Disc bearings appear to be getting more and more popular in bridge construction projects in the United States, as evidenced by the number of RESTON®DISC bearings supplied by mageba in recent years. And this is not surprising, considering the disc bearing’s significant advantages over other bearing types in certain circumstances.
The key component of a disc bearing is the disc at its center, which carries the load of the structure above and allows rotations about any horizontal axis. The disc is molded from high-strength Polyether Urethane (PU), a thermoplastic with excellent mechanical properties. The allowable compressive stress on the disc is as high as 5 ksi (34.5 MPa), and it does not require confinement – as does, for example, the elastomeric pad at the heart of a pot bearing. This enables the behavior and condition of the disc to be observed during factory testing and in service, and the problem of inadequate sealing sometimes suffered by the elastomeric pads of pot bearings does not arise in disc bearings. The disc is also highly resistant to environmental impacts such as corrosive marine atmospheres, ozone, etc., and remains effective at a very wide range of temperatures – from -94 to +250 °F (-70 to +121 °C).
Having been already successfully used in recent years in major US bridges such as the Bayonne Bridge, St. Croix Bridge and Ohio River Bridges Downtown Crossing, and with projects such as the Colman Dock Pedestrian Bridge in Seattle already lined up for the future, the RESTON®DISC bearing certainly seems to have a promising future in the United States.