Adding Piers to a 2D HEC-RAS Terrain and Mesh

[@Mike-yg9zw]

Thanks so much Stanford! Very helpful. Would be great if the next version of HEC-RAS had additional 2D pier scour tools to help grab proper output for use in the hydraulic toolbox etc.

[@mohamedelgamal6333]

Many thanks, Gibson for this great video.

[@stanfordgibson]

You can also rotate the pier graphically by clicking the green dot in Mapper

[@tomng9604]

Another great video. Thank you Stanford!

[@michaelo9588]

Great video, Stanford! Thanks for sharing. Bridges still seem like a bit of an afterthought at USACE. Getting detailed info through bridges is primary importance for DOT's and other owners. This is a good procedure toward that end. Our group will work with this methodology for skewed bridges, column bents, etc. where we need to have good understanding of what's happening under and around our bridges. Hope you'll provide other similar videos in the near future! Also hoping USACE will finally address their outdated scour procedures. Maybe version 7.0?

[@leeadams5816]

Hi Sanford. Very helpful modeling approach you demonstrate here. I am interested in what you might think of this approach. It was challenging to get the cells in the refinement regions lined up so perfectly with the pier terrain modification. I kept seeing leakage at the piers, so I did the following: Place the piers in the model at just a tenth or two smaller than they really are. Establish the Refinement Regions by tracing over the pier modifications, mesh the model, edit the Computational Points as needed. Then, return to the pier terrain modification editor and edit the pier width to the real, slightly wider width. I'm hoping that the result will be that the Terrain is modified for the pier and it will widen into the adjacent cell, effectively blocking that side of the cell and preventing flow from "leaking" through it.

[@stanfordgibson]

Sounds good to me!

[@stanfordgibson]

Also, RAS2025 already includes gaps, so it will be much easier in the new version.

[@DanDoerfler]

Would you need to do this if you model the piers in the SA/2D Connection bridge routine?

[@sivagamimusicals6958]

for circle pier of 1.75 radius what is the x and y value sir

[@moonlighttreasure1099]

Many thanks! May I ask what's the rules/requirements for adjusting the mesh around the piers? You mentioned that you changed the mesh around the nose, is it more or less a personal preference based on experience or is there a certain rule to abide? Thanks.

[@stanfordgibson]

In the current version of RAS, Mesh design is a bit of an art (note: this will all change with the next major release). I try to use Breaklines and refinement regions to reflect the impact of these structures in the subgrid. And some of it is iterative. Do the velocity vectors make sense (ro are they jumping through the piers or generating unrealistic eddys)

[@tomng9604]

What 2D computational parameters that you used for this simulation (equation set, turbulence parameters)?

[@mars889]

hi, can you make a video about 2D piers and bridge scour? thank you

[@gretabaumann2519]

Amazing video, do you know if we can use HEC-RAS for simulation water flow in opend drainage ditches! Many thanks in advance

[@stanfordgibson]

Sure. I can't think of any limitation that would make open drainage ditches challenging.

[@cusco4x295]

If we make Manning's value in piers area iqual 100....the flow don't pass there, right?

[@stanfordgibson]

High n value regions are a hack that will approximate obstructions, but I prefer stamping them into the terrain now that the mode tools are available. There is just less ambiguity about water volume, wetted perimeter and how the model is interpolating hydraulics.

[@cusco4x295]

@@stanfordgibsonMany thanks for your answer.

[@davidedimauro4804]

Quality!