Loads/Reactions from tnxTower to RISA Foundation 1

[azcats]

Is there interoperability between tnxTower and RISA foundation? I'm struggling to get the envelope of reactions from tnxTower, thru (or not) RISA-3D and into RISA Foundation.

I can open my tnx model in 3D. Help says that I need to make sure that the each BLC is assigned to a load category. But I've got ~20 wind loads each at different angles around the tower. If I add them all to category WL, when imported into Foundation the reactions are all stacked on top of each other as one load case of WL. Is there a way to keep the reactions from different angles of wind load separate in the transition from 3D to Foundation? Or is there another pass thru? Or do I just need to do this the old fashioned/tedious way?

Help and/or input appreciated.

 

[JoshPlumSE]

Let's see if I can respond in a way that is true, but doesn't open me up to a lawsuit....

There isn't any DIRECT interaction between TnxTower and RISAFoundation. My guess is that there will never be one. There is someone at RISA that (this is purely my opinion) doesn't like Peter / TnxTower and is a little petty / vengeful about it. In that person's defense, Peter can, at times, be difficult to get along with. It's not that he's a bad guy.... He's just really opinionated about what works best for him and for his program.

Now, just because there isn't a direct link between the two programs doesn't mean you can't make something work. You can export the TnxTower model into RISA-3D. Then run your analysis from there. Initially it comes in as an *.rt3 file (at least that's what used to happen). The RT3 file is really just a binary version of RISA's regular input text file. If you can save it out as a regular RISA-3D file, then you should be able to bring it over to RISAFoundation. I think RISA may allow you to save RT3 files now as regular RISA files. But, I'm not 100% certain.

There are some technical drawbacks associated with this. The more important the 2nd order effects are, the less likely the RISA-3D reactions are going to match the more accurate reactions you get from TnxTower. RISA, in general, does a pretty good job with P-Delta effects of frames and building structures. However, TnxTower tends to have very tall, slender towers. These may require an analysis with a more advanced second order solver. Not so important for monopoles, or relative short SST's. However, it is probably very important for towers with guys / cables.

 

[azcats]

Thanks for your candor and input Josh.

Not having any luck saving the .rt3 as .r3d however.

Right now, I'm working with relatively short monopoles so I don't believe the second order effects are very important...especially for foundation design. I plan to leave the tower analysis in tnx. My ideal hope was that there was a thoughtful way to get envelope reactions from tnx to R-FDN.

I've worked with Peter's beta of the his foundation program, but I found it unwieldy enough that we bought RISA & LPile instead of waiting and hoping. The thing it did wonderfully was to bring loads over from tnxTower.

I think I've worked out a way to get this done. I'll try it one more time in the AM and explain here in case anyone else is listening.

 

[azcats]

So here is the somewhat ham-fisted approach to getting loads from tnxTower into RISA Foundation (FDN).
- Solve tnx with custom wind direction of 0 thru 150° including the 45° angles (8 segments)
- Open that model in RISA 3D.
- In the Basic Load Cases, there will are 9 loads (DL and the 8 wind loads) Make the load categories DL and OL1-OL8. They must be assigned to Load Categories in order to move over to FDN. If all assigned to WL, they will stack when moved to FDN and you cannot add them discretely to combinations.
- Solve DL load case.
- Use 'Director' to open in RISA Foundation.
- Now the loads come in as DL and the wind loads are all discretely labeled as OL1 thru OL8 and I can make my own Load Combinations from there.

This particular analysis was a large mat foundation with a pedestal and the pole atop. So I needed the wind from multiple directions as the foundation flexure was governed by the loads parallel to the X and Z axes, but the soil pressures were controlled by the quartering forces. I likely used more loads than necessary.

 

[skeletron]

@azcats: how do you like using RISAFDN for tower foundation design? I'm kind of in the same boat with trying to find foundation software program that provides design and meaningful analysis.

 

[azcats]

Honestly, I'm still too new at it to offer a real solid opinion. At this point it appears to be a fairly powerful piece of software that will likely do more than I need.

There's a 'footing element' that provides a quick, simple analysis that is fast and I really liked the output. But you don't have much control of the elements so it's not great for analyzing something existing. So now I'm working thru better understanding the slab and pedestal elements so I have more control and using the design strips.