S2-1 Bridging The Gap DO

Revit Structure 2010
Bridging the Gap: Bridge modeling with imported

Civil 3D Files
Dawn Ouchi
S2-1
Course Summary:
Focus on topics an advanced user would need to know for bridge modeling including utilizing Civil 3D files to
create bridges and customizing complex families such as decks, abutments and piers. The concepts and
details of creating families are covered step-by-step with a special section on how to create various types of
families like: in-place families, profiles, railings and guardrails.
Instructor:
Ms. Ouchi is a Certified Revit Architecture and AutoCAD 2009 Professional and a Technical Specialist in
Structural Engineering and AutoCAD® for U.S. CAD of Hawaii with nearly nine years of CAD experience. Prior
to joining US CAD of Hawaii, while earning her A.A.S. degree in Architectural Engineering & CAD Technology,
she worked in a structural engineering office for nearly five years. Currently, her main focus is on
implementation in various architectural and engineering offices and educating clients with AutoCAD and Revit
Structure in various training classes.
U.S. CAD
www.uscad.com ‫ ׀‬www.uscadbim.com
Introduction
If you’ve been using Revit Structure (referred to as “Revit” for the rest of the handout) for a project or
two, you’re probably getting used to how Revit “thinks”. In other words, learning how some objects
are affected by others, recognizing warnings and fixing errors as well as beginning to create your own
families. This intermediate level of Revit knowledge is perfect for this course.
Today, we will be focusing on the first two levels of bridge modeling, regarding concrete bridges and
Civil Engineers who use AutoCAD Civil 3D.
1. Coordinating with Civil Engineers

2. Parametric Bridge Modeling
3. Bridge Modeling with Revit Extensions
4. Phasing
5. Revit Structure Tools for Visualization and Collaboration
Overall steps for our focus:
I. Civil Engineers prepare the Civil 3D drawing for output

II. Structural Engineers link in Civil 3D drawing and coordinate origin points
III. Structural Engineers create component families
IV. Structural Engineers model bridges with column, slab, profile families, etc.
U.S. CAD 2
Copyright © U.S. CAD: CAD Camp 2009
Coordinating with Civil Engineers
I. Civil Engineers prepare the Civil 3D drawing for output
It is important for the Civil side to prepare their files for Structural to prevent funky things from
happening in Revit that may be unfixable. (Insert scary music here)
Civil should:
1. Check organization in AutoCAD Civil 3D

a. Road centerline strings should be on separate layers
b. Check / delete erroneous lines and triangles
c. Pick a coordinate on the existing location around the middle of the site
*It doesn’t matter exactly where. You’ll just need to convey these coordinates to
structure
i. Draw a circle on its own layer to define the those coordinates, (Let’s call this the
“Big Red Circle”)
ii. Write and save the noted coordinate and the units on a text or spreadsheet file
and save it in the project folder. Don’t forget to send this to Structural along with
your .dwg files.
d. Move the site and the Big Red Circle to 0,0, where
the base point are the coordinates you chose.
*Once linked into Revit, anything that is more than a
mile away from the origin in will not function properly.
Move the site to 0,0

by using the center
of the Big Red Circle
as the base point
U.S. CAD 3
2. Create separate files using the above techniques with the same reference coordinates for the
minimum following files
a. 3D Site Plan (Let’s refer to this as the “Site File”)
i. Design String Lines (Contour Lines)
ii. Surface Triangles (Lines connecting the elevation marks)
*A.K.A. TIN – Triangulated Irregular Network
b. 2D flat versions of the road (Let’s refer this as the “Road File”)
i. Bent marks
ii. Road Boundaries
iii. Road Centerlines in segments, from Bent to Bent
*Although all of these elements can be inserted into Revit at one time, separation
makes managing much easier.
II. Structural Engineers link in Civil 3D drawing and coordinate origin points
Once the Structural Engineer receives the Civil 3D file, it is important to take a look at the file in its
native environment. The first two steps take you through this process. If you do not have AutoCAD or
AutoCAD Civil 3D, you may find yourself having to re-coordinate with Civil or do a lot of manipulation
to the Revit model after completing most or the entire model.
Structure should:
1. Open each Civil 3D file

a. Check the Location
i. Make sure that the Site File and the Road File have the same origin points and
that they line up with each other
*Each file’s origin points should be at 0,0 where it defines near the center of the
drawings, defined by Civil’s coordinate notes.
ii. Make sure that there is a Big Red Circle (on its own layer) defining 0,0 on at least
the Site File
b. Check elevation points. You may need to adjust the level heights in Revit Structure
c. Check which layer(s) the triangulated surface resides in
d. Check the units. If different from your Revit project, you may need to specify the units
upon linking.
U.S. CAD 4
2. Open the Road File
i. You should have Bent Marks and Road Centerlines
*Road Boundaries are optional (explained later in the handout)
ii. Road Centerlines should be in segments from Bent to Bent
*These will be used as references to create Girders
iii. Optional - You may want to add and align Light blocks (if light symbols are
required for the project) for easier placement of street lights in Revit.
3. Begin a new Revit project, adjust the level heights, and add new levels as necessary
a. Suggested Levels
i. Ground level (where the Site File and Toposurface is placed)
ii. Road level(s) (where the Road File and Girder is placed)
iii. T.O. Bent level(s) (where the Bent’s Top Level should match)
4. Link (not Import) the AutoCAD Civil 3D files on the coordinating level
a. Link the Site File
i. Positioning – “Origin to Origin” (preferable); or “Center to Center”
ii. Place at – Ground level
iii. (2010) Insert Tab>Link Panel>Link CAD>Browse for file
b. Acquire Coordinates
i. (2010) Manage Tab>Project Location Panel>Coordinates drop-down>Acquire
Coordinates> Pick the Site File link
c. Link the Road File (and other files from Civil, if any)
i. Positioning – “Auto - By Shared Coordinates”
*Double check the placement of the .dwg files in 3D and Elevation views
U.S. CAD 5
5. Setting Project Location
a. Select the Site File
b. Go to the Element Properties>Instance Properties
c. Click on the Value “DefaultLocation” and select
“Do not share location of selected instance”
(repeat for all linked dwg files)
d. Use Temporary Hide/Isolate to isolate the Site File

*If you cannot see the Big Red Circle, change your Model Graphics Style to Wireframe
e. Draw a Gridline from the center of the Big Red Circle to somewhere outside the of circle
U.S. CAD 6
f. Specify the Project Location with the original Civil World Coordinates, being aware of
any unit conversion
i. (2010) Manage Tab>Project Location Panel>Coordinates drop-down>Specify
Coordinate of a Point
ii. Pick the end of the Gridline which is the center of the Big Red Circle
iii. In the dialogue box, enter the coordinates from the original Civil World
Coordinates
6. Setting True North

a. Reset the Temporary Hide/Isolate
b. Open View Properties and set the Orientation parameter to True North
U.S. CAD 7
c. Set the Project North
i. (2010) Manage Tab>Project Location Panel>Position drop-down>Rotate Project
North
ii. Select Rotate to place selected line/plane parallel to North/South or East/West
iii. Select the Road File’s road centerline

d. Set the View Properties to Project North (select ok with the warning)
*You’ll see the view rotated to the road centerline being horizontal or vertical
This line was

selected.
U.S. CAD 8
7. Create a Toposurface
a. (2009) Site>Toposurface>Use Imported>Import Instance>Pick the Site File link
b. (2010) Architectural & Site Tab>Model Site Panel>Toposurface>Edit Surface
Tab>Tools Panel>Create from Import>Select Import Instance>Pick the Site File link
*Ignore any warnings. You may have to uncheck layers within the Site File so that you
don’t create a Toposurface on non-surface layers
c. Change the material of the Toposurface in the Element Properties
d. Turn off the Visibility/Graphic Overrides in views or unload the Civil File link
Parametric Bridge Modeling

III. Structural Engineers Create Component Families
When modeling concrete bridges, think about their individual parts and their behavior rather than it
being a specialized structure. Typically, we refer to a bridge made of a deck, girders, bents and
possibly abutments. In Revit terms, that would be equivalent to a slab, beam, columns and walls,
respectively. Isn’t it already easier to think of a bridge that way?
Since a bridge can take on different shapes, such as a box girder or T-beams, bents with piles or
curved bents, you may need to create families. These can be in-place families or component families.
Component families is preferred for future use in other projects. Today, we’ll create two component
families – a box girder and a bent. Of course all bridges are different, so please use this as a guide
and have fun exploring the possibilities!
*If you are on subscription, you can download and edit a bunch of pre-made families from the
Subscription Center on Autodesk.com.
Box Girders:
With creating any girder, you need to take into consideration what material and behavior are you
looking for. Since we are creating a simple concrete girder and may want to adjust the girders with
beam handles and shape handles, we’ll begin with what a precast concrete beam is based on.
U.S. CAD 9
We’ll begin with creating a profile which will be the Sweep Profile family in the beam.
1. Start a new profile family (We’ll call this “Box Girder-Profile.rfa”)

2. Add reference planes, dimensions and then labels as shown
*Note that the top most horizontal reference plane is the default Center (Front/Back) plane and
the longest vertical reference plane is the default Center (Left/Right) plane
*You can create the parameters in Family Types before you add labels to the dimensions. This
will set the distances of the reference planes once you add the labels.
U.S. CAD 10
3. Add profile lines to the reference planes, making sure you lock them as you go
*Be sure to flex the profile to test the parameters
Now we can create a beam, using the Box Girder-Profile.rfa as a sweep.
1. Start a new family based on

Structural Framing - Beams and
Braces.rft (We’ll call this “Box
Girder.rfa”)
U.S. CAD 11
2. Delete the default reference
planes, sweep and symbolic lines
as shown. We’ll be using only the
vertical reference planes called
Member Left and Member Right
*You won’t be able to delete
some default objects
3. Begin the Solid Sweep tool

a. (2010) Create tab>Forms panel>Solid drop-down>Sweep
4. Sketch a line which will serve as
a path for the profile to sweep
a. (2010) Sweep tab>Mode
panel>Sketch Path
5. Load the Box Girder-Profile.rfa

a. (2010) Modify Profile tab>Edit panel>Load profile
U.S. CAD 12
6. Apply the profile to the sweep
Element Properties
a. (2010) Modify Profile
tab>Element
panel>Element
Properties>Instance
Properties
7. Align and lock the solid sweep to

the reference planes called
Member Left and Member Right
U.S. CAD 13
8. Add a concrete material in the Solid
Sweep’s Family Properties
a. (2010) Modify Sweep tab>Family
Properties drop-down>Category
and Parameters
9. Once the Solid Sweep is finished, you

can add Types in the Family Properties
so that you have various sizes available
for your project
*Types can also be added after the Box
Girder.rfa is loaded in the project
a. (2010) Modify Sweep tab>Family
Properties drop-down>Types
U.S. CAD 14
Bents:
Although Oahu has freeway overpasses with many rectangular or cylindrical columns, there are a few
with curved bents. Curves can be daunting to create and sometimes it takes more than a super size
meal. But, let’s create a simple bent family with curves and see how easy it can be.
First, like the girder, we need to create a profile family.
1. Start with Profile.rft and create the

profile as shown. (Let’s call this “Pier
Sweep-Profile.rft”)
Now we can load “Pier Sweep-Profile.rft” into our new Bent family. Because bents are vertical
supports, they behave like columns.
1. Start a new family based on Structural Column.rft. (Let’s call this “Bent-Curve Pier.rft”)
U.S. CAD 15
2. On the Lower Ref. Level, add reference planes, dimensions and labels as shown.
U.S. CAD 16
3. On the Front Elevation, add reference planes, dimensions and labels as shown.
4. Set the Center (Front/Back) reference plane as the work plane.

a. (2010) Create tab>Work Plane panel>Set
U.S. CAD 17
5. Add reference lines as shown and lock to the vertical reference planes.
Add these
reference lines
U.S. CAD 18
6. Add arc reference lines as shown and lock the ends
*Yes, you can align and lock ends of lines and

arcs. It takes a little practice. Hit the tab key
while you hover over the end of the line or arc
to cycle through your selection until you see a
symbol at the end of the arc or line, then click.
It will look like a square or circle grip. (You may
need to move your cursor a little and try again.)
U.S. CAD 19
7. Create a solid sweep using the Pier Sweep-Profile.rft
a. (2010) Create tab>Forms panel>Sweep
b. Use the Pick Path option and
select one of the arcs
c. Once you finish the path, choose the loaded profile, Pier Sweep-Profile.rft from the
Profile drop-down.
d. Pick Flip on the Options bar to change the orientation of the sweep and Finish the
sweep.
Before Flip After Flip
U.S. CAD 20
8. Once you finish the solid sweep, (and complete the other side), you’ll have the following
sweeps.
9. Use the Join Geometry to join the two piers

a. (2010) Modify tab>Edit Geometry panel>Join Geometry drop-down>Join Geometry
U.S. CAD 21
10. Create an Extrusion Void and lock it to the reference plane as shown.
Create a Void
11. Extra options to complete details on the Bent:

a. Create a an extrusion for the base
b. Add a nested Bearing family to the top of piers
c. Add an extrusion as a joining beam between the piers
*Just be aware of which work planes are set before you place nested families or solid
extrusions. Also, don’t forget to align and lock to planes.
U.S. CAD 22
IV. Structural Engineers Model bridges with column, slab, profile families, etc.
Once the components of your bridge are created, open your project, load the component families,
and we can start building bridges. It’ll feel like putting together Legos!
Add Girders:
1. Open the plan view that you want to add the girders
2. Select the beam tool and change the Element Type from the type selector drop-down
3. Use the Pick lines tool to pick the road center lines from the Road File
U.S. CAD 23
Add Bents:
1. Open the plan view that you want to add the bents
*Can’t see the Road File? Adjust the view range or use an Underlay in the View Properties
2. Hide the visibility of any girders
3. Start the structural column tool and change the Element Type from the type selector drop-
down
4. Place the bents using the Road File bent marks to align and lock into place
*Make sure that the base level is set to a ground level
5. Don’t forget to unhide those girders
Add a Deck:
1. Open the plan in which you placed the girders

2. Use the slab tool to sketch.
*Make sure that the placement level compensates for the thickness of the slab
Add Medians, Lights, Cars, etc.:
1. Load the components and embellish your model.

*This is where Road Boundary lines may be helpful, if included in the Civil Road File.
U.S. CAD 24
Bridge Modeling Methodology
1. Create a bridge of component families such as…
a. Girders – beam tool
b. Guardrails – railing tool
2. Create bridge of in-place families such as…
a. Girders – solid sweep with a sketched or loaded profile
b. Guardrails – solid sweep with a sketched or loaded profile
3. Combination of the above
Tips
Expansion joints: Set the material of the slab and girder to Precast Concrete. This automatically
shows the edge of elements. Cast-In-Place materials automatically blend and hide edges when
elements are very close or touching. If you need adjustable expansion joint placement, start your
girders using the existing family, Precast Rectangular Beam. This family is found in the Imperial
Library upon installation of Revit.
Concrete Medians: You can place these using three different methods: in-place families (solid sweep),
railings or slab edges. If you use slab edges, just make sure that the Vertical Profile Offset is set at
the correct height or that the profile which you use is drawn above the reference plane.
Bridge Challenges
Concrete reinforcement and connection details: Similar to buildings, Revit does not easily create
fabrication shop drawings. While typical details can easily be created with Revit tools, fabrication and
shop drawings are difficult to create using Revit.
Integration with Structural Analysis software: The current analytical model focus is for buildings.
While it can be done, the analytical model will need extensive manipulation.
Bridges with multiple cross section profiles: Although possible, it requires extensive manipulation of
girders.
Bridges longer than 1 mile span: Revit has a difficult time with graphics and modeling when the bridge
is more than a mile long.
U.S. CAD 25

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Revit Structure 2010

Bridging the Gap: Bridge modeling with imported

1. Coordinating with Civil Engineers

Overall steps for our focus:

I. Civil Engineers prepare the Civil 3D drawing for output

1. Check organization in AutoCAD Civil 3D

b. Check / delete erroneous lines and triangles

Move the site to 0,0

1. Open each Civil 3D file

d. Use Temporary Hide/Isolate to isolate the Site File

6. Setting True North

iii. Select the Road File’s road centerline

This line was

Parametric Bridge Modeling

1. Start a new profile family (We’ll call this “Box Girder-Profile.rfa”)

Now we can create a beam, using the Box Girder-Profile.rfa as a sweep.

1. Start a new family based on

3. Begin the Solid Sweep tool

5. Load the Box Girder-Profile.rfa

7. Align and lock the solid sweep to

9. Once the Solid Sweep is finished, you

First, like the girder, we need to create a profile family.

1. Start with Profile.rft and create the

4. Set the Center (Front/Back) reference plane as the work plane.

*Yes, you can align and lock ends of lines and

Before Flip After Flip

9. Use the Join Geometry to join the two piers

11. Extra options to complete details on the Bent:

1. Open the plan in which you placed the girders

Add Medians, Lights, Cars, etc.:

1. Load the components and embellish your model.

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