JOINT CONDITION 2

[LOKSTR]

Could anybody clear my concept for followings:

1. In gerber beams construction i.e. when beam runs on top of column and is connected to column thru cap plate and 4-A325 bolts, then column end will act as a PINNED or FIXED JOINT?

2. How to model this thing in any frame analysis software?

 

[dik]

I generally design it as pinned... but due to the relative stiffness of the beam to the column, with a reasonable crown plate, the connection will behave more like a fixed condition. If the beam is twice the depth of the column, the relative stiffness will be approximately 8:1... therefore, fixed.

If you do a lot of Gerber beams... you might want to look at plastic design of the beams... generally much cheaper.

Dik

 

[UcfSE]

In reality neither. It will behave as a partially restrained joint. Instead of going through the more complicated analysis with partial fixity, you can assume the joint is a pin. This is fairly common. If you want it to be fixed you will have to detail it such that the joint will rotate very very little and will have the necessary strength to carry a moment. In order to model it as a partially fixed joint you will need information on the rotational stiffness of the joint which is probably hard to come by.

 

[JAE]

We assume its pinned.

By the way - dik - nice to hear from you - seems like you've been absent a while.