Question on fixity

[NKCH]

Dear all,

I am wondering if there's any typical guidelines or rule of thumb to determine fixity at supports of (say)bridge piers...

Thankx

 

[jjeng2]

I think you need to elaborate a little bit. Are you talking about establishing a % of fixity to put into a program based on what the physical field conditions are?

 

[JAE]

Most bridge piers are supported by piling and these, relative to the pier itself, don't have a lot of fixity/stiffness. I know that we either assume a rotational pin, or, if we want to get more exact, model the piling for about 5 or more feet and fix the bottom of the piling. That way, the rotational stiffness of the piling are included in the model.