Location:
San Francisco, CA
Owner:
California Department of Transportation
Project Completion:
2006
Project Details
The deck resurfacing project required milling of the existing bridge deck and replacing it with PPC during nightly shifts of only 5 to 8 hours of total lane closure time.
FACT:
300,000
Average Daily Traffic
Project Background
The deck surface of the San Francisco-Oakland Bay Bridge on the suspension span from Treasure Island to the San Francisco anchorage was in need of rehabilitation. A total of 1.2 million square feet of surface, 5 lanes on the upper deck and 5 lanes on the lower deck, approximately two miles long, was repaired using PPC 1121. 300,000 cars per day travel this major feeder structure to San Francisco and fast return to traffic was imperative.
The Solution
First the contractor removed existing, unsound asphalt/epoxy surface and concrete mortar cap. Next they repaired the unsound light weight concrete structural surface with polyester polymer concrete, as well as high performance concrete expansion joint headers. Next, they replaced the riding surface with a polyester polymer concrete overlay approximately 1” thick.
The contractor fabricated its own mixers to provide accurate component mixing and high volume output of PPC components. Combining 4 volumetric mixers with a 12’ wide, two track slip form paver, provided the necessary muscle to place 3200 cubic meters of PPC in a 115 day work schedule. The short nighttime lane closure meant roughly 1/4 mile of placement per day with only 2.5 hours of actual paving time.
Lasting Success
Cal-Trans has nearly 30 years of experience with polyester concrete. PPC 1121 product demonstrated the capability of returning traffic within 2 hours of placement at temperatures of 50°F and even lower.