Unexpected interruption of calculation. Model of PT RC viaduct with post tensioned rib slab superstructure. Two construction stages.

[Anonymous]

Hi,Could you help me to decide this issue. At first I have created the model with only one construction stage, with post tensioned tendons and the program calculated it properly, including influence lines generations and live loading optimizations. But after dividing the model by two construction stages, because of post tension reasons, the program has started interrupt calculations without making an analysis log file. 

Thank you in advance, Vladimir

[dave_geeves]

Hi Vladimir,

Thanks for attaching your model. This sound like a memory problem but I can’t be sure until I have tried running it myself, later today.  Try increasing the memory settings from the options menu.

let me know if you have any luck, otherwise I will contact you as soon as I have more to suggest.

kind regards

Dave Geeves

[Anonymous]

Hi, Dave Thank you for your reply. I have tried to increase the memory for an analysis but it did not help.

FYI It's interrupted after compiling data for the loadcases at the construction stage 2

 

 

[dave_geeves]

Hi Vladimir,

It has taken me a while to make any progress on this as I needed to understand your model and how the staged construction was working.  You were correct that it is not really a memory problem so I first changed the memory requirements to a large model.

I first noticed that when I opened the tendon definition form when in Stage 2 construction I get an "EEFACE" error when looking at the stressing details and the tendon forces were not being shown.  This is an internal error so only the developers will be able to debug this problem.

However,  I then inspected your construction stages and noticed that in stage 2 you made 4 tendons inactive which you had previously stressed in stage 1.  This didn't seem logical as you can't remove already stressed tendons (you can of course "destress" them if necessary in the tendon definition form or set them to "no Change").  When I set these four tendons to "No Change" then the error message I was getting previously disappeared and I was able to get further with the analysis.  In fact the analysis completes but it seems to fail in processing the results ready for the results viewer.

I will need to investigate this problem a bit more tomorrow but it is generally an inconsistency in the structure between stages where there are too many or few results that are expected.  Again only the developers would be able to debug this efficiently to see what the inconsistency may be.

I will keep you posted if I find a solution.

|Kind regards

Dave Geeves

[Anonymous]

Hi, Dave.

Thank you for the information, I hope the developers will decide this problem soon.

As about these four inactive tendon - it was my misunderstanding. You are right, I am going to stress the tendons at a first construction stage, to reduce first losses, and keep the tendons as they are on a second construction stage. So, as far as I understand you, I should set them to "no change" at the second construction stage.

Sincerely, Vladimir

[Anonymous]

FYI, I am working with version 20.2.140.0 of the program. I saw that there are newer versions but I can not get them because they are missing in my Autodesk Desktop App (I am using corporate floating license)

[simon_hooper]

Hi Vladimir

I was able to get a successful analysis by making all the tendons inactive at stage 1 (via the Construction Stages form).  Was that your intention as I see there were a couple of tendon parts that were active at stage 1?

Simon

[Anonymous]

Hi Simon Thank you for your attention to my issue. Actually I need to tension these tendons Type 4 at the first construction stage. Because of a tight time schedule for this project I have decided to use a system of equivalent forces to model these tendons - I am going to include these forces into a dead load combination for the first stage of construction.
Vladimir