(8:00PM EST – promoted by Nightprowlkitty)
Over Labor Day weekend the San Francisco-Oakland Bay Bridge (Bay Bridge, for short) was closed for a seismic retrofit project featuring an unprecedented construction feat. A football field length, double-deck section, weighing 3,200 tons was excised and a new section slid into place to form an S-shaped detour. The huge pieces moved verrrrry slowly on specially built rails. A distance of 100 feet took several hours not including delays when the rails needed to be adjusted. All of this took place 150 feet above the ground. Construction on this scale will require workers who have received training on safety at heights to ensure that they are prepared for the dangers that come with working at heights on a regular basis. During the construction process, there are many other safety steps to take in and around the construction site, for example, signs that indicate danger in the immediate area will need to be put up to make everyone aware. Checking out danger signage in the UK/US is important to make sure safety is consistent.
Here is a picture from a few weeks ago with some of the bridge formwork in construction, in preparation for the detour. The scene is looking west where the East Span of the bridge meets Yerba Buena Island. The detour is on the left and the old bridge on the right. The connecting piece that was installed this weekend is shown below.
Here is an illustration of the project.
I downloaded high-resolution images from the construction cams before, during, and after the movement of the sections.
Here is a close-up (sorta) during the phase between moving out the old section (on the left) and moving in the new section (on the right).
The bridge is out!
09/05/09 11:17 a.m. photo from EarthCam
The West side camera (looking east to Berkeley/Oakland) updated its images hourly. This slide show has a nice sequence from Saturday where you can see the fog rolling in and off the East Bay hills and boats visiting the construction area in the lower right during the day. The final three shots in the slide show are from this morning at sunrise just before the bridge opened and just after opening at 7 AM (PDT).
photos from EarthCam
The camera below the bridge updated more frequently but I have fewer images in this slide show. Note the helicopter that appears in a few of the day shots. A National Geographic crew was filming the bridge engineering project – not sure if that’s their copter or a news organization’s.
photos from EarthCam
As expected there were a few glitches in the process:
The old bridge segment was originally scheduled to begin moving at 1 PM but experienced delays in disconnecting steel pins from the old structure . The section finally started rolling out around 6 PM. By 8 PM the gap was completely free and at 8:30 the segment finished moving a total distance of 100 feet.
The second phase of rolling in the new structure began around 11:30 AM on Saturday. After about an hour it appeared to be stuck. A Twitter reply indicated they were “aligning the rails”. It started up again about 5:15 PM. At 8:30 PM Twitter announced: “tie-in completed its move, now it’s onto the bearings…”
Meanwhile, CalTrans took advantage of the bridge closure to paint and maintain other parts of the bridge and toll plaza. An inspection on Saturday revealed a crack that needed to be repaired before the bridge could reopen. Although the bridge was scheduled to reopen on Tuesday morning at 5 AM for the post-holiday commute, it was thought that the bridge might not be ready until Wednesday. Fortunately, the construction crews worked hard through the night and the bridge was open by 7 AM this morning.
Work is far from over though, and I can only hope that all of the construction workers have the relevant safety equipment to the available equipment from somewhere like choosetoolbox.com. Well, the new bridge has already been under construction for about three years and is not expected to finish until sometime in 2013. The total cost estimate is $5.5 billion but that is sure to go up if there are unforeseen delays or issues. The weekend detour project is expected to cost $140 million.
This is what the single-tower suspension bridge will look like when done. Beautiful!
Reference: Unless cited otherwise, info and pictures are from the official baybridgeinfo.org site. They have more information about the entire bridge project, webcams, and simulations of what the new bridge will look like. See also SFGate’s Bay Bridge Page.