I-405/SR 518 Concrete Pavement Rehabilitation

I-405/SR 518 Concrete Pavement Rehabilitation upgrades roadways with surfaces that were more than 40 years old. Years of heavy use on both roadways had resulted in severe cracks, bumps, and ruts. This project's scope aimed to produce a smoother drive—with better traction and new high visibility striping—by replacing damaged and broken panels, repaving sections, and grinding existing panels.

The project encompassed a complete replacement of concrete pavement in all four lanes of northbound I-405, spanning from SE 8th Street to just north of Main Street in Bellevue. Additionally, extensive pavement grinding was carried out across all lanes, and 82 failing concrete panels on northbound I-405, south of SE 8th Street, and from Main Street to SR 520 were replaced. Other work included hot mix asphalt (HMA) paving for inside/outside shoulders, the installation of traffic loops, striping, and drainage enhancements. Drainage improvements featured catch basins and pipe installations at the median and the northwest approach slab of the SE 8th Street Bridge.

Nearly a mile of SR 518 pavement between I-5 and Sea-Tac Airport was also improved, involving the replacement of over 50 concrete panels and the use of a diamond grinder to rectify bumps and ruts in other highway sections. Additional tasks on SR 518 encompassed data loop installations and striping.

To minimize disruptions to commuters, the majority of the work on I-405 was executed during two 54-hour weekend closures of northbound I-405, with crews handling tasks such as pavement demolition, subgrade material placement, asphalt pavement underlayment, joint dowel bar installation, and PCCP roadway section repaving during each closure.

Quantities for this project included 6,288 cubic yards of PCCP paving, 5,059 tons of HMA asphalt paving, and 16,280 square yards (rough grade) and 4,687 tons (fine grade) of crushed surfacing base course (CSBC).