ASPHALT CONCRETE PAVED YARD FOR THE UNION PACIFIC IN SEATTLE

The Union Pacific Railroad Company's Seattle Intermodal Facility was expanded approximately 3,300 feet by 500 feet. The location has a floodplain about 2 to 12 feet below the present ground surface. Site investigations revealed extremely variable subsurface materials. The entire area was proofed-rolled with a fully loaded 50-ton pneumatic-tired roller with 50 psi tire pressure. By 12 passes the soft areas were detected and their boundaries delineated for future excavation. Designs were developed for portland cement concrete and asphaltic concrete pavements. No design was prepared for Roller Compacted Concrete pavements because of the soft and deformable subgrade likely to be present during construction. The Union Pacific Railroad Company secured bids and much of the work was done during wet fall weather and paving was done in January 1987. The new facility has now been in service about 1-1/2 years. It has been subjected to high Piggy-Packer and trailer usage. The only known pavement failure has been a small section at the trailer entrance where there was insufficient removal of soft material.