Background:
The WMATA Station Platform Rehabilitation Program is a $400M project to rehabilitate twenty stations along the Blue, Yellow, Green, Silver, and Orange Lines of the Washington Metropolitan Area Transit System. The stations were built over 40 years ago and required rehabilitation and modernization to reduce service disruptions. The project was broken down into 4 phases, with the design/build project was awarded to Kiewit Construction. Work began in 2019 and was completed in 2022. R.J. Watson’s low-profile disc bearings were selected by Kiewit for Phase 4 of the project to replace failed spherical bearings.
R. J. Watson’s design and fabrication team developed a distinctive bearing solution to fit within the limited space available for bearing replacement. There are a total of 328 Disktron bearings installed on aerial structures at Landover, Cheverly, and New Carrollton Stations along the Orange Line. The bearings ranged from 175 to 300 kips in vertical capacity with horizontal loads ranging from 8-10% of vertical loads on the expansion bearings but 47-57% on the fixed bearings. The rotational capacity of the bearings was +/- 0.025 radians (strength load).
In addition to the bearings, R. J. Watson also supplied the expansion joint seals for the aerial structures in Phase 4. The Silicoflex preformed silicone bridge expansion joint system was chosen for its long-term durability, low maintenance, and ease of installation. A total of 1,580 linear feet of the SF325 model was installed to accommodate up to 3 ¼” inches of total movement, and 960 linear feet of the SF150 model was installed to accommodate up to 1 ½” of total movement.
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