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Re: Application of 3Rw/8 - How to apply

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Dennis:
 
The Rw should be 6.
 
I tend to provide a rigid connection that would have at least the same capacity of the members framing into the joint and therefore tend to go beyond the 3Rw/8 increase.  The obvious goal is to have the girder yield before the column or joint begin to yield/fail.
 
-----Original Message-----
From: Dennis S. Wish PE <wish(--nospam--at)cwia.com>
To: SEA International List <seaint(--nospam--at)seaint.org>
Date: Wednesday, September 23, 1998 1:40 PM
Subject: Application of 3Rw/8 - How to apply

I design very little steel so I apologize up front for my lack of understanding regardless of the number of posts which have been sent on this issue. I am in need of a fast answer and would appreciate any responses.
 
I have designed a simple (Ordinary) moment frame for a seismic retrofit. The frame is one bay - 25 feet between columns and 12 feet in height.  The lateral load applied from the results of the UCBC design is 10.57 Kips. The frame is pinned at the base and therefore develops moment in the connection of beam to column.
 
Do I apply 3Rw/8 to the moment at the connection or is it applied to both the moment and the shear at the end of the beam?
 
Also, is it correct to assume Rw is equal to 8 for use with an Ordinary Moment Frame?
 
I appreciate any fast responses.
 
thanks
Dennis Wish PE