Elastomeric Bearing Shear Deformation

[bags1235]

Working on a new bridge construction project in which the elastomeric bearings have experienced excessive shear deformation. Reason for the excessive deformation is still under investigation, but is likely due to construction staging conditions. Regardless, there is no noticeable distress in the bearings. The bearings are steel laminated, 16" square, 5" tall and have deformed approx. 1". We instructed the contractor to jack and reset the bearings, but they did not rebound. Could anyone explain this and are these bearing now permanently damaged due to this excessive deformation?

 

[dtoli]

You have a shear deformation which is small (i.e. ~ 1"/4"=0.25<0.7) so normally there wouldn't any problem for rebounding.

If you are certain that contact surface was released (it is not an anchored bearing) then the only thing I could imagine is a slip between lamination and rubber due to bad vulcanization process.


URL:

http://www.diolkos-eng.gr

 

[Drumchaser]

I my memory serves....there was some hubub about incorrectly manufactured pads vs. requirements....I would start there.

 

[wiktor]

1" displacement for a 5" thick elastomer that's only 40% of the maximum displacement for this bearing and it's not excessive.
It's make me wonder how big is the bridge? 250' total?
The bearing should move back, once the structure was jacked, and the only reason for not doing so is some kind of fabrication error. Or may be it's a fixed bearing with the steel rod inside?