Steel reinforced elastomeric bearings

[caroengr]

I am designing bearings for a railway bridge. Through my research I am designing steel reinforced elastomeric bearings at the fixed and expansion bearings. Is designing for a dowel in the fixed bearings a practical solution for this to limit translation? Also are there any limitations on having a steel top and bottom plate? I am trying to obtain a certain height and hoping this will work.

 

[BridgeSmith]

Typically, the restraint would external to an elastomeric bearing. Usually, the anchor bolts would extend through a hole in the sole plate beside the bearing pad. If the restraint required exceeds the bending capacity of the anchor bolts, you can add a block to the edge of the underside of the sole plate to decrease the moment arm of the anchor bolts. Although, at a fixed bearing, where only the rotation and compression need to be accommodated, the bearings can be fairly short. If it's a long bridge, I would recommend designing the fixed and expansion bearings separately, in order to minimize the height of the fixed bearing. Another note for the fixed bearings - wider is better for minimizing the height of the bearing, but worse for the thickness of the sole plate. Optimizing the bearings is a multi-parameter balancing act, with typically lots of iterations to get to the best result, especially the first few times, until you get a 'feel' for a good starting point.