Engineering Design Consultants

New East Riding Bridge Swings into Action

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The pintle bearing on which the bridge rotates consists of a convex steel plate on the central pier which marries with a concave block of Orkot resin composite material on the bridge deck, which provides some shock-absorption when the bridge is being moved. A combination of steel and Orkot is also used for the seven bearing blocks on which the bridge rests when it is in the ‘road open' position. These are curved in the lateral direction to allow for movement in the bridge caused by traffic, wind, temperature and other factors.

The use of Orkot and steel avoids catastrophic failure, which can occur with conventional rolling element bearings. Instead, the components will gradually wear. ‘We believe this is the first time this combination of materials has been used for bridge bearings', said James Hill, the project engineer with Bennett Associates.

All the bearings have been designed to be replaceable without special tooling and without closing the bridge to road traffic. Provision has been made so that conventional jacks can be used to take the weight off each of the static bearings, remove them and replace them, working entirely below the deck. The pintle bearing can also be replaced when the bridge is open to traffic, as it is not loaded in this position. It is also possible to replace the wearing surfaces of bearings during a slightly extended swinging operation.