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Re: Pedestrian Bridge Bearing

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Rich,
 
Generally, for short (e.g., 40') spans of pedestrian bridges, the below detailing may not be necessary, and steel-on-steel movement (baseplate-embedded plate) may be sufficient. 
 
However, here is a pretty standard practice for pedestrian bridges:
 
1) make baseplates leveled (horizontal) under DL;
2) install neoprene pads not less than 3/4" thick against abutment seat (refer to MASCTICORD manual);
3) bond 3/16" min. TEFLON pads to the neoprene pad;
4) weld mirror-polished stainless steel pad to the bottom of the baseplate (size to allow movement).
 
Items 1 and 2 - for fixed and slide supports;
Items 3 and 4 - for slide support only.
 
According to research, nothing (short of actual rollers) can assure movement to the extent the above assembly does. 
 
Continental Bridge may have some details at the web site. 
 
HTH
 
Steve Gordin SE
Irvine CA
----- Original Message -----
From: Rich Lewis
Sent: Thursday, January 19, 2006 11:19 AM
Subject: Pedestrian Bridge Bearing

I was asked to design the support buttresses for a 40 ft. long pedestrian bridge spanning over a gully.  The bridge has a camber of about 36? at midspan.  I ran an analysis of a pinned end and roller end.  The pinned end had a 48 kip thrust force.  The roller end had a 0.50? movement.  So I would like to detail a bearing condition of roller instead of pinned.  I never had the pleasure of working for a DOT or doing bridge work.  Are there any standard bearings I could specify that are readily available to provide a roller bearing for a cambered beam?  Are there any typical details someone can share with me showing a roller end bearing?

 

Thanks for any insight you may provide.

 

Rich