Rocker & Roller Bearing

Brief Description :

For railway bridges with spans 30.5m & above 30.5m, where open web girders are generally provided, the amount of movement needed and the vertical load transmitted through each bearing is too large to be catered by the sliding bearings. It is common, on Indian Railways, to provide rocker & roller bearings at the free end of open web girders and rocker bearings at the fixed end.

Fig. 1: Rocker at Fixed End

Fig. 2: Roller at Free End

A typical rocker and roller bearing for open web girders of 45.7 m span is shown in Figure. The roller bearing consists of a base plate, two or more rollers and a top plate. The rocker & roller end is made by providing a saddle and knuckle plate on top of the rollers whereas the same arrangement except rollers is at the rocker end. The rocker & roller end of bearing permits translation as well as rotation, whereas the rocker end permits only rotation.