fixed bearing modelling???

[mpaksoy]

Hi Vesna and all,

I am modelling a 3 bent and 5 pier per bent simply supported RC bridge. The superstructure consists of I beams. The I beams rests on the fixed steel bearings which are located on the cap beam.
I modelled the piers with nonlinear beam column and assigned rigid offset till the middle of cap beam through geometric transformation. The elevation of cap beam and superstructure centroids are different due to the centroid of superstructure. I need to define the fixed bearings btw the SS node and cap beam node. I wanted to simulate the fixed bearing by equal dof command but I dont get reasonable results from the mode shapes. Is it true to define the fixed bearings without any elemnt but with just a constraint? If not would you give me a hint??

for example

node 200 30 5 0 is cap beam center node
node 105 30 7.5 0 is deck node of previous span
node 106 30 7.5 0 is deck node of next span
#equalDOF 200 105 2 3
#equalDOF 200 106 1 2 3


Thank you

Murathan

[vesna]

Why do you mean by fixed bearings?

[mpaksoy]

By fixed I mean translation in both transverse and long direction is fixed. So at both side the deck in transverse direction deck nodes will be moving together with the pier cap center.

[vesna]

In that case you need to define an element in between.