of the concrete segment is important from an esthetic stand-point, but irrelevant for the geometry control. The actual placement of the bolts is also unimportant as long as it is accurately known. So the bolt elevations being surveyed (measured) are important only in their values relative to each other.

23. Starter Segment First Segment of a Casting Set to be cast
Must be cast between Fixed Bulkhead and a “Floating Bulkhead” (or another already cast segment)
MC3D assumes that second joint (Fixed Bulkhead for Starter Segment) is always positioned on theoretical.
We’ve already talked about the Starter Segment concept. An important assumption for the starter, is the it’s bulkhead joint is always assumed to be placed exactly on the theoretical joint (not practically, but simply assuming that it will be). Based on this assumption the floating bulkhead can be located as to meet the actual geometry. MC3D also allows for some movement of the fixed bulkhead – for starter segment as well as for typical segments.

24. Typical Segment
Wet-Cast segment is cast between Fixed Bulkhead and Match-Cast Segment
Match-Cast Set-up is based on computed As-Cast Coordinates at previous step
Set-up accounts for twist that may occur when moving segments from wet-cast to match-cast position
Here is the definition of the typical segment. After casting, each typical segment is used as match-cast for the next segment. Once bolts and hairpins are surveyed and input for both segments, MC3D computes the general as-cast coordinates.

25. Starter Segment Set-Up
Floating Bulkhead Set-Up
East Punch Mark Elevation
West Punch Mark Elevation
Center Punch Mark Offset
Fixed Bulkhead Set-Up
Lengths of East and West Line
This is the length to be given to the starter segment
For the Starter segment, the set-up is a bit different from typical. It consists in the elevations and horizontal offsets of punch marks on both bulkheads.

26. Typical Match-Cast Set-Up
4 bolts elevations
North East Bolt Elevation
North West Bolt Elevation
South East Bolt Elevation
2 Hairpin Offsets
North Hairpin Horizontal Offset
South Hairpin Horizontal Offset
Length on Center
This is the length to be given to the wet-cast segment
For a typical segment, the Set-Up values are the 4 bolt elevations, the 2 hairpin offsets (North and South) and the length on center (the length is the wet-cast length, i.e. thedistance on center where the match cast should be positioned)

27. Typical Survey After typical segment is cast (wet-cast)
The 4 bolt elevations, hairpin offsets and length on centerline of both wet-cast and match-cast are surveyed
This produces the relative position of wet-cast and match-cast.
From these measurements, MC3D computes the general as-cast coordinates of the typical segment (wet-cast).
As-Cast coordinates indicate how the structure is actually cast as compared to the theoretical general coordinates.
This slide outlines the procedure after a typical segment is cast. Survey of the bolt elevations and hairpin offsets for both segments, recording of the survey in MC3D in order to produce the as-cast coordinates for the match-cast. From these, the Set-Up for the next segment is automatically created. You can review As-Cast values for information and in case some aspect of the casting of the segment did not go as planned – this provides an idea of magnitude of the difference between as-cast and theoretical coordinates, possibly resulting in other corrective measures.

28. Match-Cast Set-Up - Concept
Expression of General Coordinates from Local Coordinates
{P} ={ O} + [ R ] {p}
Where O is Origin of Local System
[ R ] is Rotation Matrix
In Matrix Form:
MC3D performs all computations using 3D Matrix Algebra. Without getting into details, we see here the general formulation used to transform a point coordinates from local to general. This formulation is used throughout the computational process. The next slide shows how this formulation is used
To evaluate the Match-Cast Segment Setup.

29. Match-Cast Set-Up - Concept
Local Coordinates in Match-Cast System:
Local Coordinates in Wet-Cast System (Cell)
In As-Cast System of the Match-Cast:
The above matrix equation represent the “Set-Up” of the Match-Cast Segment, i.e. the Transformation to be applied to the Match-Cast Local System to achieve exact theoretical coordinates at the fixed bulkhead.
This is simply intended here for information and to show the type of matrix formulation used in MC3D. The computation of the Match-Cast setup is just one step of the process. The computation of as-cast coordinates is based on similar concepts.

30. As-Cast Coordinates
Express General Coordinates of Wet-Cast Points based on Local System built with Match-Cast Survey (As-Cast) z x
To compute As-Cast coordinates, MC3D simply computes the general coordinates of the wet-cast segment, expressed in the local system of the Match-Cast segment when it is placed in the general system (i.e. on the final structure geometry as if perfectly erected)

31. As-Cast vs. Theoretical Joint Coordinates
MC3D displays the As-Cast Coordinates at the last joint, compared with the theoretical required general coordinates
Also Displayed are the As-Cast coordinates of the bolts (may be used for Erection Control)
MC3D displays the As-cast coordinates in the “As-Cast Tab” (We will see in detail later) for the purpose of comparing as-cast with theoretical gneral coordinates at the north joint of the last segment being cast (i.e. the bulkhead joint). This will give the surveyor a precise idea of how the casting has progressed to that point – controlling the general Z (elevation) as well as the horizontal position (given by the X and Y coordinates) is of course crucial.

32. Twist Control
A change of slope on East or West Bolt Line occurring from Wet-Cast to Match-Cast
Match-Cast Twist must be Controlled and Corrected
If not corrected, it will induce a constant warp
Twist errors are magnified at the end of casting-set (cantilever tip or last span segment)
MC3D automatically corrects Match-Cast Bolt Elevations for Twist
Here we have a definition of the concept of “twist”. The control of eventual match-cast twist is critical. If ignored, twisting a segment when it is placed in match-cast position will induce an enormous error when magnified at the end of the casting unit.

33. Getting Started with MC3D
Project Setup
Casting-Set Constant Dimensions A, B &C
Segment Definitions
MC3D needs a general definition of the casting set, including the three “constant” dimensions A B and C (we’ve seen that A and C can be changed per segment – however the B distance must be constant on both elevation lines for the complete casting-set). But in fact, the main inpout requirement is for the base point general coordinates, done in the second Tab view: General Coordinates.

34. Input of General Coordinates
Manually in Tab View Grid
Importing for Text Files
Copy/Paste from MS Excel (must be properly layed-out)
MC3D requires input of the base points (at the joint) general coordinates for the East and West points and the Center Point. This can be accomplished in three different ways: Manually, Importing text input file or importing from Microsoft Excel.

35. General Coordinates Tab
Click Read File For Text Input
Click Apply to “initialize” joints and segment definitions
Click Preview For Orientation Check
On the General Coordinates tab, the “Read File” button may be used to import coordinates from a text file. We will review next. Once the coordinates are input users must “initialize” the coordinates wich formally defines the “joints” as well as the “segments” in MC3D.

36. Import from Text File
Text File extension can be anything, but usually “xyz”
Input of Joint Base Point Coordinates
East, West and Center
Joints Numbered In order of casting sequence
Here is an example of general coordinates for the base points (East, West and Center) in a text file. The picture on the right shows the file format. Even though the text input is done in free format, the sequence of the data input is important and it is self-explanatory.

37. Copy/Paste from MS Excel
Excel Coordinates must be formatted exactly like the MC3D coordinates grid
Another option is to cut and paste from an excel file created to compute the coordinates. Of course, the Excel grid must be configured exactly the same way as the MC3D grid – i.e X, Y and Z for East Center and West points..

38. Vertical Deflection at Joint
Camber Values
Vertical Deflection at Joint
Camber Values can be input separately
Values are vertical adjustments to coordinates
Based on long term deflections
MC3D adds camber to general coordinates prior to Set-Up
The third tab view may be used to input camber values – vertical correction usually aimed at counteracting the long term deflections. Inputing camber values is not mandatory. In some cases, the general coordinates may have the camber already included.

39. Working with MC3D Creating Casting-Set Input of General Coordinates
Complete Project Definition
Create Camber Input
Starter Segment Setup and Survey
Typical Segment Set-Up and Survey
Review (and Export) As-Cast Coordinates
Here is a synopsis of what it takes to use MC3D.

40. Joint and Segment Initialization
Once the general coordinates are input, the general casting-set parameters are defined, and the camber values are given – then it is important to “initialize” the coordinates – clicking Apply button will initialize the coordinates. Once this is done, we can review and check the accuracy of the given coordinates by clicking the Preview button.
Click Apply For Initialization

41. Coordinate Check and Preview
Check of Bulkhead Angle
Check of Cross-Slope
Check of “B” Constant
Check of Local System Orientation
On the Preview form, we have an evaluation of the accuracy of the input coordinates. We can check that the B value is acceptable and equal the B value indicated for the project. Also we can see an evaluation of the angle centerline/bulkhead (it should be 90 degrees), the resulting cross slope on both bolt lines and the orientation of the z (vertical) axis of the casting-cell (must be upward!).

42. Set-Up & Survey Operation
Starter Segment
Run MC3D for Starter Segment Setup
Cast Starter Segment (Wet-Cast) and Survey
Input Starter Segment Survey
Set-Up as Match-Cast
Typical Segment
Run MC3D for Match-Cast Segment Setup
Cast Typical Segment (Wet-Cast) and Survey
Input Wet-Cast and Match-Cast Survey
Consult As-Cast Results
This is a run down of the casting/surveying operation for both starter and typical segments.

43. Starter Segment Survey
Floating Bulkhead Set-Up
Bolt Longitudinal Offsets
Survey
Here is a screen-shot of the Starter Segment Set-Up form – with Floating Bulkhead Set-Up and Survey values. On the Survey form, there is a “Perfect Cast” check box. This is to be used for testing only – should not be used during the casting operations. The “perfect cast: will initialize the bolt elevation to some arbitrary values, and will provide the resulting setup for the next segment. When using the “Perfect Cast” option, the As-Cast coordinates should be exactly equal to the Theoretical Coordinates. If used at all, this feature should only be used prior to starting the casting operation, for testing purpose.
It provides a good idea of the best casting that can be done using the coordinates provides in input.
“Perfect Cast” to be used for testing only
Click Apply to record the Survey

44. Typical Segment Survey
Match-Cast Set-Up
Survey
This is the Typical Segment Survey form. Here we provide the bolts and hairpin survey for both wet-cast and match-cast segments. The user must click Apply to record the survey. A “Print” option is available at this point to print the Set-Up values and the resulting As-Cast Coordinates.
Twist
Value
Bulkhead Movement
Click Apply to record the Survey

45. Twist Control
Twist can occur when moving segment in Match-Cast Position
Twist induces a Warping error which would be magnified at end of Casting-Set
MC3D Compares East and West Line Longitudinal Slope and Displays a difference in Elevation
MC3D corrects Match-Cast Elevations so the original Slopes (measured in Wet-Cast Position) are maintained
The twist value is indicated in the Match-Cast Survey form. As discussed earlier, MC3D will automatically correct the twist and re-establish the original slopes of the East and West line in order to avoid a constant error due to warping of the match-cast segment.

46. As-Cast Coordinates As Cast-Coordinates
The is a view of the As-Cast Tab View and Form. Here we can compare the as-cast coordinates on the bulkhead joint to the theoretical coordinates, and view the as-cast coordinates on the bolts and hairpins, as well as the resulting segment lengths. A Preview button is available for print and print preview.

47. As-Cast Coordinates - Reports
Click for MS Excel Export
The last tab view is to access, preview and print various forms. There is an “Excel” button that can be used to export as-cast coordinates to an Excel compatible file.

48. As-Cast Coordinates – Export to MS Excel
Here is a view of the Excel file created – with joint as-cast coordinates and bolts as-cast coordinates.

49. Print and Print Preview
This is an example of what is obtained by clicking the Preview button – here we see As-Cast coordinates at the joint. Of course, we can see more As-Cast information by using the scroll bar at the right.
Click Preview Button

50. Working with Files MC3D creates one file per casting set
The files have extension .mc3
They can be saved and re-opened as needed.
When working with multiple casting cells, we suggest to use one folder per casting cell.
Several surveyors can use the same copy of MC3D on one computer, assuming the files are stored as suggested.
Backing-up mc3 files is also strongly suggested and can be done per directory
MC3D will create one file for one casting-set. Here are some suggestions for working with MC3D files.

51. Project Directory Structure
One Directory per Casting-Machine
One File per Casting-Set in this Directory
So to recap, several casting machines can be used for the same project – but it is suggested to have one directory per casting-machine.

52. Example of Survey Form
This is an example of Survey Form used by an MC3D user – for information.

53. What’s New for MC3D V1.1 Crowned Top Slab
General and Local System Orientation Check
Finally the last update for MC3D Version 1.1 has these two features that were added relatively recently.

54. Crowned Top Slab MC3D computes Theoretical Center Point Coordinates
West Base Point
East Base Point
Computed Center Point
MC3D accepts points input on a crowned top slab. The program computes a projection of the base center point it then uses for computations. In doing so, MC3D still provides as-cast results and coordinates on the given center point.

55. General and Local Systems Orientation Check
MC3D V1.1 checks that the local z axis of the Cell local system is positive upward
This check ensures that:
The General System is orthogonal and properly orientated
The North-South orientation of the Casting-Set is correct
Elevations are positive upward
This was discussed before.. MC3D checks the orientation of the z axis of the call local system. Both the general Z axis and the local z axis must be orientated such that a positive elevation is Upward. If it is not the case, then MC3D flags an error and send the user a message via the user interface (i.e a message box).

56. Current and Future Developments
Structure Geometry – General Coordinates GEOM3D
GEOM3D Export of Base Point General Coordinates
GEOM3D/MC3D Client Server Configuration
We’ll take a quick look at current developments.

57. Structure Geometry – General Coordinates GEOM3D
IDS has developed the GEOM3D program. This program can be used to produce the general coordinates for all casting-sets of a project. GEOM3D can handle multiple horizontal alignments, vertical profiles, variable super-elevations and variable widths. Base of the casting-set definitions (Cantilever sides and/or span-by-span units), it automatically generates the base point coordinates which meet all requirements for MC3D: bulkhead plane perpendicular to centerlines, base points at constant distance B. GEOM3D currently exports text files that can be read in MC3D.

58. GEOM3D Export of Base Point General Coordinates
Here is an example of text file generated bu GEOM3D.

59. GEOM3D/MC3D Client Server Configuration
Site Office
MC3D Web Client
Geom3D Database Server
MC3D Web Client
Geom3D Client
MC3D Client
IDS plans to develop a new environment that will integrate GEOM3D and the MC3D programs. In this Client-Server approach, the GEOM3D module can be used to generate all casting-set coordinates for multiple projects maintained on a central database server. GEOM3D can be accessed via office based GUI (graphical user interface) similar to current GUI. The MC3D clients will be designed to access the server database internally in the design office as well as off-site via Internet access and Web based UI. This way, a user can maintain multiple projects on a database server, and access the database from multiple remote sites using basic internet protocols, or simply a browser based UI.
Design Office