Project Description : Roller Rehab Bridge Bearing Service , 24th April, 2018.
Bearing rust removal, internal cleaning, painting, greasing and oiling. Mark bearings to gauge future movement and report on service and any defects identified.
Recently replaced pot bearings on both the abutment and next pier are in excellent condition.
The rusted ‘nest of rockers’ bearing with rusted cover. This cover was removed and will be replaced with new cover with easy access flap for servicing and greasing.
Once the covers were removed the rockers could be seen. The spaces between the rockers were blocked with dry debris. They looked as though they had not be lubricated for some time. Looking across the deck both the bearings looked in a consistent position, both being at full extension which is to be expected during the warmer months when there is longitudinal movement in the girders due to thermal expansion.
This image of the flank of the nest of rockers shows the recessed oil bath in the bottom plate. Note the recess is full of dirt and dry rust which highlights the inadequacies of the old bearing covers. This bath was totally blown out and the drain hole cleaned. It was then filled with grease to keep water out until the new covers are designed, manufactured and fitted.
We ensured the spaces between the rockers were totally clear before moving onto the oiling and greasing phase. These images show rockers to be totally free to move.
The fixed end pivots were also in a rusted condition. Note the greasing points including the one on the centre pin are blocked hindering lubrication.
The rockers and fixed end bearings were pressure washed with water only. This non abrasive treatment, if set at the right pressure, removes the top coat and leaves the lead based undercoat intact.
Rocker Bearings de-rusted cleaned inside and out and coated in Carboline 615 Miox Grey.
Greasing points on all pivots now totally cleared to accept new lubricant.
Bearings marked and greased to gauge future movement.