Deep Beam Analysis Software

[Enginerdad]

I'm designing a multi-column pier cap and the DOT is requiring that we use the strut and tie or other deep beam analysis method. Most software that I can find (ETPier, OpenBridge/RC Pier) doesn't do that, they use elastic beam theory. I found this STM-CAP from the University of Toledo Link that does strut and tie. Is anybody familiar with this program or any others that can do strut and tie or another deep beam method (I think the only other real option is FEM like VBent).

 

[wth]

I believe IdeaStatica does strut&tie.

https://www.ideastatica.com/concrete

 

[centondollar]

Suitable strut & tie-models can be constructed and solved (with FEM or by hand, depending on complexity) by first solving the deep beam problem as a membrane in FEM (in-plane actions only, a "2D-beam") and using the resulting elastic stress fields to approximate where compression and tension will primarily occur. There also exist tables for "deep beam" (membrane) elastic solutions (with various boundary conditions and loads) which could be used to find the stress field.

 

[dik]

I thought strut and tie simplicity lended itself to hand calculations... Can you post a sketch of your model to see what it looks like. KootK is the strut and tie guy around here (among others), and maybe he can provide some insight.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Enginerdad]

It is pretty hand calc-friendly. The bigger issue is that, this being a pier cap, determining the live loads is a complicated procedure. So in an ideal world I would find a specific pier design program that also does STM or FEA, be a use those automate the live load scenario process.

 

[KootK]

Having a single program handle both the global analysis and he strut and tie design sounds like a pretty big ask given the current state of technology. Maybe you can export the load cases from your FEM software and feed that into a spreadsheet of your own that tends to the STM work.

 

[Enginerdad]

The VBent program I referenced above is a pier analysis program that does FEM, which is an acceptable alternative to STM for deep beams. So I do have at least one option, I was just seeing if anybody knew about any others.

 

[user277418]

AStrutTie and IdeaStatica are most powerful commercial software in the field

CAST is free and pretty nice

 

[Enginerdad]

Thanks, I'll check those out

 

[TLHS]

You could also model the system as a truss in software but define as tension or compression only elements as required and then work from that to do hand checks on capacity

That being said, get a design you're pretty sure will work first. Doing it this way as a verification is not bad but modifying and iterating is a giant pain.

 

[3Fan]

I have used the STM-CAP spreadsheet you list above once or twice. It was sponsored by the DOT we do work for. It is fairly simple to use, but yes you will need to determine your reactions with another program. The Project Report provides several worked examples using the spreadsheet. The intent of that spreadsheet was to evaluate existing pier caps that may have been designed using the Sectional Method which may produce overly-conservative results for deep members. When analyzing existing pier caps, the shear capacity was contributing to inventory rating factors less than 1.0 for the current design loading.

Bentley's Leap Bridge Concrete will perform STM on hammerhead piers only.

 

[Enginerdad]

Bentley's Leap Bridge Concrete will perform STM on hammerhead piers only.

Yes, that's what I found as well. It's all part of their OpenBridge package now, and it's too bad we can't use it since we have the license.