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Re: stiffener welded to tension flange?

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Angel,

I'm assuming that in order to provide restraint to the compression flange, the
transverse stiffener also acts as a connection plate for a diaphragm or cross
frame.  If so, AASHTO 1996 with interims to 1998 (Sec. 10.19.3.2) recommends
that the connection plate be rigidly attached to the top and bottom flanges to
prevent the lateral forces from loading the web in out-of-plane.

HOWEVER, I highly recommend you refer to the Department of Transportation
standards for the state in which you are working (are you in the U.S.?).  NYS
DOT standards prohibit the welding of connection plates to the tension flanges,
they recommend tight fit.  Whereas, NJ DOT is the opposite.  But NJDOT requires
full RT/UT of the weld at the tension flange.

If you do weld to the tension flange and are not using LRFD specifications, I
would consider the detail Stress Category C (see Figure 6 and Table 10.3.1B),
but please refer to footnote b of Table 10.31A for additional information.  LRFD
Specs, 2nd edition consider these details catgeory C'.  Also, make sure to
terminate the plate to flange weld at least 6 mm ( 1/4" from the end of the
connection plate) and cope the plate a minimum of 25 mm (1") from the face of
the web.

Now I'd like to ask a question.  Is this a temporary condition which you are
worried about?  Normally for simple spans, the shear connectors at the top
flange provide composite action between the concrete deck and compression flange
and the deck is assumed to provide lateral restraint.

Hector






"
Ángel Gómez" <agomezes(--nospam--at)vianet.com.mx> on 10/05/99 12:02:38 PM

Please respond to seaint(--nospam--at)seaint.org

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Subject:  stiffener welded to tension flange?


In a unssuported compresion flange for a simple span girder (bridge) if
transverse stiffener,,joined to a stringer,is used to stabilize the compresion
flange. Should the transverse stiffener be welded to the tension flange wheter
the fatige category at the stiffener weld termination is still AASHTO fatigue
category C?