Grim days for the 6th Street Bridge, which has so-called concrete cancer (official name: Alkali-Silica Reaction or ASR). According to Blogdowntown, the bridge, which has a 70% chance of collapsing in the next 50 years, has undergone numerous probing and testing: In January, the Bureau of Engineering held meetings about the bridge, only to deduce that full replacement was necessary, while in April, the Getty held a series of discussions on how to save the structure, which opened in 1933.
The next step, according to Blogdowntown, will come later this year when the Bureau of Engineering releases a Draft Environmental Impact Report offering two retrofit alternatives and three replacement options. More via the blog: "Whereas replacement options are designed to last 75 years, retrofit options would max out at 30. They would also involve significant visual changes to the structure, filling in the space between support piers and replacing significant amounts of substructure." The blog has the three replacement options listed on its site--one example is seen above. [Top photo, rendering via Blogdowntown]
· After Much Study, 6th Street Viaduct's Saving Highly Doubtful [Blogdowntown]