The problem of invert flexibility on 3D column.

[Jihoon]

Hi~ I posted about this topic Jul 27. I can't solve this problem yet.
So that's how I repost it. please help me~

I'm modeling Meloland Road Overpass(continuous 2 span, 1 single poer) now.

Pier : nonlinearBeamColumn (fiber section)
Deck : elasticBeamColumn
Pier & Deck connection : Ligid Link
Boundary : foundation Pile spring (Jian Zhang and Nicos Makris .2002)

It can not work when I use slcaled ground motion(amplitude : <min -0.3972g>/<max 0.3623>).
On the other hand It works when i use other ground motion(lower value of amplitude).

It shows just ' ForceBeamColumn3d::update()--could not invert flexibility' message.

ForceBeamColumn3d::update()--could not invert flexibility
ForceBeamColumn3d::update()--could not invert flexibility
ForceBeamColumn3d::update()--could not invert flexibility
.
.
.
ForceBeamColumn3d::update()--could not invert flexibility

I think this problem appear on the pier(fiber section).

How can I solve this problem?

Thanks~~!!!

[fmk]

to solve the problem you need to:
a) try something different in the analysis script, e.g. cut down step increment, change solution algorithm or integrator.
b) modify the material or sections supplied to the element by possibly throwing in some small elastic fibers
c) and of course you could try a dispBeamColumn element instead which may move the problem to the global level but which will give you a "theoretically" inferior answer if you indeed have a beam -column type element.