Boss Dambreak - General Question on Model Set-up - Modeling bridges

Joe:

Note that we have a BOSS DAMBRK Troubleshooting Guide on our website in our DAMBRK Download Section. This may help you in troubleshooting your models.

You are correct, bridges are quite a "pain" to get to "run" in DAMBRK. DAMBRK does not do a tremendous job of supporting them, causing lots of difficulty. Therefore, many times individuals will assume that the bridge is "washed out" and hence only describe the bridge abutments as a restriction in the channel geometry. This is a conservative solution method, causing a more severe flood event further downstream. If this is still within allowable limits, then your finished with the model. However, if these flood elevations results are too high, or it is highly unlikely that the bridge will be washed out, then you attempt to model the bridge as a dam structure with a "hole in it" to mimic the hydraulics of the bridge opening. You can use a spillway rating curve to model the bridge opening hydraulic flow characteristics. Many people have had great success with this method.

Please feel free to contact me directly if you have any questions or need any further information.

Sincerely,

Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com

Do many of the users of Boss Dambreak try to model the dambreak flood wave thru the existing bridges as a bridge or as normal cross-sections?

In your Example No.2, this example does not modeled the bridges, the bridges are modeled as normal cross-sections.

Do most users assume if the bridges are being overtopped significantly, they do not impact the water levels and do not need to be modeled as bridges only as normal cross sections? (basically disregarding the superstructure)