Category: Bay Bridge

Caltrans To Do More Innovative Implosions of Old Bay Bridge Piers

OAKLAND – Caltrans continues the removal of the remaining marine foundations of the original east span of the San Francisco-Oakland Bay Bridge (SFOBB). Beginning on Saturday, Caltrans will remove Piers E4 and E5 of the Old Bay Bridge with the same implosion method used to bring down Pier E3 last fall. This method reduces the environmental impact and costs to taxpayers.

Watch the Caltrans News Flash on the upcoming implosion:

“Caltrans appreciates the guidance environmental organizations and permitting agencies provided to achieve an effective underwater demolition plan for these two 1935 east span bridge foundations,” said Caltrans Bay Area District Director Bijan Sartipi.

Pier E5 will be imploded on October 15 with 8,000 pounds of explosives, in less than three seconds. Pier E4’s implosion will occur two weeks later, on October 29 in less than four seconds, with approximately 12,000 pounds of explosives.

Significant environmental monitoring will take place pre, during and post blast, including water quality, sonar, marine mammal and fish. October provides the window when the least possible number of fish and marine mammals are present in the area. There will be brief impacts to water quality, turbidity is expected to dissipate in just over an hour and implementation is relatively easy with low risk to human safety.

A Blast Attenuation System, better known as the “bubble curtain,” will minimize impacts to biological resources in the Bay on each foundation-blasting project. The implosion will again take place near “slack tide,” the time when tidal fluctuation is at a balance point between ebb and flow to help minimize potential impacts to the environment by maximizing the effectiveness of the Blast Attenuation System.

Last November, Caltrans successfully removed the 50 million pound Pier E3, the largest of the marine foundations, by use of highly controlled sequential charges. These innovative controlled charges have been shown to be more efficient and the environmentally preferable alternative to traditional marine foundation removal.

Beginning with the implosion of Piers E4 and E5 this month, there will be three consecutive blasting seasons over the next two years. Caltrans will demolish Piers E6 through E11 in fall 2017, and Piers E12 through E18 will be removed in late 2018, when the demolition project is scheduled for completion.

There will be rolling closures on the Bay Bridge during the demolition. Caltrans will also close the bridge’s bike path. The removal of the piers on October 15 coincides with the 10th anniversary of the Treasure Island Music Festival. For more information on the festival or to send an inquiry to festival organizers, see the following links: http://www.treasureislandfestival.com

Music festival contacts page: http://treasureislandfestival.com/2016/contact/

We have limited space for media personnel and vehicles, so please confirm media attendance at Pier 1 to cover the blast by submitting name(s) to: leah_robinson-leach@dot.ca.gov

Submitted names will be placed on the media list for approved entrance at Avenue N. The media will be guided, by festival personnel, to the designated area on Pier 1.

While there are no public viewing areas, the public may watch the implosion on October 15 between noon – 12:40 pm at the following link: http://www.dot.ca.gov/oldbaybridgedemolition

 

Caltrans Performs Test Blast, Implosion Dates Set for 10/15 and 10/29

Today, Caltrans performed a test blast in preparation for the upcoming implosions of two piers of the old Bay Bridge scheduled for later this month.  The test blast allowed Caltrans to test the Environmental monitoring systems, bird cannon, bubble curtain, safety checks and signals.

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The Pier E4 and Pier E5 implosions are scheduled for October 15 and October 29 during slack tide pending weather conditions. Caltrans performed a walk-through with environmental and biological experts earlier this week to ensure that no protected species is harmed. Each implosion is a coordinated effort to ensure limited environmental impact on the Bay and wildlife. Caltrans produced a news flash detailing the efforts of staff to limit that impact:

We’ll continue to post more updates on the action, traffic concerns, and other implosion related information so be sure to keep your eyes on our blog. Don’t forget to check Twitter next Saturday at @ca_trans_agency as we show the E5 implosion in action.

In the meantime, you can watch last year’s implosion here:

For more about the implosion process:
https://calstablog.wordpress.com/2016/08/24/bcdc-greenlights-permits-for-next-round-of-bay-bridge-pier-demolition/

BCDC greenlights permits for next round of Bay Bridge pier demolition

Last Thursday, the San Francisco Bay Conservation and Development Commission granted Caltrans permits to implode two piers of the Bay Bridge’s old east span in October. The project uses controlled explosives to demolish fifteen pier foundations of the old east span. As part of the permitting process, BCDC also granted permits for the implosions of Piers E6-18 which are scheduled to occur in 2017 and 2018.

This year’s implosion will occur over two weekends in October during slack tide, Caltrans will be publicizing the implosion dates shortly. For the first two piers, the debris would fall into its hallow casing below the mudline of the Bay Bridge. Like the previous implosion of Pier E3, a blast attenuation system (bubble curtain) will be used to cut down noise and sound pressure waves from the explosive charges. Caltrans will continue to work with environmental and biological experts to monitor the area preceding, during, and after the blast to ensure no protected species is harmed.

Watch the video simulation for Pier E5 here: https://vimeo.com/179255514/790e4a57f3

This follows the successful implosion of Pier E3 in which the largest pier was demolished in just six seconds. Watch the implosion of Pier E3 here:

Each implosion is a coordinated effort to ensure limited environmental impact on the Bay and wildlife. Caltrans produced a news flash detailing the efforts of staff to limit that impact:

[Live Feed] Demolition of Historic Bay Bridge Continues

Oakland – Caltrans’ removal of the original east span of the San Francisco-Oakland Bay Bridge continues today with the lowering of the fourth of five 504-foot trusses.  As demolition progresses, Caltrans’ focus remains on public safety and protection of the environment.

Unlike the building methods used during the original construction of the Old Bay Bridge, today’s lowering process is extensive, taking into account safety and environmental stewardship factors not considered when the bridge was built in 1935.

The 504-foot truss must be lowered, and then set down on barges to be transported to the Port of Oakland for disassembly. During the process, contractors will be working closely with a bird deterrence contractor and engineers to coordinate activities.

This operation is highly weather-dependent, and is expected to take two days, with an anticipated 12 to 14 hours of work, each day. High winds could cause schedule changes. The operation may be completed in one day, if weather cooperates.

“Although we have already successfully completed this truss lowering operation on three recent occasions, we are diligent in our continued commitment to safety and the environment.” explained Chief Bridge Engineer, Brian Maroney.

Two live streams (displayed above) allow for public viewing during the operation. Caltrans encourages the public to use this method for observing the operation. The bike path will be closed during the operation.

Yerba Buena Island camera: http://www.youtube.com/channel/UCm-wXGyG0tHq4NAco-TzKRg/live

Bike path camera: http://www.youtube.com/channel/UCky7z7aBl7uEwHDLhMtsgsw/live

The lowering of these five 504-foot trusses is the second part in a three-part process to dismantle the Old Bay Bridge. Phase I was completed at the end of 2015, with the demolition of the cantilever section and S-curve to Yerba Buena Island.

The final phase will involve the dismantling of 14 288-foot truss span sections that extend to the Oakland shore — a completely different engineering challenge from the removal of the 504-foot trusses.

Caltrans, contractors and partners are diligently planning for the successful removal of the first of these 14 288-foot truss sections, the removal of which will require consideration of varied marine foundations and water depth.

More information about the Phase III removal process will be shared as the demolition work continues.

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Caltrans Prepares to Bring Down Major Section of the Old Bay Bridge

FIRST 504 Truss Span to be Lowered by Jacks

Oakland – Caltrans has reached another historic milestone in the removal of the original east span of the San Francisco-Oakland Bay Bridge. Starting as soon as tomorrow, crews will begin lowering the first 504-foot truss span. This is scheduled to take place over a 2-day period, beginning as soon as Thursday, February 4th, weather permitting.

In 1935, the building of the “504s”, as they’re called, was relatively straightforward and used disruptive piles to hold the steel frame high above the bay. The lowering and dismantling process later this week is more complex, but also more environmentally friendly.

The five 504s stretch from Pier E4 to Pier E9, extending approximately half a mile. The weight in steel of each 504 truss to be lowered is equivalent to 2,500 tons.

“The deconstruction of the cantilever was a bold and outstanding engineering achievement and the implosion of the Pier E3 foundation was an environmental success. Now, the lowering of the first 504-foot truss, without using a single pile, is our next environmental challenge,” explained Chief Bridge Engineer, Brian Maroney.

Day one of the project will focus on severing the truss from its towers and its slow decent toward the bay below. The second day will concentrate on setting the truss down on barges and transporting it to the Port of Oakland for disassembly. Each day is expected to take anywhere from 12 to 14 hours. The lowering operation is highly weather dependent. Heavy rains and/or high winds could cause changes.

This is the second part in a three part process to dismantle the Old Bay Bridge. Phase I was completed the end of 2015, with the complete demolition of the cantilever section and S-curve to Yerba Buena Island. Now, Phase II continues with removal of the first five 504s and then removal of fourteen 288-foot truss span sections that extend to the Oakland shore. Phase III will focus on the demolition of the remaining marine foundations.

The lowering of the 504s is a slow and methodical operation compared to the 6-second implosion of Pier E3 that was performed in mid November. Although these are very different operations, environmental measures have been priorities for both. In addition to no piles being needed for this process, contractors are working closely with a bird deterrence contractor and engineers to coordinate activities to avoid other impacts.

A live stream will allow for public viewing during the operation. We encourage the public to use this method for observing the operation. You can see the stream here: http://www.youtube.com/channel/UCm-wXGyG0tHq4NAco-TzKRg/live

Schedule:

Day 1 – Truss Lowering
Work hour 6:00 am to 8:00 pm
(Best visuals for media will likely occur at mid to late morning, when strands are hanging down. The truss is scheduled to be lowered at a rate of 25 feet per hour.)

Day 2 – Truss Set-Down and Transport
(Throughout the day, the truss will be closer the barges.)

You can see an animation of the lowering at this link:

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Largest Pier of Old East Span Imploded

Innovative Method Employed to Protect the Bay, Environment

OAKLAND–Today, the largest of the piers of the San Francisco-Oakland Bay Bridge’s old east span was removed from the Bay through a careful and extensively planned implosion.

Early this morning at slack tide, years of preparation, more than half-a-dozen permits, and thousands of hours of labor culminated in what appears to be a successful implosion. In just six seconds, nearly 600 controlled charges weakened the 50-feet of Pier E3 which stood above the bay floor, allowing gravity to collapse the tower into its hallow casing below the mudline.

“In the coming weeks, we’ll be exhaustively collecting extensive data and determining the effect the implosion had on the environment and fish nearby,” said Brian Maroney, Chief Bridge Engineer of Caltrans’ Toll Bridge Program. “We don’t know exactly what it looks like down there, not yet. The information will be critical for determining the best method for demolishing the remaining 21 piers.”

While there is much still to be analyzed, a number of goals were met today by Caltrans, its contractors, and participating and permitting agencies:

  • The implosion occurred during the target month of November, the month with the least environmental impact, including the fewest marine animals present.
  • The blast attenuation system, or “bubble curtain,” which is estimated to cut down the pressure waves from the charges by about 80%, was successfully deployed.
  • Dozens of environmental and biological experts carefully monitored areas surrounding the blast zone, verifying large animals were not nearby during the implosion.
  • The brief traffic stop on the Bay Bridge and BART trains in the Transbay Tube protected the public from distraction. The stop is now lifted.

The only remaining visible evidence of the event is the floating timber that sat atop the pier, and the slowly progressing dust cloud, which should be visible from above for the next couple of hours. It is being carefully monitored by deployed experts. You can see a predicted map of its advance and dissipation with the tides here: http://ow.ly/UtSkJ

In the coming weeks you can expect updates on the following items:

  • Three dimensional imaging of what it looks like on the bay floor. This data is pivotal to assessing the effectiveness of the implosion, and how much, if any, debris needs to be picked up from outside the remainder of Pier E3, and placed inside the hallow structure.
  • The effect of the implosion forces on fish and wildlife.
  • The composition of the dust cloud created by the implosion.
  • If the traffic and BART stops will be necessary for future potential implosions.

Eight different public agencies permitted the implosion of Pier E3. Their input and assistance was crucial. Data collected over the next several months will be compiled into a report to assist in determining if Caltrans will seek additional approvals to implode some or all of the remaining 21 piers from the old east span.

Additional information can be found at http://dot.ca.gov/e3implosion

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