Edge of Deck Modeling Issues

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Visitor (not verified)
Edge of Deck Modeling Issues

I am currently modeling a 48 span bridge with the deck varying from 28 feet to 48 feet in width. The area of concern is where another bridge joins the bridge I am modeling and increases the width of my bridge to 48'. When I enter my edge of deck points everything works correctly until I change the taper type to parallel. When I select parallel this changes my edge of deck offset from 19' to 34' (the same as the previous point) so that there is no taper. I am then unable to change the value of the offset until I change the offset type back to linear.

I am sorry my post may be a bit confusing, if you have any questions to narrow down my post please feel free to ask and if you have a solution please post!

Rick Brice
My first word of warning is

My first word of warning is don't get too carried away with modeling the edge of deck. The concept is to model a smooth deck edge with simple transitions between points.

The parallel transition type means the edge of deck is parallel to the bridge line or alignment, depending on your Measured From datum. The offset at the start and end of the parallel transition must be the same (otherwise it wouldn't be parallel). This is why the second offset is constrained to be the same as the first offset.

If you can send a copy of the deck layout, I may be able to provide you with additional guidance.


Richard Brice, PE
Software Applications Engineer
WSDOT Bridge and Structures Office

Justin Christ (not verified)
An Example

We are trying to see if we can use PG Super to double check all of our bearing seat elevations, deck geometry and prestress design. With that said we are trying to be as accurate as possible when modeling this structure although I know this is a very specialized situation that is probably not often encountered in bridge geometry. Thank you for your assistance in looking at the attached example.

Also: Is there a zoom function available with this program. If I stretch the working window to include both my monitors then it enlarges the bridge, but I would like to zoom in more at specific spans to view beam geometry and edge of deck easier.

Thanks again!

Justin Christ

Rick Brice
To model your bridge deck, go

To model your bridge deck, go to your CAD system and measure several station and offsets from the alignment to the edge of deck. Then input these station and offsets using the Spline transitation type. The Spline transition curve fits a cubic spline between the points you input to create an approximate of the deck edge. The more points you use, the more accurate the curve.
There is not a zoom feature. I can see where it would be helpful for a bridge with 48 spans. Adding pan and zoom capabilities is on our To Do List.

Justin Christ (not verified)
Thank you!

Thank you so much for your assistance and quick responses. I have one last question concerning PG Super. The import function currently has a greyed out selection that says "custom importers not installed". Do you know if there are any available importers or if that is a future function? Thanks again for all your assistance and it really had been a very helpful and intuitive program to learn.


Rick Brice
The PGSuper you get from

The PGSuper you get from TxDOT and WSDOT don't have any custom importers,however this is an active feature of the software. Third parties can develop importers and link them into PGSuper. A custom importer might import geometry, loads, or the entire bridge description from an external data source.
I think that BridgeSight is developing some importers and exporters.

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