Minimum Fillet

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Minimum Fillet

I use the minimum fillet as a minimum haunch check. It would be nice to be able to define multiple minimum fillets. The DOT has different minimums for different beams, and working on a bridge with multiple types of girders requires multiple models to get a passing haunch geometry check. Unless I'm using the fillet completely wrong.

Let me know and thanks!

AttachmentSize
PDF icon Min. Coping BDM Section19.2 KB
PDF icon Schematic6.55 KB
Rick Brice
Minimum Fillet

The minimum fillet is a minimum haunch check at mid-span. There is an addition minimum build-up check at bearings. I'm sure you are using it correctly.

WSDOT and TxDOT don't have per-girder-type minimums so there is only a global setting.

Please provide references to the DOT Bridge Design Manual, or other appropriate references, so we can assess this as a possible feature enhancement. Ideal, the DOT in question would like to contribute to the software by sponsoring the development of such a feature.

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GDOT

I wasn't aware that it was only at midspan. That may be a good addition as well. I just finished a design where the bridge is on a sag curve and the minimum doesn't happen at midspan. I had to use some interesting mathematics to find where the minimum occurred.

It is the Georgia Department of Transportation. I don't work directly for them, but as a consultant; so I'm not fully aware of the level of contribution they have or will have in the future. I do know that they did sponsor a PGSuper training a while back; so they may be becoming more involved. I've attached a pdf of section of the BDM in question to my original post. And BTW, thanks for all your work on this site and the program.

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Rick Brice
Mid-Span

It's actually all points along the span - just typically controls at mid-span.

I'd be curious to see the bridge layout, sag curve, etc, that makes the minimum haunch somewhere other than mid-span. This isn't common.

Can you send me the layout and PGSuper file. You can send it to my WSDOT account (bricer@wsdot.wa.gov) if you don't want to post it in the forums.

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I unfortunately can't share

I unfortunately can't share anything on that project right now, but I have uploaded a schematic of the situation in the OP. We have a sag curve ending within the span. For constructability and GDOT standards the ends of the beams need to be equidistant to the alignment, which forces the minimum haunch out to the PVT.

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Rick Brice
No worries - the schematic is

No worries - the schematic is helpful. PGSuper handles this case. It searches along the span to figure out what the slab haunch build up ("A" dimension/Slab Offset) needs to be so that the minimum fillet is achieved within the span. The solution is numerical, using a minimum of span 10th points, so it's got your case covered.

You can see the detailed calculations in the Details Report. For each 10th point (or so) it computes what the build up at the ends of the girder needs to be so that the build up at the point under consideration is equal to the fillet. The maximum required build up is the "A" dimension/Slab Offset.

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Great to Know!

Thx!

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