topic Re: Influence surface in Structural Bridge Design Forum

Influence surface

Anonymous — Thu, 26 Oct 2017 13:31:32 GMT

I tried to model my bridge as a grillage (see the picture), now I would like to obtain the diagram of influence surface but the program says "no property assigned to the beam", someone can tell to me what i didn't do? and what I have to do?

Re: Influence surface

Philip.Lee — Thu, 26 Oct 2017 20:58:34 GMT

Have you got any transverse members in the grillage? Are you able to zip your model file up and attach it to the forum?

Re: Influence surface

Anonymous — Fri, 27 Oct 2017 08:10:06 GMT

Hi Philip,

Of course I am able to. No I didn't use any transversal element because in my design it was not foreseen.

Please help me, because I am stuck.

Thank you a lot

Re: Influence surface

Philip.Lee — Fri, 27 Oct 2017 10:03:22 GMT

A grillage is made up of a mesh of longitudinal and transverse beam elements. If you don't have any transverse elements representing the transverse stiffness of the structure (usually just the slab), the model will not analyse. The Examples Manual which is accessible from the Help menu includes examples of grillage models. It does show ASBD 2014 which has a different interface, but the modelling principles are the same.

Looking at your model, there are a number of beam elements which don't have any properties assigned to them. These are shown in grey when you go to the Structure Properties tab. These will need to have properties assigned to them for the model to work.

You also need to define supports so the program knows how the model is supported.

Re: Influence surface

Anonymous — Fri, 27 Oct 2017 13:58:01 GMT

Hi Philip,

Could you set the bridge for the analysis and upload it, please, also with every arrangement that you want, then I will modify for the case of mine?

thanks in advance

Re: Influence surface

Philip.Lee — Fri, 27 Oct 2017 14:00:05 GMT

I'm afraid I'm not able to make edits to your model and upload them. If you need help like that you should contact customer support.