The California Department of Transportation (Caltrans) reports extensive preparations are underway in the San Francisco Bay as Caltrans works to put the final pieces in place to implode Pier E3 of the old Bay Bridge on Nov. 14, 2015. As the largest of the marine foundations that once held the now decommissioned eastern span of the bridge, this operation is the equivalent of taking down a five-story building but entirely underwater.
Bay Bridge spokesperson Leah Robinson-Leach says the innovative technologies are in place to remove the pier in the most environmentally sound and efficient way possible. More from Leah and a behind-the-scenes, or rather under-the-surface, glimpse at the unique “bubble curtain” that will absorb about 80 percent of the shock wave from the implosion, is available at www.cdrecycler.com/video/bay-bridge-pier-3-demolition.
A unique blend of technologies and innovations are being combined to demolish the old pier in the most environmentally sound and efficient way possible, according to Robinson.
Pier E3 is described as a hollow-chambered, steel-reinforced concrete structure. It stretches from the waterline to 175 feet beneath the bay floor. It is the largest of 21 in-water piers from the old east span bridge.
The charges will be placed in predrilled holes and fired in a sequence lasting 6 seconds. Most debris will fall into or be placed in existing chambers below the mud line. Caltrans says fine particles will form a cloud-like plume, visible for hours after event.
The implosion will be contained through an attenuation mat – large, connected planks placed over top of pier – will remain floating as the pier collapses and through a bubble curtain encircling pier. Compressors on barges will pump air through perforated pipes on the bay floor, creating a steady “curtain” of bubbles that dampen the shock of the implosion.
This is our process at work," said Brian Maroney, Chief Bridge Engineer for the Caltrans Toll Bridge Program. "Safety is the first priority. We commend the contractor for their diligent and extensive verification of the product they received, and for swiftly notifying us of the desire to reschedule. Safely and responsibly executing the implosion within the month of November remains our main objective."
Members of the public are asked by Caltrans to keep the following in mind during the implosion:
- The implosion is expected to total six seconds, and will occur mostly underwater.
- The single best place to watch the implosion will be online. Follow along on twitter at #E3Implosion, or check www.dot.ca.gov/e3implosion for more information.
- There is a perimeter of 1,500 feet around the demolition site, which will be enforced by the California Highway Patrol.
- Bay Bridge traffic will be held for approximately 15 minutes to prevent potential distraction to drivers.
- BART trains will be held temporarily outside of the Transbay Tube, resulting in slight delays.
- The public will have no access to viewpoints on the eastern side of Yerba Buena Island.
- The bike path will be closed to the public starting at 6pm on Nov. 13 until after the implosion, at least 10 a.m. on Saturday, Nov. 14.