State of the Art in High-Load Multi-Rotational Disc Bearings: Design, Practice, and Future Needs

Abstract

High-load multi-rotational (HLMR) disc bearings have been available domestically since the 1970s. In the decades since, they have become an increasingly attractive option for use when bridges require higher rotations or loads than typical elastomeric bearings can transfer. These bearings can be designed for rotations higher than 0.1 rad, translate more than 36 in., transfer vertical loads in excess of 15,000 kips, and horizontal loads in excess of 1,000 kips. Moreover, unlike pot bearings, a common alternative to disc bearings, they have no seals that can leak. Although the system was initially patent-protected, about ten domestic manufacturers have developed product lines since the patent expired in the mid-1990s. Nevertheless, research on these systems has largely taken place outside the public domain. This review paper examines past work on disc bearings, existing research, US standards, state departments of transportation (DOTs) design manual language, and DOT inspection procedures; identifies research gaps; and proposes future research needs on disc-bearing behavior, design, and inspection. Altogether, DOT requirements vary greatly from state to state, and the American Association of State Highway and Transportation Officials Load and Resistance Factor Design provisions are brief in comparison to other HLMR systems. This leaves the design of disc bearings in the hands of manufacturers and limits the resources of state DOT personnel for design validation or assessment. Although this system has many advantages, additional research is necessary to better understand the behavior and design of these bearings and standardize system reliability.