Title: High Cycle Bearing Tests for the Manhattan Bridge

Author(s): Ronald M. Mayrbaurl

Publication: Symposium Paper

Volume: 94

Issue:

Appears on pages(s): 343-370

Keywords: bridge bearings; cyclic loads; fatigue tests; loads (forces); pads; performance; suspension bridges; tests; thickness; trusses; Construction

DOI: 10.14359/3483

Date: 9/1/1986

Abstract:
Since subway traffic causes large magnitude stress cycles and reversals numbering about 500 per day on the stiffening truss support hangers of this suspension bridge, the support hangers have had to be replaced three times. Multirotational bearings and slide bearings are considered to replace the pins at these locations. Since the usual durability and wear tests are made on small-scale samples for (usually) less than 10,000 cycles, it was felt that a longer-term test program on large samples with stresses and motions approximating those on the bridge was needed. Full-size multirotational bearings were tested for repeated load application and rotation for 700,000 cycles. Preliminary tests (1000 to 3000 cycles) indicated that pot bearings were not suitable for this application, so only a disc-type bearing was subjected to the long-term test. Large-scale specimens of teflon material were also tested for 500,000 cycles of reciprocating motion with a 4-in. amplitude. The paper describes the tests and provides photos of the bearings after testing with measured wear versus cycle data for the slide bearings.