Run optimisation problem

[Anonymous]

Hello,

I am working in a model and when I try to run the optimisation it get stuck. I tried to move the carriageway, I have generated the influence surface again, working from the server, from the desktop, other colleagues have tried in their computers, in versions 2017 and 2018… and I do not know what else I can do. Someone knows what can it be?  Has this happened to anyone else?

Thanks in advance,

P.S: I attach the file in case someone wants to have a look.
Christian.

[dave_geeves · Accepted solution]

Hi Christian,

Thanks for attaching your data files.  I will certainly take a look and get back to you.

Kind regards

Dave Geeves

[dave_geeves · Accepted solution]

Hi,

I've been trying quite a few things but I'm afraid with little luck at the moment.  I thought this was going to be an easy fix as the mesh is  not a conventional grillage mesh with some shapes in the deck having 5 sides.  I removed this by adding a few nominal beam elements to split the shapes so they had three or four sides.  Still no luck.  As you correctly say, moving the carriageway so that it is completely on the deck still makes no difference.  Even making it a single carriageway over the full width has the same effect.  However, a narrower carriageway works so I suspect it is all in the carriageway definition.  I seem to remember there was a problem a few years ago where some tight radius carriageways could not be processed unless the reference design line was shifted (and the offsets altered so that the carriageway was in the same location).  I will give this a try tomorrow and get back to you.

Kind regards

Dave Geeves

[Anonymous]

Good morning 😉

Thank you very much for your help. As you say, I suspect that it could be the definition of the Design Line since it is the first time that I make it curved. I'm going to test with different radios and inclinations since it doesn't have to be strictly the line that your are seeing in the model that I have shown you. If another similar Design Line works, then I'm happy. 

Thanks again and I'm going to try. I will let you know if it works.

Regards,
Christian.

[dave_geeves · Accepted solution]

Hi Christian,

I don't know the exact cause but I did find a workaround solution.  It does seem to be the kind of design line used.  I opened your model and created a second design line using a simple cubic spline by defining a series of points that were as close to possible as the original design line.

I then created a second carriageway with exactly the same parameters but by referring to the second design line.

In the load optimisation form I set the carriageway to the second carriageway and the load optimisation worked.  I did limit the number of combinations and vehicles just to speed things up.

I hope this has given you a good enough workaround to allow you to continue with your project.  It is a great model by the way and shows a great use of the software.

One thing I have found in the past is that the load optimisation generally works best in a grillage when the intersection grillage members form triangle or quadrilaterals (without reflected angles).  I noticed that in your mesh you had a few five sided shapes which at first I thought that this was the problem.  To get round the condition I simply added an additional member to split these shapes and assigned it to a 10mmx10mm concrete shape (which would have no real effect on the stiffness of the structure) 

However, the mesh as you defined seems to work fine but please bear it in mind for the future if the influence surfaces look a bit odd.

If this has answered your query please mark this reply as a solution so that others may benefit. Hopefully the developers will notice this post and investigate to establish a reason..

Kind regards

Dave Geeves

Dave Geeves

[Anonymous]

Hello Dave,

Thanks so much for your time and effort to find a solution to the problem. RIght now  I was modifying the current Design Line with the option of assigning it a specific length, I have also modified a bit the angle and radius. It seems that this has worked but I have to check it well.

I'm going to try waht you tell me because it is an option that I have never used and I find it interesting.

Regarding the mesh, thanks for the tips, I will take them in account! The truth is that it is a bit difficult to stablish an optima mesh in this bridge.

Again, thanks so much for your help

Kind regards,

Christian.