The $300-million project restored parallel 40-year-old, 3,000-ft-long tunnels and an adjacent bridge for another half-century of service. The multifaceted effort included an eight-month service shutdown, leak mitigation, tunnel steel liner repair and steel-to-concrete interfaces and installation of new and relocated utilities. Because industry-standard work trains were too large for the tunnels, the project team designed and fabricated custom equipment to support blasting and painting. To minimize the risk of schedule-disrupting rework, the team developed a pilot program to test proposed steel repair design solutions and leak mitigation grout application methods for the varying conditions inside the tunnels, helping to determine the overall project’s design direction and construction scheduling. An air quality monitoring program included specially configured temporary ventilation systems, contributing to the project’s remarkable safety record of nearly 400,000 work hours with no lost-time accidents.

Bridge rehabilitation work included jacking and installing nearly 90 bearing bars, new deck expansion joints, concrete deck spall repair, painting steel elements and grounding cable replacement. All work required extensive coordination with more than 40 local, regional and federal agencies to obtain more than 75 permits. The project’s predetermined outage window could not be extended, requiring a 24/7 construction activity to meet the demanding 23-month schedule at budget.